NSN EDGE System Feature Description


BSC3153 Nokia GSM/EDGE BSS, Rel. BSS13, BSC and TCSM, Rel. S13, Product Documentation, v.4 EDGE System Feature Description DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 1 (272) EDGE System Feature Description The information in this document is subject to change without notice and describes only the product defined in the introduction of this documentation. This documentation is intended for the use of Nokia Siemens Networks customers only for the purposes of the agreement under which the document is submitted, and no part of it may be used, reproduced, modified or transmitted in any form or means without the prior written permission of Nokia Siemens Networks. The documentation has been prepared to be used by professional and properly trained personnel, and the customer assumes full responsibility when using it. Nokia Siemens Networks welcomes customer comments as part of the process of continuous development and improvement of the documentation. 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All rights reserved. 2 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Contents Contents Contents 3 Summary of changes 7 1 2 2.1 2.2 2.3 2.4 3 4 4.1 4.2 4.3 4.4 4.5 5 5.1 5.2 5.3 5.4 5.5 5.6 6 6.1 6.1.1 6.1.2 6.1.3 6.1.4 6.1.5 6.1.5.1 6.1.5.2 6.1.5.3 6.1.5.4 6.1.5.5 6.1.6 6.1.7 6.1.8 6.1.9 6.1.10 6.2 6.2.1 About this document 13 GPRS 15 GPRS data transfer protocols 21 Optimised GPRS Radio Resource Management Frame Relay and Gb Interface 27 GPRS in Nokia Base Stations 29 EDGE 31 Software related to GPRS/EDGE 41 Extended Uplink TBF Mode 41 GPRS Coding Schemes 42 Link Adaptation for GPRS 46 Priority Class Based Quality of Service (QoS) System Level Trace 49 23 47 Software related to EGPRS 55 EGPRS Modulation and Coding Schemes 55 EGPRS Packet Channel Request on CCCH 56 Incremental Redundancy 57 Link Adaptation for EGPRS 58 Nokia Smart Radio Concept for EDGE 60 8 Phase Shift Keying 67 System impact of GPRS/EDGE 69 System impact of GPRS 69 Requirements 69 Restrictions 71 Impact on transmission 72 Impact on BSS performance 72 User interface 73 BSC MMI 73 BTS MMI 74 BSC parameters 74 Alarms 80 Measurements and counters 82 Impact on Network Switching Subsystem (NSS) Impact on NetAct products 88 Impact on mobile terminals 89 Impact on interfaces 89 Interworking with other features 90 System impact of EDGE 98 Requirements 98 88 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 3 (272) EDGE System Feature Description 6.2.1.1 6.2.2 6.2.3 6.2.4 6.2.5 6.2.5.1 6.2.5.2 6.2.5.3 6.2.5.4 6.2.5.5 6.2.6 6.2.7 6.2.8 6.2.9 6.2.10 7 7.1 7.1.1 7.1.2 7.1.3 7.1.4 7.1.5 7.1.6 7.1.7 7.1.8 7.2 7.2.1 7.2.2 7.2.3 7.2.4 7.2.5 7.2.6 7.2.7 7.2.8 7.2.9 7.3 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 7.3.6 7.3.7 7.3.8 7.4 7.4.1 7.4.2 7.4.3 7.4.4 7.4.5 7.4.6 EDGE BTSs and hopping 100 Restrictions 103 Impact on transmission 105 Impact on BSS performance 105 User interface 109 BSC MMI 109 BTS MMI 109 BSC parameters 109 Alarms 111 Measurements and counters 112 Impact on Network Switching Subsystem (NSS) Impact on NetAct products 120 Impact on mobile terminals 121 Impact on interfaces 122 Interworking with other features 123 118 System impact of GPRS/EDGE related software 133 System impact of EGPRS Packet Channel Request on CCCH 133 Requirements 133 Impact on transmission 134 Impact on BSS performance 134 User interface 135 Impact on Network Switching Subsystem (NSS) 136 Impact on NetAct products 136 Impact on mobile terminals 136 Impact on interfaces 136 System impact of Extended Uplink TBF Mode 137 Requirements 137 Impact on transmission 138 Impact on BSS performance 138 User interface 139 Impact on Network Switching Subsystem (NSS) 140 Impact on NetAct products 140 Impact on mobile terminals 141 Impact on interfaces 141 Interworking with other features 142 System impact of Nokia Smart Radio Concept for EDGE 142 Requirements 142 Impact on transmission 143 Impact on BSS performance 143 User interface 144 Impact on Network Switching Subsystem (NSS) 145 Impact on NetAct products 145 Impact on mobile terminals 146 Impact on interfaces 146 System impact of Priority Class based Quality of Service 147 Requirements 148 Impact on transmission 149 Impact on BSS performance 149 User interface 150 Impact on Network Switching Subsystem (NSS) 153 Impact on NetAct products 153 4 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Contents 7.4.7 7.4.8 7.4.9 7.5 7.5.1 7.5.2 7.5.3 7.5.4 7.5.5 7.5.6 7.5.7 7.5.8 7.5.9 8 8.1 8.2 8.3 9 9.1 9.2 10 10.1 10.2 10.3 10.4 10.5 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 12 12.1 12.2 12.3 12.4 12.5 12.6 12.7 12.8 12.9 12.10 12.11 Impact on mobile terminals 154 Impact on interfaces 154 Interworking with other features 154 System impact of System Level Trace 154 Requirements 155 Impact on transmission 156 Impact on BSS performance 156 User interface 157 Impact on Network Switching Subsystem (NSS) Impact on NetAct products 161 Impact on mobile terminals 162 Impact on interfaces 162 Interworking with other features 163 161 Requirements for GPRS/EDGE 165 Packet Control Unit (PCU) 165 Gb interface functionality 170 Additional GPRS hardware needed in BSCi and BSC2i Radio network management for GPRS Routing Area 175 PCU selection algorithm 177 175 173 Gb interface configuration and state management 179 Protocol stack of the Gb interface 179 Load sharing function 182 NS-VC management function 182 BVC management function 187 Recovery in restart and switchover 189 Radio resource management 193 Territory method 194 Circuit switched traffic channel allocation in GPRS territory BTS selection for packet traffic 203 Quality of Service 204 Channel allocation and scheduling 206 Quality Control 215 MS Multislot Power Reduction (PCU2) 216 Error situations in GPRS connections 218 GPRS/EDGE radio connection control 221 Radio channel usage 221 Data Transfer Protocols and Connections 222 Paging 223 Mobile terminated TBF (GPRS or EGPRS) 226 Mobile originated TBF (GPRS or EGPRS) 229 Suspend and resume GPRS 235 Flush 236 Cell selection and re-selection 237 Traffic administration 237 Coding scheme selection in GPRS 240 Coding scheme selection in EGPRS 251 202 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 5 (272) EDGE System Feature Description 12.12 12.13 13 13.1 14 14.1 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 Power control 254 MS Radio Access Capability update Implementing GPRS 257 Implementing GPRS overview Implementing EGPRS 259 Implementing EGPRS overview 257 259 255 Configuring Intelligent Downlink Diversity 265 Functional requirements and restrictions 265 Supported configurations 266 Configuring BTS to IDD mode with BTS Manager 268 Configuring IDD in the BSC 270 Alarm handling 270 RX antenna supervision and IDD/4UD 271 Object state management 271 TRX reconfiguration 272 TRX tests 272 6 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Summary of changes Summary of changes Changes between document issues are cumulative. Therefore, the latest document issue contains all changes made to previous issues. Changes made between issues 9-0 and 8-1 The name of the document has been changed from (E)GPRS System Feature Description to GPRS/EDGE System Feature Description. The contents of (E)GPRS in BSC have been merged into this document. Chapters Support for PBCCH/PCCCH and System impact of Support for PBCCH/PCCCH have been removed. Chapters Dynamic Abis and System Impact of Dynamic Abis have been moved from this document to Dynamic Abis. Chapter Software related to GPRS/EDGE has been modified to only include descriptions of such GPRS/EDGE-related features that do not have their own separate description documents. GPRS Coding Schemes Support for 2nd generation BTS and PrimeSite BTS has been removed. System Level Trace Section System Level Trace in BSC has been moved here from (E)GPRS in BSC. EGPRS Packet Channel Request on CCCH A reference to PCCCH/PBCCH has been removed. System impact of GPRS DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 7 (272) EDGE System Feature Description Support for 2nd generation BTS and PrimeSite BTS has been removed. 91 PBCCH Availability Measurement has been removed. Extended Cell Range restriction has been removed. Section Restrictions has been moved here from GPRS in BSC. 110 PCU Utilization Measurement has been added. New counters have been added to 72 Packet Control Unit Measurement. Interworking with EGSM 900 - PGSM 900 BTS has been updated. A reference to GPRS/EDGE Support for PGSM-EGSM BTS was added. The name of alarm 3273 (E)GPRS TERRITORY FAILURE has been updated to 3273 GPRS/EDGE TERRITORY FAILURE. System impact of Nokia EDGE Support for 2nd generation BTS and PrimeSite BTS has been removed. 91 PBCCH Availability Measurement has been removed. Extended Cell Range restriction has been removed. Section Restrictions has been moved here from (E)GPRS in BSC. 110 PCU Utilization Measurement has been added. New counters have been added to 72 Packet Control Unit Measurement and 79 Coding Scheme Measurement. The name of alarm 3273 (E)GPRS TERRITORY FAILURE has been updated to 3273 GPRS/EDGE TERRITORY FAILURE. System impact of EGPRS Packet Channel Request on CCCH Support for 2nd generation BTS and PrimeSite BTS has been removed. Interworking with PCCCH/PBCCH has been removed. System impact of Nokia Smart Radio Concept for EDGE Support for 2nd generation BTS and PrimeSite BTS has been removed. System impact of Priority Class based Quality of Service Support for 2nd generation BTS and PrimeSite BTS has been removed. System impact of System Level Trace Support for 2nd generation BTS and PrimeSite BTS has been removed. 8 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Summary of changes New counters have been added to 25 TBF Observation for GPRS Trace. System impact of Extended Uplink TBF Mode Support for 2nd generation BTS and PrimeSite BTS has been removed. New PRFILE parameters have been added. Requirements for GPRS/EDGE The chapter has been moved here from (E)GPRS in BSC. Information on PCCCH/PBCCH has been removed. Radio network management for GPRS The chapter has been moved here from (E)GPRS in BSC. A reference to Packet Control Unit (PCU2) Pooling has been added. Information on PCCCH/PBCCH has been removed. Gb interface configuration and state management The chapter has been moved here from (E)GPRS in BSC. A reference to Multipoint Gb Interface has been added. Radio resource management The chapter has been moved here from (E)GPRS in BSC. Information on PCCCH/PBCCH has been removed. GPRS/EDGE radio connection control The chapter has been moved here from (E)GPRS in BSC. Section PACKET PSI STATUS procedure has been removed. Information on PCCCH/PBCCH has been removed. The GPRS and EGPRS implementing instructions have been combined into single chapters. Changes made between issues 8-1 and 8-0 Changes made between issues 8-1 and 8-0 lists the changes made to the document after the Nokia GSM/EDGE BSS, Rel. BSS12, System Documentation pilot release. The following changes have been made: DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 9 (272) EDGE System Feature Description . Nokia MetroSite BTS does not support Intelligent Downlink Diversity (IDD) or Interference Rejection Combining (IRC). Information on MetroSite support for IDD and IRC has been removed from chapters Configuring Intelligent Downlink Diversity, Nokia Smart Radio Concept for EDGE, and System impact of Nokia EDGE. The RDIV parameter value has been corrected in chapter Configuring Intelligent Downlink Diversity. PCU2 support for PBCCH/PCCCH has been removed from chapter Packet Control Unit in BSC. . . Changes made between issues 8-0 and 7-0 Information on the following new software and hardware products has been added: . Dual Transfer Mode Extended Dynamic Allocation High Multislot Classes Space Time Interference Rejection Combining Nokia Flexi EDGE BTS . . . . The following system impact information has been added: . System impact of Priority Based Quality of Service System impact of Dynamic Abis System impact of Support for PBCCH/PCCCH System impact of Nokia Smart Radio Concept for EDGE (Nokia SRC) . . . Chapter Support for PCU2 has been removed and the content moved to Packet Control Unit (PCU) in BSC. Information on BSC3i 1000 and BSC3i 2000 has been added. Chapter Coding Schemes CS-3 and CS-4 has been removed and the content moved to GPRS Coding Schemes. Chapter Nokia Smart Radio Concept for EDGE (Nokia SRC) has been updated with information on ST-IRC. 10 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Summary of changes The implementing instructions for GPRS and EGPRS have been thoroughly revised to include the entire implementation procedure. The chapter title Adding and removing TSLs to/from EDAP has been changed to Modifying EDAP timeslots. The following new chapters have been added: . Activating GPRS Modifying GPRS Deactivating GPRS Configuring EDAP for BTS Testing the activation of EGPRS Deactivating EGPRS in BSC . . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 11 (272) EDGE System Feature Description 12 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 About this document 1 About this document This document includes information on both Nokia EDGE and Nokia GPRS. If you need information on GPRS alone, see GPRS System Feature Description. This document is for S13/BSS13 level software. In the context of this description, the term 'PCU' refers to both PCU variants, PCU1 and PCU2. All mentioned issues apply to both variants, unless otherwise stated. This text is applicable to both ANSI and ETSI environments. The system impact chapters on GPRS/EDGE related features without their own System Feature Descriptions are also included in this document. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 13 (272) EDGE System Feature Description 14 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS 2 GPRS General Packet Radio Service (GPRS) provides packet data radio access for GSM mobile phones. It upgrades GSM data services to allow an interface with Local Area Networks (LANs), Wide Area Networks (WANs) and the Internet. GPRS makes the radio interface usage more efficient: . GPRS enables a fast method for reserving radio channels GPRS uses the same resources with circuit switched connection by sharing the overhead capacity GPRS provides immediate connectivity and high throughput. . . On a general level, GPRS connections use the resources only for a short period of time when sending or receiving data: . in a circuit-switched system, the line is occupied even when no data is transferred in a packet-switched system, the resources are released so they can be used by other subscribers. . GPRS is therefore well adapted to the bursty nature of data applications. GPRS has minimal effects on the handling of circuit switched calls, but the interoperability of existing circuit switched functionalities needs to be taken into account. GPRS uses statistical multiplexing instead of static time division multiplexing: when the user is ready to receive new data, the terminal sends a request, and resources are again reserved only for the duration of transmitting the request and initiating a second data transfer. The data to be transferred is encapsulated into short packets with a header containing the originating and destination address. No pre-set time slots are used. Instead, network capacity is allocated when needed and released when not needed. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 15 (272) EDGE System Feature Description GPRS offers a very flexible range of bitrates, from less than 100 bit/s to over 100 kbit/s. Applications that need less than one time slot benefit from GPRS's ability to share one time slot among several users. Moreover, the high bitrates that GPRS provides by using multiple time slots give short response times, even if a lot of data is transmitted. The main functions of the BSC with GPRS are to: . manage GPRS-specific radio network configuration control access to GPRS radio resources share radio resources between GPRS and circuit switched use handle signalling between the MS, BTS and Serving GPRS Support Node (SGSN) transfer GPRS data. . . . . BSC operational software includes support for GPRS coding schemes CS1 and CS-2. Support for coding schemes CS-3 and CS-4 is an application software product that requires PCU2 and Dynamic Abis. GPRS is an application software product and requires a valid licence in the BSC. For more information, see Licensing in BSC. Benefits of GPRS GPRS offers the following additional benefits for the operators/end users: . resources are used more efficiently, thus there is less idle time circuit switched traffic is prioritised, but quality is guaranteed by reserving time slots for GPRS traffic only new services, application, and businesses for the operators fast connection set-up for end users high bit rate in data bursts possibility of being charged only for transferred data generally, any service that can be run on top of IP protocols (the UDP or TCP transfer) is supported by the Nokia GPRS solution (taking into account data rate and delay requirements). . . . . . . 16 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS An investment in the GPRS infrastructure is an investment in future services. GPRS paves the way and is already part of the third generation (3G) network infrastructure. Migration to 3G comprises deployment of the new WCDMA radio interface – served by the GSM and GPRS core networks. Many of the 3G services are based on IP, and the GPRS Core network is the key step of introducing the IP service platform into the present GSM networks. When migrating to 3G services, preserving the Core Network investments is a top priority. Introducing UMTS will complement the GSM network – not replace it. Required network changes Nokia offers a total end-to-end General Packet Radio Service (GPRS) solution including the GPRS core, network management, and charging gateway with high capacity, scalability, and carrier class availability. As a part of the GPRS solution, the Nokia BSS offers GPRS support in the BSS with powerful radio resource management algorithms, optimised BSS network topology, and transmission solutions to ensure an optimal investment to operators and high capacity and quality service for end users. While the current GSM system was originally designed with an emphasis on voice sessions, the main objective of the GPRS is to offer access to standard data networks such as LAN using the TCP/IP protocol. These networks consider the GPRS to be a normal subnetwork, as seen in the figure below. A gateway in the GPRS network acts as a router and hides GPRS-specific features from the external data network. WAP (Wireless Application Protocol) based services see the GPRS as one carrier (UDP). Wireless Markup Language (WML) based services in the GPRS can be accessed using the standard WAP gateways. The WAP is essential in creating applications that are 'useable' in the mobile environment (for example, small screen display, low data rates). DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 17 (272) EDGE System Feature Description Figure 1. GPRS network seen by another data network GPRS is the first GSM Phase 2+ service that requires major changes in the network infrastructure. In addition to the current GSM entities, GPRS is based on a number of new network elements: . Serving GPRS Support Nodes (SGSN) GPRS backbone Legal Interception Gateway (LIG). . . 18 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS Figure 2. GPRS architecture Along with the new network elements, the following functions are needed: . GPRS-specific mobility management Network management capable of handling the GPRS-specific elements A new radio interface for packet traffic New security features for the GPRS backbone and a new ciphering algorithm New MAP and GPRS-specific signalling. . . . . Related topics in GPRS System Feature Description . Extended Uplink TBF Mode GPRS Coding Schemes Link Adaptation for GPRS Priority Class Based Quality of Service (QoS) System Level Trace System impact of GPRS . . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 19 (272) EDGE System Feature Description . System impact of Extended Uplink TBF Mode System impact of Priority Class based Quality of Service System impact of System Level Trace Requirements for GPRS Radio network management for GPRS Gb interface configuration and state management Radio resource management GPRS radio connection control Implementing GPRS overview . . . . . . . . Other related topics . Feature Descriptions . Data . Dual Transfer Mode . Dynamic Abis . Extended Cell for GPRS/EDGE . Extended Dynamic Allocation . Gb over IP . High Multislot Classes . Inter-System Network-Controlled Cell Re-selection . Multipoint Gb Interface . Network-Assisted Cell Change . Network-Controlled Cell Re-selection . Packet Control Unit (PCU2) Pooling Test and activate . Data . Activating and testing BSS9006: GPRS Reference . Commands . MML Commands . EA - Adjacent Cell Handling . EE - Base Station Controller Parameter Handling in BSC . EG - GSM Timer and BSC Parameter Handling . EQ - Base Transceiver Station Handling in BSC . ER - Transceiver Handling . . 20 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS . ES - Abis Interface Configuration EU - Power Control Parameter Handling . FX - Gb Interface Handling . Service Terminal Commands . PCU2 Service Terminal Commands Counters/Performance Indicators . Circuit-switched measurements . 106 CS DTM Measurement . Packet-switched measurements . Observations . 25 TBF Observation for GPRS Trace . 27 GPRS Cell Re-selection Report . 28 GPRS RX Level and Quality Report . . . Parameters . BSS Radio Network Parameter Dictionary . PAFILE . PAFILE timer and parameter lists . PRFILE and FIFILE . PRFILE and FIFILE parameters 2.1 GPRS data transfer protocols Figure 3. Transmission plane DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 21 (272) EDGE System Feature Description The GSM RF is the normal GSM physical radio layer. The Radio Link Control (RLC) function offers a reliable radio link to the upper layers. The Medium Access Control (MAC) function handles the channel allocation and the multiplexing, that is, the use of physical layer functions. The RLC and the MAC together form the OSI Layer 2 protocol for the Um interface. The Logical Link Control (LLC) layer offers a secure and reliable logical link between the MS and the SGSN to upper layers and is independent of the lower layers. The LLC layer has two transfer modes, the acknowledged and unacknowledged. The LLC conveys signalling, SMS, and SNDCP packets. The Subnetwork Dependent Convergence Protocol (SNDCP) is a mapping and compression function between the network layer and lower layers. It also performs segmentation, re-assembly, and multiplexing. The Base Station System GPRS Protocol (BSSGP) transfers control information and data between a BSS and a SGSN. The Network Services relays the BSSGP packets over the Gb interface and has load sharing and redundancy on top of Frame Relay. The L1bis is a vendor-dependent OSI Layer 1 protocol. The Relay function relays LLC PDUs (Protocol Data Units) between the LLC and BSSGP. The Packet Control Unit is responsible for the following GPRS MAC and RLC layer functions as defined in 3GPP TS 43.064: . LLC layer PDU segmentation into RLC blocks for downlink transmission LLC layer PDU re-assembly from RLC blocks for uplink transmission PDCH scheduling functions for the uplink and downlink data transfers PDCH uplink ARQ functions, including RLC block ack/nack PDCH downlink ARQ function, including buffering and retransmission of RLC blocks Channel access control functions, for example, access requests and grants Radio channel management functions, for example, power control, congestion control, broadcast control information, etc. . The Channel Codec Unit (CCU) takes care of the channel coding functions, including FEC and interleaving Radio channel measurement functions, including received quality level, received signal level, and information related to timing advance measurements. . . . . . . . For more information on the PCU, see Packet Control Unit (PCU). 22 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS The Network Protocol Data Units (N-PDU) are segmented into the Subnetwork Protocol Data Units (SN-PDU) by the Subnetwork Dependent Convergence (SNDC) protocol, and SN-PDUs are encapsulated into one or several LLC frames. LLC frames are of variable length. The maximum size of the LLC frame is 1600 octets minus GP protocol control information. See 3GPP TS 23.060 for information on SNDC and LLC. The details on SNDC can be found in 3GPP TS 44.065 and the details on LLC in 3GPP TS 44.064. LLC frames are segmented into RLC Data Blocks. In the RLC/MAC layer, a selective ARQ protocol (including block numbering) between the MS and the network provides retransmission of erroneous RLC Data Blocks. When a complete LLC frame is successfully transferred across the RLC layer, it is forwarded to the LLC layer. Figure 4. Transmission and reception data flow 2.2 Optimised GPRS Radio Resource Management The Nokia BSS offers dynamic algorithms and parameters to optimise the use of radio resources. A dynamic and flexible GPRS radio resource management is important in effective usage of the Air interface capacity to ensure maximum and secure data throughput. The limited radio resources must be used effectively. The figure below introduces the dedicated GPRS DCH channels: DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 23 (272) EDGE System Feature Description Figure 5. GPRS DCH dedicated channels GPRS packets are sent uni-directionally; uplink and downlink are separate resources. An MS can also have a bi-directional connection while using GPRS, by having simultaneous uplink and downlink packet transfers. A Temporary Block Flow (TBF) is made for every new data flow. One or more packet data traffic channels (PDTCHs) are allocated for the TBF. The TBF is used to send RLC/MAC blocks carrying one or more LLC PCUs. The TBF reservations of PDTCHs are released when all the RLC/MAC blocks have been sent successfully. Basically all TBFs have the same priority, that is, all users and all applications get the same service level. The needs of different applications differ and mechanisms to have separate service levels are required. ETSI specifications define QoS functionality which gives the possibility to differentiate TBFs by delay, throughput and priority. Priority Based Scheduling is introduced as a first step towards QoS. With Priority Based Scheduling the operator can give users different priorities so that higher priority users will get better service than lower priority users. There will be no extra blocking to any user, only the experienced service quality changes. Packet Associated Control Channel (PACCH) conveys signalling information related to a given MS. The PACCH is a bi-directional channel and is located in the PDCH. It transmits signalling in both directions although data is transmitted (PDTCH) only in the assigned direction. 24 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS Multiple MSs can share one PDTCH, but the PDTCH is dedicated to one MS (TBF) at a time. This means that the PDTCH is reserved for multiple TBFs, but one TBF is receiving or sending at a time. All the GPRS TBFs allocated to a PDTCH are served equally. The number of TSLs allocated for a multislot MS is determined by the mobile's multislot capability and network resources. Reallocations are done when the transfer mode is changed between uni-directional (only uplink or downlink data transfer) and bi-directional (simultaneous uplink and downlink data transfer). All the full rate or dual rate traffic channels are GPRS capable. With the Nokia GPRS solution, the operator can define dynamically multiple parameters related to network configuration, such as: . GPRS capacity cell by cell and TRX by TRX GPRS only traffic channels (Dedicated GPRS capacity) Default amount of GPRS capable traffic channels (Default GPRS capacity) and Whether BCCH TRX or non-BCCH TRX is preferred for GPRS. . . . The adjustable parameters help the network planners to control and optimise GPRS radio resources. Circuit Switched Territory GPRS Territory Max GPRS Capacity Additional GPRS Capacity Dedicated GPRS Capacity Default GPRS Capacity TRX 1 TRX 2 BCCH Territory border moves based on Circuit Switched and GPRS traffic load Figure 6. Example of a GPRS capable cell The BSS is upgraded with enhanced RLC/MAC protocols and TRAU for the radio and Abis interfaces. Circuit Switched (CS) traffic has priority over Packet Switched (PS) traffic. In a CS congestion situation, the CS may use the Default GPRS traffic channels, but Dedicated GPRS traffic channels are reserved to carry PS traffic. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 25 (272) EDGE System Feature Description The default GPRS capacity determines the number of traffic channels (TCHs), which are always switched to the PCU when allowed by CS traffic load. With these TCHs, the operator can supply the need for fast GPRS channel reservations for the first data packets. During peak GPRS traffic periods, additional channels are switched to GPRS use, if the CS traffic load allows it. Figure 7. Air interface traffic management Dedicated, default, and additional GPRS TCHs form a GPRS pool consisting of consecutive radio interface timeslots. When the GPRS pool is upgraded, intra-cell handovers of CS connections may be needed to allow for the selection of consecutive timeslots for GPRS use. New CS connections may be allocated to a TCH in the GPRS pool only when all the TCHs not belonging to the GPRS pool are occupied. IUO super reuse frequencies are not used for GPRS traffic, but the feature itself can be used to release resources for GPRS usage. In cells where Base Band Frequency Hopping is in use, TSL 0 is not used for GPRS traffic. When Extended Cell for GPRS/EDGE application sotware is used, the Extended Cell GPRS channels (EGTCH) in Extended TRX (E-TRX) are reserved only for fixed GPRS traffic and dynamic GPRS radio resource management is not used for them at all. For more information, see Extended Cell for GPRS/EDGE. 26 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS 2.3 Frame Relay and Gb Interface Gb is the interface between a BSC and an SGSN. It is implemented using either Frame Relay or IP. For more information on Gb over IP, see Gb over IP. Frame Relay can be either point-to-point (PCU–SGSN), or there can be a Frame Relay network located between the BSC and SGSN. The protocol stack comprises BSSGB, NS, and L1. Frame Relay as stated in standards is a part of the Network Service (NS) layer. On top of the physical layer in the Gb-interface, the direct point-to-point Frame Relay connections or intermediate Frame Relay network can be used. The physical layer is implemented as one or several PCM-E1 lines with G.703 interface. The FR network will be comprised of third-party off-the-shelf products. The following figure displays examples of Gb interface transmission solutions: Figure 8. BSC - SGSN interface In the first solution (1) spare capacity of Ater and A interfaces is used for the Gb. The Gb timeslots are transparently through connected in the TCSM and in the MSC. If free capacity exists, it is best to multiplex all Gb traffic to the same physical link to achieve possible transmission savings. In many cases, the SGSN will be located in the MSC site, and thus the multiplexing has to take place there as well. Normal cross-connect equipment, for example, Nokia DN2 can be used for that purpose. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 27 (272) EDGE System Feature Description The second solution (2) represents any transmission network that provides a point-to-point connection between the BSC and the SGSN. In the third solution (3) Frame Relay network is used. The Gb interface allows the exchange of signalling information and user data. The Gb interface allows many users to be multiplexed over the same physical resources. At least one timeslot of 64 kbps is needed for each activated PCU bearer. One PCU1 can handle a maximum of 64 BTSs and 128 TRXs. One PCU2 can handle a maximum of 128 BTSs and 256 TRXs. This capacity cannot be shared with other cells connected to other PCUs in the BSC so there is no pooling. The PCU has to be installed into every BCSU for redundancy reasons, but the FR bearer has to be connected only to the active ones. Considering the transmission protection, it also needs to be decided whether two Frame Relay bearers are needed for each PCU using different ETs (external 2Ms) or if the transmission is protected with cross connection equipment. It is possible to multiplex more than one Gb interface directly to the SGSN, or multiplex them on the A interface towards the MSC and cross-connect them to the SGSN from there. The 2M carrying the Gb timeslots can be one of the BSC's existing ETs, or an ET can be dedicated to the Gb interface. The Gb interface allows the exchange of signalling information and user data. It also allows many users to be multiplexed over the same physical resources. The logical structure of the point-to-point Gb interface is presented in the following figure: Figure 9. Gb logical structure 28 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS In the BSC, each PCU represents one Network Service Entity with own Identifier (NSEI). Each PCU can have one to four (ffs) FR bearer channels. The Access Rate of a FR Bearer Channel can be configured in 64kbit steps. Each Bearer channel carries one to four Network Service Virtual Connections (NS-VC). Each BTS has a BSSGP Virtual Connection of its own. The NSE takes care of the multiplexing of BSSGP Virtual Connections into the NS Virtual Connections and load sharing between the different NS Virtual Connections (= Bearer Channels). The following figure displays the Gb protocol layers: Figure 10. Gb interface 2.4 GPRS in Nokia Base Stations Radio resources are allocated by the BSC (PCU). The BCCH/CCCH is scheduled by the BTS; messages are routed via TRXSIG link between the BTS and BSC. GPRS data itself is transparent to the BTS; routed via TCH channels in Abis. The CCU (Channel Coding Unit) in the BTS DSP performs channel coding for the following rates: . CS-1 (Channel Coding Scheme 1) - 9.05 kbps CS-2 (Channel Coding Scheme 2) - 13.4 kbps CS-3 (Channel Coding Scheme 3) - 14.4 kbps CS-4 (Channel Coding Scheme 4) - 20.0 kbps . . . In Packet Transfer Mode, the MS will use the continuous timing advance update procedure. The procedure is carried out on all PDCH timeslots. The mapping in time of these logical channels is defined by a multi-frame structure. It consists of 52 TDMA frames, divided into 12 blocks (of four frames) and four idle frames. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 29 (272) EDGE System Feature Description 30 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 EDGE 3 EDGE Enhanced Data rates for Global Evolution (EDGE), introduced to GSM/ GPRS standard Release 99, boosts GSM/GPRS network capacity and data rates to meet the demands of wireless multimedia applications and mass market deployment. The Nokia EDGE Solution includes Enhanced GPRS (EGPRS) for packet switched data. EDGE uses 200 kHz radio channels, which are the same as the current GSM channel widths. From a technical perspective, EDGE BSS allows the GSM and GPRS core network to offer a set of new radio access bearers. EDGE is designed to improve spectral efficiency through efficient link utilisation with GMSK and 8-PSK modulation schemes, which can be alternated on the same radio timeslot according to radio channel conditions. With new modulation, EDGE increases the radio interface data throughput in average three-fold compared to today's GSM and boosts both circuit switched and packet switched services. The maximum standardised data rate per timeslot will triple, and the peak throughput, with eight time slots in the radio interface, can be up to 473 kbit/s. Since it is fully based on GSM, introducing EDGE to the existing network requires relatively small changes to the network hardware and software. EDGE does not entail any new network elements. The operators need not make any changes to the network structure or invest in new regulatory licenses. Oversea roaming of GSM/EDGE is better than that of any other radio technology. EDGE is an application software product and requires a valid licence in the BSC. For more information, see Licensing in BSC. You do not need a separate GPRS licence to be able to use GPRS, a valid EDGE licence is enough. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 31 (272) EDGE System Feature Description Benefits of Nokia EDGE solution EDGE is compatible with GSM/GPRS equipment and services as well as all new emerging 3G services. The Nokia EDGE solution was created to give operators a competitive edge, to help them generate more revenues, and to strengthen their market share by offering a wide selection of modern 3G value-added services. Nokia's design target is to protect operators’ existing investments and provide a smooth and cost-efficient evolution from GSM/GPRS to 3G by optimising the use of the radio resources with the existing infrastructure platform as a basis. Backed by Nokia’s long, solid expertise in GSM and GPRS systems and a comprehensive knowledge of 3G systems, the Nokia EDGE solution provides standardised EDGE features from the very beginning. Nokia EDGE offers greater capacity and a higher Quality of Service (QoS) with existing site densities and frequency plans. The Nokia EDGE solution provides an unlimited EDGE growth path, not only for macrocellular and microcellular solutions, but also for local area solutions, such as indoor and picocellular. It improves operators’ competitiveness in those segments with the most demanding subscribers. EDGE is especially attractive for GSM 800, GSM 900, GSM 1800, and GSM 1900 operators who wish to offer mobile multimedia applications at an early stage because EDGE offers means to provide 3G services for end users in the existing GSM frequencies. Compared to the data services currently available from GSM, EDGE provides significantly higher capacity than GPRS. While GPRS offers improved data services, EDGE provides more speed for GPRS. With EDGE, operators realise their full revenue potential through incorporating international roaming in a convenient and cost-effective manner. Operators with UMTS licenses can offer 3G capabilities to all end users in a cost-effective manner. Wideband Code Division Multiple Access (WCDMA) combines well with EDGE for data intensive applications that require data user rates up to 473 kbp/s. Benefits of EDGE include, for example, the following: . migration path to wireless multimedia services: operators can increase their data revenues by offering new, attractive services movement to third generation applications flexibility in pricing due to lower costs for data capacity in high-speed data applications, potentially leading to lower price per bit . . 32 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 EDGE . fast network implementation by building full coverage using existing sites: EDGE requires no new network elements and the EDGE capability can be introduced incrementally to the network optimised network investment flexible, demand-based deployment of data capacity improved service quality and end user satisfaction: increased data capacity and higher data throughput decrease blocking and response times for all data services lower tariffs, resulting from more efficient networks . . . . Required network changes EDGE technology is introduced on the existing GSM network and does not compromise network performance and quality. OSS Nokia Flexi EDGE BTS Nokia UltraSite EDGE BTS Nokia MetroSite EDGE BTS GSM compatible SGSN Gn BTS GGSN EDGE functionality in network elements BSC Abis BTS Gb A MSC EDGE capable GSM/EDGE coverage terminal, GSM compatible More capacity in interfaces to support higher data usage and higher user rates Figure 11. Impacts of EDGE on the mobile network (ETSI release 99 implementation) DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 33 (272) EDGE System Feature Description EDGE support requires minimum hardware changes for existing networks. Only GSM/EDGE TRX Radio Frequency (RF) and Baseband units need to be installed — all other units stay the same. GSM/EDGE and GSM TRXs can co-exist, or operators can create a configuration using all-EDGE components. The EDGE capability is available with Nokia MetroSite EDGE Base Transceiver Station (BTS), Nokia UltraSite EDGE BTS and Nokia Flexi EDGE BTS solutions as an easy unit upgrade. Nokia UltraSite EDGE BTS also provides site evolution to WCDMA since it houses both EDGE and WCDMA carriers. The Nokia UltraSite EDGE and Nokia Flexi EDGE solutions offer the traditional benefits of high capacity and coverage along with full data support. GSM/EDGE-capable TRXs for Nokia MetroSite EDGE BTS and Nokia UltraSite EDGE BTS are compatible with GSM TRXs and fit into the same slot in the BTS cabinets. In addition to providing EDGE services, GSM/ EDGE TRXs are fully GSM compatible and support GSM voice, data, HSCSD, and GPRS plus EGPRS. They are also backward compatible with all legacy GSM terminals. All Nokia Flexi EDGE TRXs are EDGE and GSM capable. These solutions provide an unlimited EDGE growth path and full functionality for micro and macrocellular networks. The rest of the network requires supporting software releases and capacity expansions for higher data rates. EDGE terminals will be available in line with the network infrastructure. EDGE terminals continue to support all GSM and GPRS services. Nokia EDGE features and functions Nokia EDGE key features and functions . 8-PSK modulation downlink and uplink The benefits of 8-PSK modulation include three times the number of bits per second through existing BTS EDGE hardware and GSM radio spectrum and smaller power consumption per delivered bit. Also, fewer new TRXs and BTS cabinets are required. For more information, see 8 Phase Shift Keying. . Nokia GSM/EDGE Radio Resource Management With radio resource allocation using the Territory Method, the operator can define the amount of GPRS/EDGE radio resources flexibly. The EDGE radio resources can also be extended to circuit switched timeslots at times when there is no traffic. 34 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 EDGE For more information, see Optimised GPRS Radio Resource Management. . Nokia Dynamic Abis Dynamic Abis is a non-blocking and real time transmission solution for optimising EDGE and GPRS capacity in Abis. For more information, see Dynamic Abis. . Nokia BSS Radio Link Adaptation Nokia Link Adaptation ensures that maximum throughput and minimum delay (RTT) is achieved in changing radio conditions by selecting the optimum Modulation and Coding Scheme (MCS). For more information, see Link Adaptation for EGPRS. . Nokia Incremental Redundancy downlink and uplink Nokia Incremental Redundancy works in co-operation with Nokia Link Adaptation to improve throughput by automatically adapting the total amount of transmitted redundancy to the changing radio channel conditions. For more information, see Incremental Redundancy. . Gb Flow Control Gb Flow Control maximises the downlink data transmission from SGSN to BSS. Gb Flow Control ensures that the BSS downlink data buffer is not overflown or run empty during data downlink transmission. Gb Flow Control is 3GPP standardised and applied only to the downlink direction. For more information, see BSC-SGSN Interface Specification BSS GPRS Protocol (BSSGP). . Nokia EDGE BTS downlink radio re-transmissions A transmitted radio block is stored in BTS memory. In retransmissions, the stored block is re-transmitted and only a 16 kbit/s connection is needed at Abis. For example, if MCS-9 radio block is re-transmitted, a 16 kbit/s Abis channel is enough compared to 5*16 kbit/s required at the initial transmission. With EDGE BTS downlink radio re-transmissions, the required re-transmission capacity in Abis is reduced by 80%. . Proactive downlink re-transmissions DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 35 (272) EDGE System Feature Description When the PCU has sent a downlink radio block to the MS, it puts it into a ‘pending acknowledgement’ state until it receives acknowledgement from the MS. When the PCU doesn’t have any new radio blocks to send it will start to re-transmit the blocks which are in the ‘pending acknowledgement’ state. This will improve the robustness of the sent data and allow faster radio block decoding in the MS. The benefits of Proactive downlink re-transmission include improving data transfer latency and robustness as well as the responsiveness and quality for real time data services, such as VoIP, PoC and video services. . Delayed uplink TBF release An uplink TBF is not released immediately when the transmitted uplink data ends. If the PCU receives downlink data during the uplink TBF release delay period, the downlink TBF can be established on an associated signalling channel instead of a common signalling channel. The use of an associated signalling channel reduces the downlink TBF establishment time significantly. The benefits of Delayed uplink TBF release include smaller end-toend latency (RTT) as well as improved responsiveness and quality for real time data services, such as VoIP, PoC and video services. . EDGE counters and KPIs EDGE counters and KPIs enable network level optimisation for best end-user data service experience over EDGE. The KPI recommendations are actively improved and updates are published accordingly. For more information, see System impact of Nokia EDGE and EDGE key performance indicators (KPIs). Nokia EDGE recommended supporting features and functions . Delayed downlink TBF When the BSS has sent all the downlink data from its buffer, it delays the release of the downlink TBF. During the release delay, if there is no existing uplink TBF for the MS, the BSS sends dummy blocks to the MS. This is done in order to allow the MS to request an uplink TBF. Also, if the BSS receives more downlink data during the release delay, the PCU cancels the delayed release and begins to send new downlink data blocks using the same TBF. With Delayed downlink TBF, idle packet data latency is shortened and more users can be served at the same time. 36 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 EDGE . Priority Class Based Quality of Service With Priority Class based Quality of Service, end-user service quality may be differentiated. This allows flexible service categories and pricing. For more information, see Priority Class Based Quality of Service. . Uplink Power Control Uplink Power Control decreases the uplink interference level in the network and enables higher end-user uplink throughput. For more information, see Power Control. . Extended Uplink TBF Extended Uplink TBF increases the application level (e.g. HTTP, WAP, FTP) performance remarkably by reducing system Round Trip Time (RTT) and TCP slow start impact. For more information, see Extended Uplink TBF Mode. . One phase access for EDGE One phase access for EDGE gives EDGE mobile stations faster access to the network resources. . GPRS Resume When a GPRS attached MS receives a CS call, the GPRS Resume will suspend data transfer. When the CS call is completed, GPRS service is resumed with no need for a Routing Area update. GPRS Resume decreases the number of Routing Area updates and thus decreases the capacity used for signalling data. . USF Granularity 4 (PCU2) USF Granularity 4 with PCU2 enables higher use of 8-PSK in downlink, as well as during GPRS timeslot sharing in uplink. It optimises the multiplexed scheduling of GPRS and EDGE users and at its best, 2,8 folds the EDGE users’ throughput. Related topics in GPRS/EDGE System Feature Description . EGPRS Modulation and Coding Schemes EGPRS Packet Channel Request on CCCH Incremental Redundancy Link Adaptation for EGPRS Nokia Smart Radio Concept for EDGE . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 37 (272) EDGE System Feature Description . 8 Phase Shift Keying System impact of Nokia EDGE System impact of EGPRS Packet Channel Request on CCCH System impact of Nokia Smart Radio Concept for EDGE Requirements for GPRS/EDGE in BSC Radio network management for GPRS in BSC Gb interface configuration and state management Radio resource management GPRS/EDGE radio connection control Implementing EGPRS Configuring Intelligent Downlink Diversity . . . . . . . . . . Other related topics . Feature Descriptions . Data . Dual Transfer Mode . Dynamic Abis . Extended Cell for GPRS/EDGE . Extended Dynamic Allocation . Gb over IP . High Multislot Classes . Inter-System Network-Controlled Cell Re-selection . Multipoint Gb Interface . Network-Assisted Cell Change . Network-Controlled Cell Re-selection . Packet Control Unit (PCU2) Pooling Dimension . BTS EDGE Dimensioning . Abis EDGE Dimensioning . BSC EDGE Dimensioning . Gb EDGE Dimensioning Test and Activate . Data . Activating and testing BSS10083: EGPRS . Activating and testing BSS9006: GPRS . . 38 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 EDGE . Reference . Commands . MML Commands . EA - Adjacent Cell Handling . EE - Base Station Controller Parameter Handling in BSC . EG - GSM Timer and BSC Parameter Handling . EQ - Base Transceiver Station Handling in BSC . ER - Transceiver Handling . ES - Abis Interface Configuration . EU - Power Control Parameter Handling . FX - Gb Interface Handling . Service terminal commands . PCU2 Service Terminal Commands . Counters/Performance Indicators . Circuit-switched measurements . 106 CS DTM Measurement . Packet-switched measurements . Observations . 25 TBF Observation for GPRS Trace . 27 GPRS Cell Re-selection Report . 28 GPRS RX Level and Quality Report Parameters . BSS Radio Network Parameter Dictionary . PAFILE . PAFILE timer and parameter lists . PRFILE and FIFILE . PRFILE and FIFILE parameters . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 39 (272) EDGE System Feature Description 40 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to GPRS/EDGE 4 4.1 Software related to GPRS/EDGE Extended Uplink TBF Mode With Extended Uplink TBF Mode the uplink TBF may be maintained during temporary inactive periods, where the mobile station has no data to send. Without Extended Uplink TBF Mode a new uplink TBF has to be established after every inactive period. When both the MS and the network support Extended Uplink TBF Mode, the release of the uplink TBF can be delayed even if the MS occasionally has nothing to transmit. Right after the MS has new data to send, the same uplink TBF can be used and data transmission can be reactivated. Extended Uplink TBF Mode requires 3GPP Rel. 4 GERAN feature package 1 mobile stations. Benefits of the Nokia solution . With Extended UL TBF Mode the UL TBF release can be delayed in order to make it possible to establish the following downlink TBF using Packet Associated Control Channel (PACCH). Using PACCH enables faster TBF establishment compared to using CCCH. Extended UL TBF Mode allows the mobile station to continue the data transfer if it gets more data to send when the countdown procedure has begun. Without Extended UL TBF Mode, the release of the current TBF is required and a new one is established, causing more delay and signalling load. . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 41 (272) EDGE System Feature Description . Extended UL TBF Mode is effective in preventing the breaks in data transfer. Occasional short breaks in data transmission do not delay the activation of a new Uplink TBF, which increases the perceived service quality by the end user, for example, in speech delivery in PoC. Extended UL TBF Mode saves capacity, because it decreases the number of random access procedures during and after an active stream, when a TBF is needed for the other direction. . Related topics . Activating and Testing BSS11151: Extended Uplink TBF Mode 4.2 GPRS Coding Schemes GPRS provides four coding schemes, from CS-1 to CS-4, offering data rates from 9.05 to 21.4 kbit/s per channel. By using PCU1 and 16 kbit/s Abis links, it is possible to support CS-1 and CS-2. Figure 12. GPRS Coding Schemes Coding scheme CS-1 is always used in unacknowledged RLC mode, except with PCU2 where it is also possible to use other coding schemes in unacknowledged RLC mode. In acknowledged mode, RLC data blocks are acknowledged, and both CS1 and CS-2 are supported. Each TBF can use either a fixed coding scheme (CS-1 or CS-2), or Link Adaptation (LA). The link adaptation algorithm is based on the RLC BLER (Block Error Rate). Retransmitted RLC data blocks must be sent with the same coding as was used initially. 42 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to GPRS/EDGE Coding Schemes CS-3 and CS-4 Before the introduction of Dynamic Abis, only CS-1 and CS-2 GPRS coding schemes were supported because of Abis frame restrictions. Dynamic Abis makes it possible to use CS-3 and CS-4. CS1 and CS2 offer data rates of 8.0 and 12.0 kbps per timeslot. With the rates of 14.4 and 20.0 kbps, CS-3 and CS-4 provide a considerable gain in data rates for GPRS mobile stations not supporting EGPRS (the mandatory RLC header octets are excluded from the data rate values). CS-3 and CS-4 can boost GPRS throughput bit rates by a maximum of 60% compared to CS-1 & CS-2. With average real network conditions (average C/I value distribution) a throughput increase of 0-30% can be achieved depending on the network’s C/I values. Coding Schemes CS-3 and CS-4 can be used in both GPRS and EGPRS territories. For hardware requirements, see section Requirements. Requirements The hardware and software requirements of Coding Schemes CS-3 and CS-4 are specified in the tables below. Coding Schemes CS-3 and CS-4 are an application software product and require a valid licence in the BSC. All GPRS-capable mobile stations support CS-3 and CS-4. Table 1. Required additional or alternative hardware or firmware Network element Hardware/firmware required BSC BTS PCU2 The BaseBand hardware of the BTS must support Dynamic Abis. EDGE capable TRXs are required. No requirements No requirements TCSM SGSN DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 43 (272) EDGE System Feature Description Table 2. Required software by network elements Network element Software release required BSC Nokia Flexi EDGE BTSs Nokia UltraSite EDGE BTSs Nokia MetroSite EDGE BTSs Nokia Talk-family BTSs Nokia InSite BTSs MSC/HLR SGSN Nokia NetAct S13 EP2 CX6.0 CXM6.0 Not supported Not supported Not applicable Not applicable OSS4.2 CD Set 1 User interface BTS MMI Coding Schemes CS-3 and CS-4 cannot be managed with BTS MMI. BSC MMI The following MML commands are used to handle Coding Schemes CS-3 and CS-4: . Base Transceiver Station Handling in BSC: EQV, EQO BSC radio network object parameters The following parameters are introduced due to Coding Schemes CS-3 and CS-4: . coding schemes CS3 and CS4 enabled (CS34) DL coding scheme in acknowledged mode (DCSA) UL coding scheme in acknowledged mode (UCSA) DL coding scheme in unacknowledged mode (DCSU) . . . 44 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to GPRS/EDGE . UL coding scheme in unacknowledged mode (UCSU) adaptive LA algorithm (ALA) . Due to a new Link Adaptation algorithm the following existing parameters are no longer relevant when CS-3 and CS-4 is used: . coding scheme no hop (COD) coding scheme hop (CODH) . For more information on radio network parameters, see BSS Radio Network Parameter Dictionary. PRFILE parameters The values of the following MS-specific flow control parameters must be increased due to CS-3 and CS-4: . FC_MS_B_MAX_DEF FC_MS_R_DEF FC_R_TSL. . . For more information on PRFILE parameters, see PRFILE and FIFILE Parameter List. Alarms The following new alarm is introduced due to Coding Schemes CS-3 and CS-4: . 3273 GPRS/EDGE TERRITORY FAILURE For more information, see Diagnosis Reports (3700-3999). Measurements and counters Two new object values are added to the 79 Coding Scheme Measurement due to Coding Schemes CS-3 and CS-4. No new counters are needed. Interworking with other features CS-3 and CS-4 do not fit into one 16kbit/s Abis/PCU channel and require the use of Dynamic Abis and EDGE TRXs. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 45 (272) EDGE System Feature Description Related topics . Activating and testing BSS11088: Coding Schemes CS-3 and CS-4 79 Coding Scheme Measurement . 4.3 Link Adaptation for GPRS From BSS11.5 onwards, there are two GPRS Link Adaptation algorithms, the use of which depends on the PCU type (PCU1 or PCU2). Although the Coding Schemes CS-3 and CS-4 are licence-based, the LA algorithm is provided with PCU2. Link Adaptation algorithm for PCU1 The GPRS Link Adaptation (LA) algorithm selects the optimum channel coding scheme (CS-1 or CS-2) for a particular RLC connection and is based on detecting the occurred RLC block errors and calculating the block error rate (BLER). The BSC level parameters coding scheme no hop (COD) and coding scheme hop (CODH) define whether a fixed CS value (CS-1 or CS-2) is used or if the coding scheme changes dynamically according to the LA algorithm. When the LA algorithm is deployed, the initial CS value at the beginning of a TBF is CS-2. Regardless of the parameter values, CS-1 is always used in unacknowledged RLC mode. Link Adaptation algorithm for PCU2 A new Link Adaptation algorithm is introduced with PCU2, which replaces the previous GPRS LA algorithm and covers the following coding schemes: . CS-1 and CS-2 if CS-3 and CS-4 support is disabled in the territory in question CS-1, CS-2, CS-3, and CS-4 if CS-3 and CS-4 support is enabled in the territory in question . The following BTS-level parameters define, whether a fixed CS value (CS1 - CS4) is used or if the coding scheme changes dynamically according to the LA algorithm. The parameters can also be used to define the initial CS value at the beginning of a TBF: 46 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to GPRS/EDGE . DL coding scheme in acknowledged mode (DCSA) UL coding scheme in acknowledged mode (UCSA) DL coding scheme in unacknowledged mode (DCSU) UL coding scheme in unacknowledged mode (UCSU) adaptive LA algorithm (ALA) . . . . For more information on radio network parameters, see BSS Radio Network Parameter Dictionary. The LA algorithm measures the signal quality for each TBF in terms of the received signal quality (RXQUAL). RXQUAL is measured for each received RLC block, which makes it a more accurate estimate than BLER. The PCU determines the average BLER value separately for each BTS by continuously collecting statistics from all the connections in the territory in question. Based on the estimates, the LA algorithm determines which coding scheme will give the best performance. The new LA algorithm can be used in both RLC acknowledged and unacknowledged modes in both uplink and downlink direction. 4.4 Priority Class Based Quality of Service (QoS) With Priority Based Scheduling, an operator can give users different priorities. Higher priority users will get better service than lower priority users. There will be no extra blocking to any user, only the experienced service quality changes. The concept of ‘Priority Class’ is based on a combination of the GPRS Delay class and GPRS Precedence class values. Packets will be evenly scattered within the (E)GPRS territory between different time slots. After that packets with a higher priority are sent before packets that have a lower priority. Mobile-specific flow control is part of the QoS solution in the PCU. It works together with the SGSN to provide a steady data flow to the mobile from the network. It is also an effective countermeasure against buffer overflows in the PCU. Mobile-specific flow control is performed for every MS that has a downlink TBF. There is no uplink flow control. The PCU receives the QoS (Precedence class) information to be used in DL TBFs from the SGSN in a DL unitdata PDU. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 47 (272) EDGE System Feature Description In case of UL TBF, the MS informs its radio priority in a PACKET CHANNEL REQUEST (PCR) or a PACKET RESOURCE REQUEST (PRR), and this is used for UL QoS. Exceptions to this rule are one phase access and single block requests; in these cases the PCU always uses Best Effort priority. Priority Class Based Quality of service is an operating software in the BSC and is always active in an active PCU. The subscriber priority must be defined in the HLR once Priority Class Based QoS is taken into use. Priority based scheduling algorithm The description below covers the PCU1 implementation; PCU2 implementation emulates this operation closely. The priority based scheduling algorithm hands out radio resources according to the latest service time and scheduling step size of the TBFs. Each TBF allocated to a timeslot has a timeslot-specific latest service time, before which the TBF should get a chance to use the radio resource. In each scheduling round, the TBF with the lowest service time is selected. After the TBF has sent a radio block, its latest service time is incremented by a predefined scheduling step size. The higher the scheduling step size, the less often the TBF is selected and given a transmission turn. In BSS9 (Nokia GPRS Release 1) the scheduling steps of all TBFs are set to the same constant value. In the BSS10.5 release the step sizes depend on the priority class of the TBF: each priority class has its own scheduling step size that can be adjusted by the operator. There are 4 QoS classes for uplink and 3 QoS classes for downlink. Each service class is given a fair amount of radio time. The best effort customers are an exception to the rule and are only given a small share of the radio interface. The allocation process is designed to ensure that better priority TBFs are not gathered into the same radio timeslot. TBFs in the same time slot that have the same QoS get an equal share of air time. However, equal air time does not provide equal data rates for the TBFs in the same time slot, it only guarantees that inside a QoS group the air time is divided equally and that a higher QoS class gets more air time. 48 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to GPRS/EDGE Figure 13. Example of transmission turns 4.5 System Level Trace System Level Trace is an operating software, which extends the current GSM tracing to the GPRS service. GSM tracing is available in the network elements of the GSM network to trace circuit switched calls. System Level Trace enables customer administration and network management to trace activities of various entities (IMSIs and IMEIs), which result in events occurring in the PLMN. The trace facility is a useful maintenance aid and development tool, which can be used during system testing. In particular, it may be used in conjunction with test-MSs to ascertain the digital cell 'footprint', the network integrity, and also the network quality of service as perceived by the PLMN. The network management can use the facility, for example, in connection with a customer complaint, a suspected equipment malfunction or if authorities request for a subscriber trace for example in an emergency situation. The ETSI specifies the tracing facility for GSM, where it refers both to subscriber tracing (activated using IMSI) and equipment tracing (activated using IMEI). The subscriber tracing can be defined for a certain subscriber in the HLR or in a specific SGSN. Equipment tracing can be defined in the SGSN. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 49 (272) EDGE System Feature Description Figure 14. Trace activation/deactivation and report generation The trace is already implemented in the GSM network, but introduction of GPRS-service adds new network elements to the GSM network (GGSN, SGSN) and changes old principles. Therefore, new tracing facilities are needed. In order to get full advantage of System Level Trace, it must be implemented in all main network elements of the GPRS network: the SGSN, GGSN, BSC, MSC/HLR, and OSS. The figure GPRS network and related network elements presents the overall picture of GPRS trace and shows all the network elements that can send trace reports to NetAct. GPRS trace is activated by OSS. The HLR, SGSN, GGSN, and BSS send trace records to OSS when an invoking event occurs. 50 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to GPRS/EDGE Figure 15. Architecture of the GPRS network and related network elements Trace from an operator's viewpoint In the SGSN trace, three different scenarios can be identified from an operator's point of view: . HPLMN operator traces its own IMSI within the HPLMN When an operator wishes to trace a GPRS subscriber in its own (home) network, the trace is first activated in the HLR. If a subscriber is not roaming outside the HPLMN and he/she is represented as a register in the HLR, the HLR activates the trace in a specified SGSN. Otherwise, the HLR waits until the subscriber becomes active in HPLMN before it activates a trace in the SGSN. . HPLMN operator tracing a foreign roaming subscriber (IMSI) within its own HPLMN When an operator wants to trace a foreign subscriber, the trace is activated directly via MMI commands to all SGSNs in an operator's network. The trace of a subscriber is in a state of active pending until an invoking event occurs. The amount of active trace cases can be limited. . HPLMN operator tracing equipment (IMEI). DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 51 (272) EDGE System Feature Description When an operator wants to trace equipment, the trace is activated directly via MMI commands to all SGSNs in operator's network. The trace of equipment is in a state of active pending until an invoking event occurs. The amount of active trace cases can be limited. The tracing of roaming IMSIs and the exchange of data is subject to bilateral agreements, and the request to trace a particular IMSI comes through administrative channels. The HPLMN operator can use the HLR parameters to define whether the trace settings are sent to the VPLMN. System Level Trace in BSC The SGSN invokes the trace by sending a BSSGP SGSN-INVOKETRACE (3GPP TS 48.018) message to the BSS when SGSN trace becomes active or when SGSN receives a trace request. When the BSC receives this message it starts tracing. The BSS does not send an acknowledgement of the BSSGP message to the SGSN. In case of a handover between BSCs, the tracing is deactivated in the source BSC side and activated in the target BSC side by an SGSN-INVOKE-TRACE message from SGSN. The System Level Trace for GPRS in the BSC is implemented as three different observation types: . TBF Observation for GPRS Trace GPRS Cell Re-Selection Report GPRS RX Level and Quality Report . . These observations cannot, however, be started or stopped by MML commands or from the NMS. The trace as a whole is handled only by the SGSN-INVOKE-TRACE messages from the SGSN. If you attempt to start these observations (without trace) from NetAct, the BSC replies with an error status. The BSC sends the generated trace reports to Nokia NetAct. Trace reports are also stored in observation files on the BSC's disk. TBF Observation for GPRS Trace A TBF report is created when a subscriber performs actions causing an allocation of TBF in BSS during tracing. There is one report per each allocated TBF, so simultaneous TBF allocations produce multiple reports. TBF release completes the report, which is then ready for post-processing. 52 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to GPRS/EDGE During TBF allocation, TBF Observation for GPRS Trace records resource consumption by the user and call quality related transactions. In addition to TBF allocation and release, recorded events include TBF reallocations, MCS changes and MS Flow Control changes. For further information, see 25 TBF Observation for GPRS Trace. GPRS Cell Re-selection Report GPRS Cell Re-selection is a trace report for GPRS trace. It contains information about NCCR triggering, NACC usage and possible failures. The report is closed and sent further to NetAct when flush is received from the SGSN, the MS returns to source cell by Packet Cell Change failure, or NCCR context is released in the PCU. For further information, see 27 GPRS Cell Re-selection Report. GPRS RX Level and Quality Report GPRS RX Level and Quality Report is a report type needed to periodically record serving and neighbour cell measurements and quality data. The report contains the following information: . downlink RX level of serving cell and neighbour cells from packet (enhanced) measurement report downlink RX quality class or BEP values from (EGPRS) PACKET DOWNLINK ACKNOWLEDGEMENT message uplink RX level and quality from BTS measurements. . . For further information, see 28 GPRS RX Level and Quality Report. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 53 (272) EDGE System Feature Description 54 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to EGPRS 5 5.1 Software related to EGPRS EGPRS Modulation and Coding Schemes EGPRS supports higher data rates compared to basic GPRS, using several Modulation and Coding Schemes (MCSs) varying from 8.8 kbit/s to 59.2 kbit/s in the radio interface. Altogether nine MCSs are designed for EGPRS. When an RLC data block is sent, the information is encoded using one of the MCSs to resist channel degradation and modulated before transmission over the radio interface. Since the resources are limited, the higher the level of protection for information, the less information is sent. The protection that best fits the channel condition is chosen for a maximum throughput. The GMSK modulation provides the robust mode for wide area coverage while 8PSK provides higher data rates. Table 3. MCS MCS-1 MCS-2 MCS-3 MCS-4 MCS-5 MCS-6 MCS-7 MCS-8 MCS-9 Peak data rates for EGPRS Modulation and Coding Schemes Modulation GMSK Code Rate .53 .66 .80 1 Family C B A C B A B A A User Rate 8.8 kbit/s 11.2 kbit/s 14.8 kbit/s 17.6 kbit/s 22.4 kbit/s 29.6 kbit/s 44.8 kbit/s 54.4 kbit/s 59.2 kbit/s 8PSK .37 .49 .76 .92 1 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 55 (272) EDGE System Feature Description In EGPRS, it is possible to switch between any of the MCSs, from one data block to another, as in GPRS. In EGPRS, however, it is possible also to change the retransmission MCS whereas with GPRS, the retransmission takes place with exactly the same level of protection as the initial transmission. This is useful since the level of protection needed in a retransmission may differ due to varying channel conditions and the existing protection from earlier Incremental Redundancy (IR) transmissions. MCSs are organised in families to allow re-segmentation of data blocks in case of retransmissions, using Link Adaptation (LA). The retransmission can be accomplished with lower coding schemes, that is, if the transmission failed with the original, higher coding scheme, the same data can be retransmitted with a lower codec within the same family. Note that GPRS is not a subset of EGPRS. The GPRS coding schemes, CS-1 to CS-4, are different than the EGPRS GMSK coding schemes, MCS-1 to MCS-4. Related topics . EDGE GPRS Coding Schemes . 5.2 EGPRS Packet Channel Request on CCCH When the MS wants to send data or upper layer signalling messages to the network, it requires the establishment of an uplink TBF from the BSC. With EGPRS terminals, this has typically been done as two phase access on CCCH where the MS first requests an RLC block from the BSC and after it has been assigned, the MS provides information about its EGPRS capabilities. Based on that information, a Packet Data Channel, if available, is assigned for the TBF and the MS is instructed with attributes to be used in uplink transmission by BSC. By using EGPRS Packet Channel Request on CCCH the uplink TBF establishment can be speeded up substantially since one phase access is also available for an EGPRS MS. The MS provides information about its EGPRS capabilities already while requesting TBF establishment from the BSC. Based on this information the BSC can assign a Packet Data Channel for the TBF right away, if one is available. 56 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to EGPRS Benefits of the Nokia solution Fast uplink TBF establisment for EGPRS terminals on CCCH. 5.3 Incremental Redundancy Incremental Redundancy (IR) is an efficient combination of two techniques: . Automatic Repeat reQuest (ARQ) Forward Error Correction (FEC). . The ARQ method means that if the receiver detects the presence of errors in a received RLC block, it requests and receives a re-transmission of the same RLC block from the transmitter. The process continues until an uncorrupted copy reaches the destination. The FEC method adds redundant information to the re-transmitted information at the transmitter, and the receiver uses the information to correct errors caused by disturbances in the radio channel. IR needs no information about link quality in order to protect the transmitted data. Thus, the benefits of IR include increased throughput due to automatic adaptation to varying channel conditions, and reduced sensitivity to link quality measurements. Incremental Redundancy scheme In the IR scheme (also known as Type II Hybrid ARQ scheme) is implemented using the nine EGPRS MCSs. Only a small amount of redundancy is sent first, which yields a high user throughput if the decoding is successful. However, if the decoding fails, a re-transmission takes place according to the ARQ method and the transmitter transmits a different set of FEC information from the same RLC block. These sets are called protection schemes. There can be either two (P1 and P2) or three (P1, P2 and P3) protection schemes in each of the nine MCSs. A data block is first protected with the P1 of a certain MCS. If the decoding fails, the received P1 is stored in the receiver's memory for future use and data block is re-transmitted using the P2 of the same MCS. If after P3 the data still cannot be recovered, P1 is sent again and combined with the stored P1, P2, and P3 schemes (reaching a protection level of about four times P1), and so on, until the data is recovered. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 57 (272) EDGE System Feature Description The IR scheme is illustrated in the figure Incremental Redundancy scheme. Since the combination includes more information than any individual transmission, the probability of correct reception is increased. IR co-operates with Link Adaptation (LA) that selects the amount of redundant information transmitted in each transmission. Data Block P1 One MCS P2 P3 Transmitter P1 P2 P3 1st transmission P1 Protection Level 1 1st re-transmission upon reception failure 2nd re-transmission upon reception failure No data recovered P1 Stored Combination: Protection Level x 2 P2 No data recovered Receiver P1 Stored Combination: Protection Level x 3 P2 Stored P3 Figure 16. Incremental Redundancy scheme 5.4 Link Adaptation for EGPRS The purpose of the Link Adaptation (LA) mechanism is to provide the highest throughput and lowest delay available by adapting the protection level of the transmitted information according to link quality. LA uses various measurements of the past link to predict the upcoming channel quality. 58 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to EGPRS The link adaptation algorithm works in cooperation with Incremental Redundancy (IR). While IR improves throughput by adapting the total amount of transmitted redundancy automatically to the radio channel conditions, LA selects the amount of redundancy individually for each transmission. This helps to reduce the number of retransmissions, and thus keeps the transfer delay reasonably low. Normally, LA adapts to path attenuation and slow fading but not fast fading. This corresponds to the "ideal LA" curves in link level simulations. Link Adaptation can be enabled and disabled with the parameter EGPRS link adaptation enabled (ELA). Other LA-related parameters include: . initial MCS for acknowledged mode (MCA) initial MCS for unacknowledged mode (MCU) maximum BLER in acknowledged mode (BLA) maximum BLER in unacknowledged mode (BLU) mean BEP offset 8PSK (MBP) mean BEP offset GMSK (MBG) enable answer to paging call on FACCH (EPF) . . . . . . For more information on radio network parameters, see BSS Radio Network Parameter Dictionary. Link quality measurements Enabling Link Adaptation requires accurate link quality measurements and a set of modulation and coding schemes (MCSs) with different degrees of protection. The efficient EGPRS measurements provide accurate predictions of the upcoming link quality in several propagation channels that have various speeds (for example, typical urban and rural areas and hilly terrain). The link adaptation algorithm is based on Bit Error Probability (BEP) measurements performed at the MS (downlink TBF) and the BTS (uplink TBF). In acknowledged mode, the algorithm is designed to optimise channel throughput in different radio conditions. In unacknowledged mode, the algorithm tries to keep below a specified Block Error Rate (BLER) limit. For more information, see 28 GPRS RX Level and Quality Report. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 59 (272) EDGE System Feature Description MCS selection LA selects the optimal MCS for each radio condition. The LA procedure is based on static MCS selection tables in the PCU. The MCS selection can be divided into four classes: 1. 2. 3. 4. initial MCS to be used when entering packet transfer mode modulation selection MCS selection for initial transmissions of each RLC block in ACK mode MCS to be used for re-transmissions. 5.5 Nokia Smart Radio Concept for EDGE The Nokia Smart Radio Concept (SRC) enhances the radio performance of the BTS in both EDGE and GSM modes and is an important software for gaining the maximum coverage for EDGE. Nokia SRC consists of the following uplink and downlink performance enhancement solutions: . 4-way uplink diversity reception (4UD) Sensitivity-optimised High Gain Mast Head Amplifier (UltraSite MHA) Interference Rejection Combining (IRC) If the BSS12 licensed application software Space Time Interference Rejection Combining (STIRC) is used, it replaces IRC. . . . Intelligent Downlink Diversity Transmission (IDD) The uplink (4UD, UltraSite MHA, IRC) and downlink (IDD) enhancement solutions can also be used independently, except for 4UD, which is used with IDD. The SRC concept, introduced in BSS10.5, is supported by the Nokia UltraSite BTS family. Nokia Flexi EDGE BTS supports Nokia SRC from EP2.0 onwards. Nokia SRC utilises auxiliary transceivers effectively for both UL and DL. 60 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to EGPRS The figure Nokia Smart Radio Concept for EDGE, one carrier per cell shows one carrier/cell configuration of Nokia Smart Radio Concept for EDGE with IDD and by-pass combination configuration and MHAs. TRX RF units Receive Multicoupler Dual Duplex Unit X-pol Antenna Duplexer TX RX main div M2xA RX1 DRX1 RX2 DRX2 RX DRX LNA MHA MHA Duplexer Duplexer TX RX main div LNA Figure 17. Nokia Smart Radio Concept for EDGE, one carrier per cell The figure Nokia Smart Radio Concept for EDGE, two carriers per cell with all SRC solutions shows an example of two carriers/cell configuration with IDD and 4-way Uplink Diversity in Nokia UltraSite EDGE BTS. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 61 (272) EDGE System Feature Description TRX RF units Receive Multicouplers Dual Duplex Units Antennas TX RX main div Duplexer M2xA RX1 DRX1 RX2 DRX2 RX DRX LNA MHA MHA MHA MHA Duplexer Duplexer TX RX TX RX main div main div LNA Duplexer M2xA RX1 DRX1 RX2 DRX2 RX DRX LNA Duplexer Duplexer TX RX main div LNA Figure 18. Nokia Smart Radio Concept for EDGE, two carriers per cell with all SRC solutions. Interference Rejection Combining with 4-way Uplink Diversity and High Gain MHA In Nokia SRC, the uplink performance (BTS reception) is enhanced with the combination of Interference Rejection Combining (IRC) via 4-way diversity reception of the BTS and sensitivity-optimised high-gain Nokia UltraSite Masthead Amplifiers (UltraSite MHA introduced already in BSS9). IRC can also be used together with 2-way diversity reception. IRC is an operating software product which eliminates correlated noise (interference) received by both antennas. If there is no correlated noise, then IRC behaves like normal Maximum Ratio Combining (MRC). The combining gain depends on the dominant interference ratio and angular spread of interference. 62 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to EGPRS In 4-way diversity reception, post detection Maximum Ratio Combining is then used for two IRC-combined signals. This method is ideal for a dual Xpolarised antenna concept, providing up to 3dB gain. The gain of 4UD comes from enhanced UL diversity performance as well as enhanced energy collection surface of the antenna system, providing capacity and coverage enhancements. An example for two pairs of X-polarised antennas is presented in the figure Two pairs of X-polarised antennas. Spacing: 0.5WL IRC MRC IRC Figure 19. Two pairs of X-polarised antennas The UltraSite High Gain MHA is especially designed to enhance the UltraSite BTS site performance by optimising a noise figure of the receiver chain including the antenna system and BTS receiver front end. Space Time Interference Rejection Combining Space Time Interference Rejection Combining (STIRC), introduced in BSS12, is an enhancement to Interference Rejection Combining (IRC). STIRC is an application software product, and requires a valid licence in the BSC. When STIRC is activated, it replaces Interference Rejection Combining (IRC) in all TRXs in the sector. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 63 (272) EDGE System Feature Description STIRC is an uplink receiver DSP software technology enhancement that gives improved uplink interference rejection performance, both adjacent channel and co-channel, to both traffic and signalling channels, when compared to the current IRC technology. All antenna configurations are supported. However, 4-way uplink diversity configurations provide the best performance. For more information on STIRC, see Space Time Interference Rejection Combining. Intelligent Downlink Diversity Intelligent Downlink Diversity (IDD) transmission is a hybrid antenna concept based on Delay Diversity. It increases the coverage area of cells by enhancing downlink radio performance and antenna diversity gain of the BTS. The Delay diversity mode of operation is displayed in figure Intelligent Downlink Diversity (IDD) concept (Delay diversity). For downlink IDD the required number of antennas is two, whereas a full SRC downlink/uplink solution requires four antennas. Currently deployed main and diversity antennas can be used. BTS TX 1 filter TX 1 TX 2 F-bus filter TX 2 TX1 main transmitter TX2 auxiliary, delayed, transmitter MS Abis Figure 20. Intelligent Downlink Diversity 64 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to EGPRS Delay Diversity (DD) The downlink DD improves the performance of a cellular system by transmitting through two antennas. The cell coverage area is extended by sending the same radio time slots or bursts, with a slight delay, simultaneously through two transmitters and antennas, regardless of the logical channel. One cell requires two antennas (or X-polarised antennas). To the BSC, the main and auxiliary TRXs appear as a single (logical) TRX, and the auxiliary TRX takes on all TRX configuration parameters and administration state as set by the BSC for the main TRX. BTS Main TX Delay & Random Phase MS Received Signal Delayed TX Figure 21. Intelligent Downlink Diversity (IDD) concept (Delay diversity) DD provides a good performance for all modulation schemes. Delay is optimized in terms of a combination of the requested logical channel and used modulation. IDD boosts downlink performance by up to 5 dB (a minimum of 3 dB) in all radio time slots, compared to a single transmission system. DD creates an artificial multi path propagation component, which can be resolved by all the legacy terminals, thus creating multi path diversity. The IDD method provides its best gain in low-correlated Rayleigh channels; therefore, phase hopping is used to change phasing between adjacent bursts, and, consequently, to decrease correlation between a main and auxiliary transmitter. Random or periodic phase hopping is used, according to modulation type and EGPRS coding rate used. The figure Nokia EDGE downlink diversity solution, one carrier per cell shows an example of the IDD solution. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 65 (272) EDGE System Feature Description In IDD, the downlink signal is split between transmitters of two TRXs. The delay is processed between the signals and random phase hopping is added. MS Baseband units EDGE TRX RX + TX RX DIV. + TX DIV. DVxx EDGE TRX Combined Uplink signal MHA MHA Downlink signal Figure 22. Nokia EDGE downlink diversity solution, one carrier per cell. The typical configurations in one Nokia UltraSite EDGE BTS cabinet are: . 1+1+1 with combiner by-pass. 2+2+2 with 4-way diversity. 6 TRXs per cell with Remote Tune Combiners for large coverage and high-capacity needs. . . In each case, an additional TRX is needed for transmitting. Related topics . EDGE Double Power TRX for Flexi EDGE BTS Activating and Testing BSS20870: Double Power TRX for Flexi EDGE BTS . . 66 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Software related to EGPRS 5.6 8 Phase Shift Keying While GSM uses only Gaussian Minimum Shift Keying (GMSK), EDGE uses both 8 Phase Shift Keying (8-PSK) and GMSK. 8-PSK is a linear, higher-order modulation. Introducing 8-PSK in addition to GMSK allows the data transmission rates to be tripled. An 8-PSK signal carries three bits per modulated symbol over the radio path, compared to a GMSK signal, which carries only one bit per symbol. Table 4. 8-PSK and GMSK comparison 8-PSK GMSK GMSK, 1 bit/sym 270.833 ksps 116 bits 23.2 kbit/s Modulation Symbol rate Payload/burst Gross rate/time slot 8-PSK, 3 bit/sym 270.833 ksps 346 bits 69.6 kbit/s Nokia uses standardized 3pi/8 offset rotation to reduce amplitude variations with 8-PSK modulation, as shown in the figure 8-PSK modulation scheme. The standard GSM carrier symbol rate (270.833 ksps) is the same as with 8-PSK. The burst lengths are the same as the existing GMSK Time Division Multiple Access (TDMA) structure, and the same 200 kHz nominal frequency spacing between carriers is used. (d(3k),d(3k+1),d(3k+2))= (0,0,0) (0,0,1) (0,1,0) (0,1,1) (1,1,1) (1,0,1) (1,0,0) (1,1,0) Figure 23. 8-PSK modulation scheme DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 67 (272) EDGE System Feature Description 68 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE 6 6.1 System impact of GPRS/EDGE System impact of GPRS The system impact of BSS09006: GPRS is specified in the sections below. For an overview, see GPRS. For implementation instructions, see Implementing GPRS overview. GPRS is an application software product and requires a valid licence in the BSC. 6.1.1 Requirements The following network elements and functions are required to implement GPRS: . Serving GPRS Support Nodes (SGSN) Gateway GPRS Support Nodes (GGSN) GPRS backbone Point-to-multipoint Service Centre (PTM SC) Lawful Interception Gateway (LIG) Charging Gateway (CG) Gb interface between the BSC and SGSN Packet Control Unit (PCU) GPRS-specific mobility management, where the location of the MS is handled separately by the SGSN and by the MSC/VLR even if some cooperation exists . . . . . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 69 (272) EDGE System Feature Description . the network management must be capable of handling the GPRSspecific elements new security features for the GPRS backbone a new ciphering algorithm a new radio interface (Um) for packet data traffic new MAP and GPRS-specific signalling. Additionally, coding schemes CS-3 & CS-4 require EDGE-capable TRXs (EDGE hardware and attached to EDAP) . . . . . For the full use of GPRS all these need to be taken into consideration. The radio interface and GPRS signalling are relevant to the functioning of the BSC. Software requirements Table 5. Required software Network element Software release required BSC Nokia Flexi EDGE BTSs Nokia UltraSite EDGE BTSs Nokia MetroSite EDGE BTSs Nokia Talk-family BTSs Nokia InSite BTSs MSC/HLR SGSN Nokia NetAct S13 EP2.0 CX6.0 CXM6.0 No requirements Not supported M14 SG7 OSS4.2 CD Set 1 Frequency band support The BSC supports GPRS on the following frequency bands: . GSM 800 PGSM 900 . 70 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . EGSM 900 GSM 1800 GSM 1900 . . 6.1.2 Restrictions . If Baseband hopping is employed in a BTS, radio timeslot 0 of any TRX in the BTS will not be used for GPRS. BTS testing cannot be executed on the packet control channel. Network operation mode III is not supported. In PCU1 Coding Scheme CS-1 is always used in unacknowledged RLC mode. In acknowledged RLC mode, the Link Adaptation algorithm uses both CS-1 and CS-2. In PCU2, because of CS-3 & CS-4 implementation, there is a new Link Adaptation algorithm that uses all the Coding Schemes in both unacknowledged and in acknowledged RLC mode. . . . . Paging reorganisation is not supported. The master and slave channels must be cross-connected in the same way; the EDAP and the TRXs tied to it shall use a single PCM line. If they use different PCM lines, transmission delay between the lines may differ. This may cause a timing difference with the result that synchronisation between the master and slave channels is not successful. GPRS territory can be defined to each BTS object separately. GPRS and EGPRS territories cannot both be defined to a BTS object at the same time. TRXs inside a BTS object must have common capabilities. An exception to this is that EDGE-capable and non-EDGE-capable TRXs can be configured to the same BTS object, if EGPRS or CS-3 & CS-4 is enabled in the BTS. In this case, GPRS must be disabled in the non-EDGE/non-CS–3 & CS–4-capable TRXs, and these TRXs cannot be attached to EDAP. An EDGE/CS–3 & CS–4-capable TRX has EDGE hardware and is added to EDAP. A non-EDGE/non-CS–3 & CS–4-capable TRX has no EDGE hardware or it is not added to EDAP. . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 71 (272) EDGE System Feature Description . To get BCCH recovery to work correctly, it is recommended that the operator takes the following conditions into account, when unlocked EDGE and non-EDGE-capable TRXs or unlocked CS–3 & CS–4 and non-CS–3 & CS–4-capable TRXs exist in the same EGPRS or CS-3 & CS-4 enabled BTS: . If a BCCH TRX is EDGE hardware-capable, added to EDAP, and it has the GTRX parameter set to Y, then all unlocked TRXs, which are added to EDAP, are EDGE hardware-capable, and have GTRX set to Y, should be marked Preferred BCCHs. . If a BCCH TRX is non EDGE/non-CS–3 & CS–4capable, and has the parameter GTRX set to N, then all non-EDGE/non-CS–3 & CS–4-capable unlocked TRXs, which have GTRX set to N, should be marked Preferred BCCHs. For information on restrictions when baseband hopping is used, see EDGE BTSs and hopping in System impact of EDGE in EDGE System Feature Description. . The BSS does not restrict the use of 8PSK modulation on TSL7 of the BCCH TRX, using the highest output power. The maximum output power is 2dB lower than with GMSK. This is fully compliant with 3GPP Rel 5. PCU1 does not support CS–3 & CS–4, Extended Dynamic Allocation (EDA), High Multislot Classes (HMC) or Dual Transfer Mode (DTM). For restrictions related to Dynamic Abis, see Dynamic Abis. . . 6.1.3 Impact on transmission No impact. 6.1.4 Impact on BSS performance OMU signalling No impact. TRX signalling No impact. 72 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE Impact on BSC units Table 6. BSC unit OMU MCMU BCSU PCU Impact of GPRS on BSC units Impact No impact No impact No impact The PCU controls the GPRS radio resources and acts as the key unit in the following procedures: . . . . . GPRS radio resource allocation and management GPRS radio connection establishment and management data transfer coding scheme selection PCU statistics. TCSM No impact Impact on BTS units No impact. 6.1.5 6.1.5.1 User interface BSC MMI The following command groups and MML commands are used to handle GPRS: . Base Station Controller Parameter Handling in BSC: EE GSM Timer and BSC Parameter Handling: EG Base Transceiver Station Handling in BSC: EQ Transceiver Handling: ER Power Control Parameter Handling: EU Gb Interface Handling: FX Licence and Feature Handling: W7 Parameter Handling: WO . . . . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 73 (272) EDGE System Feature Description For more information on the command groups and commands, see MML Commands under Reference/Commands in the PDF view. 6.1.5.2 BTS MMI GPRS cannot be managed with BTS MMl. 6.1.5.3 BSC parameters Base Transceiver Station parameters . GPRS non BCCH layer rxlev upper limit (GPU) GPRS non BCCH layer rxlev lower limit (GPL) direct GPRS access BTS (DIRE) max GPRS capacity (CMAX) GPRS rxlev access min (GRXP) GPRS MS txpwr max CCH (GTXP1) GPRS MS txpwr max CCH 1x00 (GTXP2) priority class (PRC) HCS threshold (HCS) RA reselect hysteresis (RRH) routing area code (RAC) GPRS enabled (GENA) network service entity identifier (NSEI) default GPRS capacity (CDEF) dedicated GPRS capacity (CDED) prefer BCCH frequency GPRS (BFG) transport type (TRAT) coding schemes CS3 and CS4 enabled (CS34) BTS downlink throughput factor for CS1-CS4 (TFD) (PCU2) BTS uplink throughput factor for CS1-CS4 (TFU) (PCU2) quality control GPRS DL RLC ack throughput threshold (QGDRT) . . . . . . . . . . . . . . . . . . . . 74 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . quality control GPRS UL RLC ack throughput threshold (QGURT) DL adaption probability threshold (DLA) UL adaption probability threshold (ULA) DL BLER crosspoint for CS selection no hop (DLB) UL BLER crosspoint for CS selection no hop (ULB) DL BLER crosspoint for CS selection hop (DLBH) UL BLER crosspoint for CS selection hop (ULBH) coding scheme no hop (COD) (PCU1) coding scheme hop (CODH) (PCU1) DL coding scheme in acknowledged mode (DCSA) (PCU2) UL coding scheme in acknowledged mode (UCSA) (PCU2) DL coding scheme in unacknowledged mode (DCSU) (PCU2) UL coding scheme in unacknowledged mode (UCSU) (PCU2) adaptive LA algorithm (ALA) (PCU2) EGPRS inactivity alarm weekdays (EAW) EGPRS inactivity alarm start time (EAS) EGPRS inactivity alarm end time (EAE) . . . . . . . . . . . . . . . . Adjacent Cell parameters . adjacent GPRS enabled (AGENA) HCS signal level threshold (HCS) GPRS temporary offset (GTEO) GPRS penalty time (GPET) . . . Gb Interface Handling parameters . data link connection identifier (DLCI) committed information rate (CIR) network service virtual connection identifier (NSVCI) network service virtual connection name (NAME) network service entity identifier (NSEI) . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 75 (272) EDGE System Feature Description . bearer channel identifier (BCI) bearer channel name (BCN) . Gb Interface Handling parameters (IP) . network service virtual connection identifier (NSVCI) network service virtual connection name (NAME) network service entity identifier (NSEI) BCSU logical index (BCSU) PCU logical index (PCU) local UDP port number (LPNBR) remote IP address (RIP) remote host name (RHOST) remote UDP port number (RPNBR) preconfigured SGSN IP endpoint (PRE) remote data weight (RDW) remote signalling weight (RSW) packet service entity identifier (PSEI) . . . . . . . . . . . . Power Control Handling parameters . binary representation ALPHA (ALPHA) binary representation TAU (GAMMA) idle mode signal strength filter period (IFP) transfer mode signal strength filter period (TFP) . . . TRX Handling parameters . GPRS enabled TRX (GTRX) dynamic abis pool ID (DAP) . Base Station Controller parameters . GPRS territory update guard time (GTUGT) maximum number of DL TBF (MNDL) . 76 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . maximum number of UL TBF (MNUL) CS TCH allocate RTSL0 (CTR) CS TCH allocation calculation (CTC) PFC unack BLER limit for SDU error ratio 1 (UBL1) (PCU2) PFC ack BLER limit for transfer delay 1 (ABL1) (PCU2) QC NCCR action trigger threshold (QCATN) (applicable if NCCR . . . . . is activated) . QC reallocation action trigger threshold (QCATR) free TSL for CS downgrade (CSD) free TSL for CS upgrade (CSU) EGPRS inactivity criteria (EGIC) events per hour for EGPRS inactivity alarm (IEPH) supervision period length for EGPRS inactivity alarm (SPL) mean BEP limit MS multislot pwr prof 0 with 2 UL TSL (BL02) mean BEP limit MS multislot pwr prof 0 with 3 UL TSL (BL03) mean BEP limit MS multislot pwr prof 0 with 4 UL TSL (BL04) mean BEP limit MS multislot pwr prof 1 with 2 UL TSL (BL12) mean BEP limit MS multislot pwr prof 1 with 3 UL TSL (BL13) mean BEP limit MS multislot pwr prof 1 with 4 UL TSL (BL14) mean BEP limit MS multislot pwr prof 2 with 3 UL TSL (BL23) mean BEP limit MS multislot pwr prof 2 with 4 UL TSL (BL24) RX quality limit MS multislot pwr prof 0 with 2 UL TSL (RL02) RX quality limit MS multislot pwr prof 0 with 3 UL TSL (RL03) RX quality limit MS multislot pwr prof 0 with 4 UL TSL (RL04) RX quality limit MS multislot pwr prof 1 with 2 UL TSL (RL12) RX quality limit MS multislot pwr prof 1 with 3 UL TSL (RL13) RX quality limit MS multislot pwr prof 1 with 4 UL TSL (RL14) RX quality limit MS multislot pwr prof 2 with 3 UL TSL (RL23) RX quality limit MS multislot pwr prof 2 with 4 UL TSL (RL24) . . . . . . . . . . . . . . . . . . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 77 (272) EDGE System Feature Description For more information on radio network parameters, see BSS Radio Network Parameter Dictionary. PAFILE parameters These parameters have no Q3 interface and are stored in PAFILE, not BSDATA: . DRX TIMER MAX MSC RELEASE SGSN RELEASE . . For more information on PAFILE parameters, see PAFILE Timer and Parameter List. PRFILE parameters The following parameters are related to Gb interface configuration and state management, the PCU, and the MAC and RLC protocols (Abis interface): . TNS_BLOCK TSNS_PROV TNS_RESET TNS_TEST TNS_ALIVE SNS_ADD_RETRIES SNS_CONFIG_RETRIES SNS_CHANGEWEIGHTS_RETRIES SNS_DELETE_RETRIES SNS_SIZE_RETRIES NS_BLOCK_RETRIES NS_UNBLOCK_RETRIES NS_ALIVE_RETRIES NS_RESET_RETRIES TGB_BLOCK . . . . . . . . . . . . . . 78 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . TGB_RESET TGB_SUSPEND BVC_BLOCK_RETRIES BVC_UNBLOCK_RETRIES BVC_RESET_RETRIES SUSPEND_RETRIES TGB_RESUME RESUME_RETRIES RAC_UPDATE_RETRIES TGB_RAC_UPDATE RAC_UPDATE_RETRIES FC_B_MAX_TSL FC_B_MAX_TSL_EGPRS FC_MS_B_MAX_DEF FC_MS_R_DEF FC_MS_R_MIN FC_R_DIF_TRG_LIMIT FC_R_TSL GPRS_DOWNLINK_PENALTY GPRS_DOWNLINK_THRESHOLD GPRS_UPLINK_PENALTY GPRS_UPLINK_THRESHOLD MEMORY_OUT_FLAG_SUM PRE_EMPTIVE_TRANSMISSIO TBF_LOAD_GUARD_THRSHLD TBF_SIGNAL_GRD_THRSHLD TERRIT_BALANCE_THRSHLD TERRIT_UPD_GTIME_GPRS UPLNK_RX_LEV_FRG_FACTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 79 (272) EDGE System Feature Description . DL_TBF_RELEASE_DELAY UL_TBF_RELEASE_DELAY UL_TBF_REL_DELAY_EXT UL_TBF_SCHED_RATE_EXT (PCU1) POLLING_INTERVAL (PCU2, replaces UL_TBF_SCHED_RATE_EXT) CHA_CONC_UL_FAVOR_DIR CHA_CONC_DL_FAVOR_DIR GPRS_UL_MUX_DEC_FACTOR (PCU2) BACKGROUND_ARP_1 BACKGROUND_ARP_2 BACKGROUND_ARP_3 . . . . . . . . . . The following parameters are related to alarm 0125 PCU PROCESSOR LOAD HIGH. . PCU_LOAD_NOTIF_LIMIT SUSPEND_PCU_LOAD_NOTIF . For more information on PRFILE parameters, see PRFILE and FIFILE Parameter List. 6.1.5.4 Alarms This section lists the main GPRS-related alarms. Keep in mind that several other alarms may also be generated with the use of GPRS. . 0125 PCU PROCESSOR LOAD HIGH 0136 PCU CONNECTIVITY EXCEEDED 2114 FR VIRTUAL CONNECTION FAILED 2115 FR USER LINK INTEGRITY VERIFICATION FAILED 2117 FR TRUNK FAILED 2188 FR ACCESS DATA UPDATING FAILED 2189 COMMUNICATION FAILURE BETWEEN FR TERMINAL AND FRCMAN 3019 NETWORK SERVICE ENTITY UNAVAILABLE . . . . . . . 80 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . 3020 NETWORK SERVICE VIRTUAL CONNECTION UNAVAILABLE 3021 NETWORK SERVICE VIRTUAL CONNECTION UNBLOCK PROCEDURE FAILED 3022 NETWORK SERVICE VIRTUAL CONNECTION BLOCK PROCEDURE FAILED 3023 NETWORK SERVICE VIRTUAL CONNECTION RESET PROCEDURE FAILED 3024 NETWORK SERVICE ENTITY CONFIGURATION MISMATCH 3025 NETWORK SERVICE VIRTUAL CONNECTION TEST PROCEDURE FAILED 3026 NETWORK SERVICE VIRTUAL CONNECTION PROTOCOL ERROR 3027 UPLINK CONGESTION ON THE NETWORK SERVICE VIRTUAL CONNECTION 3028 NETWORK SERVICE VIRTUAL CONNECTION IDENTIFIER UNKNOWN 3029 BSSGP VIRTUAL CONNECTION UNBLOCK PROCEDURE FAILED 3030 BSSGP VIRTUAL CONNECTION BLOCK PROCEDURE FAILED 3031 BSSGP VIRTUAL CONNECTION RESET PROCEDURE FAILED 3032 BSSGP VIRTUAL CONNECTION PROTOCOL ERROR 3033 UNKNOWN ROUTING AREA OR LOCATION AREA DURING PAGING 3068 EGPRS DYNAMIC ABIS POOL FAILURE 3073 FAULTY PCUPCM TIMESLOTS IN PCU 3164 PCU PROCESSOR OVERLOAD ALARM 3209 SUB NETWORK SERVICE SIZE PROCEDURE FAILED 3210 SUB NETWORK SERVICE CONFIGURATION PROCEDURE FAILED 3211 LAST REMOTE IP DATA ENDPOINT DELETED . . . . . . . . . . . . . . . . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 81 (272) EDGE System Feature Description . 3261 FAILURE IN UPDATING BSC SPECIFIC PARAMETERS TO PCU 3273 GPRS/EDGE TERRITORY FAILURE 3324 FAILURE IN UPDATING CONFIGURATION DATA TO PCU 7724 CONFLICT BETWEEN BSS RADIO NETWORK DATABASE AND CALL CONTROL 7725 TRAFFIC CHANNEL ACTIVATION FAILURE 7730 CONFIGURATION OF BCF FAILED 7738 BTS WITH NO TRANSACTIONS 7769 FAILURE IN UPDATING CELL SPECIFIC PARAMETERS TO PCU 7789 NO (E)GPRS TRANSACTIONS IN BTS . . . . . . . . For more information on alarms, see Notices (0-999), Failure Printouts (2000-3999) and Base Station Alarms (7000-7999). 6.1.5.5 Measurements and counters The following measurements are related to GPRS: . 72 Packet Control Unit Measurement 73 RLC Blocks per TRX Measurement 74 Frame Relay Measurement 76 Dynamic Abis Measurement . For counters of 76 Dynamic Abis Measurement, see System impact of Dynamic Abis. 79 Coding Scheme Measurement 90 Quality of Service Measurement 95 GPRS Cell Re-selection Measurement . For counters of 95 GPRS Cell Re-selection Measurement, see System impact of Network Controlled Re-selection. 96 GPRS RX Level and Quality Measurement 98 Gb Over IP Measurement . For counters of 98 Gb over IP Measurement, see System impact of Gb over IP. 105 PS DTM Measurement . . . . . . . . . 82 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . For counters of 105 PS DTM Measurement, see System impact of Dual Transfer Mode. . 106 CS DTM Measurement . For counters of 106 CS DTM Measurement, see System impact of Dual Transfer Mode. 110 PCU Utilization Measurement . 72 Packet Control Unit Measurement Table 7. Name Counters of Packet Control Unit Measurement related to GPRS Number 072062 072063 072064 072065 072068 072069 072070 072071 072173 072174 072195 072196 072222 072223 072224 072225 072226 072227 072229 RLC DATA BLOCKS UL CS1 RLC DATA BLOCKS DL CS1 RLC DATA BLOCKS UL CS2 RLC DATA BLOCKS DL CS2 RETRA RLC DATA BLOCKS DL CS1 RETRA RLC DATA BLOCKS DL CS2 BAD FRAME IND UL CS1 BAD FRAME IND UL CS2 RETRA DATA BLOCKS UL CS1 RETRA DATA BLOCKS UL CS2 WEIGHTED DL TSL ALLOC GPRS NUMERATOR WEIGHTED DL TSL ALLOC GPRS DENOMINATOR RLC RETRANSMITTED DL CS1 DUE OTHER THAN NACK RLC RETRANSMITTED DL CS2 DUE OTHER THAN NACK DL CS1 DATA FOR DUMMY LLC IGNORED RLC DATA BLOCKS UL DUE TO BSN CS1 IGNORED RLC DATA BLOCKS UL DUE TO BSN CS2 1-PHASE UL GPRS TBF ESTABLISHMENT REQUESTS 1-PHASE UL GPRS TBF SUCCESSFUL ESTABLISHMENTS For more information, see 72 Packet Control Unit Measurement. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 83 (272) EDGE System Feature Description 73 RLC Blocks per TRX Measurement Table 8. Name Counters of RLC Blocks per TRX Measurement Number 073000 073001 073002 073003 UR DL RLC MAC BLOCKS RETRANS DL RLC MAC BLOCKS SCHED UNUSED RADIO BLOCKS DL RLC MAC BLOCKS For more information, see 73 RLC Blocks per TRX Measurement. 74 Frame Relay Measurement Table 9. Name Counters of Frame Relay Measurement Number 074000 074001 074002 074003 074004 074005 074006 074007 074008 074009 074010 074011 074012 074013 074014 074015 074016 074017 074018 FRMS WRONG CHECK SEQ ERR FRMS WRONG DLCI OTHER FRAME ERROR T391 TIMEOUT STAT MSG WRONG SEND SEQ NBR STAT MSG WRONG REC SEQ NBR BEAR CHANGED UNOPER BEAR RET OPER STAT MSG UNKNOWN PVC STAT MSG SENT TOO OFTEN TIME BEAR UNOPERATIONAL DLCI 1 ID DLCI 1 SENT FRMS DLCI 1 KBYTES SENT DLCI 1 REC FRMS DLCI 1 KBYTES REC FRMS DLCI 1 DISC SENT FRMS DLCI 1 BYTES DISC SENT FRMS DLCI 1 DISC REC FRMS 84 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE Table 9. Name Counters of Frame Relay Measurement (cont.) Number 074019 074020 074021 074022 074059 074060 074061 074062 074063 074064 074065 074066 074067 074068 074069 074070 DLCI 1 BYTES DISC REC FRMS DLCI 1 STAT ACT TO INACT DLCI 1 INACTIVITY TIME DLCI 1 DISC UL NS UDATA DLCI 5 ID DLCI 5 SENT FRMS DLCI 5 KBYTES SENT DLCI 5 REC FRMS DLCI 5 KBYTES REC FRMS DLCI 5 DISC SENT FRMS DLCI 5 BYTES DISC SENT FRMS DLCI 5 DISC REC FRMS DLCI 5 BYTES DISC REC FRMS DLCI 5 STAT ACT TO INACT DLCI 5 INACTIVITY TIME DLCI 5 DISC UL NS UDATA For more information, see 74 Frame Relay Measurement. 79 Coding Scheme Measurement Table 10. Name Counters of Coding Scheme Measurement Number 079000 079001 079002 079003 079004 NUMBER OF DL RLC BLOCKS IN ACKNOWLEDGED MODE NUMBER OF DL RLC BLOCKS IN UNACKNOWLEDGED MODE NUMBER OF UL RLC BLOCKS IN ACKNOWLEDGED MODE NUMBER OF UL RLC BLOCKS IN UNACKNOWLEDGED MODE NUMBER OF BAD RLC DATA BLOCKS WITH VALID HEADER UL UNACK MODE DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 85 (272) EDGE System Feature Description Table 10. Name Counters of Coding Scheme Measurement (cont.) Number 079005 079006 079007 079008 079009 NUMBER OF BAD RLC DATA BLOCKS WITH BAD HEADER UL UNACK MODE NUMBER OF BAD RLC DATA BLOCKS WITH VALID HEADER UL ACK MODE NUMBER OF BAD RLC DATA BLOCKS WITH BAD HEADER UL ACK MODE RETRANSMITTED RLC DATA BLOCKS UL RETRANSMITTED RLC DATA BLOCKS DL For more information, see 79 Coding Scheme Measurement. 90 Quality of Service Measurement Table 11. Name Counters of Quality of Service Measurement related to GPRS Number 090000 090001 090002 090003 090004 090005 090006 090007 090008 NUMBER OF TBF ALLOCATIONS TOTAL NBR OF RLC BLOCKS TOTAL DURATION OF TBFS DROPPED DL LLC PDUS DUE TO OVERFLOW DROPPED DL LLC PDUS DUE TO LIFETIME EXPIRY AVERAGE MS SPECIFIC BSSGP FLOW RATE AVERAGE MS SPECIFIC BSSGP FLOW RATE DEN VWTHR NUMERATOR GPRS VWTHR DENOMINATOR GPRS For more information, see 90 Quality of Service Measurement. 96 GPRS RX Level and Quality Measurement Table 12. Counters of GPRS RX Level and Quality Measurement 096000 096001 096002 RXL UP BOUND CLASS 0 RXL UP BOUND CLASS 1 RXL UP BOUND CLASS 2 86 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE Table 12. Counters of GPRS RX Level and Quality Measurement (cont.) 096003 096004 096005 096012 096013 096020 096021 096028 096029 096036 096037 096044 096045 096052 096053 096060 096061 096068 096069 096076 096077 096084 096085 096092 096093 096100 RXL UP BOUND CLASS 3 RXL UP BOUND CLASS 4 UL SAMPLES WITH RXL 0 RXQ 0 UL SAMPLES WITH RXL 0 RXQ 7 UL SAMPLES WITH RXL 1 RXQ 0 UL SAMPLES WITH RXL 1 RXQ 7 UL SAMPLES WITH RXL 2 RXQ 0 UL SAMPLES WITH RXL 2 RXQ 7 UL SAMPLES WITH RXL 3 RXQ 0 UL SAMPLES WITH RXL 3 RXQ 7 UL SAMPLES WITH RXL 4 RXQ 0 UL SAMPLES WITH RXL 4 RXQ 7 UL SAMPLES WITH RXL 5 RXQ 0 UL SAMPLES WITH RXL 5 RXQ 7 DL SAMPLES WITH RXL 0 RXQ 0 DL SAMPLES WITH RXL 0 RXQ 7 DL SAMPLES WITH RXL 1 RXQ 0 DL SAMPLES WITH RXL 1 RXQ 7 DL SAMPLES WITH RXL 2 RXQ 0 DL SAMPLES WITH RXL 2 RXQ 7 DL SAMPLES WITH RXL 3 RXQ 0 DL SAMPLES WITH RXL 3 RXQ 7 DL SAMPLES WITH RXL 4 RXQ 0 DL SAMPLES WITH RXL 4 RXQ 7 DL SAMPLES WITH RXL 5 RXQ 0 DL SAMPLES WITH RXL 5 RXQ 7 For more information, see 96 GPRS RX Level and Quality Measurement. 110 PCU Utilization Measurement Table 13. Counters of PCU Utilization Measurement 110000 PEAK RESERVED PCUPCM CHANNELS DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 87 (272) EDGE System Feature Description Table 13. Counters of PCU Utilization Measurement (cont.) 110001 110002 PEAK OCCUPIED PDTCH UL PEAK OCCUPIED PDTCH DL For more information, see 110 PCU Utilization Measurement. 6.1.6 Impact on Network Switching Subsystem (NSS) No impact. 6.1.7 Impact on NetAct products NetAct Reporter NetAct reporter can be used to view reports from measurements related to GPRS. For a list of the measurements, see Measurements and counters. NetAct Monitor NetAct Monitor can be used to monitor all alarms related to GPRS. For a list of the alarms, see Alarms. NetAct Tracing Nokia NetAct Tracing supports GPRS-capable Nokia network elements in OSS3.1 ED2. Data Tracing must be supported by the BSS and the Packet Core Network. NetAct Administrator Standard Nokia NetAct Administration applications, such as Network Editor, Time Management, User Group Profiles, Authority Manager, and Service Access Control are used to administer GPRS. NetAct Optimizer No impact. NetAct Planner GPRS has no direct impact on NetAct Planner. However, GPRS can be taken into consideration when network traffic is planned and simulated with NetAct Planner. 88 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE NetAct Radio Access Configurator (RAC) NetAct Radio Access Configurator (RAC) can be used to configure the radio network parameters related to GPRS. For more information, see BSS RNW Parameters and Implementing Parameter Plans in Nokia NetAct Product Documentation. For a list of the radio network parameters, see BSC parameters. 6.1.8 Impact on mobile terminals GPRS-capable mobile terminals are required. GPRS defines three classes of mobile terminals: . Class A terminals support simultaneous circuit-switched (CS) and packet-switched (PS) traffic. Class B terminals attach to the network as both CS and PS clients but only support traffic from one service at a time. Class C terminals may support both CS and PS services. . . With Class C terminals, users must manually select either CS or PS mode, or the terminals can be set up to accept data only. Class C terminals cannot accept paging from both CS and PS at the same time. However, Class B terminals can accept paging of any type when in idle mode. 6.1.9 Impact on interfaces Impact on radio interface No impact. Impact on Abis interface . Dynamic Abis Dynamic Abis pools need to be configured for GPRS if CS-3 & CS-4 is in use. . GPRS messages The Abis interface supports GPRS messages. Impact on A interface No impact. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 89 (272) EDGE System Feature Description Impact on Gb interface Nokia BSC supports the Gb interface (BSC-SGSN) as specified in GSM Recommendations (3GPP): . 3GPP TS 48.018, General Packet Radio Service (GPRS); Base Station System (BSS) - Serving GPRS Support Node (SGSN); BSS GPRS Protocol (BSSGP) 3GPP TS 48.016, General Packet Radio Service (GPRS); Base Station System (BSS) - Serving GPRS Support Node (SGSN) interface; Network Service . Impact on Gs interface Nokia SGSN and MSC support the Gs interface (SGSN-MSC/VLR) although it is specified as optional by 3GPP. The advantages of Gs interface include: . support for TIA/EIA-136 networks by offering a connection for the tunneling of non-GSM signalling messages via the GPRS network to a non-GSM MSC/VLR. more effective radio resource usage with combined GPRS/IMSI attach/detach and combined RA/LA updates, that is, reduced signalling over the radio interface. the possibility to page GPRS terminals for circuit-switched services (for example circuit-switched calls) via GPRS. . . 6.1.10 Interworking with other features The implementation of GPRS causes changes to the following existing functions of the BSC: . the PCU plug-in unit is introduced in Hardware Configuration Management GPRS-related radio network parameters are introduced in Radio Network Configuration Management co-operation between circuit-switched traffic and GPRS traffic is defined in Radio Channel Allocation GPRS traffic is monitored with GPRS-specific measurements and counters the serving PCU must be the same for all TRXs under one segment. . . . . 90 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE For more information on the implementation procedure, see: . Implementing GPRS overview Radio network management for GPRS in BSC Gb interface configuration and state management Radio resource management GPRS radio connection control . . . . The GPRS related measurements are introduced in section Measurements and counters. Circuit-switched traffic In the BSC the introduction of GPRS means dividing the radio resources (circuit-switched and GPRS traffic) into two territories. This has an effect on the radio channel allocation features in which the BSC makes decisions based on the load of traffic. For some features only the resources of the circuit-switched territory are included in the decisions. However, for most features also the traffic channels in the GPRS territory need to be taken into consideration when the BSC defines the traffic load, because radio timeslots (RTSL) in the GPRS territory may be allocated for circuitswitched traffic if necessary. Only if there are radio timeslots that are permanently reserved for GPRS use (dedicated GPRS resources), these cannot be used for circuit-switched calls and the BSC excludes these in its decisions on traffic load. Frequency Hopping In Baseband hopping, radio timeslot 0 belongs to a different hopping group than the other radio timeslots of a TRX. This makes radio timeslot 0 unusable for multislot connections. If Baseband hopping is employed in a BTS, radio timeslot 0 of any TRX in the BTS is not used for GPRS. Optimisation of MS Power Level The BSC attempts to allocate traffic channels within the circuit-switched territory according to the interference level recommendation the BSC has calculated, to allow the performing of optimisation of the MS power level. When the BSC has to allocate a traffic channel for a circuit-switched request in the GPRS territory, the interference level recommendation is no longer the guiding factor. Now, the first GPRS radio timeslot next to the territory border is taken regardless of whether its interference level is among the recommended ones or not. For more information on the division of territories, see section Radio resource management. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 91 (272) EDGE System Feature Description Intelligent Underlay-Overlay, Enhanced Coverage by Frequency Hopping, Handover Support for Coverage Enhancements Super-reuse TRX frequencies are not supported for GPRS. Dynamic SDCCH allocation The BSC selects a traffic channel timeslot to be reconfigured as a dynamic SDCCH timeslot always within the circuit-switched territory. TRX prioritisation in TCH allocation The operator can set the BCCH TRX or the non-BCCH TRXs as preferred TRX for the GPRS territory with the parameter prefer BCCH frequency GPRS (BFG). If no preference is indicated, no prioritisation is used between the different TRX types when the GPRS territory is formed. Trunk Reservation In trunk reservation, the BSC defines the number of idle traffic channels. The BSC adds together the number of idle traffic channels in the circuitswitched territory and the number of traffic channels in the radio timeslots of the GPRS territory. The traffic channels in the radio timeslots that the BSC has allocated permanently for GPRS, are excluded. TRX fault When a TRX carrying traffic channels becomes faulty, the radio timeslots on the TRX are blocked from use. The BSC releases the ongoing calls and the call control resources. The BSC downgrades the traffic channels belonging to the GPRS territory in the faulty TRX from GPRS use. To replace the lost GPRS capacity, the BSC determines the possibility of a GPRS territory upgrade in another TRX. For more information on GPRS territory upgrades and downgrades, see section Radio resource management. If the faulty TRX functionality is reconfigured to another TRX in the cell, the value of the GPRS enabled TRX (GTRX) parameter is also transferred to the new TRX. If the faulty TRX is EDGE-capable, and GPRS in enabled in the TRX and CS-3 & CS-4 or EGPRS is enabled in the BTS, the system tries to reconfigure its functionality to another EDGE-capable TRX in the BTS. 92 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE Resource indication to MSC In general, the BSC’s indication on the resources concerns traffic channels of a BTS excluding those allocated permanently to GPRS (dedicated GPRS channels). GPRS territory resources other than the dedicated ones are regarded as working and idle resources. Half Rate Permanent type half rate timeslots are not used for GPRS traffic. Therefore, it is recommended not to configure permanent half rate timeslots in TRXs that are planned to be used for GPRS. When the BSC can select the channel rate (full rate or half rate) to be used for a circuit-switched call based on the traffic load of the target BTS, the load limits used in the procedure are calculated using the operator defined BSC and BTS parameters lower limit for HR TCH resources (HRL), upper limit for HR TCH resources (HRU), lower limit for FR TCH resources (FRL), and upper limit for FR TCH resources (FRU) . The BSC parameter CS TCH allocation calculation (CTC) defines how the GPRS territory is seen when the load limits are calculated. Depending on the value of CTC either only CS territory or both CS and GPRS territories (excluding the dedicated GPRS timeslots) are used to calculate the load limits. Additionally, with the CTC parameter the user can define whether the resources in GPRS territory are seen as idle resources or as occupied resources. High Speed circuit-switched Data (HSCSD) If GPRS has been enabled in a BTS, the HSCSD-related load limits are calculated based on the existing HSCSD parameters and the following rules: . the number of working resources includes all the working full rate traffic channel (TCH/F) resources of a BTS, excluding the ones that have been allocated permanently to GPRS the number of occupied TCH/F resources includes all the occupied TCH/Fs of the circuit-switched territory, as well as the default GPRS territory TCH/Fs, excluding the GPRS radio timeslots defined as dedicated HSCSD parameter HSCSD cell load upper limit (HCU) is replaced with the radio network GPRS parameter free TSL for CS downgrade (CSD) if the latter is more restricting; thus the one that limits HSCSD traffic earlier is used. . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 93 (272) EDGE System Feature Description The parameter free TSL for CS downgrade (CSD) defines a margin of radio timeslots that the BSC tries to keep idle for circuit-switched traffic by downgrading the GPRS territory when necessary. If HSCSD multislot allocation is denied based on the appropriate parameters, the BSC rejects the transparent HSCSD requests and serves the non-transparent HSCSD requests with one timeslot. If the timeslot share in HSCSD allocation is not restricted, the transparent requests are served preferably in the circuit-switched territory, and only if necessary in the GPRS territory. If a transparent HSCSD call ends up in the GPRS territory, the BSC does not try to move it elsewhere with an intra cell handover. Instead, it tries to replace the lost GPRS capacity by extending the GPRS territory on the circuit-switched side of the territory border. When the transparent HSCSD call inside the GPRS territory is later released, the BSC returns the released radio timeslots back to GPRS use to keep the GPRS territory continuous and undivided. For more information on how the resources form the territories, see section Radio resource management. The non-transparent HSCSD requests are always served in the circuitswitched territory as long as there is at least one TCH/F available. A normal HSCSD upgrade procedure is applied later to fulfill the need of the non-transparent request, if the call starts with less channels than needed and allowed. In order for the non-transparent call to get the needed number of timeslots, the BSC starts an intra cell handover for suitable single slot calls beside the non-transparent HSCSD call. At the start of the handover, the BSC checks that a single slot call can be moved to another radio timeslot and that an HSCSD upgrade is generally allowed. A non-transparent HSCSD call enters the GPRS territory only if there is congestion in the circuit-switched territory. If multislot allocation was originally defined as allowed, it is also applied within the GPRS territory to serve the non-transparent request. If the BTS load later decreases, enabling a GPRS territory upgrade, the non-transparent HSCSD call is handed over to another location in the BTS so that the GPRS territory can be extended. When deciding whether to downgrade an HSCSD call or the GPRS territory, the BSC checks first if the margin of idle resources defined by the parameter free TSL for CS downgrade (CSD) exists. If a sufficient margin exists, the BSC acts as without GPRS, that is, using the state information 94 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE that the HSCSD parameters define for the BTS, the BSC performs an HSCSD downgrade if necessary. If the number of idle resources is below the parameter free TSL for CS downgrade (CSD), the actions proceed as follows: . if there are GPRS radio timeslots that are above and beyond the operator defined default GPRS territory then these additional GPRS radio timeslots are the first target for the GPRS territory downgrade if there are no additional GPRS radio timeslots, the BSC examines if there are more HSCSD traffic channels than the parameter HSCSD TCH capacity minimum (HTM) requires and if so, executes an HSCSD downgrade if the minimum HSCSD capacity is not in use, a GPRS territory downgrade is made to maintain the margin defined by the parameter free TSL for CS downgrade (CSD). . . As a TCH/F becomes free through a channel release, the BSC first examines the need and possibility for an HSCSD upgrade. If the BSC starts no HSCSD upgrade, it further checks the need and possibility for a GPRS upgrade. The GPRS territory can be upgraded although the parameter HSCSD TCH capacity minimum (HTM) is not in use and there are pending HSCSD connections in the cell. The parameter free TSL for CS upgrade (CSU) and the margin it defines is the limiting factor for a GPRS territory upgrade. Parameter free TSL for CS upgrade (CSU) defines the number of radio timeslots that have to remain idle in the circuit-switched territory after the planned GPRS territory upgrade has been performed. For more information on GPRS territories, see section Radio resource management, and for more information on HSCSD, see HSCSD and 14.4 kbit/s Data Services in BSC. Radio Network Supervision Actions of the radio network supervision do not apply for timeslots that have been included in the GPRS territory. The only reasonable thing to monitor is the uplink interference on timeslots in GPRS use. Radio Network Supervision does not apply to the packet control channel. BTS testing BTS testing cannot be executed on the packet control channel. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 95 (272) EDGE System Feature Description Multi BCF Control, Common BCCH Control Multi BCF introduces a radio network object called the segment. Several BTS objects can belong to one segment. Only one BTS object of the segment can have a BCCH. The segment can have BTS objects, which differ in: . frequency band (GSM800, PGSM900, EGSM900, GSM1800, and GSM1900) power levels (Talk-family and UltraSite base stations) regular and super-reuse frequencies EDGE capability. . . . TRXs inside a BTS object must have common capabilities. An exception to this is that EDGE-capable and non-EDGE-capable TRXs can be configured to the same BTS object. When EGPRS or CS-3 & CS-4 is enabled in the BTS, there exist some restrictions related to TRX configuration. For more information, see section Resrictions. PS territory can be defined to each BTS object separately. GPRS and EGPRS territories cannot both be defined to a BTS object at the same time. Superreuse frequencies are not supported in GPRS. For information on restrictions when baseband hopping is used, see EDGE BTSs and hopping in System impact of EDGE in EDGE System Feature Description. There is only one BCCH /CCCH in one segment. You must define GPRS territory to the BCCH frequency band in a Common BCCH cell in which more than one frequency band is in use. Otherwise GPRS does not work properly in the cell. The reason for this requirement is that in cases when the MS RAC of the GPRS mobile is not known by the BSC, the temporary block flow (TBF) must be allocated on the BCCH frequency band first. During the first TBF allocation, the GPRS mobile indicates its frequency capability to the BSC. After that, other frequency bands of the cell can be used for the GPRS mobile accordingly. GPRS territory must be configured into the BCCH BTS of a segment with two or more BTSs on the BCCH band if BTS(s) containing GPRS channels are hopping. 96 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE This is because hopping frequency parameters are encoded to the IMMEDIATE ASSIGNMENT message on CCCH with indirect encoding. When the allocated BTS is hopping, indirect encoding can only refer to the SYSTEM INFORMATION TYPE 13 message, which in the Nokia BSS contains GPRS Mobile Allocation only for the BCCH BTS. The limitation to use only indirect encoding with hopping frequency parameters in IMMEDIATE ASSIGNMENT comes from the fact that IMMEDIATE ASSIGNMENT message segmentation is not supported in the Nokia BSS. The other two possible hopping frequency encodings, direct 1 and 2, might use a large number of octets for the frequency hopping. Large sized frequency parameters cause control message segmentation. Thus as IMMEDIATE ASSIGNMENT segmentation is not supported, direct 1 and 2 encoding cannot be used. Therefore, in a segment where BCCH band GPRS channels are on hopping BTS(s), the TBFs must initially be allocated to the BCCH BTS. Later, the TBFs may be reallocated to other BTSs as well. See Common BCCH Control in BSC and Multi BCF Control in BSC for more information on Multi BCF and Common BCCH. Dual Transfer Mode GPRS must be available and active in the network for Dual Transfer Mode (DTM) to work. The BSC supports DTM data transfer in both GPRS and EGPRS modes. If GPRS is deactivated when DTM is in use, the MSs that have an active DTM connection keep their CS connection but lose their TBFs. A DTM TBF is established in EGPRS mode if the MS is EGPRS capable and if the DTM call is allocated from an EGPRS-capable PS territory. If not, the DTM TBF is established in GPRS mode. For more information on DTM, see Dual Transfer Mode. EGSM 900 - PGSM 900 BTS When the BCCH is on PGSM 900 frequency band in the PGSM-EGSM BTS and RF hopping is used, GPRS has to be disabled in the RF hopping TRXs. Set the GPRS enabled TRX (GTRX) parameter of the RF hopping TRXs to value 'N'. The following restrictions apply when there are EGSM 900 and PGSM 900 frequencies in the BTS and GPRS/EDGE Support for PGSM-EGSM BTS is not used: DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 97 (272) EDGE System Feature Description . When BCCH is on EGSM 900 frequency band and there is a TRX on PGSM 900 frequency band in the BTS, GPRS/EDGE cannot be used in the PGSM 900 TRXs in the BTS. Set the GPRS enabled TRX (GTRX) parameter of the PGSM 900 TRXs to value 'N'. When BCCH is on PGSM 900 frequency band and there is a TRX on EGSM 900 frequency band in the BTS, GPRS/EDGE cannot be used in the EGSM 900 TRXs in the BTS. Set the GPRS enabled TRX (GTRX) parameter of the EGSM 900 TRXs to value 'N'. . Extended Cell Range GPRS/EDGE cannot be used in Extended TRXs (E-TRX) without extended cell GPRS/EDGE channels (EGTCH). Extended Cell for GPRS/EDGE With GPRS/EDGE and Extended Cell for GPRS/EDGE application software products GPRS/EDGE traffic can be used in EGTCH channels of Extended TRXs (E-TRX). EGTCHs constitutes of fixed PS channels and they cannot be used for CS traffic. 6.2 System impact of EDGE The system impact of BSS10091: EDGE is specified in the sections below. For an overview, see EDGE. For implementation instructions, see Implementing EGPRS overview. EDGE is an application software product and requires a valid licence in the BSC. 6.2.1 Requirements Hardware requirements The following network elements are required to implement EDGE: . Nokia MetroSite EDGE BTS, Nokia UltraSite EDGE BTS or Nokia Flexi EDGE BTS. Nokia Talk-family BTS site can be upgraded to support Nokia EDGE with the installation of a Nokia UltraSite EDGE BTS (housing Nokia EDGE-capable TRXs) on site as an extension cabinet. Site compatibility is achieved with the synchronisation of Nokia Talk- 98 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE family BTS and Nokia UltraSite EDGE BTS and by using existing antenna and feeding structures. The synchronised BTSs share a single BCCH (per sector) and function in the network as a single cell. The site is then seen as one object by NetAct and the BSC (Multi BCF control). In this configuration, the Nokia Talk-family TRXs support voice, circuit-switched data, HSCSD, and GPRS. . EDGE-capable TRXs Packet Control Unit (PCU1/PCU2) . EGPRS can be implemented in the BSC with S9 level GPRS PCUs. . The maximum amount of PCUs differ between the BSC generations. For more information on PCU, see Packet Control Unit (PCU). Additional or optional hardware for GPRS/EDGE needed by BSCi and BSC2i . optional fourth SW64B plug-in unit and SWBUS4 connector to the bit group switch (GSWB) The PCU requires the GSWB extension (2 per BSC) for multiplexing the 256 Abis sub-timeslots into it. The second PCU card for the BSC unit requires an extension of the GSWB with a fourth SW64B plug-in unit. . ET5C cartridge (optional) Additional ET5C cartridges are optional as they are not needed for GPRS. However, they are needed to increase the PCMs from 80 to 112. In the S8 optional upgrade to High Capacity BSC they have been added. . AS7-X, adapter for CCS7 signalling (replaces AS7-V and AS7VA in new deliveries) . . Software requirements Table 14. Required software Network element Software release required BSC Nokia Flexi EDGE BTSs Nokia UltraSite EDGE BTSs Nokia MetroSite EDGE BTSs S13 EP2 CX6.0 CXM6.0 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 99 (272) EDGE System Feature Description Table 14. Required software (cont.) Network element Software release required Nokia Talk-family BTSs Nokia InSite BTSs MSC/HLR SGSN Nokia NetAct Not supported Not supported M14 SG7 OSS4.2 CD Set 1 Frequency band support The BSC supports Nokia EDGE on the following frequency bands: . GSM 800 GSM 900 GSM 1800 GSM 1900 . . . 6.2.1.1 EDGE BTSs and hopping It is possible to have non-EDGE and EDGE TRXs under the same BTS object if RF Hopping or No Hopping is used. BTS object is an object in the BSC that corresponds to a set of TRXs in a single BTS cabinet, which cover the same geographical area, use the same frequency band, and (normally) have the same output power. A BTS object may contain one to 12 TRXs and one segment may contain one or more BTS objects. For non-EDGE and EDGE TRXs within a BB Hopping BTS object, see Tables Compatible TRXs, 'GMSK TRX' hopping and Compatible TRXs, 'EDGE TRX' hopping. Nokia EDGE-capable TRXs for Nokia MetroSite EDGE BTS and Nokia UltraSite EDGE BTS are compatible with GSM TRXs. In addition to providing Nokia EDGE services, Nokia EDGE TRXs are fully GSM compatible and support GSM voice, data, HSCSD, GPRS, and EGPRS. They are also backward compatible with all legacy GSM mobiles. All Nokia Flexi EDGE TRXs are EDGE and GSM capable. 100 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE BTS hopping modes The different TRX hopping modes are: . No hopping . TRX RF units Tx/Rx on fixed frequency . radio channel to MS is fixed frequency BB hopping . TRX RF units Tx/Rx on fixed frequency . radio channel to MS Tx/Rx is via different TRX RF units RF hopping . TRX RF unit Tx/Rx is on different frequencies . radio channel to MS is from the same (hopping) RF unit Antenna hopping . TRX RF unit Tx/Rx is on different frequencies . radio channel to MS Tx/Rx is via different TRX RF units . [to give antenna diversity on the link from BTS to MS] . note that Antenna hopping requires an EDGE TRX . . . UltraSite TRX units . UltraSite GMSK RF units are: 'TSxA' UltraSite EDGE RF units are: 'TSxB' . Where x is the letter (T, G, D, P) which identifies the frequency band (800, 900, 1800, 1900 MHz). . UltraSite GMSK BB unit is: BB2A UltraSite EDGE BB units are: BB2E, BB2F . The TSxB EDGE RF unit always requires an EDGE-capable baseband unit, BB2E or BB2F, even if it works in GSM mode only. The EDGE-capable baseband unit, BB2E or BB2F, is backward compatible and also supports the GSM RF unit, TSxA. Table UltraSite TRX units shows the compatibility matrix for all the different BB2x and TSxx combinations. EGPRS support requires both EDGE-capable baseband unit, BB2E or BB2F and EDGE-capable RF unit, TSxB. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 101 (272) EDGE System Feature Description Table 15. Units UltraSite TRX units Compatible OK NOK OK OK OK OK Modes of operation GMSK GMSK GMSK, EDGE GMSK GMSK, EDGE BB2A + TSxA BB2A + TSxB BB2E + TSxA BB2E + TSxB BB2F + TSxA BB2F + TSxB GMSK and EDGE TRX hopping group compatibility Because of the different data rates with GMSK and EDGE, there are restrictions on mixing GMSK-only TRXs and EDGE-capable TRXs within a baseband hopping group. Note that it is possible to set up GMSK-only TRXs in one BTS object, and EDGE-capable TRXs in a second BTS object, within the same segment by using Common BCCH. With RF hopping, any combination of TRXs within a hopping group is possible. Allowed TRX combinations for baseband hopping are listed in the following tables: Table 16. Units Compatible TRXs, 'GMSK TRX' hopping 'GMSK TRX' hopping compatible OK OK OK OK TRX mode of operation GMSK GMSK GMSK GMSK BB2A + TSxA BB2E + TSxA BB2F + TSxA BB2F + TSxB Note that BB2E + TSxB is not ‘GMSK TRX’ hopping compatible. 102 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE Table 17. Units Compatible TRXs, 'EDGE TRX' hopping 'EDGE TRX' hopping Modes of operation compatible OK OK EDGE or GMSK EDGE or GMSK BB2E + TSxB BB2F + TSxB MetroSite TRX units . MetroSite EDGE TRX units are: 'WTxA' or 'CTxA' MetroSite GMSK-only TRX units are: 'VTxA' or 'HVxA' . Where x is the letter (T, G, D, P) which identifies the frequency band (800, 900, 1800, 1900 MHz). MetroSite TRXs use RF hopping, so EDGE and GMSK-only TRXs may be used in the same hopping group. 6.2.2 Restrictions . If Baseband hopping is employed in a BTS, radio timeslot 0 of any TRX in the BTS will not be used for GPRS. BTS testing cannot be executed on the packet control channel. Network operation mode III is not supported. In PCU1 Coding Scheme CS-1 is always used in unacknowledged RLC mode. In acknowledged RLC mode, the Link Adaptation algorithm uses both CS-1 and CS-2. In PCU2, because of CS-3 & CS-4 implementation, there is a new Link Adaptation algorithm that uses all the Coding Schemes in both unacknowledged and in acknowledged RLC mode. . . . . Paging reorganisation is not supported. Only EDGE-capable TRXs are capable of using shared EGPRS Dynamic Abis Pool (EDAP) resources. There can be 16 EGPRS Dynamic Abis Pools per Packet Control Unit. One EDAP resource should not be shared between several BCF cabinets. It may damage the TRX or DTRU hardware if the operator tries to share EDAP between several cabinets. . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 103 (272) EDGE System Feature Description . The master and slave channels must be cross-connected in the same way; the EDAP and the TRXs tied to it shall use a single PCM line. If they use different PCM lines, transmission delay between the lines may differ. This may cause a timing difference with the result that synchronisation between the master and slave channels is not successful. GPRS territory can be defined to each BTS object separately. GPRS and EGPRS territories cannot both be defined to a BTS object at the same time. TRXs inside a BTS object must have common capabilities. An exception to this is that EDGE-capable and non-EDGE-capable TRXs can be configured to the same BTS object, if EGPRS or CS-3 & CS-4 is enabled in the BTS. In this case, GPRS must be disabled in the non-EDGE-capable TRXs. An EDGE-capable TRX has EDGE hardware and is added to EDAP. A non-EDGE-capable TRX has no EDGE hardware or it is not added to EDAP. . To get BCCH recovery to work correctly, it is recommended that the operator takes the following conditions into account, when unlocked EDGE and non-EDGE-capable TRXs exist in the same EGPRS or CS-3 & CS-4 enabled BTS: . If a BCCH TRX is EDGE hardware-capable, added to EDAP, and it has the GTRX parameter set to Y, then all unlocked TRXs, which are added to EDAP, are EDGE hardware-capable, and have GTRX set to Y, should be marked Preferred BCCHs. . If a BCCH TRX is non-EDGE-capable, and has the parameter GTRX set to N, then all non-EDGE-capable unlocked TRXs, which have GTRX set to N, should be marked Preferred BCCHs. For information on restrictions when baseband hopping is used, see EDGE BTSs and hopping in System impact of EDGE in EDGE System Feature Description. . . . The BSS does not restrict the use of 8PSK modulation on TSL7 of the BCCH TRX, using the highest output power. The maximum output power is 2dB lower than with GMSK. This is fully compliant with 3GPP Rel 5. PCU1 does not support CS–3 & CS–4, Extended Dynamic Allocation (EDA), High Multislot Classes (HMC) or Dual Transfer Mode (DTM). For restrictions related to Dynamic Abis, see Dynamic Abis. . . 104 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE 6.2.3 Impact on transmission EDGE sets new demands on Abis interface transmission. The Abis interface transmission data rate varies depending on the call type. Instead of allocating fixed transmission capacity according to the highest possible data rate for every traffic channel from the Abis interface, it is recommended to share common transmission resources between several traffic channels. Dynamic Abis makes it possible to define common transmission resources for EDGE-capable TRXs situated in the same Abis ETPCM. This common resource is called the Dynamic Abis Pool. There are fixed transmission resources for Abis signalling links and traffic channels in Abis ETPCM as before but extra transmission resources needed for EGPRS calls are reserved from the Dynamic Abis Pool. 6.2.4 Impact on BSS performance EGPRS impact on TCP performance Data link bandwidth of EGPRS The dynamic sharing of resources and variable radio conditions introduce variation to available link level bandwidth. In addition, the signalling procedures on the MAC layer generate interruptions in the data transfer and increase the round-trip delay on the upper layers. Several mechanisms, such as delayed TBF release, have been implemented to reduce the latency introduced by the MAC layer. The asymmetry ratio between uplink and downlink is quite low for typical MS multislot classes, with 8-PSK uplink capability. EGPRS protocol overhead consists of the following fields: SNDCP header LLC headers LLC length indicator in RLC 4 bytes per IP packet 6 bytes per LLC block 2 bytes per LLC block The BSC uses MCS-1 or CS-1 synchronisation frame for every 18th block, which reduces the maximum TCP throughput by 4% for MCS-9. The table below summarises the maximum link bandwidth limited TCP throughput [kB/s] for MTU=1500. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 105 (272) EDGE System Feature Description Table 18. Maximum TCP throughput per MCS for single slot Max. TCP throughput for UL (1 slot) Max. TCP throughput for DL (2 slots) 2.0 kB/s 2.6 kB/s 3.4 kB/s 4.0 kB/s 5.1 kB/s 6.7 kB/s 10.0 kB/s 12.0 kB/s 13.0 kB/s Modulation and Coding Scheme MCS-1 (8.8 kbit/s) MCS-2 (11.2 kbit/s) MCS-3 (14.8 kbit/s) MCS-4 (17.6 kbit/s) MCS-5 (22.4 kbit/s) MCS-6 (29.6 kbit/s) MCS-7 (44.8 kbit/s) MCS-8 (54.4 kbit/s) MCS-9 (59.2 kbit/s) 1.0 kB/s 1.3 kB/s 1.7 kB/s 2.0 kB/s 2.5 kB/s 3.3 kB/s 5.0 kB/s 6.1 kB/s 6.7 kB/s GPRS and EGPRS TBF multiplexing If GPRS UL TBF and EGPRS DL TBF have been allocated on the same timeslot, the uplink state flag (USF) signalling to the GPRS TBF requires GMSK modulation on DL which may reduce the DL throughput for the EGPRS TBF. However, the BSC allocates the EGPRS and GPRS TBFs to different territories whenever possible so this constraint is not valid if there are separate territories for the GPRS and EGPRS TBFs. On the single territory case, the BSC allocates the maximum number of slots as per MS capability and tries to allocate GPRS and EGPRS TBFs to different timeslots whenever possible. So the larger the territory size the less significant is the impact on performance. When size of territory equals the sum of typical slot capabilities of GPRS and EGPRS MSs, the impact is neglected. Cell re-selection The impact of cell change depends on the type of cell change: . RA+LAC update RA update Inter PCU Cell re-selection Intra PCU Cell re-selection . . . 106 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE Round-trip Delay TCP data transfer is very sensitive to round-trip delay of the end-to-end link. Therefore, one of the main targets in the end-to-end optimisation is to minimise the overall delay. This concerns not only the RLC/MAC layer, which is probably the main delay source in EGPRS data transfer, but also the terminal equipment on the mobile side as well as the core network and the application server. The data transmission time is only one part of the round-trip delay. Other contributors include: . MAC layer signalling delays processing delays at the PCU and MS. . The round trip time (RTT) of EGPRS on TCP layer varies considerably because of variation of link layer bandwidth. The obtainable RTT over the EGPRS bearer is approximately 1 second for a segment size of 1500 B. Cell change may cause a peak delay of several seconds, especially if NACC is not used. Bandwidth delay product The bandwidth-delay product of the EGPRS link is rather high, around ten kilobytes. EGPRS increases the data transmission capability, that is, bandwidth of the radio link, but the round-trip delay of the link is still rather long. Large bandwidth-delay product requires large window sizes on the TCP layer, which in turn sets high buffering requirements at the SGSN, PCU, and MS. Packet (SDU) Loss TCP protocol slows down the transmission rate each time a packet loss is detected by the TCP transmitter. Therefore, it is crucial to avoid bit errors in the radio transmission as well as packet discarding in the network elements. This requires RLC ACK mode and adequate buffering capability at the SGSN, PCU and MS. The PDP context related Rel99 QoS attributes can be used to select different operation modes for RLC and LLC protocol layers. The 12bit CRC error detection scheme for RLC may pass some errors to LLC layer at low C/I or Es/No ratios. In unACK mode the LLC can detect the errors with 24bit CRS but not correct them. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 107 (272) EDGE System Feature Description The resulting TCP/IP packet loss in EGPRS non ACK LLC mode is typically of the order 10-3 … 10-5. 1.E-02 SDU Error Probability 1.E-03 MCS-9 MCS-1 1.E-04 1.E-05 1.E-06 0 5 10 15 20 25 30 C/I [dB] Figure 24. Simulated SDU error probability because of bit errors passed by RLC (TU3iFH) Mobile station synchronisation requirements GSM specification 45.008 requires that for synchronisation purposes, the network shall ensure that each MS with an active TBF in uplink or downlink receives at least one block transmitted with a coding scheme and a modulation that can be decoded by that MS every 360 milliseconds (78 TDMA frames). There is no special implementation for this GSM specification requirement in GPRS territories (EGENA = N). In EGPRS territories (EGENA =Y), this GSM specification requirement is implemented as follows: The PCU registers when each MS was expected to successfully decode a downlink block. Then, in the scheduling phase, each MS is checked. If an MS has not been decoding anything for a 17 block period, the PCU sets the limit of the MCS/CS for GPRS in the next downlink block so low that the MS can be expected to decode it. The block may be addressed to other MSs too but the MCS/CS is limited according to the rules below. 108 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . An EGPRS MS is expected to decode blocks that are using an MCS/ CS lower or equal to the one selected by link adaptation for the MS’s downlink TBF. If an EGPRS MS only has an uplink TBF, (M)CS-1 or (M)CS-2 in the downlink is considered robust enough to be decoded correctly. A GPRS MS is expected to decode blocks that are using CS-1 or CS-2. If a GPRS MS has not been decoding anything for a 17 block period, the PCU sends a CS-1 or CS-2 coded block. If possible, the turn is given to a GPRS downlink TBF. If only an EGPRS TBF exists on the downlink connection, the PCU sends a CS-1 (dummy) control block. . . 6.2.5 6.2.5.1 User interface BSC MMI The following command groups and MML commands are used to handle Nokia EDGE. . Base Transceiver Station Handling in BSC: EQ Power Control Parameter Handling: EU Transceiver Handling: ER Base Station Controller Parameter Handling in BSC: EE Licence and Feature Handling: W7 Parameter Handling: WO GSM Timer and BSC Parameter Handling: EG Gb Interface Handling: FX . . . . . . . For more information on the command groups and commands, see MML Commands under Reference/Commands in the PDF view. 6.2.5.2 BTS MMI Nokia EDGE cannot be managed with BTS MMI. 6.2.5.3 BSC parameters BSC radio network object parameters Base Tranceiver Station parameters DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 109 (272) EDGE System Feature Description . BTS uplink throughput factor for MCS1-MCS4 (TFUM1) (PCU2 only) BTS downlink throughput factor for MCS1-MCS9 (TFDM) (PCU2 only) BTS uplink throughput factor for MCS1-MCS9 (TFUM) (PCU2 only) quality control EGPRS DL RLC ack throughput threshold (QEDRT) quality control EGPRS UL RLC ack throughput threshold (QEURT) EGPRS enabled (ENA) EGPRS Link Adaptation enabled (ELA) initial MCS for acknowledged mode (MCA) initial MCS for unacknowledged mode (MCU) maximum BLER in acknowledged mode (BLA) maximum BLER in unacknowledged mode (BLU) mean BEP offset 8PSK (MBP) mean BEP offset GMSK (MBG) coding schemes CS3 and CS4 enabled (CS34) . . . . . . . . . . . . . Power Control parameters . bit error probability filter averaging period (BEP) For parameters related to GPRS, see section BSC parameters in System impact of GPRS. For more information on radio network parameters, see BSS Radio Network Parameter Dictionary. PRFILE parameters . MEMORY_OUT_FLAG_SUM EGPRS_UPLINK_PENALTY EGPRS_UPLINK_THRESHOLD EGPRS_DOWNLINK_PENALTY . . . 110 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . EGPRS_DWNLINK_THRESHOLD UPLNK_RX_LEV_FRG_FACTOR GPRS_TBF_REALLC_THRSHLD TERRIT_BALANCE_THRSHLD TERRIT_UPD_GTIME_GPRS TBF_LOAD_GUARD_THRSHLD EGPRS_RE_SEGMENTATION PRE_EMPTIVE_TRANSMISSIO BCCH_BAND_TBF_THRSHLD FC_MS_R_DEF_EGPRS FC_MS_B_MAX_DEF_EGPRS FC_R_TSL_EGPRS FC_B_MAX_TSL_EGPRS EGPRS_GPRS_MUX_PENALTY (PCU2 only) EGPRS_DL_MUX_DEC_FACTOR (PCU2 only) . . . . . . . . . . . . . . For more information on PRFILE parameters, see PRFILE and FIFILE Parameter List. PAFILE parameters . BS_CV_MAX For more information on PAFILE parameters, see PAFILE Timer and Parameter List. 6.2.5.4 Alarms The following alarms can be generated in connection with Nokia EDGE: . 3068 EGPRS DYNAMIC ABIS POOL FAILURE 3261 FAILURE IN UPDATING BSC SPECIFIC PARAMETERS TO PCU 3273 GPRS/EDGE TERRITORY FAILURE 3324 FAILURE IN UPDATING CONFIGURATION DATA TO PCU 7738 BTS WITH NO TRANSACTIONS . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 111 (272) EDGE System Feature Description . 7769 FAILURE IN UPDATING CELL SPECIFIC PARAMETERS TO PCU 7789 NO (E)GPRS TRANSACTIONS IN BTS . For more information on alarms, see Failure Printouts (2000-3999) and Base Station Alarms (7000-7999). 6.2.5.5 Measurements and counters The following measurements are related to Nokia EDGE: . 72 Packet Control Unit Measurement 73 RLC Blocks per TRX Measurement 74 Frame Relay Measurement 76 Dynamic Abis Measurement . For counters of 76 Dynamic Abis Measurement, see System impact of Dynamic Abis. 79 Coding Scheme Measurement 90 Quality of Service Measurement 95 GPRS Cell Re-selection Measurement . For counters of 95 GPRS Cell Re-selection Measurement, see System impact of Network Controlled Re-selection. 96 GPRS RX Level and Quality Measurement 98 Gb Over IP Measurement . For counters of 98 Gb over IP Measurement, see System impact of Gb over IP. 105 PS DTM Measurement . For counters of 105 PS DTM Measurement, see System impact of Dual Transfer Mode. 106 CS DTM Measurement . For counters of 106 CS DTM Measurement, see System impact of Dual Transfer Mode. 110 PCU Utilization Measurement . . . . . . . . . . . 112 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE 72 Packet Control Unit Measurement Table 19. Name Counters of 72 Packet Control Unit Measurement related to EGPRS Numbers 072088 072089 072090 072091 072094 072095 072109 072110 072111 072112 072113 072114 072117 072118 072120 072141 072142 072143 072144 072145 072146 072147 072148 072149 072150 072151 072152 NUMBER OF EGPRS TBFS UL NUMBER OF EGPRS TBFS DL NUMBER OF ESTABLISHED UPLINK EGPRS TBFS IN UNACK MODE NUMBER OF ESTABLISHED DOWNLINK EGPRS TBFS IN UNACK MODE UL EGPRS TBF RELEASE DUE NO RESPONSE FROM MS DL EGPRS TBF RELEASE DUE NO RESPONSE FROM MS VOLUME WEIGHTED LLC THROUGHPUT EDGE 4 DL NUMERATOR VOLUME WEIGHTED LLC THROUGHPUT EDGE 4 DL DENOMINATOR AVER EGPRS TBFS PER TSL UL AVER EGPRS TBFS PER TSL UL DEN AVER EGPRS TBFS PER TSL DL AVER EGPRS TBFS PER TSL DL DEN UL GPRS TBF IN EGPRS TERR DL GPRS TBF IN EGPRS TERR DL GPRS TBF FOR EGPRS REQ REQ 1 TSL UL FOR EGPRS MS REQ 2 TSL UL FOR EGPRS MS REQ 3 TSL UL FOR EGPRS MS REQ 4 TSL UL FOR EGPRS MS REQ 5 TSL UL FOR EGPRS MS REQ 6 TSL UL FOR EGPRS MS REQ 7 TSL UL FOR EGPRS MS REQ 8 TSL UL FOR EGPRS MS REQ 1 TSL DL FOR EGPRS MS REQ 2 TSL DL FOR EGPRS MS REQ 3 TSL DL FOR EGPRS MS REQ 4 TSL DL FOR EGPRS MS DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 113 (272) EDGE System Feature Description Table 19. Counters of 72 Packet Control Unit Measurement related to EGPRS (cont.) Numbers 072153 072154 072155 072156 072165 072166 072167 072190 072191 Name REQ 5 TSL DL FOR EGPRS MS REQ 6 TSL DL FOR EGPRS MS REQ 7 TSL DL FOR EGPRS MS REQ 8 TSL DL FOR EGPRS MS EGPRS UL CTRL BLOCKS EGPRS DL CTRL BLOCKS DL 8PSK TO GMSK DUE UL GPRS DL EGPRS TBF INIT REALL FAIL WEIGHTED DL TSL ALLOC EDGE 4 TSL NUMERATOR WEIGHTED DL TSL ALLOC EDGE 4 TSL DENOMINATOR 072192 WEIGHTED DL TSL ALLOC EDGE NUMERATOR WEIGHTED DL TSL ALLOC EDGE DENOMINATOR WEIGHTED UL TSL ALLOC EDGE NUMERATOR WEIGHTED UL TSL ALLOC EDGE DENOMINATOR WEIGHTED UL TSL ALLOC EDGE 4 TSL NUMERATOR 072193 072194 072197 072198 072199 WEIGHTED UL TSL ALLOC EDGE 4 TSL DENOMINATOR 072200 1-PHASE UL EGPRS TBF ESTABLISHMENT REQUESTS 1-PHASE UL EGPRS TBF SUCCESSFUL ESTABLISHMENTS 072228 072230 For more information, see 72 Packet Control Unit Measurement. 73 RLC Blocks per TRX Measurement Table 20. Name Counters of RLC Blocks per TRX Measurement Number 073000 073001 073002 073003 UR DL RLC MAC BLOCKS RETRANS DL RLC MAC BLOCKS SCHED UNUSED RADIO BLOCKS DL RLC MAC BLOCKS For more information, see 73 RLC Blocks per TRX Measurement. 114 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE 74 Frame Relay Measurement Table 21. Name Counters of Frame Relay Measurement Number 074000 074001 074002 074003 074004 074005 074006 074007 074008 074009 074010 074011 074012 074013 074014 074015 074016 074017 074018 074019 074020 074021 074022 074059 074060 074061 074062 074063 074064 074065 FRMS WRONG CHECK SEQ ERR FRMS WRONG DLCI OTHER FRAME ERROR T391 TIMEOUT STAT MSG WRONG SEND SEQ NBR STAT MSG WRONG REC SEQ NBR BEAR CHANGED UNOPER BEAR RET OPER STAT MSG UNKNOWN PVC STAT MSG SENT TOO OFTEN TIME BEAR UNOPERATIONAL DLCI 1 ID DLCI 1 SENT FRMS DLCI 1 KBYTES SENT DLCI 1 REC FRMS DLCI 1 KBYTES REC FRMS DLCI 1 DISC SENT FRMS DLCI 1 BYTES DISC SENT FRMS DLCI 1 DISC REC FRMS DLCI 1 BYTES DISC REC FRMS DLCI 1 STAT ACT TO INACT DLCI 1 INACTIVITY TIME DLCI 1 DISC UL NS UDATA DLCI 5 ID DLCI 5 SENT FRMS DLCI 5 KBYTES SENT DLCI 5 REC FRMS DLCI 5 KBYTES REC FRMS DLCI 5 DISC SENT FRMS DLCI 5 BYTES DISC SENT FRMS DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 115 (272) EDGE System Feature Description Table 21. Name Counters of Frame Relay Measurement (cont.) Number 074066 074067 074068 074069 074070 DLCI 5 DISC REC FRMS DLCI 5 BYTES DISC REC FRMS DLCI 5 STAT ACT TO INACT DLCI 5 INACTIVITY TIME DLCI 5 DISC UL NS UDATA For more information, see 74 Frame Relay Measurement. 79 Coding Scheme Measurement Table 22. Name Counters of Coding Scheme Measurement Number 079000 079001 079002 079003 079004 079005 079006 079007 079008 079009 079012 079013 079014 NUMBER OF DL RLC BLOCKS IN ACKNOWLEDGED MODE NUMBER OF DL RLC BLOCKS IN UNACKNOWLEDGED MODE NUMBER OF UL RLC BLOCKS IN ACKNOWLEDGED MODE NUMBER OF UL RLC BLOCKS IN UNACKNOWLEDGED MODE NUMBER OF BAD RLC DATA BLOCKS WITH VALID HEADER UL UNACK MODE NUMBER OF BAD RLC DATA BLOCKS WITH BAD HEADER UL UNACK MODE NUMBER OF BAD RLC DATA BLOCKS WITH VALID HEADER UL ACK MODE NUMBER OF BAD RLC DATA BLOCKS WITH BAD HEADER UL ACK MODE RETRANSMITTED RLC DATA BLOCKS UL RETRANSMITTED RLC DATA BLOCKS DL DL RLC DATA FOR DUMMY LLC RLC RETRANSMITTED DL DUE TO OTHER REASON THAN NACK IGNORED RLC DATA BLOCKS UL DUE TO BSN For more information, see 79 Coding Scheme Measurement. 116 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE 90 Quality of Service Measurement Table 23. Name Counters of 90 Quality of Service Measurement related to EGPRS Number 090009 090010 090011 090012 VWTHR NUMERATOR EDGE OTHER 4 VWTHR DENOMINATOR EDGE OTHER 4 VWTHR NUMERATOR EDGE 4 VWTHR DENOMINATOR EDGE 4 For more information, see 90 Quality of Service Measurement. 96 GPRS RX Level and Quality Measurement Table 24. Counters of GPRS RX Level and Quality Measurement 096000 096001 096002 096003 096004 096005 096012 096013 096020 096021 096028 096029 096036 096037 096044 096045 096052 096053 096060 096061 RXL UP BOUND CLASS 0 RXL UP BOUND CLASS 1 RXL UP BOUND CLASS 2 RXL UP BOUND CLASS 3 RXL UP BOUND CLASS 4 UL SAMPLES WITH RXL 0 RXQ 0 UL SAMPLES WITH RXL 0 RXQ 7 UL SAMPLES WITH RXL 1 RXQ 0 UL SAMPLES WITH RXL 1 RXQ 7 UL SAMPLES WITH RXL 2 RXQ 0 UL SAMPLES WITH RXL 2 RXQ 7 UL SAMPLES WITH RXL 3 RXQ 0 UL SAMPLES WITH RXL 3 RXQ 7 UL SAMPLES WITH RXL 4 RXQ 0 UL SAMPLES WITH RXL 4 RXQ 7 UL SAMPLES WITH RXL 5 RXQ 0 UL SAMPLES WITH RXL 5 RXQ 7 DL SAMPLES WITH RXL 0 RXQ 0 DL SAMPLES WITH RXL 0 RXQ 7 DL SAMPLES WITH RXL 1 RXQ 0 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 117 (272) EDGE System Feature Description Table 24. Counters of GPRS RX Level and Quality Measurement (cont.) 096068 096069 096076 096077 096084 096085 096092 096093 096100 DL SAMPLES WITH RXL 1 RXQ 7 DL SAMPLES WITH RXL 2 RXQ 0 DL SAMPLES WITH RXL 2 RXQ 7 DL SAMPLES WITH RXL 3 RXQ 0 DL SAMPLES WITH RXL 3 RXQ 7 DL SAMPLES WITH RXL 4 RXQ 0 DL SAMPLES WITH RXL 4 RXQ 7 DL SAMPLES WITH RXL 5 RXQ 0 DL SAMPLES WITH RXL 5 RXQ 7 For more information, see 96 GPRS RX Level and Quality Measurement. 110 PCU Utilization Measurement Table 25. Counters of PCU Utilization Measurement 110000 110001 110002 PEAK RESERVED PCUPCM CHANNELS PEAK OCCUPIED PDTCH UL PEAK OCCUPIED PDTCH DL For more information, see 110 PCU Utilization Measurement. 6.2.6 Impact on Network Switching Subsystem (NSS) The GPRS packet core comprising the Serving GPRS Support Node (SGSN), Gateway GPRS Support Node (GGSN), Charging Gateway (CG) and IP backbone continue to be used when EDGE is introduced in the GSM network. Support for EDGE is available starting from GPRS core release 2, which involves upgrades to the SGSN, GGSN and CG. Nokia’s MSC/HLR supports enhanced data rates for EGPRS. M11 is required to support EGPRS service subscription and QoS parameters. 118 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE Um BTS BSC Support for EDGE functions has been available starting from GPRS core release 2 GB PACKET CORE CG SGSN EDGE TRXs GPRS backbone network (IP based) BG GN Gi GGSN Internet DNS Figure 25. Support for Nokia GPRS Core GPRS architecture provides IP connectivity from a mobile station to an external fixed IP network. A quality of service (QoS) is defined for each radio access bearer that serves a connection. The parameters include priority, reliability, delay, and maximum and mean bit rates. A specified combination of these parameters defines a bearer, and different bearers are selected to suit the needs of different applications. Nokia EDGE requires an updated parameter space for the QoS parameters. Higher layer protocols, such as those used by the GGSN and the SGSN, remain the same. With these methods, Nokia EDGE delivers enhanced data rates up to a theoretical maximum of 473 kbps using the same infrastructure as GPRS. EDGE impact on CS charging DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 119 (272) EDGE System Feature Description EDGE-specific values are introduced in the channel coding fields. No new Charging Data Recods (CDRs) or fields have been added. The following values are added to the following CDRs: . Mobile Originated Call CDR Mobile Terminated Call CDR Unsuccessfull Call Attempt CDR. . . 6.2.7 Impact on NetAct products NetAct Administrator Standard Nokia NetAct Administration applications, such as Network Editor, Time Management, User Group Profiles, Authority Manager and Service Access Control are used to administer EDGE. NetAct Monitor Standard Nokia NetAct monitoring applications, such as Top-Level UI, Alarm History, Alarm Manual (modifiable), Alarm Monitor, Alarm Viewer are used to monitor the network. NetAct Radio Access Configurator (RAC) NetAct Radio Access Configurator (RAC) can be used to configure the radio network parameters related to EGPRS. For more information, see BSS RNW Parameters and Implementing Parameter Plans in Nokia NetAct Product Documentation. For a list of the radio network parameters, see BSC parameters. The features of RAC applications include the following: . basic EDGE usage enabling GUI access to configure the Dynamic Abis pool (DAP) parameters CM Provisioner automatically re-creates the TRX with the planned DAP id: use CM Provisioner for EDGE roll-out EDGE-specific rules in CM analyser (consistency check) . . . See Building and Extending EDGE Coverage in NetAct documentation for details. 120 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE NetAct Reporter and Network Doctor NetAct Reporter can be used to view reports from measurements related to EGPRS. For a list of the measurements, see Measurements and counters. NetAct Doctor Reports 226, 275 and 280 include KPIs that are relevant for EDGE. For more information, see EDGE key performance indicators (KPIs). NetAct Tracing NetAct Tracing supports EDGE capable Nokia network elements. Data Tracing must be supported by the BSS and the Packet Core Network. EDGE specific tracing content (from the BSC) includes information about the following: . Used Modulation and Coding Schemes (MCS) The amount of data transferred with each MCS Number of MCS changes caused by Dynamic Abis bus blockage . . TraceViewer offers efficient means to trace mobile equipment or subscribers in EDGE networks. 6.2.8 Impact on mobile terminals EDGE-capable mobile terminals are required. All new Nokia GPRS terminals are also EDGE-capable. There are two GSM EDGE terminal classes, 1 and 2: . Class 1 terminals can use 8-PSK in downlink and must use GMSK in uplink (also called asymmetric EDGE) Class 2 terminals can use 8-PSK in both directions. . EDGE terminal classes combine up to six types of terminals, as shown in figure EDGE terminal classes. EDGE will provide different uplink and downlink capabilities for terminals. After the roll-out of EDGE terminals, WCDMA operation must be added to appropriate products as required by the market. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 121 (272) EDGE System Feature Description Asymmetric (8PSK in Downlink only) EDGE GPRS Simultaneous Voice and Data Non-Simultaneous Voice and Data Manually selected Voice (CS) or Data (PS) or exclusively Data (PS) CLASS A CLASS B CLASS C 1 Symmetric (8PSK in Uplink and Downlink) 2 PCMCIA data-only Figure 26. EDGE terminal classes 6.2.9 Impact on interfaces Impact on Abis interface . Dynamic Abis Dynamic Abis pools need to be configured. . Support for EGPRS messages . The BTS sends EGPRS Packet Channel Request information to the PCU (BSC). . A new information field EGPRS PCR is added to the message P-CHANNEL REQUIRED. Impact on A interface No impact. Impact on Gb interface Nokia BSC supports Gb interface (BSC-SGSN) as specified in GSM Recommendations (3GPP): 122 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE . 3GPP TS 48.018, General Packet Radio Service (GPRS); Base Station System (BSS) - Serving GPRS Support Node (SGSN); BSS GPRS Protocol (BSSGP) 3GPP TS 48.016, General Packet Radio Service (GPRS); Base Station System (BSS) - Serving GPRS Support Node (SGSN) interface; Network Service . BSSGP flow control for BVC and MS: BVC and MS specific bucket sizes and leak rates are enhanced due to higher EGPRS throughput. When an EGPRS mobile uses EGPRS TBF in downlink data transfer, EGPRS-specific parameters are used in flow control calculations. If an EGPRS mobile uses normal GPRS TBF, flow control uses GPRS-specific parameters for calculating BVC and MS bucket sizes and leak rates. There are four EGPRS-specific PRFILE parameters for the Gb interface. For a list of the parameters, see PRFILE parameters. Impact on Gs interface Nokia SGSN and MSC support the Gs interface (SGSN-MSC/VLR) although it is specified as optional by 3GPP. The advantages of Gs interface include: . support for TIA/EIA-136 networks by offering a connection for the tunneling of non-GSM signalling messages via the GPRS network to a non-GSM MSC/VLR. more effective radio resource usage with combined GPRS/IMSI attach/detach and combined RA/LA updates, that is, reduced signalling over the radio interface. the possibility to page GPRS terminals for circuit-switched services (for example circuit-switched calls) via GPRS. . . 6.2.10 Interworking with other features GPRS and EGPRS GPRS and EGPRS can be multiplexed dynamically on the same timeslot. See EGPRS impact on TCP performance section GPRS and EGPRS TBF multiplexing for details. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 123 (272) EDGE System Feature Description Frequency Hopping In Baseband hopping, radio timeslot 0 belongs to a different hopping group than the other radio timeslots of a TRX. This makes radio timeslot 0 unusable for multislot connections. If Baseband hopping is employed in a BTS, radio timeslot 0 of any TRX in the BTS is not used for GPRS. Both RF and Baseband hopping are supported in EGPRS. TRX loop test is not possible with Baseband or Antenna hopping. Optimisation of the MS Power Level The BSC attempts to allocate traffic channels within the circuit-switched territory according to the interference level recommendation the BSC has calculated, to allow the performing of optimisation of the MS power level. When the BSC has to allocate a traffic channel for a circuit-switched request in the GPRS territory, the interference level recommendation is no longer the guiding factor. Now, the first GPRS radio timeslot next to the territory border is taken regardless of whether its interference level is among the recommended ones or not. For more information on the division of territories, see section Radio resource management. Intelligent Underlay-Overlay, Enhanced Coverage by Frequency Hopping, Handover Support for Coverage Enhancements Super-reuse frequencies are not supported for GPRS. Dynamic SDCCH allocation The BSC selects a traffic channel time slot to be reconfigured as a dynamic SDCCH time slot always within the circuit switched territory. TRX prioritisation in TCH allocation The operator can set the BCCH TRX or the non-BCCH TRXs as preferred TRX for the GPRS territory with the parameter prefer BCCH frequency GPRS (BFG). If no preference is indicated, no prioritisation is used between the different TRX types when the GPRS territory is formed. Trunk reservation In trunk reservation, the BSC defines the number of idle traffic channels. The BSC adds together the number of idle traffic channels in the circuit switched territory and the number of traffic channels in the radio timeslots of the GPRS territory, excluding the ones that are in the radio timeslots that the BSC has allocated permanently for GPRS. 124 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE TRX fault When a TRX carrying traffic channels becomes faulty, the radio timeslots on the TRX are blocked from use. The BSC releases the ongoing calls and the call control resources. The BSC downgrades the traffic channels belonging to the GPRS territory in the faulty TRX from GPRS use. To replace the lost GPRS capacity, the BSC determines the possibility of a GPRS territory upgrade in another TRX. For more information on GPRS territory upgrades and downgrades, see section Radio resource management. If the faulty TRX functionality is reconfigured to another TRX in the cell, the value of the GPRS enabled TRX (GTRX) parameter is also transferred to the new TRX. If the faulty TRX is EDGE-capable, and GPRS in enabled in the TRX and CS-3 & CS-4 or EGPRS is enabled in the BTS, the system tries to reconfigure its functionality to another EDGE-capable TRX in the BTS. Note that a TRX is an EDGE-capable TRX if the TRX HW is EDGE capable and it is added to EDAP. A TRX is a non-EDGE-capable TRX if the TRX has no EDGE HW or it is not added to EDAP. Resource indication to MSC In general the BSC’s indication on the resources concerns traffic channels of a BTS excluding those allocated permanently to GPRS (dedicated GPRS channels). GPRS territory resources other than the dedicated ones are regarded as working and idle resources. Half Rate Permanent type half rate timeslots are not used for GPRS traffic. Therefore, it is recommended not to configure permanent half rate timeslots in TRXs that are planned to be capable of GPRS. When the BSC can select the channel rate (full rate or half rate) to be used for a circuit switched call based on the traffic load of the target BTS, the load limits used in the procedure are calculated using the operator defined BSC and BTS parameters lower limit for HR TCH resources (HRL) , upper limit for HR TCH resources (HRU) , lower limit for FR TCH resources (FRL), and upper limit for FR TCH resources (FRU) . The BSC parameter CS TCH allocation calculation (CTC) defines how the GPRS territory is seen when the load limits are calculated. Depending on the value of CTC either only CS territory or both CS and GPRS territories DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 125 (272) EDGE System Feature Description (excluding the dedicated GPRS timeslots) are used to calculate the load limits. Additionally, with the CTC parameter the user can define whether the resources in GPRS territory are seen as idle resources or as occupied resources. High Speed Circuit Switched Data (HSCSD) If GPRS has been enabled in a BTS, the HSCSD-related load limits are calculated based on the existing HSCSD parameters and the following rules: . the number of working resources includes all the working full rate traffic channel (TCH/F) resources of a BTS, excluding the ones that have been allocated permanently to GPRS the number of occupied TCH/F resources includes all the occupied TCH/Fs of the circuit-switched territory, as well as the default GPRS territory TCH/Fs, excluding the GPRS radio timeslots defined as dedicated HSCSD parameter HSCSD cell load upper limit (HCU) is replaced with the radio network GPRS parameter free TSL for CS downgrade (CSD) if the latter is more restricting; thus the one that limits HSCSD traffic earlier is used. . . The parameter free TSL for CS downgrade (CSD) defines a margin of radio timeslots that the BSC tries to keep idle for circuit-switched traffic by downgrading the GPRS territory when necessary. If HSCSD multislot allocation is denied based on the appropriate parameters, the BSC rejects the transparent HSCSD requests and serves the non-transparent HSCSD requests with one timeslot. If the timeslot share in HSCSD allocation is not restricted, the transparent requests are served preferably in the circuit-switched territory, and only if necessary in the GPRS territory. If a transparent HSCSD call ends up in the GPRS territory, the BSC does not try to move it elsewhere with an intra cell handover. Instead, it tries to replace the lost GPRS capacity by extending the GPRS territory on the circuit-switched side of the territory border. When the transparent HSCSD call inside the GPRS territory is later released, the BSC returns the released radio timeslots back to GPRS use to keep the GPRS territory continuous and undivided. For more information on how the resources form the territories, see section Radio resource management. 126 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE The non-transparent HSCSD requests are always served in the circuitswitched territory as long as there is at least one TCH/F available. A normal HSCSD upgrade procedure is applied later to fulfill the need of the non-transparent request, if the call starts with less channels than needed and allowed. In order for the non-transparent call to get the needed number of timeslots, the BSC starts an intra cell handover for suitable single slot calls beside the non-transparent HSCSD call. At the start of the handover, the BSC checks that a single slot call can be moved to another radio timeslot and that an HSCSD upgrade is generally allowed. A non-transparent HSCSD call enters the GPRS territory only if there is congestion in the circuit-switched territory. If multislot allocation was originally defined as allowed, it is also applied within the GPRS territory to serve the non-transparent request. If the BTS load later decreases, enabling a GPRS territory upgrade, the non-transparent HSCSD call is handed over to another location in the BTS so that the GPRS territory can be extended. When deciding whether to downgrade an HSCSD call or the GPRS territory, the BSC checks first if the margin of idle resources defined by the parameter free TSL for CS downgrade (CSD) exists. If a sufficient margin exists, the BSC acts as without GPRS, that is, using the state information that the HSCSD parameters define for the BTS, the BSC performs an HSCSD downgrade if necessary. If the number of idle resources is below the parameter free TSL for CS downgrade (CSD), the actions proceed as follows: . if there are GPRS radio timeslots that are above and beyond the operator defined default GPRS territory then these additional GPRS radio timeslots are the first target for the GPRS territory downgrade if there are no additional GPRS radio timeslots, the BSC examines if there are more HSCSD traffic channels than the parameter HSCSD TCH capacity minimum (HTM) requires and if so, executes an HSCSD downgrade if the minimum HSCSD capacity is not in use, a GPRS territory downgrade is made to maintain the margin defined by the parameter free TSL for CS downgrade (CSD). . . As a TCH/F becomes free through a channel release, the BSC first examines the need and possibility for an HSCSD upgrade. If the BSC starts no HSCSD upgrade, it further checks the need and possibility for a GPRS upgrade. The GPRS territory can be upgraded although the parameter HSCSD TCH capacity minimum (HTM) is not in use and there are pending HSCSD connections in the cell. The parameter free TSL for CS upgrade (CSU) and the margin it defines is the limiting factor for a GPRS territory upgrade. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 127 (272) EDGE System Feature Description Parameter free TSL for CS upgrade (CSU) defines the number of radio timeslots that have to remain idle in the circuit-switched territory after the planned GPRS territory upgrade has been performed. For more information on GPRS territories, see section Radio resource management, and for more information on HSCSD, see HSCSD and 14.4 kbit/s Data Services in BSC. Radio Network Supervision Actions of the radio network supervision do not apply for time slots that have been included in the GPRS territory. You may want to monitor the uplink interference on time slots in GPRS use. Radio Network Supervision does not apply to the packet control channel. BTS testing The BTS testing cannot be executed on the packet control channel. Multi BCF Control, Common BCCH Control Multi BCF introduces a radio network object called the segment. Several BTS objects can belong to one segment. Only one BTS object of the segment can have a BCCH. The segment can have BTS objects, which differ in: . frequency band (GSM800, PGSM900, EGSM900, GSM1800, and GSM1900) power levels (Talk-family and UltraSite base stations) regular and super-reuse frequencies EDGE capability. . . . TRXs inside a BTS object must have common capabilities. An exception to this is that EDGE-capable and non-EDGE-capable TRXs can be configured to the same BTS object. When EGPRS or CS-3 & CS-4 is enabled in the BTS, there exist some restrictions related to TRX configuration. For more information, see section Restrictions. PS territory can be defined to each BTS object separately. GPRS and EGPRS territories cannot both be defined to a BTS object at the same time. Superreuse frequencies are not supported in GPRS. There is only one BCCH/CCCH in one segment. 128 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE You must define GPRS territory to the BCCH frequency band in a Common BCCH cell in which more than one frequency band is in use. Otherwise GPRS does not work properly in the cell. The reason for this requirement is that in cases when the MS RAC of the GPRS mobile is not known by the BSC, the temporary block flow (TBF) must be allocated on the BCCH frequency band first. During the first TBF allocation, the GPRS mobile indicates its frequency capability to the BSC. After that, other frequency bands of the cell can be used for the GPRS mobile accordingly. GPRS territory must be configured into the BCCH BTS of a segment with two or more BTSs on the BCCH band and BTS(s) containing GPRS channels are hopping. This is because hopping frequency parameters are encoded to the IMMEDIATE ASSIGNMENT message on CCCH with indirect encoding. When the allocated BTS is hopping, indirect encoding can only refer to the SYSTEM INFORMATION TYPE 13 message, which in the Nokia BSS contains GPRS Mobile Allocation only for the BCCH BTS. The limitation to use only indirect encoding with hopping frequency parameters in IMMEDIATE ASSIGNMENT comes from the fact that IMMEDIATE ASSIGNMENT message segmentation is not supported in the Nokia BSS. The other two possible hopping frequency encodings, direct 1 and 2, might use a large number of octets for the frequency hopping. Large sized frequency parameters cause control message segmentation. Thus as IMMEDIATE ASSIGNMENT segmentation is not supported, direct 1 and 2 encoding cannot be used. Therefore, in a segment where BCCH band GPRS channels are on hopping BTS(s), the TBFs must initially be allocated to the BCCH BTS. Later, the TBFs may be reallocated to other BTSs as well. See Common BCCH Control in BSC and Multi BCF Control in BSC for more information on Multi BCF and Common BCCH. IDD and hopping compatibility The hopping mode setup (No hopping, BB hopping, RF hopping, Antenna hopping) applies to all TRXs within a Sector/BTS object. It is not possible to mix BB, RF or Antenna hopping within a Sector/BTS object with Nokia UltraSite BTSs. Mixing different hopping modes within different sectors is possible with Nokia Flexi EDGE BTSs. Nokia Flexi EDGE BTS supports IDD from EP2.0 onwards. Note that with BB, RF and Antenna hopping it is possible to set up the hopping parameters so that a TRX, or timeslot(s) within a TRX, do not hop. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 129 (272) EDGE System Feature Description RF hopping and Antenna hopping cannot be used in a sector which uses the Remote Tune Combiner (RTC). IDD is set up per TRX, with 2 TRX units making 1 (logical) IDD TRX; the BSC sees the IDD TRX pair as a single (logical) TRX. BB hopping, Antenna hopping and IDD all use the BB hopping HW, but in slightly different ways. This restricts some of the combinations within the cabinet. . It is possible to mix BB hopping, RF hopping, and Antenna hopping sectors within an UltraSite cabinet. Within a cabinet it is not possible to have a single sector that is BB hopping and uses IDD; Sector with IDD and BB hopping will be introduced in future releases. It is not possible to have an IDD sector and a BB hopping sector within a cabinet. It is not possible to have an IDD sector and an Antenna Hopping sector within a cabinet. . . . Table 26. First Sector Type BB hopping BB hopping BB hopping BB hopping BB hopping BB hopping RF hopping RF hopping RF hopping Antenna hopping IDD and hopping compatibility Third Sector Type Antenna hopping IDD IDD IDD - Second Sector Type RF hopping Antenna hopping IDD RF hopping RF hopping Antenna hopping Antenna hopping IDD Antenna hopping IDD Mixed Sectors Within Cabinet Possible Possible Not possible Possible Not possible Not possible Possible Possible Not possible Not possible 130 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE Rx Antenna Supervision Rx Antenna Supervision by comparing RSSI value is possible with RF, Baseband and Antenna hopping, but with some combinations of RF cabling configuration and hopping type, the results need care in interpretation. The RSSI values for a sector are summarised as follows: . Each TRX calculates an average of the RSSI difference between Main and Div Antennas. The O&M then takes the average of the RSSI difference figures from all TRXs in the sector, and reports the single sector-wide average figure. . Dual Transfer Mode GPRS must be available and active in the network for Dual Transfer Mode (DTM) to work. The BSC supports DTM data transfer in both GPRS and EGPRS modes. If GPRS is deactivated when DTM is in use, the MSs that have an active DTM connection keep their CS connection but lose their temporary block flows (TBFs). A DTM TBF is established in EGPRS mode if the MS is EGPRS capable and if the DTM call is allocated from an EGPRS-capable PS territory. If not, the DTM TBF is established in GPRS mode. For more information on DTM, see Dual Transfer Mode. EGSM 900 - PGSM 900 BTS The following restrictions apply when there are EGSM 900 and PGSM 900 frequencies in the BTS and GPRS/EDGE Support for PGSM-EGSM BTS is not used: . When BCCH is on EGSM 900 frequency band and there is a TRX on PGSM 900 frequency band in the BTS, GPRS/EDGE cannot be used in the PGSM 900 TRXs in the BTS. Set the GPRS enabled TRX (GTRX) parameter of the PGSM 900 TRXs to value 'N'. When BCCH is on PGSM 900 frequency band and there is a TRX on EGSM 900 frequency band in the BTS, GPRS/EDGE cannot be used in the EGSM 900 TRXs in the BTS. Set the GPRS enabled TRX (GTRX) parameter of the EGSM 900 TRXs to value 'N'. . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 131 (272) EDGE System Feature Description 132 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software 7 7.1 System impact of GPRS/EDGE related software System impact of EGPRS Packet Channel Request on CCCH The system impact of BSS11156: EGPRS Packet Channel Request on CCCH is specified in the sections below. For an overview, see EGPRS Packet Channel Request on CCCH. EGPRS Packet Channel Request on CCCH is an operating software product in the BSS, but it requires Nokia EDGE as a prerequisite. 7.1.1 Requirements Hardware requirements Table 27. Required additional or alternative hardware or firmware. Network element Hardware/firmware required BSC BTS TCSM SGSN No requirements EDGE TRXs are required No requirements No requirements DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 133 (272) EDGE System Feature Description Software requirements Table 28. Required software Network element Software release required BSC Nokia Flexi EDGE BTSs Nokia UltraSite EDGE BTSs Nokia MetroSite EDGE BTSs Nokia Talk-family BTSs Nokia InSite BTSs MSC/HLR SGSN Nokia NetAct S13 EP2 CX6.0 CXM6.0 No requirements No requirements No requirements No requirements No requirements Frequency band support The BSC supports EGPRS Packet Channel Request on CCCH on the following frequency bands: . GSM 800 GSM 900 GSM 1800 GSM 1900 . . . 7.1.2 Impact on transmission No impact. 7.1.3 Impact on BSS performance OMU signalling No impact. 134 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software TRX signalling No impact. Impact on BSC units Table 29. BSC unit OMU MCMU BCSU PCU Impact on BSC units Impact No impact. No impact. No impact. Faster EGPRS Uplink TBF establishment on cells without PCCCH. Impact on BTS units No impact. 7.1.4 User interface BSC MMI No impact. BTS MMI EGPRS Packet Channel Request on CCCH cannot be managed with BTS MMI. BSC parameters No impact. Alarms No alarms are specifically related to EGPRS Packet Channel Request on CCCH. Measurements and counters No impact. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 135 (272) EDGE System Feature Description 7.1.5 Impact on Network Switching Subsystem (NSS) No impact. 7.1.6 Impact on NetAct products NetAct Administrator No impact. NetAct Monitor No impact. NetAct Optimizer No impact. NetAct Planner No impact. NetAct Radio Access Configurator (RAC) No impact. NetAct Reporter No impact. NetAct Tracing No impact. 7.1.7 Impact on mobile terminals EDGE-capable mobile terminals are required. 7.1.8 Impact on interfaces Impact on radio interface No impact. 136 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Impact on Abis interface EGPRS Packet Channel Request information is sent to the PCU (BSC). New information field EGPRS PCR is added to message P-CHANNEL REQUIRED. Impact on A interface No impact. Impact on Gb interface No impact. 7.2 System impact of Extended Uplink TBF Mode The system impact of BSS11151: Extended Uplink TBF Mode is specified in the sections below. For an overview, see Extended Uplink TBF Mode. For implementation instructions, see Activating and Testing BSS11151: Extended Uplink TBF Mode. Extended Uplink TBF Mode does not require a licence, but it requires the Nokia GPRS functionality as a prerequisite. 7.2.1 Requirements Hardware requirements Table 30. Required additional or alternative hardware or firmware. Network element Hardware/firmware required BSC BTS TCSM SGSN No requirements No requirements No requirements No requirements DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 137 (272) EDGE System Feature Description Software requirements Table 31. Required software Network element Software release required BSC Nokia Flexi EDGE BTSs Nokia UltraSite BTSs Nokia MetroSite BTSs Nokia Talk-family BTSs Nokia InSite BTSs MSC/HLR SGSN Nokia NetAct S13 No requirements No requirements No requirements No requirements No requirements No requirements No requirements OSS4.2 CD Set 1 Frequency band support The BSC supports Extended Uplink TBF Mode on the following frequency bands: . GSM 800 GSM 900 GSM 1800 GSM 1900 . . . 7.2.2 Impact on transmission No impact. 7.2.3 Impact on BSS performance OMU signalling No impact. 138 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software TRX signalling No impact. Impact on BSC units Table 32. BSC unit OMU MCMU BCSU PCU Impact of Extended Uplink TBF Mode on BSC units Impact No impact. No impact. No impact. Faster uplink data flow continuing after short breaks. Impact on BTS units No impact. 7.2.4 User interface BSC MMI The following command groups and MML commands are used to handle Extended Uplink TBF Mode: . Parameter Handling: WOA, WOI, WOC Base Transceiver Station Handling in BSC: EQV . For more information on the command groups and commands, see MML Commands under Reference/Commands in the PDF view. BTS MMI Extended Uplink TBF Mode cannot be managed with BTS MMI. BSC parameters PRFILE parameters . UL_TBF_REL_DELAY_EXT UL_TBF_SCHED_RATE_EXT . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 139 (272) EDGE System Feature Description . POLLING_INTERVAL_STRM POLLING_INTERVAL_IA POLLING_INTERVAL_BG POLLING_INTERVAL_STR_LOW POLLING_INTERVAL_IA_LOW POLLING_INTERVAL_BG_LOW . . . . . For more information on PRFILE parameters, see PRFILE and FIFILE Parameter List. Alarms No alarms are specifically related to Extended Uplink TBF Mode. Measurements and counters The following measurements and counters are related to Extended Uplink TBF Mode. 72 Packet Control Unit Measurement Table 33. Name Counters of 72 Packet Control Unit Measurement Number 072115 072116 UL DATA CONT AFTER COUNTDOWN EXTENDED UL TBFS The counters are collected on BTS level. For more information, see 72 Packet Control Unit Measurement. 7.2.5 Impact on Network Switching Subsystem (NSS) No impact. 7.2.6 Impact on NetAct products NetAct Administrator No impact. 140 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software NetAct Monitor No impact. NetAct Optimizer No impact. NetAct Planner No impact. NetAct Radio Access Configurator (RAC) No impact. NetAct Reporter NetAct reporter can be used to create reports from measurements related to Extended Uplink TBF Mode. For a list of the measurements, see Measurements and counters. NetAct Tracing No impact. 7.2.7 Impact on mobile terminals 3GPP Rel.4 GERAN feature package 1 MS required. 7.2.8 Impact on interfaces Impact on radio interface No impact. Impact on Abis interface Support for Extended UL TBF Mode related signalling with the MS. Impact on A interface No impact. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 141 (272) EDGE System Feature Description Impact on Gb interface No impact. 7.2.9 Interworking with other features No impact. 7.3 System impact of Nokia Smart Radio Concept for EDGE The system impact of BSS10104: Nokia Smart Radio Concept for EDGE (Nokia SRC) is specified in the sections below. For an overview, see Nokia Smart Radio Concept for EDGE. Nokia Smart Radio Concept for EDGE does not require a licence. 7.3.1 Requirements Hardware requirements Table 34. Required additional or alternative hardware or firmware Network element Hardware/firmware required BSC BTS No requirements EDGE TRXs EDGE baseband units (BB2E/BB2F) TCSM SGSN No requirements No requirements 142 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Software requirements Table 35. Required software Network element Software release required BSC Nokia Flexi EDGE BTSs Nokia UltraSite EDGE BTSs Nokia MetroSite EDGE BTSs Nokia Talk-family BTSs Nokia InSite BTSs MSC/HLR SGSN Nokia NetAct S13 EP2 CX6.0 Not supported Not supported Not supported Not applicable Not applicable Not applicable Frequency band support The BSC supports Nokia SRC on the following frequency bands: . GSM 800 GSM 900 GSM 1800 GSM 1900 . . . 7.3.2 Impact on transmission No impact. 7.3.3 Impact on BSS performance OMU signalling No impact. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 143 (272) EDGE System Feature Description TRX signalling No impact. Impact on BSC units Table 36. BSC unit OMU MCMU BCSU PCU Impact of Nokia SRC on BSC units Impact No impact No impact No impact No impact Impact on BTS units When Nokia SRC is used, BB hopping must be disabled. The downlink gain of IDD in terms of signal level is 4 dB on average over one way transmission. This is mainly achieved due to 3 dB power gain using 2 TRXs transmission at the same time, and the provided diversity gain of delay diversity and phase hopping. The diversity gain is dependent on the propagation environment, frequency hopping and mobile speed. The uplink gain of 4UD is from 2 to 2,5 dB on average over 2-way diversity reception. 7.3.4 User interface BSC MMI Nokia SRC cannot be managed with BSC MMI. BTS MMI Nokia SRC is managed with BTS MMI. Nokia SRC is set up during BTS commissioning. The TRXs are displayed in the Supervision window – Equipment view in BTS Manager. BSC parameters There are no BSC parameters related to Nokia SRC. 144 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Alarms . IDD changes to the alarm handling function primarily address the need to “hide” the IDD auxiliary TRXs from the BSC. If an alarm is generated for an IDD main TRX, the alarm will be reported normally to the BSC and MMI. In case of a faulty alarm, alarm 7606 will be sent to the BSC and MMI. Only the main TRX will be blocked out of use but in effect the auxiliary TRX will be blocked as well. Alarms for IDD auxiliary TRXs are treated differently. If an alarm is generated for an IDD auxiliary TRX, the alarm will be reported to MMI and the BSC in the same way as its partner, the IDD main TRX alarm. In case of a faulty alarm, all signalling and traffic to the auxiliary TRX will stop, and the alarm is reported to the BSC and MMI as degraded service of the partner IDD main TRX. However, in order to let the BSC tell which unit the alarm comes from, new plug-in types will be defined for the alarm messages to the BSC. . . . . Measurements and counters There are no measurements related to Nokia SRC. 7.3.5 Impact on Network Switching Subsystem (NSS) No impact. 7.3.6 Impact on NetAct products NetAct Administrator No impact. NetAct Monitor NetAct Monitor can be used to monitor all alarms related to Nokia SRC. For a list of the alarms, see Alarms. NetAct Optimizer No impact. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 145 (272) EDGE System Feature Description NetAct Planner No impact. NetAct Radio Access Configurator (RAC) No impact. NetAct Reporter No impact. NetAct Tracing No impact. 7.3.7 Impact on mobile terminals There are no requirements for mobile terminals. 7.3.8 Impact on interfaces Impact on radio interface Nokia Smart Radio Concept is a performance enhancement solution. Nokia SRC is a combination of increased Tx/Rx signal power and diversity solution in both uplink and downlink directions. It consists of two TRXs, where the main and auxiliary TRXs are combined together with software for one operable logical TRX in the BSC. Nokia SRC consists of the following downlink and uplink performance enhancement solutions: . Intelligent Downlink Diversity Transmission (IDD) Interference Rejection Combining (IRC) Sensitivity-optimised High Gain Mast Head Amplifier (UltraSite MHA) 4-way Uplink Diversity reception (4UD) . . . In downlink direction, Intelligent Downlink Diversity (IDD) is a method, where a combination of delay diversity and phase hopping is used. Delay Diversity is a function of auxiliary TRX in IDD, and it creates an artificial multipath, which can be resolved by any mobile receiver. This reduces the impact of fast fading, in other words, the fading dips are not so deep. 146 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Phase Hopping is also a function of auxiliary TRX in IDD, and it artificially increases the channel fading rate, which would be comparable to frequency hopping and increased mobile speed. This reduces the time correlation of the channel, thus improving the performance. Uplink Diversity means that the same signal is received by multiple antennas at the same time. In uplink, Interference Rejection Combining (IRC) is an extension to the Maximum Ratio Combining (MRC) method. IRC can reject the interference and constructively combine multiple input signals from different antenna sources into one signal, while MRC only takes into account the noise difference between the received signals. IRC decorrelates input signal branches (IRC step) and performs signal combining (MRC step) for decorrelated branches. If there is no interference, IRC behaves like normal Maximum Ratio Combining without loss in terms of sensitivity performance. In case of 4-way Uplink Diversity, both main and auxiliary TRXs defined in IDD are used to process the received signal in uplink. The 4-way reception is done by 2-way IRC combining independently in both TRXs, followed by 2-way MRC post-detection combining stage in the main TRX. Impact on Abis interface No impact. Impact on A interface No impact. Impact on Gb interface No impact. 7.4 System impact of Priority Class based Quality of Service The system impact of BSS10084: Priority Class based Quality of Service is specified in the sections below. For an overview, see Priority Class based Quality of Service. Priority Class based Quality of Service does not require a licence. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 147 (272) EDGE System Feature Description 7.4.1 Requirements Hardware requirements Table 37. Required additional or alternative hardware or firmware Network element Required hardware or firmware BSC BTS TCSM SGSN PCU1/PCU2 No requirements No requirements No requirements Software requirements Table 38. Required software Network element Software release required BSC Nokia Flexi EDGE BTSs Nokia UltraSite EDGE BTSs Nokia MetroSite EDGE BTSs Nokia Talk-family BTSs Nokia InSite BTSs MSC/HLR GGSN S13 No requirements No requirements No requirements No requirements No requirements M14 GGSN2 CG2/3 SGSN Nokia NetAct SG7 OSS4.2 CD Set 1 148 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Frequency band support The BSC supports Priority Class based Quality of Service on the following frequency bands: . GSM 800 GSM 900 GSM 1800 GSM 1900 . . . 7.4.2 Impact on transmission No impact. 7.4.3 Impact on BSS performance OMU signalling No impact. TRX signalling No impact. Impact on BSC units Table 39. BSC unit OMU MCMU BCSU PCU Impact of Priority Class based Quality of Service on BSC units Impact No impact No impact No impact Both PCU1 and PCU2 support Priority Class based Quality of Service. Impact on BTS units No impact. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 149 (272) EDGE System Feature Description 7.4.4 User interface BSC MMI The following command group and MML commands are used to handle Priority Class based Quality of Service: . Base Station Controller Parameter Handling in BSC: EEV, EEO BTS MMI Priority Class based Quality of Service cannot be managed with BTS MMI. BSC parameters BSC radio network parameters There are different radio network parameters for priority based scheduling in PCU1 and PCU2. Table Radio network parameters for Priority Based Scheduling describes the correspondence of these parameters between PCU1 and PCU2. The following parameters apply to PCU1: . DL high priority SSS (DHP) DL normal priority SSS (DNP) DL low priority SSS (DLP) UL priority 1 SSS (UP1) UL priority 2 SSS (UP2) UL priority 3 SSS (UP3) UL priority 4 SSS (UP4) . . . . . . The following parameters apply to PCU2: . background traffic class scheduling weight for ARP 1 (BGSW1) background traffic class scheduling weight for ARP 2 (BGSW2) background traffic class scheduling weight for ARP 3 (BGSW3) . . 150 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software . interactive 1 traffic class scheduling weight for ARP 1 (ISW11) interactive 1 traffic class scheduling weight for ARP 2 (ISW12) interactive 1 traffic class scheduling weight for ARP 3 (ISW13) interactive 2 traffic class scheduling weight for ARP 1 (ISW21) interactive 2 traffic class scheduling weight for ARP 2 (ISW22) interactive 2 traffic class scheduling weight for ARP 3 (ISW23 interactive 3 traffic class scheduling weight for ARP 1 (ISW31) interactive 3 traffic class scheduling weight for ARP 2 (ISW32) interactive 3 traffic class scheduling weight for ARP 3 (ISW33) streaming traffic class scheduling weight for ARP 1 (SSW1) streaming traffic class scheduling weight for ARP 2 (SSW2) streaming traffic class scheduling weight for ARP 3 (SSW3) . . . . . . . . . . . Table 40. Radio network parameters for Priority Based Scheduling Scheduling step Scheduling size (PCU1) weight (PCU2) 1 2 3 4 5 6 7 8 9 10 60 30 20 15 12 10 9 8 7 6 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 151 (272) EDGE System Feature Description Table 40. Radio network parameters for Priority Based Scheduling (cont.) Scheduling step Scheduling size (PCU1) weight (PCU2) 11 12 5 5 For more information on radio network parameters, see BSS Radio Network Parameter Dictionary. Alarms No impact. Measurements and counters The following measurement and counters are related to Priority Class based Quality of Service: 90 Quality of Service Measurement Table 41. Name Counters of Quality of Service Measurement Number 090000 090001 090002 090003 090004 NUMBER OF TBF ALLOCATIONS TOTAL NBR OF RLC BLOCKS TOTAL DURATION OF TBFS DROPPED DL LLC PDUS DUE TO OVERFLOW DROPPED DL LLC PDUS DUE TO LIFETIME EXPIRY AVERAGE MS SPECIFIC BSSGP FLOW 090005 RATE AVERAGE MS SPECIFIC BSSGP FLOW 090006 RATE DEN VWTHR NUMERATOR GPRS VWTHR DENOMINATOR GPRS VWTHR NUMERATOR EDGE OTHER 4 VWTHR DENOMINATOR EDGE OTHER 4 VWTHR NUMERATOR EDGE 4 090007 090008 090009 090010 090011 152 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Table 41. Name Counters of Quality of Service Measurement (cont.) Number 090012 VWTHR DENOMINATOR EDGE 4 For more information, see 90 Quality of Service Measurement. 7.4.5 Impact on Network Switching Subsystem (NSS) The subscriber priority must be defined in the home location register (HLR) once Priority Class based Quality of Service is introduced in the network. 7.4.6 Impact on NetAct products NetAct Administrator No impact. NetAct Monitor No impact. NetAct Optimizer TRECs are supported in Service Optimizer (OSS3.1). NetAct Planner Priority Class based Quality of Service is supported in NetAct Planner. The precedence class and traffic class can be set for packet switched services. NetAct Radio Access Configurator (RAC) NetAct Radio Access Configurator (RAC) can be used to configure the radio network parameters related to Priority Class based Quality of Service. For more information, see BSS RNW Parameters and Implementing Parameter Plans in Nokia NetAct Product Documentation. For a list of the radio network parameters, see BSC parameters. NetAct Reporter NetAct Reporter can be used to view and create reports based on measurements related to Priority Class based Quality of Service. For a list of the measurements, see Measurements and counters. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 153 (272) EDGE System Feature Description NetAct Tracing The Quality of Service type is shown in the GPRS trace report in NetAct Tracing. 7.4.7 Impact on mobile terminals GPRS/EDGE-capable mobile terminals are required. 7.4.8 Impact on interfaces Impact on radio interface See Priority Class based Quality of Service for details. Impact on Abis interface No impact. Impact on A interface No impact. Impact on Gb interface No impact. 7.4.9 Interworking with other features PCU and Priority Class based Quality of Service Priority Class based Quality of Service works with both PCU1 and PCU2. There is an efficient Quality of Service differentiation mechanism in Priority Class based Quality of Service with PCU1. The differentiation is implemented by tuning the scheduling step size parameters (SSS). These parameters correspond to the scheduling weight parameters with PCU2. The SSS parameters cannot be used with PCU2. 7.5 System impact of System Level Trace The system impact of BSS10089: System Level Trace is specified in the sections below. For an overview, see System Level Trace. 154 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software System Level Trace does not require a licence. 7.5.1 Requirements Hardware requirements Table 42. Required additional or alternative hardware or firmware Network element Hardware/firmware required BSC BTS TCSM SGSN No requirements No requirements No requirements No requirements Software requirements Table 43. Required software Network element Software release required BSC Nokia Flexi EDGE BTSs Nokia UltraSite EDGE BTSs Nokia MetroSite EDGE BTSs Nokia Talk-family BTSs Nokia InSite BTSs MSC/HLR GGSN SGSN Nokia NetAct S13 No requirements No requirements No requirements No requirements No requirements M14 GGSN2 SG7 OSS4.2 CD Set 1 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 155 (272) EDGE System Feature Description Frequency band support The BSC supports System Level Trace on the following frequency bands: . GSM 800 GSM 900 GSM 1800 GSM 1900 . . . 7.5.2 Impact on transmission No impact. 7.5.3 Impact on BSS performance OMU signalling No impact. TRX signalling No impact. Impact on BSC Table 44. BSC unit OMU MCMU BCSU PCU Impact of System Level Trace on BSC units Impact No impact No impact No impact Faster uplink data flow continuing after short breaks. Impact on BTS units No impact. 156 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software 7.5.4 User interface BSC MMI No impact. BTS MMI System Level Trace cannot be managed with BTS MMI. BSC parameters No impact. Alarms No impact. Measurements and counters The following observations and counters are related to System Level Trace. 25 TBF Observation for GPRS Trace Table 45. Name Counters of TBF Observation for GPRS Trace Number 025000 025001 025002 025003 025004 025005 025006 025007 025008 025009 025010 025011 025012 SEGMENT ID BTS ID TRX ID IMSI TBF ALLOCATION TIME TBF ALLOCATION CALENDAR TIME TBF RELEASE TIME TBF DIRECTION QOS PRIORITY CLASS NBR OF FLOW CNTRL CHANGES FLOW CTRL CHANGE TIME 0 BUCKET SIZE 0 QOS LEAK RATE 0 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 157 (272) EDGE System Feature Description Table 45. Name ... Counters of TBF Observation for GPRS Trace (cont.) Number ... 025067 025068 025069 025070 025071 025072 025073 025074 025075 025076 ... 025167 025168 025169 025170 025171 025172 025173 025174 025175 025176 025177 025178 025179 025180 025181 ... 025272 025273 025274 025275 FLOW CTRL CHANGE TIME 19 BUCKET SIZE 19 QOS LEAK RATE 19 NBR OF TCHS IN BEG NBR OF REALLOC REALLOC TIME 0 REALLOC CAUSE 0 BTS ID 0 TRX ID 0 NEW NBR OF TCHS 0 ... REALLOC TIME 19 REALLOC CAUSE 19 BTS ID 19 TRX ID 19 NEW NBR OF TCHS 19 AMOUNT OF LLC DATA NBR OF RLC BLOCKS LAST MCS INITIAL CODING SCHEME NBR OF DYNABIS MCS CHANGES MCS CHANGES MCS CHANGE TIME 0 CAUSE MCS CHANGE 0 NEW MCS 0 NBR OF RLC BLOCKS PREV MCS 0 AMOUNT OF LLC DATA PREV MCS 0 ... MCS CHANGE TIME 19 CAUSE MCS CHANGE 19 NEW MCS 19 NBR OF RLC BLOCKS PREV MCS 19 158 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Table 45. Name Counters of TBF Observation for GPRS Trace (cont.) Number 025276 025277 025278 025312 025313 025314 AMOUNT OF LLC DATA PREV MCS 19 CAUSE TBF RELEASE TRACE STATUS TBF DTM FLAG MULTISLOT CLASS DTM MULTISLOT CLASS For more information, see 25 TBF Observation for GPRS Trace. 27 GPRS Cell Re-Selection Report Table 46. Name LAC CI RAC Counters of GPRS Cell Re-Selection Report Number 027000 027001 027002 027003 027004 027005 027006 027007 027008 027009 027010 027011 027012 027013 027014 027015 SEGMENT ID BTS ID TRX ID IMSI NC MODE CELL RESEL START TIME CELL RESEL START CAL TIME NCCR TRIGGERING CAUSE TARGET CELL ID TARGET RNC ID NACC START TIME CELL CHANGE TIME CELL RESEL END CAUSE CELL RESEL END TIME For more information, see 27 GPRS Cell Re-Selection Report. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 159 (272) EDGE System Feature Description 28 GPRS RX Level and Quality Report Table 47. Name LAC CI RAC BTS ID TRX ID IMSI Counters of GPRS RX Level and Quality Report Number 028000 028001 028002 028003 028004 028005 028006 028007 028008 028009 028010 028011 ... 028026 028027 028028 028029 028030 ... 028087 028088 028089 028090 028091 028092 028093 ... 028208 028209 REP PERIOD IDLE REP PERIOD TRANSF BEP USED RECORD START TIME RECORD END TIME NR OF MEASUREMENTS UL MEAS RESULTS 1 ... UL MEAS RESULTS 16 IS PACKET TRANSF MODE 1 REPORT TIME SEC AND 100TH SEC 1 DL RX LEV AND QUAL 1 NCELL MEAS RESULTS 1 ... IS PACKET TRANSF MODE 16 REPORT TIME SEC AND 100TH SEC 16 DL RX LEV AND QUAL 16 NCELL MEAS RESULTS 16 NCELL INDEX 1 NCELL RADIO TYPE 1 NCELL ID 1 ... NCELL INDEX 40 NCELL RADIO TYPE 40 160 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Table 47. Name Counters of GPRS RX Level and Quality Report (cont.) Number 028210 NCELL ID 40 For more information, see 28 GPRS RX Level and Quality Report. Table 48. CS and MCS codecs in the initial coding scheme and new MCS fields Codec (Modulation and user data rate) GPRS CS1 (GMSK 8 kbps) GPRS CS2 (GMSK 12 kbps) GPRS CS3 (GMSK 14.4 kbps) GPRS CS4 (GMSK 20 kbps) dummy value, bad header in ack mode EGPRS MCS1 (GMSK 8.4 kbps) EGPRS MCS2 (GMSK 11.2 kbps) EGPRS MCS3 (GMSK 14.8 kbps) EGPRS MCS4 (GMSK 16.8 kbps) EGPRS MCS5 (8-PSK 22.5 kbps) EGPRS MCS6 (8-PSK 29.6 kbps) EGPRS MCS7 (8-PSK 44.8 kbps) EGPRS MCS8 (8-PSK 54.4 kbps) EGPRS MCS9 (8-PSK 59.2 kbps) Counter value 0 1 2 3 4 5 6 7 8 9 10 11 12 13 7.5.5 Impact on Network Switching Subsystem (NSS) No impact. 7.5.6 Impact on NetAct products NetAct Administrator No impact. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 161 (272) EDGE System Feature Description NetAct Monitor No impact. NetAct Optimizer No impact. NetAct Planner No impact. NetAct Radio Access Configurator (RAC) No impact. NetAct Reporter NetAct reporter can be used to create reports from measurements related to System Level Trace. For a list of the measurements, see Measurements and counters. NetAct Tracing No impact. 7.5.7 Impact on mobile terminals GPRS-capable terminals are required. 7.5.8 Impact on interfaces Impact on radio interface No impact. Impact on Abis interface Support for Extended Uplink TBF Mode related signalling with the mobile station is required. Impact on A interface No impact. 162 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 System impact of GPRS/EDGE related software Impact on Gb interface The SGSN invokes the trace by sending a BSSGB SGSN-INVOKE-TRACE (3GPP TS 48.018) message to the BSS when the SGSN trace becomes active or when the SGSN receives a trace request. 7.5.9 Interworking with other features No impact. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 163 (272) EDGE System Feature Description 164 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Requirements for GPRS/EDGE 8 8.1 Requirements for GPRS/EDGE Packet Control Unit (PCU) For GPRS the BSC needs the Packet Control Unit, which implements both the Gb interface and RLC/MAC protocols in the BSS. PCU functions The PCU controls the GPRS radio resources and acts as the key unit in the following procedures: . GPRS radio resource allocation and management GPRS radio connection establishment and management Data transfer Coding scheme selection PCU statistics . . . . PCU and BSC product variants The PCU hardware is positioned at the BSC site as a plug-in unit in each BCSU. Table Nokia GSM/EDGE PCU product family lists the available PCU variants and table PCUs in BSC product variants shows the amount of PCUs for each BSC product variant. Table 49. Nokia GSM/EDGE PCU product family PCU General name Packet Control Unit, a general term for all Nokia GSM/EDGE PCU variants Name of PCU product variant Explanation DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 165 (272) EDGE System Feature Description Table 49. Nokia GSM/EDGE PCU product family (cont.) PCU General name Packet Control Unit, a general term for all Nokia GSM/EDGE PCU variants Name of PCU product variant Explanation First generation PCU for BSCi and BSC2i Nokia First Generation Packet PCU Control Unit - PCU1 PCU-S PCU-T PCU-B Nokia Second Generation Packet Control Unit - PCU2 PCU2-U PCU2-D First generation PCU for BSC3i 660, includes two logical PCUs Second generation PCU for BSCi and BSC2i Second generation PCU for BSC3i 660, BSC3i 1000 and BSC3i 2000, includes two logical PCUs Table 50. BSC product variant BSCi BSC2i BSC3i 660 BSC3i 1000 PCUs in BSC product variants Amount of PCUs One PCU plug-in unit (PIU) in each BCSU, a total of 8 (+1 spare) logical PCUs. Two PCU PIUs in each BCSU, a total of 16 (+2 spares) logical PCUs. Two PCU PIUs in each BCSU, a total of 24 (+4 spares) logical PCUs. Five PCU PIUs in each BCSU, a total of 50 (+10 spares) logical PCUs. Note that only two of the PCU PIUs can be of the type PCU-B. BSC3i 2000 Five PCU PIUs in each BCSU, a total of 100 (+10 spares) logical PCUs. Note that only two of the PCU PIUs can be of the type PCU-B. When installing the PCUs to BSCi and BSC2i, the operator has to make sure that the GSWB has enough capacity. Installing the first PCU plug-in unit into the BCSUs requires three SW64B plug-in units in the GSWB (GSWB size 192 PCMs), installing the second PCU plug-in unit requires four SW64B plug-in units in the GSWB (GSWB size 256 PCMs). 166 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Requirements for GPRS/EDGE If Gb over Frame Relay is used, then the operator also has to consider the need for E1/T1 (ET) extensions. PCU capacity and connections Table 51. PCU maximum connectivity per logical PCU PCU1 PCU2 128 64 256 256 BTS IDs Cells/Segments TRXs Connectivity (traffic channels, 16 kbit/s, Abis) 64 64 128 256 PCU1 variants PCU and PCU-S: 128 16 EDAPs 16 SGSN ETs Abis ETs Packets in TRAU frames 4 Mbit/s internal PCM 256 channels PCU GSWB ET Gb Packets in FR FR: bearer channel + optional load sharing redundant bearer (2 Mbit/s) DMC bus Figure 27. PCU connections to BTS and SGSN when Frame Relay is used Refer to Enabling GPRS in BSC for instructions on how to equip and connect the PCU, and PCU-B and PCU2-D for more information on the plug-in unit hardware. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 167 (272) EDGE System Feature Description Support for PCU2 PCU2 is a high capacity embedded plug-in unit that provides additional processing power and extended functionality from BSS11.5 onwards. Second Generation PCUs have an enhanced design architecture that enable the network to meet the real time traffic requirements of new services and provide means to new enhanced functionality (GERAN) beyond GPRS and EGPRS. There are two PCU2 plug-in unit variants: PCU2-U for BSCi and BSC2i and PCU2-D for BSC3i 660, BSC3i 1000 and BSC3i 2000. Main hardware improvements when compared to the other PCU plug-in units used in BSC include: . more processing capacity: . PQII: from 300MHz to 450 MHz . DSP: from 100MHz to 200MHz 16MB External memory for each DSP new serial interface between PQII and DSPs PCM interface through one serial interface . . . Internal PCU1 restrictions . In one logical PCU1 there are 16 digital signal processor (DSP) cores. In a PCU1, one DSP core can handle only one EGPRS dynamic Abis pool (EDAP), but one EDAP can be shared by several DSP cores. In the PCU1s, one DSP core can handle 0 to 20 channels (16 kbit/s), including active EDAP channels, EGPRS channels, and GPRS channels. The maximum number of 16 kbit/s channels per PCU1 is 256. All EGPRS channels of one EDGE TRX must be handled in the DSP core which handles the related EDAP. If an EDAP is handled in several DSP cores, the EGPRS channels of one EDGE TRX can be divided among several DSP cores in a PCU1. In PCU1 there is one synchronisation master channel (SMCH) for every EDAP. Due to DSP restrictions the SMCH must be allocated on PCUPCM0. To ensure that each EDAP has SMCH candidates on PCUPCM0, the PCU1 reserves a number of subTSLs from PCUPCM0 exclusively for each EDAP, that is for the EGPRS . . . 168 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Requirements for GPRS/EDGE channels on the TRXs attached to the EDAP. The PCU1 allocates the SMCHs from the beginning of PCUPCM0 and they are usually allocated to a different PCUPCM TSL than other EGPRS channels in the same TRX. . PCU1 and PCU1-S can handle 128 radio timeslots; the supported maximum number of GPRS channels and EGPRS master channels is 128. The full 256 channel EGPRS connectivity can be reached with EGPRS slave channels, in other words, the limitation does not concern EDAP channels. This issue should be taken into account in PCU dimensioning. PCU1 does not support CS–3 & CS–4, Extended Dynamic Allocation (EDA), High Multislot Classes (HMC) or Dual Transfer Mode (DTM). . Internal PCU2 restrictions . In one logical PCU2 there are 8 digital signal processor (DSP) cores. In a PCU2, one DSP core can connect two EGPRS dynamic Abis pools (EDAP), but one EDAP can be shared by several DSP cores. The nominal capacity of one DSP core of the PCU2 is 40 channels, it can connect 0 to 40 channels (16 kbit/s), including active EDAP channels, EGPRS channels and GPRS channels. However, the maximum summary of EGPRS channels and GPRS channels is 32 per DSP core, so in order to reach 40 channels there has to be at least 8 EDAP channels. The maximum number of 16 kbit/s channels per PCU2 is 256. All EGPRS channels of one EDGE TRX must be handled in the DSP core which handles the related EDAP. In addition, all the channels of a TRX must be on the same DSP core. In PCU2 there is one synchronisation master channel (SMCH) for every DSP. The PCU2 can allocate the SMCHs to both PCUPCMs 0 and 1. PCU2 does not support GPRS with Nokia InSite BTS. . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 169 (272) EDGE System Feature Description Common restrictions for both PCU1 and PCU2 . EDAP resource usage in a PCU dynamically reserves the DSP resources in the PCU. When EGPRS and GPRS calls (TBFs) in EGPRS territory use EDAP resources, allocation of the new packet switched radio timeslots to the PCU may fail due to the current EDAP and DSP resource load. When new packet switched radio timeslots are added/upgraded to the PCU, the PCU DSP resource capacity used for the EDAPs decreases. This may lead to a situation where the desired CS/MCS cannot be assigned to the TBFs. In DL direction, the TBFs can adjust the DL data according to limited Dynamic Abis capacity. In UL direction, the PCU DSP resource load situation may cause a situation in which the UL transmission turns cannot be assigned for the MSs, for example if adequate UL Dynamic Abis resources cannot be allocated. The EDAP size itself also limits the CS/MCS usage for both DL and UL TBFs. . . 8.2 Gb interface functionality The Gb interface is an open interface between the BSC and the SGSN. The interface consists of the Physical Layer, Network Service layer (NS), and the Base Station Subsystem GPRS Protocol (BSSGP). The Network Service layer further divides into Sub-network Service and Network Service Control. The Sub-network Service uses either Frame Relay or UDP/IP based protocol. The layers are briefly described here, but their functions are discussed in more detail in Gb interface configuration and state management. For more information on Gb over IP, see Gb over IP in BSC. 170 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Requirements for GPRS/EDGE LLC RELAY RLC MAC BSSGP NS L1 BSSGP NS L1 BSS NS Gb SGSN Network Service Control / Network Service Control protocol Sub-Network Service Control / Sub-Network Service Control protocol Figure 28. Protocol stack of the Gb interface The BSSGP protocol functions are BSSGP protocol encoding and decoding, BSSGP virtual connection (BVC) management, BSSGP data transfer, paging support, and flow control support. The Network Service Control is responsible for the following tasks: . NS protocol encoding and decoding NS data transfer NS Service Data Unit (NS SDU) transmission uplink congestion control on Network Service Virtual Connection (NS-VC) load sharing between NS-VCs NS-VC state management GPRS-specific addressing, which maps cells to virtual connections Network Service Virtual Link (NS-VL) management . . . . . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 171 (272) EDGE System Feature Description The Frame Relay protocols provide a link layer access between the peer entities. Frame Relay offers permanent virtual circuits (PVC) to transfer GPRS signalling and data between the BSC and SGSN. The Gb interface may consist of direct point-to-point connections between the BSS and the SGSN, or an intermediate Frame Relay network may be placed between both ends of the Gb interface. In the case of an intermediate Frame Relay network, both BSS and SGSN are treated as the user side of the user-to-network interface. In Frame Relay, the physical link is provided by the Frame Relay Bearer channels. In the BSC this physical connection is a maximum of one 2 Mbit/ s PCM for each active PCU. For load sharing and transmission security reasons, one PCU can have up to four Frame Relay Bearer channels that are routed to the SGSN through different transmission paths. This means that the GPRS traffic from one PCU can be shared with a maximum of four physical PCM connections. The PCUs cannot be multiplexed to use a common bearer. The maximum combined Bearer Channel Access Rate is 2048 kbit/s within a PCU. This can be achieved by combining the different PCMs so that 32 subtimeslots are available for traffic. The step size is 64 kbit/s. The Committed Information Rate of Network Service Virtual Connections can be configured from 16 kbit/s up to the Access Rate of the Bearer channel in 16 kbit/s steps. In the Nokia implementation each PCU represents only one Network Service Entity (NSE), unless Multipoint Gb and Packet Control Unit (PCU2) Pooling are used. 172 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Requirements for GPRS/EDGE BSC BCSU 0 PCU FR GSWB PCM-TSL ET bearer channel ID=1 name=BSC1 time slots:1-31 access rate:1984 kbit/s SGSN Figure 29. Gb interface between the BSC and SGSN when Frame Relay (FR) is used For more information on the NS and BSSGP protocols, refer to BSCSGSN Interface Specification, Network Service Protocol (NS) and BSCSGSN Interface Specification, BSS GPRS Protocol (BSSGP). For more information on configuring and handling the Gb interface, see Enabling GPRS in BSC, Frame Relay Bearer Channel Handling, (FU) and Frame Relay Parameter Handling (FN). 8.3 Additional GPRS hardware needed in BSCi and BSC2i GSWB extension (optional) The PCU requires the GSWB extension (2 per BSC) for multiplexing the 256 Abis sub-timeslots. The second PCU plug-in unit for the BSC requires an extension of the GSWB with a third SW64B plug-in unit. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 173 (272) EDGE System Feature Description ET5C cartridge (optional) Additional ET5C cartridges are optional. They are needed to increase the amount of external PCMs, in BSCi from 56 to 88 and in BSC2i from 80 to 144. The additional PCMs may be used for Gb over Frame Relay. 174 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio network management for GPRS 9 Radio network management for GPRS For Radio Network Configuration Management the preconditions are that the PCU and Gb interface have been created and configured. In the case of Frame Relay, the user builds the Gb interface in two phases: first the Frame Relay bearer channels are created, then the NS layer. Before enabling GPRS on a cell level, you need to create the Routing Area. See Activating and testing BSS9006: GPRS for detailed instructions. 9.1 Routing Area Mobility management in the GPRS network is handled in a similar way to the existing GSM system. One or more cells form a Routing Area (RA), which is a subset of one Location Area (LA). The Routing Area is unique within a Location Area. As Routing Areas are served by SGSNs, it is important to keep in mind the network configuration plan and what has been defined in the SGSN, before configuring the BSC side. One Routing Area is served by one SGSN. When creating a Routing Area the user identifies the obligatory parameters mobile country code (MCC), mobile network code (MNC), location area code (LAC), and routing area code (RAC). Routing Areas are created in the BSS Radio Network Configuration Database (BSDATA). The MCC, MNC, LAC and RAC parameters constitute the routing area identification (RAI): RAI = MCC+MNC+LAC+RAC The Routing Area and the BTS are linked logically together by the RAI. Routing Areas are used in the PCU selection algorithm which selects a serving PCU for the cell when the operator enables the GPRS traffic in the cell. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 175 (272) EDGE System Feature Description PCU 2 RA 2 BTS BTS SGSN PCU 1 RA 1 PCU 0 BTS BTS BTS RA n BTS BTS BSC LA Figure 30. Relationship of Routing Areas and PCUs Optimal Routing Area size Paging signalling to mobiles is sent, for example, over the whole Location Area/Routing Area. An optimal Routing Area (RA) is balanced between paging channel load and Routing Area updates. Refer to GPRS radio connection control for more information on paging. If the Routing Area size is too large, paging channels and capacity will be saturated due to limited LAPD, Abis or radio interface CCCH paging capacity. On the other hand, with a small Routing Area there will be a larger number of Routing Area updates. Paging channel capacity is shared between the paging of the existing GSM users to the Location Areas (LA) and the GPRS users to the Routing Area. Based on the traffic behaviour of subscribers and the performance of the network (in terms of paging success), it is possible to derive guidelines regarding the maximum number of subscribers per LA/RA. The Routing Area dimensioning is similar to the dimensioning of the Location Area of the existing GSM service. Routing Area dimensioning balances paging traffic from subscribers and the paging capacity offered by a given paging channel configuration. The number of pages that are sent by the BTS within an LA/RA indicates the number of mobile terminating calls that are being sent to subscribers in the LA/RA. The paging demand thus depends on three factors: 176 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio network management for GPRS . the number of mobile terminating calls the number of subscribers in the LA/RA paging parameters defined by the operator in the SGSN. . . The higher the number of mobile terminating sessions for subscribers in the Routing Area, the higher the number of pages that have to be sent by the BTS in the Routing Area. The success of paging, that is the number of times that a paging message has to be resent before it is answered, also has a profound effect on paging traffic. Paging traffic can thus be observed by means of: . the number of pages per second per user the number of subscribers the paging success ratio. . . The Nokia infrastructure allows a combined Routing Area and Location Area paging by implementing the Gs interface between the SGSN and MSC/HLR. An attached GPRS mobile must send a Routing Area Update to the SGSN each time it changes Routing Area. The SGSN then forwards the relevant location area update information to the MSC reducing the RACH and AGCH load. The conclusion is that the signalling load is highly dependent on the parameters. In the same LA/RA, the paging load should be monitored. Tip The smallest cell in the LA/RA will set the paging channel limit where combined channel structure is in use. Combined channel structure is possible if the cell is GPRS enabled (Routing Area exists). 9.2 PCU selection algorithm The PCU selection algorithm in the BSC distributes GPRS traffic capacity between PCUs. Traffic is distributed on a cell level when the user enables GPRS in the cell. The algorithm then selects which PCU takes care of the traffic of a certain cell. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 177 (272) EDGE System Feature Description When GPRS is enabled, each cell is situated in a Routing Area. In the Radio Network, each Routing Area has its own object, to which the user defines the Network Service Entity Identifiers (NSEI) serving the Routing Area. The NSEIs are further discussed in Gb interface configuration and state management. The Nokia implementation is such that one PCU corresponds to one NSEI (unless Multipoint Gb and Packet Control Unit (PCU2) Pooling are used), and thus it can be said that the function of the PCU selection algorithm is to distribute GPRS traffic capacity between these NSEIs. The algorithm locates the cells (BVCIs) in the same BCF to the same NSEI. The algorithm also tries to locate the cells which have adjacencies between each other to the same NSEI. If there are no NSEIs with the same BCF or with adjacencies then the algorithm selects the NSEI to which the smallest number of GPRS capable traffic channels, defined with the parameter max GPRS capacity (CMAX), is attached. Traffic channels are counted on TRXs which are GPRS enabled but not extended or superreuse TRXs. Only unlocked NSEIs are selected. The NSEI is unlocked when it has at least one of its NS-VCs unlocked. If a Dynamic Abis Pool is defined for a TRX in a cell and when GPRS is enabled for the cell, the same NSEI (PCU) is selected for the cell as for the Dynamic Abis Pool. In this case the PCU selection algorithm is not used. The operator can choose whether the selected NSEI uses IP or FR transport with the parameter transport type (TRAT). The parameter cannot be used with manual NSEI selection. If no transport type is specified the default is that neither IP nor FR is preferred in the PCU selection algorithm. The NSEIs can also be selected manually. If manual selection is used the PCU selection algorithm is not used. For more information on manual selection, see Activating and Testing BSS9006: GPRS and Base Transceiver Station Handling in BSC (EQ). For information on the PCU selection algorithm when Packet Control Unit (PCU2) Pooling is used, see chapter Functionality of Packet Control Unit (PCU2) Pooling in Packet Control Unit (PCU2) Pooling under Feature descriptions/Data in the PDF view. 178 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Gb interface configuration and state management 10 Gb interface configuration and state management The BSC has the following functions in connection with the Gb interface: . load sharing NS-VC management NS-VL management (IP) BVC management recovery. . . . . Only Gb over Frame Relay is covered in these guidelines. For information on Gb over IP, see Gb over IP in BSC. For information on Multipoint Gb Interface, see Multipoint Gb Interface under Feature descriptions/Data in the PDF view. 10.1 Protocol stack of the Gb interface The Gb interface has a protocol stack consisting of three layers: Physical Layer, Network Service Layer (NS) and the Base Station System GPRS Protocol (BSSGP). The Network Service Layer further divides into Subnetwork Service and Network Service Control. The Sub-network Service uses either Frame Relay or UDP/IP protocol. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 179 (272) EDGE System Feature Description LLC RELAY RLC MAC BSSGP NS L1 BSSGP NS L1 BSS NS Gb SGSN Network Service Control / Network Service Control protocol Sub-Network Service Control / Sub-Network Service Control protocol Figure 31. The protocol stack on the Gb interface Network Service Virtual Connection (NS-VC) NS-VCs are end-to-end virtual connections between the BSS and SGSN. The physical link in the Gb interface is the Frame Relay Bearer channel or UDP/IP connection. In the case of Frame Relay, a NS-VC is the permanent virtual connection (PVC) and corresponds to the Frame Relay DLCI (Data Link Connection Identifier) together with the Bearer channel identifier. Each NS-VC is identified by means of a Network Service Virtual Connection Identifier (NSVCI). Network Service Entity (NSE) NSE identifies a group of NS-VCs in the BSC. The NSEI is used to identify the Network Service Entity that provides service to a BSSGP Virtual connection (BVC). One NSE is configured between two peer NSs. At each side of the Gb interface, there is a one-to-one correspondence between a group of NS-VCs and an NSEI. The NSEI has an end-to-end significance across the Gb interface at NS level, but only local significance at the BSSGP level. One NSE per PCU is supported and within one NSE a maximum of four NS-VCs are supported. 180 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Gb interface configuration and state management Network Service Virtual Connection Group According to the 3GPP standard (TS48.016), the Network Service Virtual Connection Group groups together all NS-VCs providing communication between the same peer NS entities. One NS-VC group is configured between two peer NS entities. This grouping is performed by administrative means. At each side of the Gb interface, there is a one-toone correspondence between a group of NS-VCs and an NSEI. The NSEI has an end-to-end significance across the Gb interface. BSSGP Virtual Connection (BVC) BVCs are communication paths between peer NS user entities on the BSSGP level. Each BVC is supported by one NSE and it is used to transport Network Service Service Data Units (NS SDUs) between peer NS users. Each BVC is identified by means of a BVCI which has end-to-end significance across the Gb interface. Each BVC is unique between two peer NSs. Within BSS the user identifies a cell uniquely by a BVCI. The BVCI value 0000H is used for signalling and the value 0001H is reserved for point-tomultipoint (PTM). PTM is not supported. All other values can be used for cell identifiers. Link Selector Parameter (LSP) All BSSGP UNITDATA PDUs related to an MS are passed to NS with the same LSP. This preserves the order of BSSGP UNITDATA PDUs, since the LSP is always mapped to a certain NS-VC. LSP has only local significance at each end of the Gb interface. Frame Relay Permanent Virtual Connection (PVC) See 10.1.1 Network Service Virtual Connection (NS-VC). DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 181 (272) EDGE System Feature Description 10.2 Load sharing function The BSC's load sharing function distributes all uplink Network Service Service Data Units (NS SDUs) among the unblocked NS-VCs within the NSE on the Gb interface. The use of load sharing also provides the upper layer with seamless service upon failure or user intervention by reorganising the SDU traffic between the unblocked NS-VCs. When creating the NS-VC the operator gives a CIR value (bit/s). The reorganisation may disturb the order of transmitted SDUs. All NS SDUs to be transmitted over the Gb interface towards the SGSN are passed from BSSGP to NS along with the Link Selector Parameter (LSP). All the NS SDUs of an MS have the same LSP. However, several MSs may use the same LSP. NS SDUs with the same LSP are sent on the same NSVC. The load sharing functions of the BSC and SGSN are independent. Therefore, uplink and downlink NS SDUs may be transferred over different NS-VCs. SGSN distributes downlink NS SDUs. 10.3 NS-VC management function The Network Service Virtual Connection (NS-VC) management function is responsible for the blocking, unblocking, resetting, and testing of NS-VCs. NS-VC management procedures can be triggered by both the BSC and the SGSN. Only one substate (BL-US, BL-SY or BL-RC) is valid at a time when an NS-VC is blocked. The BL-US state overrides both the BL-SY and BL-RC states. The BL-SY state overrides the BL-RC state. The BL-RC state does not override any other blocking state, so it is only possible when the NSVC is unblocked. An exception is when the NS-VC is in the BL-SY state and SGSN initiates an NS-RESET. The NS may be reset only when using Frame Relay. Refer to 10.3.1 NS-VC reset for more information. Table 52. State NS-VC operational states Possible substates – Unblocked (WO-EX Available) 182 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Gb interface configuration and state management Table 52. State Blocked NS-VC operational states (cont.) Possible substates BL-US (unavailable by user) BL-SY (unavailable by system) BL-RC (unavailable by remote user) NS-VC blocking When an NS-VC is unavailable for BSSGP traffic, the NS-VC is marked as blocked by the BSC and the peer NS is informed by means of the blocking procedure. The BSC blocks an NS-VC when: . the user locks the NS-VC, thus making it unavailable for BSSGP traffic; the cause sent to SGSN is 'O & M intervention'; operational state is BL-US. an NS-VC test fails; the cause sent to SGSN is 'Transit network failure'; operational state is BL-SY Frame Relay detects unavailability of a bearer or PVC; the cause sent to SGSN is 'Transit network failure'; operational state is BL-SY . . During user block the BSC marks the NS-VC as user blocked, informs peer NSs, and reorganises BSSGP traffic to use other unblocked NS-VCs of the NSE. User-triggered blocking is started only when the PVC or the bearer is available, otherwise the NS-VC is marked as user blocked and the block procedure is skipped. The BSC cancels any pending NS-VC management procedure and related alarm. After NS-VC test failure the NS-VC is marked as system blocked, the BSC raises the alarm NETWORK SERVICE VIRTUAL CONNECTION TEST PROCEDURE FAILED (3025) and blocks the NS-VC towards the SGSN through any 'live' NS-VC within the NSE, blocked or unblocked. The BSC also initiates the NS-VC reset procedure. BSSGP traffic is reorganised to use other unblocked NS-VCs of the NSE. If the NS-VC is user blocked while reset is attempted, the reset is stopped, the user block is accepted and the state of the NS-VC is user blocked. The BSC cancels the NETWORK SERVICE VIRTUAL CONNECTION TEST PROCEDURE FAILED (3025) alarm after the next successful test procedure on the NSVC. If the NS-VC is already user blocked, the BSC does not change the DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 183 (272) EDGE System Feature Description NS-VC state, it sets no alarms, and sends no block to the SGSN, but instead initiates the NS-VC reset procedure. After a successful reset, the test procedure is continued. If the NS-VC reset procedure fails after all the retries, no alarm is set. After the BSC detects the unavailability of a PVC or a bearer, the related NS-VC(s) is marked as system blocked and the BSC blocks it towards the SGSN through any 'live' NS-VC within the NSE, blocked or unblocked. The BSC sets the NETWORK SERVICE VIRTUAL CONNECTION UNAVAILABLE (3020) alarm for the blocked NS-VC(s) and reorganises BSSGP traffic to use other unblocked NS-VCs of the NSE. If the NS-VC(s) is already user blocked, when the unavailability of a PVC or bearer is detected, the BSC does not change the state of the NS-VC(s), does not set an alarm, and does not send a block to the SGSN, but instead stops the NS-VC(s) test. If the NS-VC(s) is already system blocked, the BSC actions are the same but it also stops a possible ongoing reset procedure. During an SGSN-initiated block, if the NS-VC is not user, system or remote blocked, the BSC marks the NS-VC as remote blocked, reorganises BSSGP traffic to use other unblocked NS-VCs of the NSE and sets the alarm NETWORK SERVICE VIRTUAL CONNECTION UNAVAILABLE (3020). If the NS-VC is user, system or remote blocked, then the BSC does not change the NS-VC state and acknowledges the received block back to the SGSN. In all the above cases, if the blocked NS-VC is the last one in the NSE, it means that all BSSGP traffic to/from PCU-managed cells stops on the Gb interface, and the BSC sends System Information messages to relevant cells indicating that GPRS is disabled. The BSC sets the NETWORK SERVICE ENTITY UNAVAILABLE (3019) alarm when PVC/bearers are unavailable, the SGSN initiates the block, or related BVCs are implicitly blocked. NS-VC unblocking When the NS-VC becomes available again for BSSGP traffic, the peer NS is informed by means of the unblocking procedure, after which the NS-VC is marked as unblocked by the BSC. The BSC unblocks an NS-VC after: . user unlocks the NS-VC thus making it available for BSSGP traffic. the system initiates a NS-VC reset, for example after a test failed NS-VC is reset or after a reset of a NS-VC whose bearer is resumed as available for NS level. . 184 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Gb interface configuration and state management During user unblock the BSC informs the peer NS and marks the NS-VC as unblocked after receiving an acknowledgement from the peer NS. New BSSGP traffic now uses this new NS link (refer to 10.2 Load sharing function). User triggered unblocking starts only when the PVC or the bearer is available, otherwise the BSC marks the NS-VC as system blocked and skips the unblock procedure. The BSC sets the NETWORK SERVICE VIRTUAL CONNECTION UNBLOCK PROCEDURE FAILED (3021) alarm and marks the NS-VC unblock as pending until NS-VC unblock can be performed and the alarm is cancelled by the BSC. During system unblock the BSC cancels the NETWORK SERVICE VIRTUAL CONNECTION UNAVAILABLE (3020) alarm. The BSC does not start system initiated unblock if the NS-VC is user blocked. During SGSN initiated unblock, the BSC marks the NS-VC as unblocked and cancels the NETWORK SERVICE VIRTUAL CONNECTION UNAVAILABLE (3020) alarm if the NS-VC is not user or system blocked. If the NS-VC is user blocked, then the BSC is not able to unblock the NSVC. The NS-VC remains user blocked and the BSC initiates the NS-VC blocking procedure by returning an NS-BLOCK PDU to the SGSN with the cause "O & M intervention". This NS-BLOCK PDU is sent on the NS-VC where the NS-UNBLOCK PDU was received. If the NS-VC is system blocked with no BSC initiated unblock procedure on, then the BSC is not able to unblock the NS-VC. The NS-VC remains system blocked and the BSC initiates the NS-VC reset procedure by returning an NS-RESET PDU to the SGSN with the cause "PDU not compatible with the protocol state". If the NS-VC is system blocked with a BSC initiated unblock procedure on, then the BSC acknowledges the received PDU back to the SGSN and it is interpreted as an acknowledgement for the sent NS-UNBLOCK PDU. In all of the above cases, if the unblocked NS-VC is the first one in the NSE, it means that BSSGP traffic to/from PCU-managed cells can start again on the Gb interface, and the BSC sends System Information messages to relevant cells indicating that GPRS is enabled. The BSC triggers the BVC reset procedure for signalling BVC and cell-specific BVCs, and cancels the NETWORK SERVICE ENTITY UNAVAILABLE (3019) alarm in cases of system unblock and SGSN initiated unblock. For more information, see BSC-SGSN Interface Specification, Network Service Protocol (NS). NS-VC reset The NS-VC reset procedure is used to reset an NS-VC to a determined state between peer NSs. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 185 (272) EDGE System Feature Description Table 53. NS-VC reset cases Case where the BSC resets an NSVC The user sets up, modifies or unlocks an NS-VC System or BCSU restarts Periodic NS-VC test fails Frame Relay detects an unavailability of a bearer Cause sent to the SGSN O & M intervention Equipment failure (see 10.5.1 BCSU restart) Transit network failure Transit network failure During a reset triggered by user unblock, the BSC marks the NS-VC as system blocked, informs the peer NS, and reorganises BSSGP traffic to use other unblocked NS-VCs of the NSE. After a completed reset procedure, the BSC starts a test procedure (periodic testing) and after successful testing unblocks the NS-VC. The BSC starts a reset triggered by user unblock only when the PVC or the bearer is available, otherwise it marks the NS-VC as system blocked, skips the reset procedure, and sets the NETWORK SERVICE VIRTUAL CONNECTION RESET PROCEDURE FAILED (3023) alarm. The BSC sets the NS-VC reset as pending until the NS-VC reset can be performed and then cancels the alarm. During an SGSN-initiated reset, the BSC marks the NS-VC as remote blocked and sets the NETWORK SERVICE VIRTUAL CONNECTION UNAVAILABLE (3020) alarm if the NS-VC is not user or remote blocked. If the NS-VC is user or remote blocked, then the BSC does not change the state, but acknowledges the received reset back to SGSN and initiates the test procedure. If the NS-VC is system blocked, then the action depends on whether the NS-VC reset is ongoing or not. If the NS-VC reset is ongoing, then the received NS-RESET is interpreted as an acknowledgement and the BSC acknowledges it back to the SGSN and initiates the test procedure. If the NS-VC reset is stopped, then the BSC changes the NS-VC state to remote blocked (to get the NS-VC up during SGSN initiated NS-VC unblock), acknowledges the received reset back to the SGSN, and initiates the test procedure. In all the above cases, if the blocked NS-VC is the last one in the NSE, it means that all BSSGP traffic to/from PCU managed cells stops on the Gb interface, and the BSC sends System Information messages to relevant cells indicating that GPRS is disabled. The BSC sets the NETWORK SERVICE ENTITY UNAVAILABLE (3019) alarm in a SGSN initiated reset and blocks the related BVCs implicitly. 186 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Gb interface configuration and state management For more information, see BSC-SGSN Interface Specification, Network Service Protocol (NS). NS-VC test The NS-VC test procedure is used when the BSC checks that end-to-end communication exists between peer NSs on a given NS-VC. The user can define the test procedure with the PRFILE parameter TNS_TEST. When end-to-end communication exists, the NS-VC is said to be 'live', otherwise it is 'dead'. A 'dead' NS-VC cannot be in the unblocked state, instead it is always marked as blocked and a reset procedure is initiated. Both sides of the Gb interface may initiate the NS-VC test independently from each other. This procedure is initiated after successful completion of the reset procedure, and is then periodically repeated. The test procedure runs on unblocked NS-VCs and also on user blocked and remote blocked NS-VCs, but not on system blocked NS-VCs, except after NS-VC reset. The test procedure is stopped when the underlying bearer or PVC is unavailable. For more information, see BSC-SGSN Interface Specification, Network Service Protocol (NS). 10.4 BVC management function The BVC management function is responsible for the blocking, unblocking and reset of BVCs. The BVC reset procedure can be triggered by both the BSC and the SGSN, but BVC blocking and unblocking procedures can only be triggered by the BSC. The user can output the BVC operational state with the command EQO. The possible states are shown in the table below. Table 54. Operational state WO-EX BL-SY BVC operational states Explanation The BVC is operational. Unavailable by system. The NSE is not functional, or a radio network object (a TRX, BTS or BCF) is blocked so that the cell does not have GPRS capability. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 187 (272) EDGE System Feature Description Table 54. Operational state unblocked BVC operational states (cont.) Explanation Either GPRS has been enabled in the cell and the BVC has been created in the SGSN, but the BVC's flow control is not yet operational, or the cell has no GPRS TSLs. The BVC has not been configured for the PCU, or the configuration has been lost from the PCU. This situation can be resolved by disabling, and the re-enabling GPRS in the cell, or by executing BCSU switchover. BVC conf lost unknown The enquired BVCI is outside the allowed value range, or the PCU does not report the state of the BVC within the time limit because of some fault situation. In the latter case the user should check the status of the PCU. BVC blocking and unblocking BVC blocking is initiated by the BSC to remove a BVC from GPRS data use. Table 55. BVC blocking cases Cause sent to the SGSN Case where the BSC blocks a BVC A user disables GPRS in a cell, disables the last O & M intervention GPRS-supporting TRX in a cell, blocks the BCCH TRX in a cell or deletes a BVC by disabling GPRS in a cell. A user or system block of the last NS-VC of the NSE No indication is sent to the SGSN. serving the BVC; related BVCs are locally blocked by the BSC. SGSN initiates a BVC-RESET procedure (if necessary). A cell level fault, for example at the beginning of site reset, BTS reset or TRX reset. BVCI-blocked Equipment failure BVC unblocking is used only in an exceptional condition when the BSC receives an unexpected BVC-BLOCK-ACK PDU relating to a BVC that is locally unblocked. The BSC then unblocks the BVC with the BVCUNBLOCK PDU. 188 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Gb interface configuration and state management For more information, see BSC-SGSN Interface Specification, BSS GPRS Protocol (BSSGP). BVC reset A BVC reset is initiated by the BSC to bring GPRS data into use in a BVC. BVC reset is used instead of BVC unblock because of the dynamic configuration of BVCs in the SGSN. Table 56. Case where BSC resets a BVC BVC reset cases Cause sent to the SGSN A user enables GPRS in a cell, enables the first O & M intervention GPRS-supporting TRX in a cell, deblocks the BCCH TRX in a cell, or creates a BVC by enabling GPRS in a cell. A user or system unblock of the first NS-VC of the NSE serving the BVC (signalling BVC is reset first, then the rest). A cell restart, for example after site, BTS or TRX reset, when the restarted object is working Network service transmission capacity modified from zero kbit/s to greater than zero kbit/s Equipment failure With the BVC reset the underlying network service must be available for use, otherwise the BSC marks the BVC as unblocked in order to get the BVC up and running when the NS-level becomes available again, skips the BVC reset procedure, and sets the BSSGP VIRTUAL CONNECTION RESET PROCEDURE FAILED (3031) alarm. The BSC cancels the alarm after the next successful BVC block, unblock or reset. For more information, see BSC-SGSN Interface Specification, BSS GPRS Protocol (BSSGP). 10.5 Recovery in restart and switchover In a recovery situation the BCSU and PCU are always handled together as a pair. The diagnostics of the PCU is included in the diagnostics of the BCSU. Diagnostics is run automatically, but the operator may also start the diagnostics routine if needed. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 189 (272) EDGE System Feature Description BCSU restart If the Gb interface uses Frame Relay, after user or system initiated BCSU restart, the BSC recreates the Gb interface on the restarted PCU right after Frame Relay level set-up. The PCU starts Frame Relay level periodic polling towards the SGSN. Spontaneous indications come from the SGSN to the BSC's PCU on Frame Relay level about bearer channel availability for NS-VCs. First all NS-VCs are created, then all BVCs are created after cell-specific block indications. The PCU maintains only user blocked information of NSVCs. The NS-VCs which have received DLCIs from the network are reset when the bearer channel is available. The PCU sets others as pending and raises the NETWORK SERVICE VIRTUAL CONNECTION RESET PROCEDURE FAILED (3023) alarm for each NS-VC. The reset procedure is completed when the PCU receives a suitable DLCI from the network, and cancels the alarm. The PCU then initiates the test procedure on the successfully reset NS-VCs, and after successful tests unblocks all tested NS-VCs, and resets the signalling BVC. After successful BVC reset the uplink BSSGP data delivery is possible on that BVC. After an initial flow control procedure for the BVCs, also downlink BSSGP data delivery is possible on that BVC. Flow control is discussed in more detail in GPRS radio connection control. BCSU switchover If the Gb interface uses Frame Relay, after BCSU switchover (either user or system initiated), the BSC recreates the Gb interface on the target PCU right after Frame Relay level set-up. The Gb interface configuration is from the source PCU and the setting up of the Gb interface is similar to what was described in section 10.5.1 BCSU restart. The BSC does not send NS level blocks from the source PCU in order not to interrupt the BVC configurations of the SGSN. Forced BCSU switchover The operation in a forced BCSU switchover is very similar to the operation in a BCSU restart. The PCU releases all PCU PCM connections related to the restarted PCU. All GPRS data connections will drop after the PCU PCM connections are released. After the switchover — whether user or system initiated — the BSC unblocks TRXs and delivers new territory to the PCU. 190 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Gb interface configuration and state management Controlled BCSU switchover A controlled BCSU switchover is either a user or a system initiated action. The user defines between which BCSUs the switchover is made. The system cancels the switchover command if the execution would lead to a situation where some of the circuit switched calls would drop. If the switchover is cancelled, the original working BCSU is restored back to the working state. If a PCU gets faulty the system may initiate the BCSU switchover. Tip Only GPRS data connections that are connected to the PCU are released. In a successful switchover, the BSC moves the control of the working BCSU/PCU pair to the spare BCSU/PCU pair as in the forced switchover, but data is copied only from the working BCSU to the spare BCSU. Because GPRS data is not copied to the PCU, the PCU sees the data as lost and thus releases all its PCU PCM connections and unblocks its BTSs. The BSC resets the new spare PCU to the working state, and defines its new GPRS territory. If the switchover is cancelled for some reason, the original working PCU is restored back to the working state, and the BSC resumes GPRS territory updatings. The BSC allows new GPRS connection setups in the old working PCU again. After an unsuccessful switchover the PCU uses the same GPRS territory as it had before the switchover. At the end of the switchover the spare PCU is restarted regardless of the switchover being successful or not. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 191 (272) EDGE System Feature Description 192 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management 11 Radio resource management GPRS radio resource management in BSC involves two processes: division of radio timeslots between circuit switched and packet switched timeslot territories on the one hand, and channel allocation for individual MSs within the PS territory on the other hand. Division of radio timeslots into territories means that BSC selects the radio timeslots that shall be used primarily for packet data traffic and which shall therefore be avoided in traffic channel allocation for circuit switched services. During channel allocation for individual MSs PCU assigns PS territory timeslots for GPRS TBFs. The radio resource management function which is responsible for the CS/ PS territory management also takes care of traffic channel allocation for circuit switched calls. PCU has its own radio channel allocation that takes care of allocating channels for GPRS TBFs. Up to seven uplink GPRS TBFs can share the resources of a single radio timeslot. Uplink and downlink scheduling processes are independent of each other, and for downlink up to nine GPRS TBFs can share the resources of a single radio timeslot. To enable GPRS traffic in a cell, and to initiate the creation of the necessary PS territory, the operator has to first activate GPRS in the BSC with the cell-specific parameter GPRS enabled (GENA) and define which TRXs are capable of GPRS with the parameter GPRS enabled TRX (GTRX). To activate EGPRS, the operator uses the BTS-specific parameter EGPRS enabled (EGENA). Only after the BSC has an update on the BTS parameters and other parameters indicating GPRS usage, does it count the number of default and dedicated GPRS timeslots in the BTS and select a TRX where it starts to establish the GPRS territory. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 193 (272) EDGE System Feature Description The BSC can upgrade or downgrade the number of radio resources allocated for GPRS use according to the varying needs of the circuit switched and GPRS traffic. These procedures are explained in detail in the following sections. 11.1 Territory method The territory method is the same for GPRS and EGPRS. The BSC divides radio resources semipermanently between circuit switched services and GPRS, thus forming two territories. The PCU uses the GPRS territory resources. The initial territories are formed on a BTS-toBTS basis according to the operator-defined parameters. The BSC can later broaden the GPRS territory based on the actual need and according to the requests of the PCU. The circuit switched services have priority over GPRS in channel allocation within common resources. In principle, GPRS releases its resources as soon as they are needed for circuit switched traffic. Only Full Rate and Dual Rate traffic channels are GPRS compatible, and within a cell only such channels may be configured into the PS territory. GPRS capacity can be divided into three types: . default GPRS capacity dedicated GPRS capacity additional GPRS capacity. . . GPRS has a predefined set of resources which it can utilise when the circuit switched load allows. This is referred to as the default GPRS capacity. Part of these default traffic channels can be reserved solely for GPRS and this means they are blocked altogether from circuit switched use. This is referred to as dedicated GPRS capacity. The user can modify these two capacities by using the respective parameters default GPRS capacity (CDEF) and dedicated GPRS capacity (CDED). Additional GPRS capacity is referred to with radio timeslots that are above and beyond the default GPRS capacity and that the BSC has allocated for GPRS use according to the requests of the PCU. GPRS territory size can be restricted by the user-modifiable parameter max GPRS capacity (CMAX). There is a GPRS territory update guard time defining how often the PCU can request new radio timeslots for GPRS use. 194 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management TRX 1 TRX 2 BCCH Circuit Switched Territory GPRS Territory Max GPRS Capacity Additional GPRS Capacity Dedicated GPRS Capacity Default GPRS Capacity Territory border moves based on Circuit Switched and GPRS traffic load Figure 32. Territory method in BSC The BSC calculates these defined resources from percentages to concrete numbers of radio timeslots based on the number of traffic channel radio timeslots (both blocked and working) capable of Full Rate traffic in the TRXs with GPRS enabled (set with the parameter GPRS enabled TRX (GTRX)). The super reuse TRXs (Intelligent Underlay Overlay) and the extended area TRXs (Extended Cell Range) are never included as available resources in the GPRS territory calculation. The calculation is as follows: . the product of default GPRS capacity (CDEF) parameter and the number of radio timeslots is rounded down to a whole number. if default GPRS capacity (CDEF) parameter value is > 0 but the rounded product equals 0, then the territory size 1 is used. default GPRS capacity (CDEF) parameter minimum value is 1. max GPRS capacity (CMAX) parameter minimum value is 1 (range 1–100%). . . . The BSC starts to create the GPRS territory by first selecting the most suitable TRXs in the BTS according to its GPRS capability, TRX type, TRX configuration, and the actual traffic situation in the TRX. The prefer BCCH frequency GPRS (BFG) parameter indicates if the BCCH-TRX is the first or the last choice for the GPRS territory or if it is handled equally with non-BCCH-TRXs. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 195 (272) EDGE System Feature Description The best candidate for GPRS territory according to the traffic load is the TCH TRX that holds the most idle successive Full Rate-capable (TCH/F or TCH/D) timeslots counted from the end of the TRX (timeslot 7). The GPRS timeslots are always allocated from TSL7 towards TSL0 per TRX. If there are two or more TRXs that have the same number of idle successive Full Rate-capable timeslots, then the TRX containing permanent TCH/F timeslots is preferred to one with Dual Rate timeslots to avoid wasting Half Rate capability in the GPRS territory. TRXs with permanent TCH/H timeslots or multislot HSCSD calls are also avoided, if possible. Having defined the GPRS capacity share and having selected the best TRX for GPRS, the BSC next begins a GPRS territory upgrade procedure where it allocates the selected radio timeslots of the TRX for GPRS use and informs the PCU. GPRS territory upgrade The BSC uses a GPRS territory upgrade procedure to allocate part of the resources for GPRS use. The BSC starts the GPRS territory upgrade procedure when the user enables GPRS in a BTS. The number of timeslots given for GPRS use is defined by the operator with the parameters dedicated GPRS capacity (CDED), default GPRS capacity (CDEF) and max GPRS capacity. All the defined timeslots cannot necessarily be delivered immediately due to the circuit switched traffic load of the BTS. However, the BSC fulfils the defined GPRS capacity as soon as possible. After the default capacity (which includes also the dedicated part) has been delivered, the PCU can request more resources for a GPRS territory upgrade based on the actual need caused by GPRS use. Each GPRS territory upgrade concerns timeslots of one TRX; thus an upgrade is a TRX-specific procedure. The BSC performs upgrades of continuous sets of successive timeslots. Starting from the end of the first TRX in the GPRS territory, the BSC includes in a GPRS territory upgrade the timeslots according to need and availability. If the GPRS territory cannot be extended to its full size due to a timeslot being occupied by circuit switched traffic, an intra cell handover is started. The aim of the handover is to move the circuit switched call to another timeslot and clear the timeslot for GPRS use (refer to the figure below). The BSC then continues with the upgrading of the GPRS territory after the release of the source channel of the handover. If the GPRS territory of a BTS needs more timeslots than one TRX can offer, the BSC selects a new TRX and starts to define the territory. 196 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management When the user enables GPRS in a cell, the BSC starts a handover to be able to allocate dedicated GPRS channels, even if the defined margin of idle timeslots is not met but there is at least one timeslot available. The BSC starts a handover to move a non-transparent multislot HSCSD call, but not for a transparent multislot HSCSD call. For a transparent HSCSD call, the HSCSD timeslots are left inside the GPRS territory, although not as actual GPRS channels. The BSC extends the GPRS territory on the other side of the timeslots reserved for the transparent HSCSD call. B S C C C C C B = BCCH TSL S = SDCCH TSL C = Circuit Switched call C C C C C C C C C C C C Default GPRS capacity (d)= 20% Dedicated GPRS capacity (D) = 10% C C d d D D D = Circuit Switched territory = GPRS territory GPRS territory upgrade Figure 33. GPRS territory upgrade when a timeslot is cleared for GPRS use with an intra cell handover Situations leading to the starting of a GPRS territory upgrade are related to configuration and traffic channel resource changes. When the user adds GPRS capable TRXs in a BTS, it results in an increase in the timeslot share that should be provided for GPRS traffic. The BSC starts the GPRS territory upgrade procedure when: . the user enables GPRS in a cell the user or BSC unblocks a GPRS enabled TRX thus enabling a pending GPRS territory upgrade the user or BSC unblocks a radio timeslot inside the GPRS territory enabling it to be included in the GPRS territory the BSC releases a circuit switched TCH/F causing the number of idle resources in the BTS to increase above a margin that is required before GPRS territory upgrade can be started . . . DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 197 (272) EDGE System Feature Description . the BSC releases a circuit switched TCH/F beside the GPRS territory border (as a consequence of handover) so that the pending GPRS territory upgrade can be performed the PCU requests a GPRS territory upgrade. . Other general conditions for a GPRS territory upgrade are: . previous GPRS territory change in the BTS has been completed sufficient margin of idle TCH/Fs in the BTS idle GPRS capable resources available in the BTS available capacity in the PCU controlling the BTS. . . . The margin of idle TCH/Fs that is required as a condition for starting a GPRS territory upgrade is defined by the BSC parameter free TSL for CS upgrade (CSU). In fact, the parameter defines how many traffic channel radio timeslots have to be left free after the GPRS territory upgrade. When defining the margin, a two-dimensional table is used. In the two-dimensional table the columns are for different amounts of available resources (TRXs) in the BTS. The rows indicate a selected time period (seconds) during which probability for an expected downgrade is no more than 5%. The operator can modify the period with the BSC parameter CSU. The default value for the period length is 4 seconds. Table 57. TRXs Time period: 0s 1s 2s 3s 4s 5s 6s 7s 8s 9s 10 s Defining the margin of idle TCH/Fs 5 0 1 0 2 0 3 0 4 0 6 0 7 0 8 0 9 0 10 0 11 0 12 0 13 0 14 0 15 0 16 0 0 1 1 1 1 1 1 1 1 2 1 1 1 2 2 2 2 3 3 3 1 2 2 2 3 3 3 4 4 4 1 2 3 3 3 4 4 4 5 5 2 2 3 4 4 4 5 5 5 6 2 3 3 4 5 5 5 6 6 7 2 3 4 4 5 5 6 6 7 7 2 3 4 5 5 6 7 7 7 8 2 3 4 5 6 6 7 7 8 8 2 4 5 6 6 7 7 7 8 8 3 4 5 6 7 7 8 8 9 9 3 4 6 6 7 8 8 9 9 9 3 4 6 7 7 8 9 9 9 9 3 5 6 7 8 8 9 9 9 9 3 5 6 7 8 9 9 9 9 9 3 5 6 7 8 9 9 9 9 9 198 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management The user can define and modify with the parameter GPRS territory update guard time (GTUGT) the guard time, which the PCU has to wait between successive requests for GPRS territory configuration updates. The BSC obeys this guard time also when it performs GPRS territory upgrades to fulfil the operator-defined default GPRS territory. If the conditions required for a GPRS territory upgrade are not met at the time the PCU requests a GPRS territory upgrade, the BSC simply does nothing but updates related statistics. There are three reasons for a GPRS territory upgrade request being rejected: lack of GPRS radio resources, circuit switched traffic load, and the capacity limit of the PCU unit. In case the PCU asks for several timeslots in one request and only a part of the requested resources are available, a statistics counter is updated. In the GPRS territory upgrade, the PCU selects a free circuit from the PCUPCM and the BSC connects it to an Abis circuit. If an error occurs when connecting the PCUPCM circuit to the Abis circuit, the BSC cancels the upgrade and saves information on the detected fault. The BSC initiates a new GPRS territory upgrade after a guard period. If two successive connection failures of a PCUDSP circuit with different Abis circuits occur, the BSC marks the PCUDSP channel as faulty and sets the alarm FAULTY PCUPCM TIMESLOTS IN PCU (3073). Alarm GPRS/EDGE TERRITORY FAILURE (3273) is set if the territory size in the BTS is below the limit specified by the BTS specific radio network parameter default GPRS capacity (CDEF). The BSC has not been able to add more radio channels to the territory within the informing delay of the alarm. Additional GPRS territory upgrade The need for additional GPRS channels is checked when a new TBF is established or an existing TBF is terminated. The PCU requests additional channels, if a GPRS territory contains less channels than could be allocated to a mobile according to its multislot class, or if the average number of TBFs per TSL is more than 1.5 after the allocation of the new TBF (average TBF/TSL>1.5). These additional channels are requested only if all GPRS default channels are already in the GPRS territory. The number of additional channels the PCU requests is the greater of the following two numbers: DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 199 (272) EDGE System Feature Description . the number of additional channels needed in the allocation according to the MS's multislot class (this criterion is used only when the GPRS territory contains fewer channels than the MS is capable of using), and the number of additional channels needed for the average number of allocated TBFs per TSL to be 1 (average TBF/TSL=1). . Example The GPRS territory consists of one (default) channel and resources should be allocated for a downlink TBF of a multislot class 4 mobile. The PCU first allocates one channel for the TBF and it requests for (at least) 2 more channels, as the mobile is capable of using 3 downlink channels. When the PCU receives this additional capacity, the TBF is reallocated to utilise all channels. Example The GPRS territory consists of three channels (one default and two additional) and a mobile of multislot class 4 has a downlink TBF of three timeslots (performing ftp for example). One of the additional channels is taken into CS use, the territory is decreased to two channels, and the downlink TBF is reallocated to these channels. When the previously reserved channel is freed from the CS side, a territory upgrade would be possible, but nothing happens (no upgrade of the territory), because the system only checks for need for upgrade when a new TBF is established. However, if the existing TBF is terminated and a new one is established or if the concurrent uplink TBF is terminated the need and possibility of the territory upgrade is re-evaluated. GPRS territory downgrade The BSC uses a GPRS territory downgrade procedure when it needs to reduce the share of timeslots in the GPRS territory, for example when there is an increase in the circuit switched traffic load. The BSC starts a GPRS territory downgrade procedure when . the user disables GPRS in a cell the user or BSC blocks the TRX that is carrying GPRS traffic the user or BSC blocks the timeslot that is carrying GPRS traffic the user or BSC blocks circuit switched resources causing the number of idle resources in the BTS to decrease below the required margin . . . 200 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management . the BSC allocates a traffic channel for circuit switched use causing the number of idle resources in the BTS to decrease below the required margin the PCU requests for a GPRS territory downgrade . The PCU initiates a GPRS territory downgrade procedure for additional type GPRS radio timeslots. This means that the PCU has requested these timeslots for GPRS traffic in addition to the default capacity, but the need for additional timeslots has ceased. If the BSC cannot start a GPRS territory downgrade at the time the PCU requests it, the PCU has to request a downgrade again after the territory update guard time has expired, if the need for the downgrade still exists. The operator defines the margin of idle TCHs that the BSC tries to maintain free in a BTS for the incoming circuit switched resource requests using the parameter free TSL for CS downgrade (CSD). If the number of idle TCH resources in the circuit switched territory of the BTS decreases below the defined margin, a GPRS territory downgrade is started if possible. The definition of the margin involves a two-dimensional table. One index of the table is the number of TRXs in the BTS. Another index of the table is the needed number of idle TCHs. Actual table items are percentage values indicating probability for TCH availability during a onesecond downgrade operation with the selected resource criterion. Default probability 95% can be changed through the free TSL for CS downgrade (CSD) parameter. Table 58. TR Xs TC H0 1 2 3 4 5 6 7 8 9 Defining the margin of idle TCHs, % 1 94 99 100 2 84 98 99 100 3 76 96 99 4 69 93 99 5 63 91 98 99 6 58 87 97 99 7 54 85 96 99 8 50 82 94 98 99 9 48 79 93 98 99 10 45 77 92 97 99 11 43 74 90 97 99 12 41 72 89 96 99 13 40 70 87 95 98 99 14 38 68 86 94 98 99 15 37 66 84 94 98 99 16 35 64 83 93 97 99 100 100 100 100 100 100 100 100 100 % 100 % 100 % 100 % 100 100 DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 201 (272) EDGE System Feature Description Additional GPRS territory downgrade Additional channels are taken into CS use whenever more channels are needed on the CS side. The need for additional GPRS channels is always checked when an existing TBF is terminated. The PCU requests the removal of additional channels, if the average TBFs per TSL is less than 0.5 (average TBF/TSL<0.5). 11.2 Circuit switched traffic channel allocation in GPRS territory The BSC maintains a safety margin of idle traffic channels for circuit switched traffic by starting a GPRS territory downgrade when the number of free traffic channels in the circuit switched territory of a BTS decreases below the limit defined by the parameter free TSL for CS downgrade (CSD). Depending on the size of the margin and on the amount of traffic on the BTS, new circuit switched traffic channel requests may come before the GPRS territory downgrade procedure has been completed. During a sudden burst of traffic channel requests, the BSC may not be able to maintain the margin with the GPRS territory downgrade procedure and the circuit switched territory may run out of idle traffic channels. If the circuit switched territory becomes congested, the BSC can allocate a traffic channel for circuit switched use in the GPRS territory — if there is one not dedicated for GPRS. The BSC first releases the channel in GPRS use from the PCU and then activates it in the BTS for circuit switched use. The BSC cannot allocate a traffic channel in the GPRS territory for circuit switched use, if the radio timeslot in question is involved in a GPRS territory upgrade procedure that has not been completed yet. In this case the circuit switched traffic channel request is put in queue to wait for the GPRS territory upgrade to finish. This kind of queuing can be performed if the MSC allows it for the request. Traffic channel queuing during GPRS territory upgrade does not require the normal queuing to be in use in the target BTS. The use of the parameter free TSL for CS upgrade (CSU) aIMS at avoiding collisions between a GPRS territory upgrade and circuit switched requests. 202 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management Multislot traffic channel allocation for an HSCSD call within the GPRS territory follows the same principles as for single slot requests. A nontransparent HSCSD call is placed inside the GPRS territory only in the case of total congestion of the CS territory. In that case the HSCSD call can have one or more TSLs depending on the HSCSD parameters of the BTS in question. A transparent HSCSD call can be allocated partly over the GPRS territory so that traffic channels for the call are allocated from both territories or the whole HSCSD call can be allocated over the GPRS territory. Baseband Hopping BTS The BSC parameter CS TCH allocate RTSL0 (CTR) defines the order of preference between the RTSL-0 hopping group and the default GPRS territory in CS TCH allocation. Value 0 of the parameter means that the default GPRS territory timeslots are preferred in CS traffic channel allocation. If no free resources are available in the default GPRS territory, the RTSL-0 hopping group is searched. Value 1 of the parameter means that the RTSL-0 hopping group is preferred in CS traffic channel allocation. If no free resources are available in the RTSL-0 hopping group, the default GPRS territory is searched. Load limit calculation The BSC parameter CS TCH allocation calculation (CTC) defines how the GPRS territory is seen when the load limits for CS TCH allocation are calculated. Additionally, it defines whether the resources in the GPRS territory are seen as idle resources or as occupied resources. Value 0 of the parameter means that only the resources in the CS territory are taken into account in load calculations. Value 1 of the parameter means that both the CS territory resources and the GPRS territory resources (excluding the dedicated GPRS timeslots) are taken into account, and the GPRS territory resources are seen as occupied resources. Value 2 of the parameter means that both the CS territory resources and the GPRS territory resources (excluding the dedicated GPRS timeslots) are taken into account, and the GPRS territory resources are seen as idle resources. 11.3 BTS selection for packet traffic Channel allocation goes through all the following steps, in the order presented, in every allocation and reallocation instance. After every step, the list of valid BTSs is relayed to the next step and the BTSs that did not meet the requirements are discarded. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 203 (272) EDGE System Feature Description BTS selection in a segment with more than one BTS 1. 2. 3. Mobile Radio Access Capability (bands) Check maximum TBF/TSL in BTS Signal Level . In case of initial allocation (DL signal level not known), DIRE is used for ruling out some BTSs. BTS with NBL value greater than DIRE is ruled out. . Reallocation based on signal level is triggered by: (RX_level (BCCH)-NBLGPU) . In reallocation case, if no BTS fullfilling (RX_level(BCCH)NBL>GPU) is found, the old BTS is selected. Capability and throughput . PCU1 only: Mobile capability (GPRS/EGPRS) vs BTS capability (GPRS/EGPRS). . PCU2 only: Throughput (Penalty, Qos, BTS throughput factor). BTS throughput factor takes MS and BTS GPRS/EGPRS capability into account and the BTS providing highest relative throughput is selected. PCU1 only: Load (Penalty, QoS). 4. 5. In UL reallocation, the uplink RX level of the TBF in the serving BTS is compared to GPL to check if the reallocation was triggered by a bad uplink RX level (uplink RX level < GPL). If the reallocation was due to bad uplink RX level, or triggered by Quality Control due to service quality degradation (see section 11.6 Quality Control), then the old serving BTS is discarded in the very beginning. 11.4 Quality of Service The concept of 'Priority Class' is introduced at system level. This is based on combinations of GPRS Delay class and GPRS Precedence class values. Packets having higher 'Priority' are sent before packets having lower 'Priority'. 204 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management ETSI specifications define QoS functionality which gives the possibility to differentiate TBFs by delay, throughput and priority. Priority Based Scheduling is introduced as a first step towards QoS. With Priority Based Scheduling the operator can give users different priorities. Higher priority users will get better service than lower priority users. There will be no extra blocking to any user, only the experienced service quality changes. The PCU receives the QoS information to be used in DL TBFs from the SGSN in a DL unitdata PDU. In case of UL TBF, the MS informs its radio priority in an (EGPRS) PACKET CHANNEL REQUEST ((E)PCR) or a PACKET RESOURCE REQUEST (PRR), or an (EGPRS) PACKET DOWNLINK ACK/NACK ((E)PDAN) and this is used for UL QoS. In the UL direction, the PCU uses the radio priority received from the MS. Exceptions to this rule are GPRS one phase access on CCCH; in this case the PCU always uses the lowest priority, and EGPRS UL TBF establishment on CCCH with access cause 'Signalling'; in this case the PCU always uses the highest priority. The PCU receives the QoS profile information element in the DL unitdata. This IE includes Precedence class information which indicates the priority of the PDU. In PCU1 each TBF allocated to a timeslot has a so-called latest (timeslotspecific) service time. In each scheduling round (performed every 20 ms), the TBF with the lowest service time is selected and given a turn to send a radio block (provided that no control blocks have to be sent). Also, the latest service time of the selected TBF is incremented by the scheduling step size of the TBF in PCU1. The PCU2 scheduling uses the Bucket Round Robin (BRR) algorithm, and there similar behaviour is obtained using scheduling weight. See parameter conversion in section BSC parameters of System Impact of Priority Class based Quality of Service. The sizes of the scheduling steps/weight determine the handing out of radio resources. If several TBFs have been allocated to a timeslot, then the higher the scheduling step size or respectively, the lower the scheduling weight of the TBF, the less often it is selected and given a turn. Scheduling step sizes/weights depend on the priority class of the TBF. In PCU1, each priority class has its own scheduling step size which is operator adjustable. The same applies also to PCU2 scheduling weight which is operator adjustable. Priorities are also taken into account in allocations of TBFs. The allocation process tries to ensure that better priority TBFs do not gather into the same radio timeslot. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 205 (272) EDGE System Feature Description Priority Based Scheduling in BSC is an operating software product and is always active in an active PCU. To get more detailed information about QoS in Gb, see BSC-SGSN interface description; BSS GPRS protocol (BSSGP). 11.5 Channel allocation and scheduling GPRS channels are allocated according to the following rules: . downlink and uplink are separate resources multiple mobiles can share one traffic channel, but the traffic channel is dedicated to one MS at a time — this is referred to as temporary GPRS connection block flow or Temporary Block Flow (TBF) — meaning that one MS is transmitting or receiving at a time; seven uplink and nine downlink TBFs can share the resources of a single timeslot; the uplink and downlink scheduling are independent channels allocated to a TBF must be allocated from the same TRX The traffic channels which would provide the maximum possible (priority based) capacity, within the restrictions of the multislot class of the mobile, are allocated for a TBF. Exceptions are TBFs for which only one channel is allocated. In PCU2, channel allocation also involves other criteria in case EDA is active. For more information on EDA, see Overview of Extended Dynamic Allocation. the Medium Access (MAC) mode capability of a mobile affects its UL transmission capability (within the Multislot Class restrictions). Dynamic Allocation MAC mode allows an MS to use a maximum of two UL timeslots; Exended Dynamic Allocation (PCU2) allows an MS to use a maximum of four UL timeslots. MAC mode does not affect the DL capability of an MS. For more information, see 11.5.1 Packet scheduling. . . . . Temporary Block Flow (TBF) is explained in GPRS radio connection control. The PCU determines the number of traffic channels that are needed and counts the best throughput for that number of traffic channels. In PCU1 the traffic channel combinations are first compared by QoS load, then by capacity type (additional < default < dedicated) and then by the Packet Associated Control Channel (PACCH) load. The QoS load of a channel is 206 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management defined as a weighted sum of the TBFs in the channel. The weights used correspond with the scheduling rate of the QoS class of TBFs in the channel. In PCU1 the PACCH load is the number of TBFs using a certain TCH as PACCH. PACCH is defined in more detail in GPRS radio connection control. In PCU2 the PACCH load is monitored by the scheduler and that is used together with the scheduling weights when the relative throughput of the channel combination is estimated. The traffic channel combinations are first compared by relative throughput and then by capacity type (additional < default < dedicated). Furthermore in PCU2, a comparison of estimated throughputs is carried out between DA (max. two slots) and EDA (max. four slots) connections in uplink. For more information, see Functionality of Extended Dynamic Allocation in Extended Dynamic Allocation in BSC. Higher priority TBFs will get more turns, therefore they will cause more load on the channel. TBF allocation After the BTS has been selected, QoS and TBF type are compared simultaneously. Different QoS classes result in different penalties for load comparing. Multiplexed and non-multiplexed TSLs are also prioritised by a penalty value. Among multiplexed TSLs, QoS is the selection criteria. In addition, the PCU monitors PACCH load (in other words signalling load) in TSLs and takes that into account in allocation. If there are both GPRS and EGPRS TBFs allocated in the same BTS, the PCU1 tries to avoid allocating the GPRS and EGPRS TBFs into the same timeslots because it would dramatically worsen the throughput of EGPRS TBFs. In PCU2 implementation multiplexing is taken into account when comparing different allocations and residual capacity provided by them. In PCU2, channel allocation does not involve special procedures for picking out resources which would not lead to multiplexing. Instead, channel allocation penalties are applied to allocations which would result in multiplexing, and then the allocation which is estimated to provide the best throughput is chosen without further selection between multiplexed and non-multiplexed connections. If we would like to allocate a new EGPRS TBF into a TRX, the channel allocator would see the TRX as follows: the timeslots where there already are some GPRS TBFs allocated would not look very attractive for this allocation, because the EGPRS TBF throughput would be reduced in those timeslots due to multiplexing. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 207 (272) EDGE System Feature Description When optimum resources for a mobile are searched for, both UL and DL resources are evaluated and the decision for the allocation is made depending on the amount of effective resources received in both directions. If a mobile is using only one direction (UL or DL), only the resources of the direction used are evaluated. If the mobile being evaluated already has an existing TBF in one direction and it requires resources from the other direction, the evaluation of concurrent resources received is first done for the adjoining allocation beside existing allocation and then for different concurrent reallocations, where existing TBF is reallocated from its current allocation. In PCU2, however, no preference is given to adjoining allocations when concurrent TBF is being created. Channel combination in concurrent allocation is determined from operator modifiable parameters CHA_CONC_UL_FAVOR_DIR and CHA_CONC_DL_FAVOR_DIR. If DL TBF exists and UL TBF is allocated as concurrent, CHA_CONC_UL_FAVOR_DIR defines the direction that should be preferred in allocation. Respectively, when allocating DL TBF as concurrent, CHA_CONC_DL_FAVOR_DIR defines the preferred direction. These parameters have three values - favour UL, favour DL and share resources - which result in different emphasis in resource division between UL and DL. During concurrent TBFs the PCU monitors the traffic, and PCU uses reallocations to modify the timeslot configuration to give preference to the direction with more traffic. The preferred direction affects the configuration when the MS multislot class allows different UL/DL timeslot combinations. If effective resources received in the adjoining allocation are the same as with concurrent reallocation, the adjoining allocation is preferred. In the evaluation of the resources, dedicated and default territory areas are preferred, so if similar resources are found from the additional and default territory, resources from the default area will be allocated. Example The GPRS territory consists of three channels, and an MS of multislot class 4 has a downlink TBF of three timeslots (performing FTP for example) and also uses an uplink TBF of one timeslot to acknowledge the received data (Note that the UL TBF is not always present as it is not always needed). A second mobile of multislot class 4 requests UL resources. These will be allocated to it and the optimum resources are evaluated for the UL direction only. As a result, the second MS gets its UL resource from a channel that is not used by the first mobile. TSL 0 1 2 3 4 5 DEF UL 6 DEF MS1 7 DEF MS2 208 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management DL MS1 MS1 MS1 Example Continuing from the previous example, downlink resources are needed for the second mobile. Available resources are evaluated for both directions and the allocation is made in such a way that optimum resources are used in both directions. Now the allocation depends on the resource usage of MS1 in both UL and DL directions. 1. A concurrent allocation for the DL TBF is made for MS2 if MS1 has an UL TBF in use when the DL TBF of MS2 is allocated. The adjoining allocation is made, because the reallocation does not provide any better resources for MS2 in this phase. 2 3 4 5 DEF UL DL MS1 6 DEF MS1 MS1 MS2 7 DEF MS2 MS1 MS2 TSL 0 1 As a result, MS1 has the resources of 3 effective timeslots (the total sum of UL and DL resources) and MS2 has the resources of 2 effective timeslots. If MS2 had been allocated in the same way as MS1 (with re-allocation), it would have resulted in both MSs having only 2 effective timeslots (the total sum of UL and DL resources). MS2 does not receive the maximum number of timeslots in the DL direction in this phase, but it will receive them later, when the territory upgrade has been completed. In case of PCU2, the allocation is made according to multislot class capabilities. In other words, adjoining allocation with fewer channels that multislot class allows is not made. If the favoured direction is set to favor DL, 3+1 allocation is reserved for MS2. As a result, MS2 is allocated similarly to MS1. TSL 0 1 2 3 4 5 DEF UL 6 DEF MS1 MS2 7 DEF DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 209 (272) EDGE System Feature Description DL MS1 MS2 MS1 MS2 MS1 MS2 In case of PCU, if the favoured direction is UL, 2+2 allocation is made. TSL 0 1 2 3 4 5 DEF UL 6 DEF MS1 MS2 DL MS1 MS1 MS2 MS1 MS2 7 DEF MS2 2. DL resources for MS2 are given with reallocation if MS1 does not have a UL TBF in use when the DL TBF of MS2 is allocated. The reallocation is made, because better resources are achieved with it. 2 3 4 5 DEF 6 DEF MS2 MS1 MS2 MS1 MS2 MS1 MS2 7 DEF TSL 0 1 UL DL In this allocation, MS1 has the resources of 1.5 effective timeslots (the total sum of UL and DL resources) and MS2 has the resources of 2.5 effective timeslots. Then the PCU would request a territory upgrade according to the rules explained in the section 11.1.1 additional GPRS territory upgrade (in case a, two channels will be requested and in case b, three channels will be requested). Example Continuing from the previous example, the PCU has received the additional capacity it has requested and the reallocation of the TBF(s) will be made. As a result, the following allocations will be made: 210 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management 1. Both mobiles will get 2.5 timeslots in the DL direction and 1 timeslot in the UL direction. TSL 0 1 2 3 ADD UL DL MS2 4 ADD MS2 MS2 MS1 MS2 5 DEF 6 DEF MS1 MS1 MS1 7 DEF 2. Both mobiles will get 3 timeslots in the DL direction and 1 timeslot in the UL direction. 2 ADD 3 ADD MS2 MS2 MS2 MS2 MS1 4 ADD 5 DEF 6 DEF MS1 MS1 MS1 7 DEF TSL 0 1 UL DL After the TBF is created in a BTS When a GPRS TBF is in a multiplexed TSL, PCU1 will constantly check: 1. 2. 3. if the channel is multiplexed if it is the only GPRS TBF in the TSL thus causing multiplexing if there are multiplexed channels where it is allowed to reallocate In PCU2, allocation is done to achieve the highest possible relative throughput. Consequently, the above mentioned checks do not apply since there is no attempt to remove multiplexing and USF Granularity 4 is used. In addition, PCU constantly checks if reallocation should take place to achieve better relative capacity. Reallocation check interval is determined by operator modifiable parameter TBF_LOAD_GUARD_THRSHLD. The parameter defines reallocation check interval for a TBF in block periods. The PCU requests for more additional channels, if a GPRS territory contains less channels than what could be allocated to a mobile according to its multislot class. These additional channels are requested only if all GPRS default channels are already in the GPRS territory. The maximum number of GPRS channels is limited by CMAX. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 211 (272) EDGE System Feature Description When ensuring the best quality and speed for end-users, planning may not rely on additional channels in the dimensioning of the GPRS territory. The use of additional channels is less efficient compared to the default channels. The reason for this is that the additional channels (territory upgrade) are always requested from circuit-switched (CS) territory and there is always some delay before the channel is moved to the GPRS territory. For example, there can be a CS call in the timeslot, which is to be moved to the GPRS territory, and intracell handover is needed before the territory upgrade can be completed. Additional channels are taken into CS use whenever more channels are needed on the CS side. The need for additional GPRS channels is always checked when an existing TBF is terminated. The PCU requests the removal of additional channels, if the average TBF/TSL is less than 0.5 (average TBF/TSL<0.5). The target in the downgrade is to achieve an average TBF/TSL equal of 1. When there is an EGPRS downlink TBF and a GPRS uplink TBF in the TSL, the MCS is limited to 1-4 (GMSK) whenever there is USF signalling to the GPRS TBF. In PCU2, USF Granularity 4 is used in such cases, meaning that one block carrying USF signalling to GPRS TBF assigns a transmission turn to GPRS TBF for four consecutive UL radio blocks. There will also be a CS-coded downlink block every 360 ms for synchronisation purposes for GPRS MSs. Packet scheduling Uplink and downlink scheduling are independent of each other. The PCU can assign multiple MSs to the same uplink traffic channels. ETSI specifications allow the scheduling of uplink transmission turns to be done by two different Medium Access Control (MAC) modes: Dynamic Allocation (DA) and Extended Dynamic Allocation (EDA). The BSC releases from S9 onwards support Dynamic Allocation, and releases from S12 onwards also support Extended Dynamic Allocation (PCU2 only). In DA and EDA, the BSC gives the MS a USF value for each assigned traffic channel in the assignment message. The MS monitors the downlink Radio Link Control (RLC) blocks on the traffic channels it has been assigned. Whenever the MS finds the USF value in the downlink RLC block, it may send an uplink RLC block in the corresponding uplink frame. The scheduling of the RLC data block in each timeslot is independent of other timeslots. DA allows an MS to use a maximum of two timeslots in UL. Radio Link Control is defined in more detail in GPRS radio connection control. 212 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management 0 1 2 3 4 5 6 7 USF USF T T 0 1 2 3 4 5 6 7 Figure 34. Dynamic Allocation MAC mode EDA allows an MS to use more than two uplink timeslot by removing the need of detecting USFs separately for each assigned traffic channel: a received USF gives the MS a permission to send, during the next transmission turn, on the corresponding UL channel and on all the following channels of the UL TBF. 0 1 USF T T T 2 3 4 5 6 7 0 1 2 3 4 5 6 7 Figure 35. Extended Dynamic Allocation MAC mode Scheduling in PCU1 is based on a kind of weighted round robin (WRR) method, which means that a higher priority (QoS) Temporary Block Flow (TBF) gets a bigger share of the PDTCHs allocated for it than a lower priority TBF. Scheduling in PCU2 is based on a Bucket Round Robin (BRR) algorithm. In addition, PCU2 uses USF granularity 4 for GPRS TBFs in EGPRS BTS to reduce the negative impact of EGPRS/GPRS multiplexing. USF granularity 4 is only used with DA, not EDA. The main difference to PCU1 WRR algorithm implementation is that BRR distributes transmission turns per MS and not per TCH as WRR in PCU1 implementation. Both WRR and BRR distribute capacity according to connection specific scheduling weights. See 11.4 Quality of service for more information on adjusting weight in priority based QoS. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 213 (272) EDGE System Feature Description Extended Uplink TBF mode Extended UL TBF mode is an optional functionality. If the MS supports Extended UL TBF Mode (indicated in MS RAC), the normal uplink release is delayed. The delay time is operator adjustable with parameter UL_TBF_REL_DELAY_EXT. During delay time MS is in extended mode. In extended mode network schedules USFs to MS with lower scheduling rate. If MS in extended mode has data to send data it returns to normal mode. For more information, see Data transfer. Scheduling in extended mode for an uplink TBF is based on operator modifiable parameters UL_TBF_SCHED_RATE_EXT in PCU1 and POLLING_INTERVAL in PCU2. In PCU1, UL_TBF_SCHED_RATE_EXT defines the next block period when a TBF in extended mode is given a transmission turn. However, a TBF in extended mode cannot have better residual capacity than it would in normal mode. In PCU2, POLLING_INTERVAL defines the time in block periods that TBF in extended state cannot have transmission time. After POLLING_INTERVAL is elapsed, TBF is returned to scheduling and once it is scheduled it is restricted again unless it is returned to normal mode. Dynamic Scheduling for Extended UL TBF Mode In PCU2, Dynamic Scheduling for Extended UL TBF Mode optimises the scheduling algorithm applied to mobile stations in extended uplink TBF mode (EUTM). When any of the uplink TSLs which can be used for polling an MS in EUTM accommodates more than one UL TBF, the POLLING_INTERVAL parameter defines the frequency of UL transmission turns scheduled for the MS in EUTM. When none of the uplink TSLs which can be used for polling an MS in EUTM accommodates more than one UL TBF, the POLLING_INTERVAL_BG_LOW parameter defines the frequency of UL transmission turns scheduled for the MS in EUTM. This method helps to improve the RTT performance for MSs in EUTM under light or moderate traffic density without affecting adversely the radio throughput of other users. 214 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management 11.6 Quality Control The purpose of Quality Control is to monitor and detect degradation periods in service quality, and to perform corrective actions to remove the service degradation. The possible actions include TBF reallocation and Network-Controlled Cell Re-selection. Monitoring of degradation in service quality includes BLER and bitrate per radioblock monitoring. The PCU monitors bitrate per radio block for each TBF in RLC ACK mode, for UL and DL separately. When the PCU sends or receives a radio block, it updates the number of bits transmitted/received in the radio block. The PCU ignores LLC dummy blocks in this calculation. For the retransmissions, the PCU shall calculate the number of bits transmitted as zero. The PCU calculates the bitrate per radio block value and checks it against the corresponding threshold value. The threshold values are operator parameters and there is a separate value for UL and DL, as well as for GPRS and EGPRS, respectively: QC GPRS DL RLC ack throughput threshold (QGDRT), QC GPRS UL RLC ack throughput threshold (QGURT), QC EGPRS DL RLC ack throughput threshold (QEDRT) and QC EGPRS UL RLC ack throughput threshold (QEURT). If the calculated value is below threshold, degradation duration time is increased. The PCU monitors the bitrate per radio block degradation duration counter. If the counter is larger than predefined triggering levels, the corresponding corrective action is performed. The PCU monitors also RLC Block Error Ratio (BLER) for each TBF. The BLER value shall be checked against the required maximum BLER. In PCU1, maximum BLER is defined by operator parameter maximum BLER in acknowledged mode (BLA) or maximum BLER in unacknowledged mode (BLU), depending on the RLC mode of the TBF. In PCU2, maximum BLER is defined by operator parameters PFC ACK BLER limit (ABL1) and PFC UNACK BLER limit (UBL1). If BLER is above maximum, degradation duration time is increased and if the counter is larger than predefined triggering levels, the corresponding corrective action is performed. When any of the degradation duration counters monitored by the PCU gets larger than a predefined action trigger threshold, the PCU shall perform a corresponding corrective action. Each action shall be triggered only once for a TBF in PCU. For example, if reallocation is already done, the next action to be performed is Network-Controlled Cell Re-selection (NCCR), triggered when a degradation duration counter exceeds the NCCR trigger threshold. The flags of already performed actions are cleared when the degradation ends, that is when all the degradation duration counters are cleared. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 215 (272) EDGE System Feature Description The action trigger thresholds are expressed in block periods and the values can be set by operator (see parameter QC Action Trigger Threshold). It is possible to change the order of different actions by modifying the action trigger threshold values. If two or more actions are set to the same threshold value, the order of actions is first reallocation and then NCCR. Although possible, it is not recommended to set the values very close to each other, for example reallocation 100, NCCR 101. Otherwise, there is no time to execute the triggered action before the next is already triggered. The default action trigger threshold values are shown below. Action Reallocation NCCR (*) Block periods 25 100 (*) Applicable if NCCR is activated. 11.7 MS Multislot Power Reduction (PCU2) When multiple timeslots have been assigned to an uplink TBF, the mobile station may reduce its transmission power as a function of the number of these timeslots: the more UL timeslots assigned, the larger the transmission power reduction applicable. This power reduction helps the MS to meet radiation regulations and to avoid heating problems. Every mobile station (Rel 5 or later) conforms to one of four standardised Multislot Power Profiles (0-3), which determine the maximum output power supported by an MS for different UL TBF configurations. An MS of Multislot Power Profile 3 does not apply power reduction to connections of four UL timeslots and less, while the amount of applicable reduction increases with each lower Power Profile. The effect of Multislot Power Reduction needs to be observed in radio resource allocation because the output power of an MS contributes to radio path quality, and consequently affects both the choice of the channel coding scheme to be used (CS1-CS4; MCS1-MCS9) and the achievable throughput per timeslot within the chosen scheme. In other words, large power reduction leads to poorer radio path quality, which in turn decreases throughput per timeslot both by necessitating robust channel coding and by increasing the number of transmission errors and retransmissions. 216 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management In resource allocation, the effect of power reduction is observed by using UL signal quality measurements by the BTS to determine the maximum number of UL timeslots that can be assigned to the MS and still keep the signal quality at an acceptable level in spite of the entailing transmission power reduction. Multislot power reduction is applicable to all multislot UL connections. If EDA is enabled, up to four timeslots may be assigned to an UL TBF. If EDA is not enabled, up to two timeslots may be assigned in UL. UL signal quality and the maximum number of timeslots If the MS UL signal quality (GMSK Mean BEP or RX Quality measured by the BTS) is known during radio resource allocation, which is normally the case during two-phase access, the PCU uses this information to determine the maximum number of UL timeslots that may be allocated for the MS. The PCU uses the signal quality measurement that is available, but typically Mean BEP is used with EGPRS connections or if Dynamic Abis is supported, and RX Quality is used in other cases. The operator can define the signal quality limits for different UL timeslot configurations by modifying the Mean BEP Limit and RX Quality Limit parameters. In determining these limits, the appropriate signal quality - as typically required by applications used in the network - must be considered together with the power reduction characteristics of different mobile stations. The limits should be set so that the signal quality remains acceptable even when the MS applies maximum power reduction. The following tables define the default values for the two signal quality limits (for Rel 5 mobiles and later). Table 59. GMSK Mean BEP Limit for UL MS Multislot Power Profile 3 — — — — MAX Number of UL TSLs 1 2 3 4 MS Multislot MS Multislot MS Multislot Power Power Profile Power Profile 0 1 Profile 2 — 21 26 30 — 20 25 30 — — 24 29 For instance, three UL timeslots may be assigned to a Multislot Power Profile 1 MS if the measured GMSK Mean BEP value is 25 or higher. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 217 (272) EDGE System Feature Description Table 60. MS Multislot Power Profile 0 — 5 3 1 RX Quality Limit for UL MS Multislot Power Profile 1 — 5 3 1 MAX Number of UL TSLs 1 2 3 4 MS Multislot MS Multislot Power Power Profile 2 Profile 3 — — 3 2 — — — — For instance, three UL timeslots may be assigned to a Multislot Power Profile 1 MS if the measured RX Quality is three or lower. If no Multislot Power Profile has been defined for an MS (Rel 4 or earlier) or the Profile is not known by the PCU for some other reason, the PCU handles the MS according to Power Profile 0. When an UL TBF is reallocated to another BTS, where the mobile station specific GMSK Mean BEP and RX Quality measurements are not available for the MS, the maximum number of timeslots that can be assigned to the reallocated connection is determined on the basis of the general RX level in the new BTS. This is done by checking what number of timeslots - considering the Multislot Power Profile of the MS - would allow at least the same average RX level to be achieved under the new BTS as under the old one. 11.8 Error situations in GPRS connections Synchronisation errors When the PCU detects a synchronisation error between itself and the BTS, the BSC downgrades the related channels from GPRS use. The BSC upgrades the radio timeslots back to GPRS use after a guard period. Traffic channel activation failures The BSC sets the alarm TRAFFIC CHANNEL ACTIVATION FAILURE 7725 if the Abis synchronisation for an GPRS traffic channel repeatedly fails. The alarm is automatically cancelled when the synchronisation succeeds and the channel is taken back into GPRS use. 218 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 Radio resource management (E)GPRS Inactivity (Sleeping BTSs) The BSC sets the alarm NO (E)GPRS TRANSACTIONS IN BTS 7789 if there have been no normal TBF releases within the supervision period in a BTS where this alarm is enabled, although there have been allocation TBF attempts. To enable this alarm functionality in the BSC, you define the triggering criteria, length of the supervision period and traffic threshold. The recommended triggering criteria is the lack of normal TBF releases both in UL and DL, but you may choose to monitor only one of the directions. The length of the supervision period shall be defined according to estimated traffic density, recommended values ranging from 15 minutes (default) to 60 minutes. Traffic threshold means the required number of TBF allocation attempts per hour, to ensure that the alarm is not raised due to low traffic volume. Default value for traffic threshold is 10 TBF allocation attempts per hour. The BSC level configuration of this alarm is done by modifying the following parameters with the MML command EEJ: EGIC= 0x00: Alarm disabled on BSC Level (default) 0x01: No normal UL TBF releases 0x02: No normal DL TBF releases 0x03: No normal UL TBF releases and no normal DL TBF releases (recommended) IEPH= Default: 10 Range: 0 ... 255 SPL= Default: 15 minutes Range: 0 ... 1440 minutes The alarm also needs to be enabled on the BTSs, which will be monitored. This is done by configuring the related BTS level parameters. Although the supervision period length is common for all BTSs within a BSC, the supervision periods (weekdays and hours) can be defined separately for each BTS. The BTS level configuration of this alarm is done by modifying the following parameters with the MML command EQV: DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 219 (272) EDGE System Feature Description EAW = < (E)GPRS Inactivity Alarm weekdays (bitmask)> Default: 00000000b (alarm disabled in BTS) Examples: 01000000 (Monday) 00100000 (Tuesday) 01111100 (Monday thru Friday) 01111111 (Every day) EAS = < (E)GPRS Inactivity Alarm start time (hours-minutes)> Default: 08-00 Range: 00-00 ... 23-45 EAE = < (E)GPRS Inactivity Alarm end time (hours-minutes)> Default: 18-00 Range: 00-00 ... 23-45 The alarm is set if the criteria is met at the end of the supervision period. The criteria is that no normal TBF releases have been detected within a 15 minute (default) period during the hours when the alarm is active on the given weekdays, and there have been at least the required number of TBF allocation attempts. The alarm is cancelled if a normal TBF release is detected within the subsequent supervision periods. Note that the cancellation is not dependent on the setting criteria, but a normal TBF release in either direction cancels the alarm. 220 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control 12 GPRS/EDGE radio connection control Radio channel usage when GPRS is in use is discussed in this section. The GPRS radio connection establishment (TBF establishment) and data transfer are described from the point of view of a mobile terminating (MT) and mobile originating (MO) GPRS TBF. Paging is described in a section of its own. This section describes the BSC's functions in relation to suspend and resume, flush, coding scheme selection, as well as traffic administration and power control in GPRS. Cell selection and re-selection are also defined. 12.1 Radio channel usage ETSI specifications (05.02) define the possibility to use dedicated broadcast and common control channels for GPRS. System information messages on BCCH The support of GPRS is indicated in a SYSTEM_INFORMATION_TYPE_3 message. GPRS-specific cell parameters are sent to the MS in a SYSTEM_INFORMATION_TYPE_13 message. For more information refer to GSM Specification (04.18). Common Control Channel (CCCH) signalling The Common Control Channel (CCCH) signalling is used for paging and uplink and downlink temporary block flow (TBF) setup. GPRS paging is made on the Paging Channel (PCH). The MS initiates uplink TBF establishment on the Random Access Channel (RACH). The network responds to the MS on the Access Grant Channel (AGCH). Network-initiated TBF establishment is done on the AGCH. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 221 (272) EDGE System Feature Description Packet Data Traffic Channel (PDTCHs) The Packet Data Traffic Channel (PDTCH) is a channel allocated for data transfer. It is temporarily dedicated to one MS. In multislot operation, one MS may use multiple PDTCHs in parallel for individual packet transfer. All PDTCHs are uni-directional, either uplink (PDTCH/U) for a mobile originated packet transfer or downlink (PDTCH/D) for a mobile terminated packet transfer. PDTCH/U and PDTCH/D can be assigned to an MS simultaneously. In the Nokia implementation, traffic channels belonging to a GPRS territory are PDTCHs and traffic channels belonging to circuit switched territory are TCHs. The PCU uses each radio timeslot which the BSC has allocated for the GPRS territory, as one PDTCH. GPRS territories are described in Radio resource management. Packet Associated Control Channel (PACCH) The Packet Associated Control Channel (PACCH) conveys signalling information related to a given MS. The signalling information includes, for example, acknowledgements and resource assignment and reassignment messages. One PACCH is associated to one or several traffic channels that are assigned to one MS. PACCH is a bi-directional channel. It can be allocated on both uplink and downlink regardless of whether the corresponding traffic channel assignment is for uplink or downlink. Assigned traffic channels are used for PACCH in the direction the data is sent. In the opposite direction the MS multislot capability has to be taken into account when allocating the PACCH. 12.2 Data Transfer Protocols and Connections Temporary Block Flow (TBF) Temporary Block Flow (TBF) is a physical connection used by two radio resource entities to support the unidirectional transfer of Logical Link Control (LLC) PDUs on packet data physical channels. The TBF is allocated radio resources on one or more PDTCHs and comprises a number of RLC/MAC blocks carrying one or more LLC PDUs. A TBF is identified by a Temporary Flow Identity (TFI) and maintained only for the duration of the data transfer. 222 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control Logical Link Control (LLC) and Radio Link Control (RLC) The Logical Link Control (LLC) layer provides a highly reliable ciphered logical link. LLC is independent of the underlying radio interface protocols in order to allow introduction of alternative GPRS radio solutions with minimum changes to the NSS. LLC PDUs are sent between the MS and the SGSN. The Radio Link Control (RLC) function provides a radio-solutiondependent reliable link. RLC blocks are sent between the MS and the BSC (PCU). There are two RLC modes: acknowledged and unacknowledged mode. The latter does not have retransmission. In downlink data transmission, the PCU receives LLC PDUs from the SGSN, segments them to the RLC blocks and sends the RLC blocks to the MS. The LLC PDU is buffered in the PCU until it has been sent to the MS or discarded. In uplink data transmission, the PCU receives the RLC data blocks from the MS and reassembles them into LLC PDUs. When the LLC PDU is ready, the PCU sends it to the SGSN and releases it from the PCU buffer. The LLC PDUs have to be sent to the SGSN in the order they were transmitted by the MS. 12.3 Paging The network may provide co-ordination of paging for circuit switched services and GPRS depending on the network operation modes supported. Network operation modes The BSC supports network operation modes I and II. Mode I requires Gs interface between the SGSN and MSC/HLR. In mode II circuit switched paging messages are transferred through the A interface from the MSC to the BSC. In mode I circuit switched paging messages are routed through the Gb interface for GPRS-attached mobiles. GPRS pages always come from the SGSN through the Gb interface. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 223 (272) EDGE System Feature Description The network operation mode is indicated as system information to mobiles, and it must be the same in each cell of a Routing Area. Based on the provided mode, an MS can choose (according to its capabilities) whether it attaches to GPRS services or to non-GPRS services, or to both. Table 61. Mode I I II Supported Network Operation Modes GPRS Paging Channel CCCH N/A CCCH Circuit Paging Channel CCCH Packet Data Channel CCCH Gb interface Yes Yes No Paging coordination Yes Yes No GPRS paging The SGSN initiates the GPRS paging process. It sends one or more PAGING_PS_PDUs messages to the BSC (PCU). These PDUs contain the information elements necessary for the BSS to initiate paging for an MS within a group of cells at an appropriate time. The BSC translates the incoming GPRS and circuit switched paging messages into one corresponding Abis paging message per cell. A GPRS paging message is sent only to cells that support GPRS services. The paging area indicates the cells within which the BSC pages the MS and they can be: . all cells within the BSC all cells of the BSC within one Location Area all cells of the BSC within one Routing Area one cell (identified with a BSSGP virtual connection identifier (BVCI)). . . . A Routing Area, a Location Area, or a BSC area is associated with one or more NSEIs (PCUs). If the cells in which to page the MS are served by several NSEIs, then the SGSN sends one paging message to each of these NSEIs. The SGSN indicates the MS's IMSI and DRX parameters, which enables the BSS to derive the paging group. If the SGSN provides a P-TMSI, then the BSC uses it to address the MS. Otherwise IMSI is used to address the MS. 224 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control In GPRS paging the BSS forwards the PACKET_PAGING_REQUEST message from the SGSN to the MS on the CCCH(s). The MS's paging response to the SGSN is handled in the PCU as any other uplink TBF. For more information, see BSC-SGSN Interface Specification, BSS GPRS Protocol (BSSGP). Tip RA0 is a routing area for cells that do not support GPRS. Tip Gs interface is obligatory in order to support CS paging. Circuit switched paging via GPRS in network operation mode I In order to initiate circuit-switched transmission between the MSC and the MS, the SGSN sends one or more PAGING CS PDUs to the BSC. These PDUs contain the information elements necessary for the BSS to initiate paging for an MS within a group of cells. The paging area is the same as in GPRS paging. The SGSN indicates the MS's IMSI and DRX parameters, which enable the BSS to derive the paging group. If the SGSN provides the TMSI, then the BSC does not use the IMSI to address the MS. If a radio context identified by the TLLI exists within the BSS, then the paging message is directly sent to the MS on PACCH. If no radio context identified by the TLLI exists within the BSS, then the TMSI is used to address the MS. Otherwise IMSI is used to address the MS. After the paging procedure, the circuit switched connection is set up as usual as described in Basic Call. If within the SGSN area there are cells that do not support GPRS services, the cells are grouped under a 'null RA' (RA0). RA0 covers all the cells in the indicated paging area that do not support GPRS services. For example, if the SGSN indicates to the BSC to initiate paging for an MS within a Routing Area the BSC sends one circuit switched paging message to all cells in the Routing Area and one message to all the cells in RA0. The RA0 in this case is all the cells that do not support GPRS services in a Location Area derived from the Routing Area. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 225 (272) EDGE System Feature Description For more details about the paging message contents, refer to BSC-SGSN Interface Specification, BSS GPRS Protocol (BSSGP). 12.4 Mobile terminated TBF (GPRS or EGPRS) When the SGSN knows the location of the MS, it can send LLC PDUs to the correct PCU. Each LLC PDU is encapsulated in one DL-UNITDATA PDU. The SGSN indicates the cell identification in every DL-UNITDATA PDU. For more details about the downlink data message contents, refer to BSC-SGSN Interface Specification, BSS GPRS Protocol (BSSGP). The PCU allocates one or more PDTCHs for the TBF, and indicates it and the TFI to the MS in the assignment message. The TBF establishment is done in one of the following ways: . on PACCH; used when a concurrent UL TBF exists or when the timer T3192 is running in the MS on CCCH; used when there is no concurrent UL TBF, and T3192 is not running . These alternatives are described in the following subsections. The procedures are the same for GPRS and EGPRS TBFs. The EGPRSspecific issues are discussed in section 12.4.1 Finding an EGPRScapable MS. Downlink TBF establishment on CCCH The PCU allocates one PDTCH for the TBF, and sends an IMMEDIATE_ASSIGNMENT message to the MS. The possible multislot allocation is done later and indicated to the MS by a reallocation message. When the MS is ready to receive on PACCH, the PCU sends a PACKET_POLLING_REQUEST message to the MS and requests an acknowledgement. This is done in order to determine the initial Timing Advance for the MS. If the channel configuration to be allocated for the downlink TBF consists of only one channel already assigned to the MS, the PCU sends the PACKET_POWER_CONTROL/TIMING_ADVANCE message to the MS to indicate the Timing Advance value. 226 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control When multiple PDTCHs are allocated to the MS, the MS GPRS multislot class must be taken into account. The MS GPRS multislot class is part of the MS Radio Access Capability IE, which is included in the DLUNITDATA_PDU message. The PCU sends the PACKET_DOWNLINK_ASSIGNMENT message, and gives the whole configuration together with the Timing Advance value to the MS. In case there are no radio resources for the new TBF, the LLC PDU is discarded and the BSC sends a LLC-DISCARD message to the SGSN. The assignment procedure is guarded with two timers, one for resending the IMMEDIATE_ASSIGNMENT message and one for aborting the establishment. Downlink TBF establishment when an uplink TBF exists Downlink TBF establishment when an uplink TBF exists follows the same principles as uplink TBF establishment when a downlink TBF exists. This is discussed more at the end of 12.5 Mobile originated TBF. The establishment is done with a PACKET_DOWNLINK_ASSIGNMENT or PACKET_TIMESLOT_RECONFIGURE message. The TBF mode (GPRS/EGPRS) is always the same as the mode of the existing UL TBF. Downlink TBF establishment when timer T3192 is running and no UL TBF exists When the DL TBF is released, the MS starts the timer T3192 and continues monitoring the PACCH of the released TBF until T3192 expires. During the timer T3192 the PCU makes the establishment of a new DL TBF by sending a PACKET_DOWNLINK_ASSIGNMENT on the PACCH of the 'old' DL TBF. Finding an EGPRS-capable MS (EGPRS downlink TBF establishment) The DL-UNITDATA message from the SGSN to the PCU includes the MS Radio Access Capability IE (RAC). If this optional field is missing only the BCCH band can be used for TBF establishment and only one PDTCH can be allocated for a GPRS-mode TBF. Multislot capability struct has the optional field EGPRS Multislot Class. If this field is not present the MS is not EGPRS capable, and a standard GPRS TBF is established with GPRS multislot capabilities. If the field is present, it defines the multislot capabilities of the MS when an EGPRS mode TBF is used. The GPRS multislot class is used, however, if the PCU allocates a TBF for the MS in GPRS mode. Downlink EGPRS-mode TBF establishment is done by including EGPRSspecific fields, for example EGPRS window size, to the assignment message. The existence of these fields defines the TBF mode. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 227 (272) EDGE System Feature Description An EGPRS-mode TBF is primarily allocated for an EGPRS capable MS (to an EDGE capable BTS). A GPRS-mode TBF can be allocated for an EGPRS capable MS to a non-EDGE capable BTS if: . there are no EDGE capable BTSs in the segment, or the average TBF / TSL is more than or equal to the parameter indicating the threshold amount of TBFs in one TSL, defined in every EDGE capable BTS. . MS-specific flow control Mobile specific flow control is part of the QoS solution in the PCU. It works together with the SGSN to provide a steady data flow to the mobile from the network. Mobile specific flow control also ensures that if an MS has better QoS, and therefore better transmission rate in radio interface (more air time), it will also get more data from the SGSN. It is also an effective countermeasure against buffer overflows in the PCU. Mobile-specific flow control is done for every MS that has a downlink TBF. There is no uplink flow control. Data transfer During the actual data transfer, the MS recognises the transmitted Radio Link Control (RLC) blocks based on the TFI, which is included in every RLC block header. Each TBF has a transmit window, which is the maximum number of unacknowledged RLC blocks at a time. The window size is 64 blocks in GPRS mode. In EGPRS mode the window size is larger than in GPRS and depends on the number of allocated timeslots. The PCU can request the MS to send an (EGPRS) _PACKET_DOWNLINK_ACK/NACK message by setting a polling flag to the RLC data block header. The PCU can send further RLC data blocks along with the acknowledgement procedure. If the PCU does not receive the (EGPRS)_PACKET_DOWNLINK_ACK/NACK message when polled, it increments a counter. After the counter reaches its maximum value of 8, the BSC considers the MS as lost, releases the downlink TBF and discards the LLC PDU from the PCU buffer. The BSC signals this to the SGSN by setting the Radio Cause information element (IE) value to 'radio contact lost with MS'. This indicates to the SGSN that attempts to communicate between the MS and the SGSN via the cell should be suspended or abandoned. The BSC thus recommends the SGSN to stop sending LLC PDUs for the MS to the cell. The counter is reset after each correctly received (EGPRS) _PACKET_DOWNLINK_ACK/NACK. 228 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control The PCU can change the downlink PDTCH configuration whenever needed by sending the MS_PACKET_DOWNLINK_ASSIGNMENT or PACKET_TIMESLOT_RECONFIGURE message. The reasons for this reallocation may be a GPRS territory downgrade, uplink TBF establishment, or a change of requirements of the SGSN. If reallocation is impossible in the case of GPRS territory downgrade, the PCU may release channels with a PDCH_RELEASE message. The normal downlink TBF release is initiated by the PCU by setting a Final Block Indicator (FBI) bit in the last RLC block header. There may still be some retransmission after this, but the PCU releases the TBF and removes the LLC PDU from the PCU buffer when the MS sends the (EGPRS)_PACKET_DOWNLINK_ACK/NACK message with the Final Ack Indicator bit on. When the PCU has sent the last buffered LLC PDU to the MS, the PCU delays the release of the TBF (by 1 s by default). If there is no concurrent UL TBF, during the delay time DUMMY LLC PDUs are sent to the MS (with polling), in order to allow the MS to request for a UL TBF. If the PCU receives more data during the delay time, the PCU cancels the delayed release and begins to send RLC data blocks to the MS, in other words the same downlink TBF continues normally. 12.5 Mobile originated TBF (GPRS or EGPRS) When the MS wants to send data or upper layer signalling messages to the network, it requests the establishment of an uplink TBF from the BSC. There are the following main alternatives for the TBF establishment: . on PACCH; used when a concurrent DL TBF exists on CCCH; used when there is no concurrent DL TBF . Additionally, on CCCH there are different options for TBF establishment, for example one phase access or two phase access, depending on the needs for the data transfer. The PCU may force the MS to make a two phase access, even if the MS requested some other access type, for instance if there is no room for the TBF in the BCCH band. These alternatives are described in the following subsections. The procedures are mainly the same for GPRS and EGPRS TBFs. The EGPRS-specific issues are discussed in separate sections. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 229 (272) EDGE System Feature Description Random access on CCCH The MS can send a CHANNEL_REQUEST message or an EGPRS_PACKET_CHANNEL_REQUEST (EPCR) message on CCCH (RACH). The EGPRS_PACKET_CHANNEL_REQUEST is supported on RACH, if the BTS supports it. In cells where EPCR is not supported, the MS cannot tell its EGPRS capability in the CHANNEL_REQUEST message, and the MS must use two phase access when it wants to initiate an EGPRS TBF on CCCH. The BSC tells the MS in the SI13 GPRS Cell Options IE about the EPCR support. One phase access on CCCH, GPRS In a one phase access the MS sends a CHANNEL_REQUEST message with the establishment cause 'one phase access'. The PCU allocates a PDTCH for the request, and informs the MS in the IMMEDIATE_ASSIGNMENT message along with TFI and USF values. The MS sends its TLLI in the first data blocks and the one phase access is finalised when the PCU sends the PACKET_UPLINK_ACK/NACK message to the MS containing the TLLI (contention resolution). If the PCU has no PDTCHs to allocate to the MS, it sends an IMMEDIATE_ASSIGNMENT_REJECT message to the MS. One phase access is guarded by a timer in the PCU. Two phase access on CCCH, GPRS In a two phase access the MS sends a CHANNEL_REQUEST message with the establishment cause 'single block access'. The PCU allocates one uplink block for the request, schedules a certain radio interface TDMA frame number for the block, and informs it to the MS in the IMMEDIATE_ASSIGNMENT message. The MS then uses the allocated block to send a more accurate request to the PCU with the PACKET_RESOURCE_REQUEST message. The PCU allocates the actual configuration for the uplink TBF according to the information received in this message. When multiple PDTCHs are allocated to an MS, the MS GPRS multislot class must be taken into account. The MS GPRS multislot class is a part of the MS Radio Access Capability IE, which is included in the PACKET_RESOURCE_REQUEST message. The PCU indicates the PDTCH configuration, USF value for each PDTCH, and the TFI to the MS in the PACKET_UPLINK_ASSIGNMENT message sent in the same timeslot in which the single block was allocated, but the assigned PDTCH(s) may be elsewhere. The channel allocation in this second phase is independent of the first phase, and if the PCU has no PDTCHs to allocate to the MS, it sends a PACKET_ACCESS_REJECT message to the MS. The second part of the two phase access is guarded with a timer in the PCU. 230 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control The two phase access is finalised when the PCU receives the first block on the assigned PDTCH . The MS sends its TLLI in the PACKET_RESOURCE_REQUEST message, and the PCU includes it in the PACKET_UPLINK_ASSIGNMENT message to the MS (contention resolution). Two phase access on CCCH, EGPRS (EPCR not supported) The PCU assigns one RLC block for an MS with the IMMEDIATE_ASSIGNMENT message. The frame number of the assigned block is told in the message. The MS sends a PACKET_RESOURCE_REQUEST message in the assigned block. There the PCU receives information about the MS's EGPRS capabilities (EGPRS multislot capability and uplink 8PSK capability). When uplink TBF establishment is done with a CHANNEL_REQUEST message, the MS might only be able to tell the RAC information from the band where the CCCH is located. If the PACKET_RESOURCE_REQUEST message does not include the EGPRS BTS band MS Radio Access Capability information, the PCU requests the full Radio Access Capability information for MS from SGSN, after which the TBF establishment continues. The multislot capability struct has the optional field EGPRS multislot class. If this field is not present, the MS is not EGPRS-capable, and a standard GPRS TBF is established with GPRS multislot capabilities. If the field is present it defines the multislot capabilities of the MS when an EGPRS mode TBF is used. The GPRS multislot class is used, however, if the PCU allocates a TBF for the MS in GPRS mode. The PCU allocates the PDTCHs for the TBF and sends a PACKET_UPLINK_ASSIGNMENT (PUA) message to the MS. The PUA includes the following new fields: . EGPRS Channel Coding Command IE, where the BSC tells the MS what MCS it must use in uplink RLC blocks. Resegment IE, which determines whether the MS must use the same MCS in RLC data block retransmission as was used initially, or resegment the retransmitted RLC data block according to the commanded MCS. EGPRS Window Size IE, where the BSC tells what RLC window size the MS must use . . One phase access on CCCH, EGPRS In one phase access using the EPCR message, the MS's multislot class is included. In addition, the training sequence indicates whether the MS supports 8PSK modulation in uplink direction. If the mobile does not have 8PSK capability in uplink, only EGPRS GMSK MCSs can be used in UL data transfer. The PCU allocates the PDTCH for the TBF (only one DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 231 (272) EDGE System Feature Description PDTCH can be assigned) and selects the initial MCS and the EGPRS window size to be used in the uplink TBF. The assignment information is sent to the MS with an IMMEDIATE_ASSIGNMENT message. When the BSC sends the message it can poll RAC information, which includes the MS's multislot capabilities and information about the supported frequency bands. When the cell supports several frequency bands, the RAC is requested for them all. The MS sends a PACKET_RESOURCE_REQUEST (PRR) message where it has included the requested RAC information from at least the first requested band. If all the requested RAC information does not fit in the PRR, the MS also sends an ADDITIONAL_MS_RADIO_ACCESS_CAPABILITIES (ARAC) message where it tells the RAC of the other frequencies. Transmission turns to that MS can be scheduled regardless of the PRR and ARAC polling. The MS uses the two radio blocks assigned first for these signalling messages. Reallocation need is checked, when the establishment is completed. Two phase access on CCCH, EGPRS IThe BSC can request RAC information from several frequency bands. When the cell supports several frequency bands the RAC is requested from them all. The multi block assignment information is sent to the MS with an IMMEDIATE_ASSIGNMENT message. It contains a multi block allocation, assigning a single block or two consecutive blocks for the MS, depending on the requested RAC information. The MS sends a PACKET_RESOURCE_REQUEST (PRR) message where it has included the requested RAC information at least from the first requested band. If all the requested RAC information does not fit in the PRR, the MS also sends an ADDITIONAL_MS_RADIO_ACCESS_CAPABILITIES (ARAC) message where it tells the RAC of the other frequencies. Short access on CCCH, EGPRS The MS may request EGPRS Short Access with or without uplink 8PSK capability if the amount of sent data is less than or equal to 8 MCS-1 coded RLC blocks. The amount of blocks is told in the EGPRS_PACKET_CHANNEL_REQUEST message. Only one PDTCH is allocated for such a request and no RAC information is polled. The assignment information is sent to the MS with an IMMEDIATE_ASSIGNMENT message. The short access is completed as the 'One phase access on CCCH, EGPRS'. 232 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control Signalling access on CCCH, EGPRS The MS may request EGPRS Signalling Access with or without uplink 8PSK Capability. Only one PDTCH is allocated for the request and no RAC information is polled. The highest priority is applied to the TBF scheduling. The assigned PDTCH and MCS are told to the MS in the IMMEDIATE_ASSIGNMENT message. The signalling access is completed as the 'One phase access on CCCH, EGPRS'. Data transfer In uplink data transfer, the RLC data blocks are collected to the PCU buffer. The TBF has a transmit window, which is the maximum number of unacknowledged RLC blocks. The window size is 64 blocks in GPRS mode. In EGPRS mode the window size is larger than in GPRS and depends on the number of allocated timeslots. The PCU can schedule the MS to send further the RLC data blocks along with the acknowledgement procedure. The PCU can at any time send the PACKET_UPLINK_ACK/NACK message to the MS. The PACKET_UPLINK_ACK/NACK message includes a bitmap which tells the correctly received blocks. The PCU can use the PACKET_UPLINK_ACK/ NACK message for other purposes too, for example to change the coding scheme, which also affects the frequency of the acknowledgements. The PCU has a counter to control the MS's ability to send RLC blocks in the frames it has been assigned by the USF values. The counter is always reset when the MS uses the frame it has been assigned to. If the counter reaches its maximum value of 15, the MS is considered lost and therefore the PCU releases the uplink TBF. The PCU delivers the LLC PDU with a UL-UNITDATA PDU to the SGSN. There is only one LLC PDU per UL-UNITDATA PDU. The underlying network service has to be available for the BSSGP level in order to deliver data to the SGSN. Otherwise the data is discarded and a counter is updated. The PCU can change the uplink PDTCH configuration whenever needed by sending the MS a PACKET_UPLINK_ASSIGNMENT or PACKET_TIMESLOT_RECONFIGURE message. Reasons for reallocation may be a GPRS territory downgrade, downlink TBF establishment, or a change of an MS's requirements. If reallocation during a downgrade is impossible, the PCU releases channels with a PDCH_RELEASE message to the MS. A normal uplink TBF release is made by countdown, where the MS counts down the last RLC data blocks (15 or less) with the last block numbered 0. There may DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 233 (272) EDGE System Feature Description still be some retransmission, but when the PCU has received all the RLC data blocks correctly, it sends the LLC PDU to the SGSN, and a PACKET_UPLINK_ACK/NACK message with final ack indicator to the MS. The MS responds with a PACKET_CONTROL_ACK message and the PCU releases the TBF. If the MS supports Extended UL TBF Mode (indicated in MS RAC), the normal uplink release is delayed. Instead of sending a PACKET_UPLINK_ACK/NACK (final ack) immediately, the network schedules USF turns to the MS in extended mode, but with a lower rate as normally. For more information on Extended UL TBF Mode, see section Channel allocation and scheduling. The MS sends a PACKET UPLINK DUMMY CONTROL BLOCK in the scheduled block if it has no data to send. If the MS has got new data, it sends an RLC data block, and after that the PCU cancels the delayed TBF release, and the TBF continues with the normal scheduling rate. Even if the MS does not support Extended UL TBF Mode, the PCU may delay the UL TBF release (by 0.5s by default). This is done when there is no concurrent DL TBF for the same MS. The purpose of the delay is to speed up the possibly following DL TBF establishment. No USF turns are scheduled during this delay. For more details about the uplink data message contents, refer to BSCSGSN Interface Specification, BSS GPRS Protocol (BSSGP). Uplink TBF establishment when downlink TBF exists During a downlink TBF the MS can request resources for an uplink TBF by including a Channel Request Description IE in the (EGPRS) _PACKET_DOWNLINK_ACK/NACK message. The TBF mode (GPRS/ EGPRS) of the new UL TBF is always the same as the mode of the existing DL TBF. If there is no need to change the downlink PDTCH configuration, a PACKET_UPLINK_ASSIGNMENT message from the PCU to the MS contains the uplink PDTCH configuration, USF values for each PDTCH, and TFI. If the downlink PDTCH configuration is changed, for instance due to MS multislot capability restrictions, the PACKET_TIMESLOT_RECONFIGURE message from the PCU informs the MS of both the uplink and downlink PDTCH configurations, USF values for the uplink PDTCHs, and the uplink and downlink TFIs. 234 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control The establishment is ready when the PCU receives the first block on the assigned uplink PDTCHs. This establishment is also guarded by a timer in the PCU. If the PACKET_UPLINK_ASSIGNMENT message fails, the uplink TBF is released. If the PACKET_TIMESLOT_RECONFIGURE message fails, both downlink and uplink TBFs are released. 12.6 Suspend and resume GPRS The GPRS suspension procedure enables the network to discontinue GPRS packet flow in the downlink direction. Suspend is referred to as the situation, which occurs when a circuit switched call interrupts a GPRS packet flow and the GPRS connection is thus discontinued or suspended. When a mobile station which is IMSI attached for GPRS services enters dedicated mode, and when the MS or network limitations make it unable to handle both dedicated mode and either packet idle mode or packet transfer mode simultaneously (in other words DTM cannot be used), the MS performs the GPRS suspension procedure. The GPRS_SUSPENSION_REQUEST message is an indication to the SGSN not to send downlink data. The MS initiates the GPRS suspension procedure by sending a message to the BSC. The BSC sends the SUSPEND_PDU message to the SGSN. The message contains the TLLIand the Routing Area of the MS. The SGSN acknowledges with a SUSPEND-ACK PDU message, which contains the TLLI, the Routing Area of the MS, and the Suspend Reference Number. The SGSN typically stops paging for a suspended mobile. If the SGSN is not able to suspend GPRS services, it sends a negative response to the BSC with the SUSPEND-NACK PDU message. The message contains the TLLI, the Routing Area of the MS and the cause of the negative acknowledgement. When a GPRS attached MS in an GPRS/EDGE-capable but non-DTMcapable cell leaves dedicated mode, disconnecting the MS from the MSC, or a DTM-capable MS is handed over from a non-DTM cell to a cell that supports DTM, the reason for the suspension disappears. In this case, the BSC either instructs the MS to initiate the Routing Area Update procedure or signals to the SGSN that the MS's GPRS service shall be resumed. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 235 (272) EDGE System Feature Description If a DTM-capable MS is handed over from a non-DTM cell to a cell that supports DTM during a dedicated connection, the MS shall perform the Routing Area Update procedure to resume GPRS services in the new cell. The MS starts the Routing Area Update procedure after detecting the DTM service in the cell. If the suspension procedure has been successfully completed and the reason for the suspension is still valid, for instance a DTM-capable MS has not been handed over from a non-DTM cell to a DTM-capable cell, the BSC resumes the GPRS services before the circuit switched call is released by sending a RESUME PDU message to the SGSN. The message contains the TLLI, the Routing Area of the MS and the Suspend Reference Number. The SGSN acknowledges the procedure with a RESUME-ACK PDU message, which contains the TLLI and the Routing Area of the MS. When the circuit switched call is released, the BSC sends a CHANNEL RELEASE message to the MS indicating that the resume procedure has been successfully completed. If the BSC has not been able to resume GPRS services or in case of a DTM-capable MS, the services are still suspended, the MS resumes the services by sending the Routing Area Update Request to the SGSN after the circuit switched connection has been released. 12.7 Flush The flush procedure is used, for example, when the MS has stopped data sending in a given cell and has moved to another cell. The SGSN sends a FLUSH-LL PDU to the BSC to ensure that LLC PDUs queued for transmission in a cell for an MS are either deleted or transferred to the new cell. The MS's TLLI indicates which mobile's data is in question and the BVCI (old) indicates the cell. The BSC deletes all buffered LLC PDUs in the cell and all contexts for the MS. If an optional new cell, BVCI (new), is given, the BSC transfers all buffered LLC PDUs to the new cell on the condition that both the BVCI (old) and the BVCI (new) are served by the same PCU and the same Routing Area. For more details on flush, refer to BSC-SGSN Interface Specification, BSS GPRS Protocol (BSSGP). 236 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control 12.8 Cell selection and re-selection Cell selection and re-selection is performed autonomously by the MS or by the network, depending on the network control mode. The following cell re-selection criteria are used for GPRS: . The path loss criterion parameter C1 is used as a minimum signal level criterion for cell re-selection for GPRS in the same way as for GSM Idle mode. The signal level threshold criterion parameter C31 for hierarchical cell structures (HCS) is used to determine whether prioritised hierarchical GPRS and LSA cell re-selection shall apply. The cell ranking criterion parameter (C32) is used to select cells among those with the same priority. . . For information on network-controlled cell re-selection, see: . Network-Controlled Cell Re-selection Inter-System Network-Controlled Cell Re-selection . For information on network-assisted cell change, see: . Network-Assisted Cell Change 12.9 Traffic administration The BSC has many overload mechanisms to protect existing traffic flow and thus ensure good quality for end-users. The cause of an overload may be, for example, in the planning of the network and capacity being too small in a particular area. In the case of overload, neither circuit switched nor GPRS connections can be set up. The BCSU continuously tries, however, to set up the GPRS connection, and the unit can in the worst case thus easily run itself into a state of malfunction. The BCSU cuts down the load by rejecting particular messages when the processor load or the link load exceeds the defined load limit. Circuit switched calls are marked in the same way as GPRS connections. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 237 (272) EDGE System Feature Description The load the BCSU can handle has been tested, but the user can determine GPRS usage and thus prevent the overload situations from happening. Refer to section BSS overload protection and flow control in BSS (BSC) Traffic Handling Capacity, Network Planning and Overload Protection for more information on the BSC's overload control in general. BCSU overload control The BCSU has an overload control to protect itself against the processor overloading and the TRXSIG link overloading. BCSU protection against excessive number of paging messages on the Gb interface The BCSU cuts down the load by rejecting particular messages when the processor load or the link load exceeds the defined load limit. The BCSU rejects messages which are sent in the downlink direction to the TRXSIG if needed. Each message sent to TRXSIG has a certain message group value. In case the message buffers of an AS7 plug-in unit begin to fill up, the BCSU rejects messages based on the message group value. The BCSU cuts down the load caused by GPRS and circuit switched paging messages sent by the SGSN. The load control is based on the number of unhandled messages in the BCSU's message queue. The BCSU checks the count of unhandled messages in the message queue every time a new paging message is received. If the load limit is exceeded, the message is deleted. BCSU protection against high GPRS RACH load In the uplink direction the BCSU cuts down the load caused by GPRS random accesses. The BCSU rejects P-CHANNEL_REQUIRED messages received from the TRXSIG if the processor load exceeds the defined load limit. The load control is based on the number of unhandled messages in the BCSU's message queue. The count of unhandled messages in the message queue is checked every time a new PCHANNEL_REQUIRED message is received. If the load limit is exceeded, the BCSU deletes the message. BSSGP flow control Flow control is part of the BSSGP protocol. It is used to adjust the flow of BSSGP DL-UNITDATA PDUs from SGSN to the PCU. PCU controls the flow by indicating its buffer size and maximum allowed throughput to the SGSN. SGSN is not allowed to transmit more data than indicated by the PCU. Flow control is performed for downlink data in BVC (cell) and MS level. Any uplink flow control is not performed. 238 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control PCU holds a buffer for storing downlink data. The amount of the data to be stored in the PCU is optimised for efficient use of the available radio resources. The BVC and MS buffer sizes indicated to the SGSN are controlled by the PRFILE parameters FC_B_MAX_TSL and FC_MS_B_MAX_DEF. PCU monitors the lifetime values of the buffered DL UNITDATA PDUs. If the lifetime of a PDU expires before the PDU is sent across the radio interface, PCU deletes the PDU locally. Local deletion is signalled to the SGSN by a LLC-DISCARDED PDU. The 3GPP Rel-5 specifications introduce a third layer for BSSGP flow control: a Packet Flow Context (PFC) flow control. The PFC flow control is an optional functionality. Flow control mode of operation The PCU sends an initial FLOW-CONTROL-BVC PDU to the SGSN after a BVC is reset in order to allow SGSN to start the downlink BSSGP data transfer. This message contains BVC specific buffer size and leak rate, as well as default values for MS buffer size and leak rate. The PRFILE parameters FC_B_MAX_TSL and FC_R_TSL define the BVC specific buffer size and leak rate together with the number of actual GPRS timeslots in the cell. The parameters FC_MS_B_MAX_DEF and FC_MS_R_DEF define the MS specific default values. SGSN uses the MS default values for controlling the flow of an individual MS until it receives a FLOWCONTROL-MS PDU regarding that MS. Upon reception of a FLOW-CONTROL PDU, SGSN modifies its downlink transmission as instructed and ensures that it never transmits more data than can be accommodated within the BSC buffer for a BVC or an MS. After the initial BVC FLOW-CONTROL PDU, PCU starts to perform periodic flow control in BVC and MS level. The frequency of FLOWCONTROL PDUs is limited so that the PCU may send a new PDU once in every C seconds for each flow. The value C in the PCU is fixed to 1 s. PCU checks the flow control status for each BVC and MS once a second and sends as a periodic FLOW CONTROL PDU to SGSN for the flows which needs to be adjusted. For this purpose the PCU keeps record of the received DL data per BVC and per MS. It knows the buffer utilisation ratio and leak rate of each flow, and compares the actual leak rate value to the value reported earlier to the SGSN. If the leak rate difference for a flow exceeds the PRFILE parameter FC_R_DIF_TRG_LIMIT, the flow control parameters in SGSN needs to be updated. For a BVC flow, the FLOWCONTROL-BVC PDU and for a MS flow, the FLOW-CONTROL-MS PDU is sent to SGSN. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 239 (272) EDGE System Feature Description If the PCU does not receive confirmation to a FLOW-CONTROL PDU, no further action is taken. If the condition which requires flow control remains effective, a new FLOW-CONTROL PDU is sent to the SGSN after one second. For more information on BVC and MS flow control, refer to BSC-SGSN Interface Specification, BSS GPRS Protocol (BSSGP). Uplink congestion control on NS-VC The BSC/PCU uses a local congestion control procedure to adapt uplink NS-UNITDATA traffic to the NS-VCs according to their throughput. The PCU sends an NS-UNITDATA, which passes the procedure, to the SGSN as long as the CIR of the NS-VC is not exceeded. The PCU deletes any NS-UNITDATA that does not pass the procedure. This updates a counter, and the BSC sets the alarm 3027 UPLINK CONGESTION ON THE NETWORK SERVICE VIRTUAL CONNECTION in the BSC. The alarm is cancelled automatically, when NS-UNITDATA again passes the procedure. 12.10 Coding scheme selection in GPRS Stealing bits in the channel coding (for more information, see ETSI specification on Channel Coding) are used to indicate the actual coding scheme (CS) which is used for each block sent between the BSC's PCU and the MS. In downlink packet transfer the PCU selects the CS, and the code word for the selected CS is included in each RLC data block sent to the MS. If the PCU changes the CS during one TBF reservation, it includes the new CS code word in the blocks. In uplink data transfer, the PCU informs the MS the initial CS to be used in either the IMMEDIATE_ASSIGNMENT or PACKET_UPLINK_ASSIGNMENT message. The PCU can command the MS to change the CS by sending the PACKET_UPLINK_ACK/NACK message, which includes the Channel Coding Command field. In retransmission the same CS has to be used as in the initial block transmission. 240 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control In PCU1 the coding schemes CS-1 and CS-2 are supported. In PCU2 the coding schemes CS-3 and CS-4 are introduced. Although the CS-3 and CS-4 coding schemea are licence based, the Link Adaptation algorithm is still provided with PCU2. However, in case the operator has both PCU1 and PCU2 in use in the same track, coding schemes CS-1 and CS-2 can only be used and the Link Adaptation algorithm with coding scheme no hop (COD) and coding scheme hop (CODH) parameters is deployed. PCU1 The BSC level parameters coding scheme no hop (COD) and coding scheme hop (CODH) define whether the fixed CS value (CS-1/CS-2) is used or if the coding scheme is changed dynamically according to the Link Adaptation algorithm. In unacknowledged RLC mode CS-1 is always used regardless of the parameter values. When the Link Adaptation algorithm is deployed, then the initial value for the CS at the beginning of a TBF is CS2. Link Adaptation algorithm The Link Adaptation (LA) algorithm is used to select the optimum channel coding scheme (CS-1 or CS-2) for a particular RLC connection and it is based on detecting the occurred RLC block errors. Essential for the LA algorithm is the crosspoint, where the two coding schemes give the same bit rate. In terms of block error rate (BLER) the following equation holds at the crosspoint: 8.0 kbps * (1 - BLER_CP_CS1) = 12 kbps * (1 - BLER_CP_CS2), where: . 8.0 kbps is the theoretical maximum bit rate for CS-1 12.0 kbps is the theoretical maximum bit rate for CS-2 BLER_CP_CS1 is the block error rate at the crosspoint when CS-1 is used BLER_CP_CS2 is the block error rate at the crosspoint when CS-2 is used . . . If CS-1 is used and if BLER is less than BLER_CP_CS1, then it would be advantageous to change to CS-2. If CS-2 is used and if BLER is larger than BLER_CP_CS2, then it would be advantageous to change to CS-1. Since CS-1 is more robust than CS-2, BLER_CP_CS2 is larger than BLER_CP_CS1. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 241 (272) EDGE System Feature Description The crosspoint can be determined separately for UL and DL directions as well as for frequency hopping (FH) and non-FH cases. For this purpose the following BSC-level parameters are used by the LA algorithm: . UL BLER crosspoint for CS selection hop (ULBH) DL BLER crosspoint for CS selection hop (DLBH) UL BLER crosspoint for CS selection no hop (ULB) DL BLER crosspoint for CS selection no hop (DLB) . . . The given parameters correspond to the BLER_CP_CS1 (see equation above). During transmission, two counters are updated: N_Number gives the total number of RLC data blocks and K_Number gives the number of corrupted RLC data blocks that have been transmitted after the last link adaptation decision. At certain intervals (in uplink transfer after approximately 10 transmitted RLC blocks, and in downlink after every PACKET_DL_ACK/NACK message reception) the LA algorithm is run by performing two of the following (either 1 and 2 or 3 and 4) statistical tests: 1. Current coding scheme is CS-1; change to CS-2? Hypothesis: BLER > BLER_CP_CS1. Reference case: N_Number of blocks have been transmitted with a constant BLER value of BLER_CP_CS1. In this reference case the number of erroneous blocks follow binomial distribution and the P-value gives the probability to get at most K_Number of block errors out of N_Number of transmissions. P-value = If the P-value is less than a certain risk level (RL), the hypothesis can be rejected with (1-RL) confidence. If the hypothesis is rejected, it means that the reference case would hardly give the observed measures with the given condition of BLER > BLER_CP_CS1. If this is the case, then it can be concluded that BLER < BLER_CP_CS1. 242 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control Action in case the hypothesis is rejected: Change to CS-2. Reset counters N_Number and K_Number. Action in case the hypothesis is accepted: No actions. 2. Current coding scheme is CS-1; confirm CS-1? Hypothesis: BLER < BLER_CP_CS1. Reference case: N_Number of blocks have been transmitted with a constant BLER value of BLER_CP_CS1. In this reference case the number of erroneous blocks follow binomial distribution and the P-value gives the probability to get at least K_Number of block errors out of N_Number of transmissions. P-value = If the P-value is less than a certain risk level, the hypothesis can be rejected with (1-RL) confidence. This means that the reference case would hardly give the observed measures with the condition of BLER < BLER_CP_CS1. If this is the case, then it can be concluded that BLER > BLER_CP_CS1. Action in case the hypothesis is rejected: Reset counters N_Number and K_Number (CS-1 is confirmed). Action in case the hypothesis is accepted: No actions. 3. Current coding scheme is CS-2; change to CS-1? Hypothesis: BLER < BLER_CP_CS2. Reference case: N_Number of blocks have been transmitted with a constant BLER value of BLER_CP_CS2. In this reference case the number of erroneous blocks follow binomial distribution and the P-value gives the probability to get at least K_Number of block errors out of N_Number of transmissions. P-value = DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 243 (272) EDGE System Feature Description If P-value is less than a certain risk level, the hypothesis can be rejected with (1-RL) confidence. This means that the reference case would hardly give the observed measures with the condition of BLER < BLER_CP_CS2. If this is the case, then it can be concluded that BLER > BLER_CP_CS2. Action in case the hypothesis is rejected: Change to CS-1. Reset counters N_Number and K_Number. Action in case the hypothesis is accepted: No actions. 4. Current coding scheme is CS-2; confirm CS-2? Hypothesis: BLER > BLER_CP_CS2. Reference case: N_Number of blocks have been transmitted with a constant BLER value of BLER_CP_CS2. In this reference case the number of erroneous blocks follow binomial distribution and the P-value gives the probability to get at most K_Number of block errors out of N_Number of transmissions. P-value = If P-value is less than a certain risk level, the hypothesis can be rejected with (1-RL) confidence. This means that the reference case would hardly give the observed measures with the condition of BLER > BLER_CP_CS2. If this is the case, then it can be concluded that BLER < BLER_CP_CS2. Action in case the hypothesis is rejected: Reset counters N_Number and K_Number (CS-2 is confirmed). Action in case the hypothesis is accepted: No actions. 244 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control In practice the threshold K_Number values have been computed beforehand to look-up tables indexed with respect to the N_Number and the link adaptation decisions can be performed by simply comparing the observed K_Number with the theshold K_Number values. The Risk Level parameters (UL adaption probability threshold (ULA) and DL adaption probability threshold (DLA)) describe the probability with which the LA algorithm may make a wrong conclusion to reject a given hypothesis. In other words, they determine the sensitivity of the LA algorithm. The larger the risk level, the more quickly the LA algorithm is able react to changes in BLER by switching the coding scheme but on the other hand the reliability of the switching decision is lowered as the risk level is increased. The PCU chooses a lower CS than what the Link Adaptation algorithm allows, if there is no room in the dynamic Abis pool for the higher CS allowed by the LA. PCU2 The Link Adaptation algorithm In PCU2 the coding schemes CS-1 - CS-4 are supported. The BTS level parameters DL coding scheme in acknowledged mode (DCSA), UL coding scheme in acknowledged mode (UCSA), DL coding scheme in unacknowledged mode (DCSU) and UL coding scheme in unacknowledged mode (UCSU) define whether the fixed CS value (CS1 - CS-4) is used or if the coding scheme is changed dynamically according to the Link Adaptation algorithm. The parameter DL coding scheme in acknowledged mode (DCSA) defines it in RLC acknowledged mode in downlink direction, UL coding scheme in acknowledged mode (UCSA) defines it in RLC acknowledged mode in uplink direction and so on. The BTS level parameter adaptive LA algorithm (ALA) defines whether the Link Adaptation algorithm is adaptive or not. The new Link Adaptation algorithm can be used both in RLC acknowledged and in unacknowledged modes both in uplink and downlink direction. When the Link Adaptation algorithm is deployed, the initial values for the CS at the beginning of a TBF can also be defined with the parameters DL coding scheme in acknowledged mode (DCSA), UL coding scheme in acknowledged mode (UCSA), DL coding scheme in unacknowledged mode (DCSU) and UL coding scheme in unacknowledged mode (UCSU). DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 245 (272) EDGE System Feature Description Note, however, that when a GPRS MS already has a TBF and a new TBF is established for the MS to the opposite direction, then the initial value of the CS of the new TBF is set to be the same that is currently used by the ongoing TBF. The new Link Adaptation algorithm replaces the current LA algorithm in GPRS and covers the coding schemes: . CS-1 and CS-2 if the CS-3 and CS-4 support is not enabled in the territory CS-1, CS-2, CS-3 and CS-4, if the CS3 and CS-4 support is enabled in the territory . The new LA algorithm is based on the following principles: . The signal quality is measured for each TBF in terms of RXQUAL, which describes the channel quality with the accuracy of eight levels (RXQUAL is expressed with three bits). Note that RXQUAL is measured for each received RLC radio block. On a block basis RXQUAL is thus more accurate estimate than the BLER, which has only two levels: 0 and 1. The PCU determines internally the average BLER separately for each coding scheme and reported RXQUAL value. This is done separately in each cell by collecting statistics continuously from all the connections in the corresponding cell. Based on the statistics (common for all the TBFs in the cell) and the received RXQUAL estimate (specific to the given TBF), the PCU is able to estimate what the BLER would be if CS1, CS2, CS3 or CS4 were deployed for this TBF. Moreover, based on these BLER estimates the PCU can compute which coding scheme would give the best performance, that is the highest throughput in RLC acknowledged mode. The new LA algorithm adapts to the radio characteristics of the cell because the BLER is dynamically measured as a function of RXQUAL and coding scheme. Therefore, there is no need for predetermined threshold values that are traditionally used in link adaptation. . . . Operation in downlink direction 246 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control The PCU uses two 2-dimensional tables (ACKS and NACKS) for the LA operation (another set of ACKS and NACKS tables are needed for UL direction). In these tables, the first index refers to the coding scheme and the second index refers to the RXQUAL value. Initially the ACKS and NACKS tables are initialised with values obtained from the simulations. Therefore, the operation of the LA algorithm is initially based on the simulation results. The PCU has separate ACKS and NACKS tables as well as separate initialisation for hopping and non-hopping BTSs. During the DL data transfer the mobile station measures the signal quality (RXQUAL) from the RLC radio blocks that are successfully decoded and addressed to the mobile station. The RXQUAL is averaged over the received RLC blocks and the averaged RXQUAL estimate is sent to the network in the Packet DL Ack/Nack messages. There can be eight different values for the RXQUAL. When the PCU receives a valid Packet DL Ack/Nack message for the DL TBF that operates in an RLC acknowledged mode, the received bitmap is analysed and the corresponding RLC blocks are marked as ACKED, if a positive acknowledgement is received, or as NACKED, if a negative acknowledgement is received. In this procedure, the RLC updates the ACKS and NACKS tables as follows: . Whenever an RLC block is positively acknowledged, ACKS [CS] [RXQ] = ACKS [CS][RXQ] + 1, where CS indicates the coding scheme with which this RLC block was transmitted and RXQ refers to the RXQUAL value received in this particular Packet DL Ack/Nack message. Whenever an RLC block is negatively acknowledged, NACKS [CS] [RXQ] = NACKS [CS][RXQ] + 1, where CS indicates the coding scheme with which this RLC block was originally transmitted and RXQ refers to the RXQUAL value received in this particular Packet DL Ack/Nack message. . If the value of the parameter adaptive LA algorithm (ALA) is N (disabled), the RLC does not update ACKS and NACKS tables but only the initial values of those tables will be used when the LA algorithm selects the optimal CS. The ACKS and NACKS tables contain ever-increasing figures. In the long run the figures would overflow resulting in erroneous behavior. To solve this, both figures are divided by 2, when the sum (ACKS [CS][RXQ] + NACKS [CS][RXQ]) for CS and RXQ exceeds a certain threshold value. DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 247 (272) EDGE System Feature Description Coding scheme selection in downlink direction in RLC acknowledged mode After the bitmap is processed, the LA algorithm selects the optimal coding scheme for a TBF as follows: 1. The throughput of the link is estimated for each coding scheme separately as follows: throughput [CS] = K * ACKS [CS][RXQ] / (ACKS [CS][RXQ] + NACKS [CS][RXQ]) * RATE[CS], where: CS = CS-1, CS-2, CS-3, CS-4, if CS-3 and CS-4 support is enabled in the territory, otherwise CS = CS-1, CS-2. . K is a correction factor that takes into account the throughput reduction due to the RLC protocol stalling . RXQ is the RXQUAL value that was received in the newlyprocessed Packet DL Ack/Nack message . RATE[4] -table contains the theoretical maximum throughput values for the available channel coding schemes The coding scheme is selected based on the highest throughput with the condition of BLER (CS) < QC_ACK_BLER_LIMIT_T , where BLER(CS) = NACKS [CS] [RXQ] / (ACKS[CS] [RXQ] + NACKS [CS] [RXQ]). If no CS fulfills this condition, the coding scheme CS-1 is selected. 2. The correction factor K depends on the BLER and on the number of RLC radio blocks scheduled to the TBF within the RLC acknowledgement delay. Its value has been determined by simulations. Coding scheme selection in downlink direction in RLC unacknowledged mode In unacknowledged mode RLC does not have to update the ACKS and NACKS tables but it can use the same ACKS and NACKS tables updated by the TBFs in acknowledged mode. The coding schemes that are in an unacknowledged mode are selected by choosing the highest CS for which BLER (CS) < QC_UNACK_BLER_LIMIT_T, where BLER (CS) = NACKS [CS] [RXQ] / (ACKS[CS] [RXQ] + NACKS [CS] [RXQ]) and RXQ is the RXQUAL estimate that is received in the Packet DL Ack/Nack message. If these conditions are not fulfilled the coding scheme CS-1 is selected. If the MS does not aswer to polling, the coding number will be decreased step-by-step as follows: 248 (272) # Nokia Siemens Networks DN03299216 Issue 9-0 en 20/03/2008 GPRS/EDGE radio connection control . If one Packet DL Ack/Nack message is missed with CS-4, then the coding scheme is changed to CS-3. If two subsequent Packet DL Ack/Nack messages are missed with CS-3, then the coding scheme is changed to CS-2. If three subsequent Packet DL Ack/Nack messages are missed with CS-2, then the coding scheme is changed to CS-1 . . Operation in uplink direction In UL direction the channel quality estimate can be either RXQUAL or GMSK_BEP depending on the Abis interface. The PCU data frame used in the non-EDGE Abis interface reports the channel quality in terms of RXQUAL, which is expressed with three bits. In this case the only possible coding schemes are CS-1 and CS-2. Whereas the PCU master data frame used in the EDGE Abis interface reports the channel quality in terms of GMSK_BEP, which is expressed with four bits. The possible coding schemes are CS-1, CS-2, CS-3 and CS-4. The PCU uses two 2-dimensional tables (ACKS and NACKS) for LA operation. In these tables, the first index refers to the coding scheme and the second index refers to the RXQUAL or GMSK BEP value. Initially the ACKS and NACKS tables are initialised to the values obtained from the simulations. The PCU has separate ACKS and NACKS tables as well as separate initialisation for hopping and non-hopping BTSs. In case of RXQUAL, the RLC averages the RXQUAL estimates sent by the BTS for the correctly received RLC radio blocks. This is done for each uplink TBF. In case of GMSK_BEP, the RLC averages the GMSK_BEP estimates sent by the BTS for both correctly and erroneously received RLC radio blocks. This is done for each UL TBF. The GMSK_BEP estimate is made also from the bad frames because the GMSK_BEP estimate for successfully received CS-4 blocks alone approaches zero in all radio conditions (there is no error correction in CS-4). During the UL data transfer the PCU updates the ACKS and NACKS tables as follows: Whenever a new RLC block is successfully received, ACKS [CS][RXQ] = ACKS [CS][RXQ] + 1, where CS indicates the coding scheme with which this RLC block was transmitted and RXQ refers to the current RXQUAL or GMSK BEP estimate for this UL TBF. Whenever a RLC block is received DN03299216 Issue 9-0 en 20/03/2008 # Nokia Siemens Networks 249 (272) EDGE System Feature Description unsuccessfully, NACKS [CS][RXQ] = NACKS [CS][RXQ] + 1, where CS indicates the coding scheme with which this RLC block was transmitted and RXQ refers to the current RXQUAL or GMSK BEP estimate for this UL TBF. As in the DL case the figures in the ACKS and NACKS tables are limited so that when the sum (ACKS [CS][RXQ] + NACKS [CS][RXQ]) for certain CS and RXQ exceeds a certain threshold value, both figures are divided by 2. Coding scheme selection in uplink direction in RLC acknowledged mode 1. The throughput of the link is estimated for each coding scheme separately as follows: throughput [CS] = K * ACKS [CS][RXQ] / (ACKS [CS][RXQ] + NACKS [CS][RXQ]) * RATE [CS], where: CS = CS-1, CS-2, CS-3, CS-4, if CS-3 and CS-4 support is enabled in the territory, otherwise CS = CS-1, CS-2. K is a correction factor that takes into account the throughput reduction due to the RLC protocol stalling, RXQ is the current RXQUAL or GMSK BEP estimate for this UL TBF and RATE [4] -table contains the theoretical maximum throughput values for the available channel coding schemes. The coding scheme is selected based on the highest throughput with the condition of BLER (CS)

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  • Tuesday, 18 June 2013

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