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63314619 e-gprs-radio-networks-planning-theory-s13

  1. 1. (E)GPRS Radio Networks Planning Theory Version 3.0
  2. 2. 2/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 DOCUMENT DESCRIPTION Title and version Reference Target Group Technology and SW release Related Service Items Service Item number Author Date Approver (E)GPRS Radio Networks - Planning Theory v3.0 Radio, Tranmission, E2E GERAN - S13 Pal Szabadszallasi Villa Salomaa CHANGE RECORD This section provides a history of changes made to this document VERSION 1.0 2.0 3.0 DATE 17.06.2005 18.12.2006 16.12.2008 EDITED BY Pal Szabadszallasi Pal Szabadszallasi Pal Szabadszallasi SECTION/S COMMENTS Copyright © Nokia Siemens Networks. This material, including documentation and any related computer programs, is protected by copyright controlled by Nokia Siemens Networks. All rights are reserved. Copying, including reproducing, storing, adapting or translating, any or all of this material requires the prior written consent of Nokia Siemens Networks. This material also contains confidential information which may not be disclosed to others without the prior written consent of Nokia Siemens Networks.
  3. 3. 3/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. Table of contents 1. Introduction ....................................................................................... 7 1.1 1.2 1.2.1 1.2.1.1 1.2.1.2 1.2.1.3 1.2.2 1.3 1.3.1 1.3.2 1.3.3 1.4 (E)GPRS Dimensioning, Planning and Optimization Structure........................................8 Data hardware and site solutions....................................................................................8 BSC and PCU variants ...................................................................................................8 PCU2 Plug-in Unit Variants and Hardware Architecture..................................................9 PCU2 Software Architecture.........................................................................................10 PCU1 and PCU2 Software Differences on Air Interface................................................11 BTS variants.................................................................................................................12 Data features................................................................................................................12 S10 / S10.5ED..............................................................................................................12 S11 / S11.5...................................................................................................................13 S12...............................................................................................................................13 S13...............................................................................................................................14 2. (E)GPRS Modulation ...................................................................... 15 2.1 2.2 2.3 2.4 GMSK and 8-PSK Modulation ......................................................................................15 Modulation Block Diagrams ..........................................................................................16 Back-off in EGPRS .......................................................................................................17 Burst Structure .............................................................................................................19 3. Coding Schemes ............................................................................ 21 3.1 3.1.1 3.1.2 3.1.2.1 3.1.2.2 3.1.2.3 3.1.3 3.1.4 3.1.5 3.2 3.2.1 3.2.2 Protocol Architecture ....................................................................................................21 Physical Layer ..............................................................................................................22 RLC/MAC Layer ...........................................................................................................22 Radio Link Control ........................................................................................................22 Medium Access Control................................................................................................22 RLC/MAC Header Formats...........................................................................................22 Logical Link Control ......................................................................................................27 SNDCP Layer ...............................................................................................................28 IP, TCP/UDP and Application Layer .............................................................................28 RLC/MAC Coding Schemes .........................................................................................30 GPRS Coding Schemes (CSs) .....................................................................................30 EGPRS Modulation and Coding Schemes (MCSs).......................................................33 4. (E)GPRS Procedures...................................................................... 36 4.1 4.1.1 4.1.2 4.1.3 4.1.3.1 4.1.3.2 4.1.3.3 4.1.3.4 4.1.3.5 4.1.3.6 4.1.3.7 4.1.3.8 4.2 4.2.1 TBF Establishment .......................................................................................................36 Channel Request and Packet Immediate Assignment ..................................................36 DL TBF Assignment .....................................................................................................37 UL TBF Assignment .....................................................................................................39 Channel Request - Packet Access Procedure (CCCH / PCCH)....................................39 EGPRS Packet Channel Request.................................................................................40 Dynamic and Extended Dynamic Allocation on UL with and without USF4 ...................41 UL TBF ASSIGNMENT, MS on CCCH, 2 phase access...............................................42 UL TBF ASSIGNMENT, MS on CCCH, 1 phase access...............................................43 EGPRS UL TBF ASSIGNMENT, MS on PCCCH with 2 phase access.........................45 EGPRS UL TBF ASSIGNMENT, MS on PCCCH with 1 phase access.........................45 Establishment of EGPRS UL TBF when DL TBF is ongoing.........................................46 (E)GPRS Data Transfer................................................................................................47 (E)GPRS Data Transfer DL ..........................................................................................47
  4. 4. 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. 4/166 CMO SBU MS Network & Service Optimization Capability Management 4.2.2 4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.4 4.4.1 4.4.2 4.4.3 (E)GPRS Data Transfer UL ..........................................................................................47 Mobility with Cell-reselection ........................................................................................49 Intra PCU Cell-Reselection...........................................................................................49 Inter PCU Cell-reselection (Intra BSC)..........................................................................50 RA/LA Update (intra PAPU)..........................................................................................51 RA/LA Update (Inter PAPU or inter SGSN)...................................................................52 TBF Release ................................................................................................................53 Packet TBF Release Content .......................................................................................54 Abnormal Releases ......................................................................................................54 TBF Release in PCU2 ..................................................................................................55 5. (E)GPRS Accessibility .................................................................... 56 5.1 5.1.1 5.1.1.1 5.1.1.2 5.1.1.3 5.1.2 5.2 5.2.1 5.2.1.1 5.2.1.2 5.3 5.3.1 5.3.2 5.4 Air Interface Signaling Load..........................................................................................56 Common Control Channels ..........................................................................................57 Paging Channel ............................................................................................................57 Access Grand Channel.................................................................................................57 Random Access Channel .............................................................................................58 SDCCH ........................................................................................................................58 TRXSIG Load ...............................................................................................................59 TRXSIG Load Theory ...................................................................................................59 Abis Protocols ..............................................................................................................59 TRXSIG Load Components, Measurement and Analysis..............................................61 BCSU Load ..................................................................................................................64 BSC RAW Measurement Results .................................................................................64 Reporting Suit 184 Report ............................................................................................64 Signaling Load with DTM Usage...................................................................................65 6. Resource Allocation in BSS ............................................................ 66 6.1 6.1.1 6.1.2 6.1.3 6.1.3.1 6.1.3.2 6.1.3.3 6.1.3.4 6.1.3.5 6.2 6.2.1 6.2.2 6.2.2.1 6.2.2.2 6.2.2.3 6.2.2.4 6.2.2.5 6.3 6.3.1 6.3.2 6.3.3 6.3.4 6.3.5 6.4 6.5 Cell Reselection............................................................................................................67 C1 and C2 ....................................................................................................................67 C31/C32 .......................................................................................................................68 Network Controlled Cell Reselection.............................................................................71 NCCR Benefits .............................................................................................................72 NCCR Functionality ......................................................................................................72 Target cell selection......................................................................................................73 Signaling Flow ..............................................................................................................74 BLER Limits are Needed for the Quality Control Function in PCU2 ..............................75 BTS Selection...............................................................................................................76 Initial BTS Selection .....................................................................................................76 BTS Selection for Reallocating TBF..............................................................................79 Uplink Rx Lev Reallocation...........................................................................................81 Downlink Rx Lev Reallocation ......................................................................................82 Downlink RX Lev Received First Time Reallocation .....................................................82 BTS Selection in PCU2.................................................................................................82 Territory Upgrade Request in PCU2 .............................................................................83 Channel Scheduling .....................................................................................................84 Priority based Quality of Service...................................................................................84 Channel Allocation........................................................................................................85 TBF Scheduling ............................................................................................................86 QoS Information Delivery..............................................................................................87 Nokia HLR QoS Settings ..............................................................................................88 Flow Control on Gb.......................................................................................................91 Gb over IP ....................................................................................................................91
  5. 5. 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. 5/166 CMO SBU MS Network & Service Optimization Capability Management 7. (E)GPRS Timeslot Data Rate ......................................................... 93 7.1 7.1.1 7.1.1.1 7.1.1.2 7.1.1.3 7.1.2 7.1.2.1 7.1.2.2 7.1.2.3 7.1.3 7.2 7.2.1 7.2.1.1 7.2.1.2 7.2.2 7.3 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5 7.4 7.4.1 7.4.2 7.4.3 7.5 7.6 7.6.1 7.6.2 7.6.2.1 7.6.3 7.6.3.1 7.6.3.2 7.6.3.3 7.6.3.4 7.6.3.5 7.6.3.6 7.6.3.7 7.7 7.7.1 7.7.2 7.7.2.1 7.7.2.2 7.7.2.3 7.7.2.4 GSM Network Performance ..........................................................................................93 Impact of Coverage Level.............................................................................................93 Signal Strength Requirements ......................................................................................94 Receiving End ..............................................................................................................95 Measurement Results...................................................................................................96 Impact of Interference Level .........................................................................................98 Simulation Results........................................................................................................98 Spectrum Efficiency and Frequency Reuse ................................................................103 Measurement Results.................................................................................................104 Mixture of Signal Level and Interference.....................................................................104 TSL Utilization Improvement.......................................................................................106 Acknowledge Request Parameters.............................................................................106 GPRS DL/UL Penalty and Threshold..........................................................................106 (E)GPRS DL/UL Penalty and Threshold .....................................................................106 PRE_EMPTIVE_TRANSMISSIO ................................................................................107 TBF Release Delay Parameters (S10.5 ED)...............................................................107 DL_TBF_RELEASE_DELAY ......................................................................................107 DL_TBF_RELEASE_DELAY in PCU2 ........................................................................108 UL_TBF_RELEASE_DELAY ......................................................................................108 Release of downlink Temporary Block Flow ...............................................................109 Release of uplink Temporary Block Flow ....................................................................109 TBF Release Delay Extended (S11 onwards).............................................................110 TBF is Continued based on EUTM .............................................................................110 TBF is Not Continued based on EUTM.......................................................................111 EUTM in PCU2 ...........................................................................................................112 BS_CV_MAX..............................................................................................................112 GPRS and EGPRS Link Adaptation............................................................................115 GPRS Link Adaptation (S11) ......................................................................................115 GPRS Link Adaptation with CS1-4 (PCU2).................................................................116 Link Adaptation Algorithm Used in Uplink Direction ....................................................118 EGPRS Link Adaptation with Incremental Redundancy..............................................121 Link Adaptation Introduction .......................................................................................121 MCS Selection............................................................................................................123 Bit Error Probability.....................................................................................................125 Link Adaptation Procedure .........................................................................................131 Incremental Redundancy in EGPRS...........................................................................138 MCS Selection Based on BLER Limits .......................................................................142 EGPRS LA in PCU2 ...................................................................................................143 Multiplexing ................................................................................................................144 Synchronization ..........................................................................................................144 Dynamic Allocation on UL...........................................................................................144 GPRS and EGPRS Dynamic Allocation......................................................................144 GPRS and EGPRS Dynamic Allocation without USF4...............................................145 GPRS and EGPRS Dynamic Allocation with USF4.....................................................145 GPRS and EGPRS Extended Dynamic Allocation with/without USF4.........................146 8. (E)GPRS Territory Settings........................................................... 147 8.1 8.1.1 8.1.1.1 8.1.1.2 8.1.1.3 Timeslot Allocation between Circuit Switched and (E)GPRS Services........................147 PSW Territory.............................................................................................................147 Dedicated (E)GPRS Capacity.....................................................................................147 Default GPRS Capacity ..............................................................................................148 Additional (E)GPRS Capacity .....................................................................................148
  6. 6. 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. 6/166 CMO SBU MS Network & Service Optimization Capability Management 8.1.2 8.1.2.1 8.1.3 8.1.3.1 8.1.3.2 8.1.3.3 8.1.3.4 8.2 8.2.1 8.3 CSW Territory.............................................................................................................148 Free Timeslots............................................................................................................149 Territory Upgrade/Downgrade – Dynamic Variation of Timeslots................................151 Downgrade .................................................................................................................151 Upgrade .....................................................................................................................152 Territory Upgrade and Downgrade S10 Changes .......................................................152 Multislot TSL Allocation for Using max Capability of Mobile........................................153 Multislot Usage...........................................................................................................153 Average Window Size ................................................................................................155 High Multislot Class (HMC).........................................................................................155 9. Mobility ......................................................................................... 157 9.1 9.1.1 9.1.1.1 9.1.1.2 9.1.2 9.2 9.2.1 9.2.1.1 9.2.1.2 9.2.1.3 9.2.2 9.3 9.4 Intra/Inter PCU Cell Re-selection................................................................................157 BSS and Data Outage ................................................................................................157 BSS Cell-reselection outage.......................................................................................158 Data outage................................................................................................................158 Benchmark Results ....................................................................................................160 LA /RA Cell-reselection...............................................................................................161 Data Outage ...............................................................................................................161 Location Area Update.................................................................................................161 Routing Area Update ..................................................................................................161 Data outage (LA/RA Update) ......................................................................................161 Benchmark Results ....................................................................................................163 Cell-reselect Hysteresis ..............................................................................................164 Network Assisted Cell Change ...................................................................................165
  7. 7. 7/166 CMO SBU MS Network & Service Optimization Capability Management 1. 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. Introduction The (E)GPRS Radio Networks – Planning Theory document was prepared to provide the basic theoretical knowledge for (E)GPRS Radio Network dimensioning, planning and optimization. The (E)GPRS Radio Networks planning document set structure listed below: • (E)GPRS Radio Networks – Planning Theory • (E)GPRS Radio Networks – Dimensioning and Planning Guidelines • (E)GPRS Radio Networks – Optimization Guidelines The Planning Theory gives the theoretical knowledge while “Dimensioning and Planning Guidelines” and “Optimization Guidelines” contain all the practical information for daily planning and optimization activities. The materials listed above are based on S10.5 ED, S11, S11.5, S12 and S13 BSS software releases; moreover both PCU1 and PCU2 are taken into account. The detailed Abis, EDAP, PCU and Gb planning theory are not included in this document. For more information pls. see the latest guidelines on the links below: GSM Access: https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/358201395 MW Radio Transmission (and Mobile Backhaul) https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/369066809 GERAN Radio https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/357448144 The 3GPP specifications can be found at the following intranet location: http://www.3gpp.org/specification-numbering
  8. 8. 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. 8/166 CMO SBU MS Network & Service Optimization Capability Management 1.1 (E)GPRS Dimensioning, Planning and Optimization Structure The general way of (E)GPRS radio dimensioning, planning and optimization procedure is listed below: (E)GPRS Dimensioning and Planning • Operators’ business plan investigation • Operators’ BSS network structure audit (with core network) • Deployment plan preparation • Capacity calculations based on deployment plan • Parameter setting (E)GPRS Optimization • Configuration and feature audit • BSS and E2E Performance measurements • GSM network optimization • (E)GPRS network optimization All the points above are described in (E)GPRS Radio Networks - Dimensioning and Planning Guidelines and (E)GPRS Radio Networks - Optimization Guidelines. (E)GPRS Radio Networks - Dimensioning and Planning Guidelines: https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/358168893 (E)GPRS Radio Networks - Optimization Guidelines: https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/358173597 1.2 Data hardware and site solutions The following sessions describe the PS related hardware elements in the BSS chain. 1.2.1 BSC and PCU variants Nokia Packet Control Unit (PCU) is a Plug-in unit in a Base Station Controller (BSC). PCU hardware is embedded in BSCs in every BCSU (BSC Signaling unit). The Nokia PCU product family consists of following products:
  9. 9. 9/166 CMO SBU MS Network & Service Optimization Capability Management PCU variant BSC Type PCU BSCE, BSC2, BSCi, BSC2i PCU-S BSCE, BSC2, BSCi, BSC2i PCU-T BSCE, BSC2, BSCi, BSC2i PCU2-U BSCE, BSC2, BSCi, BSC2i PCU-B BSC3i PCU2-D BSC3i Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Release BTS TRX Radio TSLs Abis 16 kbps channels Gb 64 kbps channels BTS TRX Radio TSLs Abis 16 kbps channels Gb 64 kbps channels BTS TRX Radio TSLs Abis 16 kbps channels Gb 64 kbps channels BTS TRX Radio TSLs Abis 16 kbps channels Gb 64 kbps channels BTS TRX Radio TSLs Abis 16 kbps channels Gb 64 kbps channels BTS TRX Radio TSLs Abis 16 kbps channels Gb 64 kbps channels BSS11 BSS11.5 ownwards 64 128 256 256 31 64 128 256 256 31 64 128 256 256 31 N/A N/A N/A N/A N/A 2 x 64 2 x 128 2 x 256 2 x 256 2 x 31 N/A N/A N/A N/A N/A 64 128 128 256 31 64 128 128 256 31 64 128 256 256 31 128 256 256 256 31 2 x 64 2 x 128 2 x 256 2 x 256 2 x 31 2 x 128 2 x 256 2 x 256 2 x 256 2 x 31 Table 1 PCU product family The PCU-S is the first and PCU-T the second evolution of PCU variant having more memory and higher CPU clock rate. 1.2.1.1 PCU2 Plug-in Unit Variants and Hardware Architecture In the PCU2 solution, there are two PCU2 plug-in unit variants which implement the new hardware architecture. PCU2-D is used for BSC3i, which includes two logical PCU2 units, and PCU2-U is used for the older BSC versions. For more information on the PCU2 plug-in unit variants, see the PCU2 hardware plug-in unit descriptions in BSC/TCSM documentation. PCU2 introduces more processing capacity for both PowerQuicc II (PQII) and digital signal processors (DSP) with external memory and hardware architecture enhancements to create a basis for new packet data related functionalities. The functionalities include enhancements in following areas: • Enhanced processing capabilities for PQII and DSPs with external memory and a higher DSP-level Abis channel connectivity to fully support the software architecture enhancements • Actual traffic and O&M information separated on different paths between PQII and DSPs
  10. 10. 10/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. Figure 1 Main hardware blocks in the PCU1 and PCU2 variants 1.2.1.2 PCU2 Software Architecture The new software architecture, with its modular decomposition and restructured task management, uses the hardware architecture changes to provide a basis for the new packet data related functionalities. With PCU2, the DSPs take care of more tasks than in PCU1. The tasks include radio link control (RLC), scheduling, quality control, as well as Abis L1 processing. With PCU1, the DSPs only take care of the Abis L1 processing. Figure 2 Restructured task management in PCU2 The PCU2’s new software architecture introduces enhancements in the following areas: • The RLC, Scheduler, and Quality control functionalities implemented on the DSPs improve the RTT and balances load between PQII and DSPs.
  11. 11. 11/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. • The asynchronous data transfer of LLC PDUs, which is used instead of the synchronous transfer of RLC/MAC blocks between PQII and DSP, reduces the load in the PQII – DSP interface and provides faster PQII – DSP transactions. • Increased BTS and TRX resources: with PCU2, the BTS resources are increased from 64 to 128, and the TRX resources extended from 128 to 256, consequently providing more flexibility to the segment concept used with MultiBCF Control and Common BCCH. • The new GPRS link adaptation algorithm enables the support for the GPRS coding schemes 3 and 4 (CS3&CS4). It also gives the possibility to reach a higher throughput per subscriber when the GPRS coding schemes 3 and 4 are used. • The use of uplink state flag (USF) granularity 4 improves the use of the radio interface resources in a situation where the GPRS and EGPRS mobiles are in the same radio time-slot (RTSL). • Dynamic Abis improvements, which enable a more efficient use of EDAPs. The recommended number of EDAP’s in PCU1 is 1, 2, 4 or 8. Recommended number of EDAP’s is in PCU2 is 1-8. • Improved end user service perception: The PCU2 software architecture implements RLC on DSPs and, depending on the radio conditions, gives benefit to application level delays i.e. active and idle RTTs. The active RTT measures delay from the data transfer point of view has an impact for example on the duration of file downloads experienced by the end users as well as on services with fast interaction requirements. The idle RTT measures delay from the access point of view, that is, the impact to TCP startup, improves on its part the end user experience for example in downloading web pages. • BTS selection improvements in case of Common BCCH / Multi BCF cell • Dynamic Abis improvements PCU2 doesn’t provide support for following functionalities available with PCU1: • • 1.2.1.3 PBCCH/PCCCH GPRS support for InSite BTS PCU1 and PCU2 Software Differences on Air Interface Due to different feature set and software architecture between PCU generations, there are multiple differences concerning to Air interface. These differences have influences to radio resource allocation and scheduling, round-trip time, throughput and cell change times. The most important differences are: • New GPRS link adaptation algorithm in the PCU2 that can use CS-3 and CS4, too • Utilization of USF granularity 4 in the PCU2 • BTS selection differences
  12. 12. 12/166 CMO SBU MS Network & Service Optimization Capability Management • Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Inter DSP TBF reallocation and cell change in the PCU2 The detailed description of the most important differences can be found in the relevant chapters below in this document. 1.2.2 BTS variants TALK InSite** PrimeSite MetroSite UltraSite FlexiEDGE GSM Ok Ok Ok Ok Ok Ok GPRS CS1 – 2 CS1 – 2 CS1 - 2 CS1 – 2* CS1-2* CS1-2* No No No MCS1-9 MCS1-9 MCS1-9 EGPRS *CS1-4 with PCU2 **Insite is not supported by PCU2 1.3 Data features The next sessions describe the most important PS features on S release basis. 1.3.1 S10 / S10.5ED The following features are implemented with S10/S10.5ED releases: BSS 10091 Enhanced Data Rates for Global Evolution, EDGE Detailed description of GPRS and EGPRS dimensioning and planning is available in (E)GPRS Radio Networks - Dimensioning and Planning Guidelines: https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/362642110 Detailed description of GPRS and EGPRS optimization is available in (E)GPRS Radio Networks - Optimization Guidelines https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/362650970 BSS 10045 Dynamic Abis Allocation https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/358201395 BSS 10074 Support of PCCCH/PBCCH Support for PBCCH/PCCCH is no longer supported from S13 onwards. BSS 10084 Priority Class Based Quality of Service 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
  13. 13. 13/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. territory between different time slots. After that packets with a higher priority are sent before packets that have a lower priority. The description of priority based QoS is available in (E)GPRS Radio Networks Optimization Guidelines https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/362650970 1.3.2 S11 / S11.5 The following features are implemented with S11/S11.5 releases: BSS 11112 Network Controlled Cell Reselection (NCCR) BSS 11506 Network Assisted Cell Change (NACC) BSS 115171 Dynamic Abis Enhancements BSS 11088 GPRS Coding Schemes CS3 and CS4 BSS 30065 GPRS Resume BSS 11151 Extended Uplink TBF BSS 11156 EGPRS: Channel Request on CCCH The detailed description of below listed features are (E)GPRS Radio Networks Dimensioning and Planning Guidelines: https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/362642110 (E)GPRS Radio Networks - Optimization Guidelines: https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/362650970 1.3.3 S12 The following features are implemented with S12 release: BSS 20088 Dual Transfer Mode (DTM) Dual Transfer Mode (DTM) provides mobile users with simultaneous circuit-switched (CS) voice and packet-switched (PS) data services. This means that users can, for example, send and receive e-mail during an ongoing phone call. The Planning Theory of DTM can be downloaded from the following link: https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/369783353 Information about DTM planning is available in DTM – Planning guidelines: https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/372797524
  14. 14. 14/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. BSS 20084 High Multislot Classes (HMC) More information about HMC is available in the (E)GPRS Radio Networks Optimization Guidelines: https://sharenet-ims.inside.nokiasiemensnetworks.com/Download/362650970 BSS 20089 Extended Dynamic Allocation (EDA) More information about EDA is available in Chapter 7.7.2. 1.4 S13 The following feature is implemented with S13 releases: BSS20094 Extended Cell for GPRS/EDGE More information is available in extended cell range and Long Reach timeslot planning guidelines: https://sharenet-ims.inside.nokiasiemensnetworks.com/Open/389927588
  15. 15. 15/166 CMO SBU MS Network & Service Optimization Capability Management 2. Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 (E)GPRS Modulation (E)GPRS uses not only GMSK but 8PSK (8 Phase Shift Keying) modulation as well, producing a 3bit word for every change in carrier phase. This effectively triples the data rate offered by GPRS. The differences between GMSK and 8-PSK, the block diagram of modulators, and the burst structure with back-off are described below in this chapter. 2.1 GMSK and 8-PSK Modulation GSM system is using GMSK (Gaussian Minimum Shift Keying), a constant-envelope modulation scheme. The advantage of the constant envelope modulation is that it allows the transmitter power amplifiers to be operated in a non-linear (saturated) mode, offering high power efficiency. The saturation means that even if the input signal level is increased, no increasement will be seen in the output power, as shown on upper part of Figure 3. 8-PSK, in the form used in EDGE, has a varying envelope, see the lower part of Figure 3. It means that the amplifier must be operated in the linear region in case of 8PSK since distortion is to be avoided. (There is an additional 22.5 deg rotation to avoid zero crossing.) Envelope (amplitude) Time GMSK (0,0,0) Envelope (amplitude) (0,1,0) (0,1,1) 8PSK (0,0,1) (1,1,1) (1,0,1) (1,1,0) (1,0,0) Figure 3 Modulation scheme for GMSK and 8-PSK Time
  16. 16. 16/166 CMO SBU MS Network & Service Optimization Capability Management 2.2 Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Modulation Block Diagrams The Figure 4 and Figure 5 show that GMSK and 8-PSK modulation arrangements are completely different. differential encoding -1, +1 Gaussian prefiltering for frequency pulses frequency modulator local oscillator Figure 4 GSM - GMSK modulation Gray mapping to 8PSK constellation rotation by k3pi/8 3 bits per symbol Figure 5 EDGE - 8-PSK modulation Linearized Gaussian Filter for Dirac pulses I &Q
  17. 17. 17/166 CMO SBU MS Network & Service Optimization Capability Management 2.3 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. Back-off in EGPRS This varying envelope generates peak-mean power difference that is 2-6 dB for 8PSK, thus the mean output power in amplifier must be at least this amount down on the saturated output power to achieve linearity. Figure 6 Phase state vector diagram in 8-PSK So the position of the information is there on the yellow dots of the dark blue circle above in Figure 6 (yellow dots: where the phase and amplitude of the signal is containing the information). The area between the dark blue circle and red circle is the room for overshooting. This “overshoot” is required to ensure smooth and continuous transition between phase-states (as shown by the yellow trace above). It means that the mean output power has to be app. 2-6 dB less (back-off) to avoid saturation in amplifier. This ‘back-off’ is shown in Figure 7.
  18. 18. 18/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Pout Envelope (amplitude) GMSK Compression point Time Pin Back Off= 2 dB Envelope (amplitude) 8PSK Time => Peak to Average of ≅ 2-4 dB Figure 7 Back-off in power amplifier In practice, BTS equipment is less likely to be in saturation than MS equipment. Therefore the back-off for the two sets of equipment may be different, and in the link budget presented a 2dB back-off is assumed for BTS and the full 4dB for MS. The amount of MS back-off also depends on the used system frequency (different output power, different PA characteristics, etc. – 900 MHz: 6dB; 1800 MHz: 4dB). The UltraSite 2 dB APD and mobiles’ 4-6 dB applies only when the transmitter is set to maximum output power. If the entire TRX is set to second highest output power, there is no difference between the average power of 8-PSK and GMSK signals.
  19. 19. 19/166 CMO SBU MS Network & Service Optimization Capability Management 2.4 Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Burst Structure 3GPP TS 05.05, Annex B identifies the following GMSK/8-PSK burst structures for transmitted power level versus time. The first figure below (Figure 8) shows the time mask for normal duration bursts at GMSK modulation. The second figure (Figure 9) shows the time mask for normal duration bursts at 8-PSK modulations. The blue “envelope” shows a conceptual example of the appearance of a normal burst. dB +4 +1 -1 -6 (**) - 30 (***) (147 bits) (*) t 10 µs 8 µs 10 µs 7056/13 (542.8) µs 10 µs 8 µs 10 µs Figure 8 GMSK Burst dB +4 +2,4 0 -2 -6 (***) -20 (147 symbols) -30 (**) 7056/13 (542,8)µs (*) 10 8 10 2 2 22 10 8 10 t (µs) Figure 9 8-PSK Burst The following figure (Figure 10) shows an example of GSM/EDGE BCCH TRX with a 3TSL EDGE mobile active on the downlink 5 normal bursts in GMSK (Average Power Decrease (APD)=0 dB) and 3 normal bursts in 8-PSK (APD=2 dB).
  20. 20. 20/166 CMO SBU MS Network & Service Optimization Capability Management TSL0 BCCH GMSK TSL1 TCH GMSK Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 TSL2 TCH GMSK TSL3 TCH GMSK TSL4 TCH GMSK TSL5 PDTCH 8-PSK/ GMSK TSL6 PDTCH 8-PSK/ GMSK TSL7 PDTCH 8-PSK/ GMSK P(dB) t(us) Figure 10 5 normal bursts in GMSK (APD=0 dB) for voice and 3 normal bursts in 8PSK (APD=2 dB) for data Note that the average power decreased by 2 dB during the last three bursts due to APD of 2 dB. This has the following key impacts on EDGE service: 1) “Slightly” lower throughput near cell edge or in poor C/I environment, 2) 2 dB lower signal level to neighboring cells or GSM phones evaluating neighbors. If the operator decides to allow 8-PSK modulation on the BCCH carrier in certain cells, the cell selection, cell reselection and handover procedures involving these cells will be somewhat sub-optimal. This is due to the fact that the signal level measured by the MS at some instances in time will be affected by the possibly lower mean power level of the 8-PSK modulation and by the power fluctuation resulting from the 8-PSK modulation characteristics. The extent of the performance degradation is dependent upon the measurement schedule in each particular MS as well as upon the used average power decrease (APD) and the current 8-PSK load. By limiting the maximum number of 8-PSK slots simultaneously allowed on the BCCH carrier, and/or carefully selecting the values of involved network parameters, the impact on the above-mentioned procedures may be minimized. Additionally, in areas with very low cell overlap, some coverage loss effects may have to be taken into account by the operator when selecting network parameters (the measurement of the cell for neighbor decision is based on the average value of TSLs’ signal level, so the reduced output power due to 8-PSK can modify this measurement results). The power budget margins for handover are around 4/6 dB. This means the signal strength in the neighbor EGPRS cell has to be 4/6 dB larger than the serving cell in order to perform the handover. Moreover, the mobiles have a certain inaccuracy when performing neighbor measurements so the impact of average power differences in GMSK and 8PSK will be probably minor. Note that the average power remains constant since both GMSK and 8-PSK are operating in the linear range of the PA.
  21. 21. 21/166 CMO SBU MS Network & Service Optimization Capability Management 3. Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Coding Schemes The following subsections describe the protocol architecture used by (E)GPRS and the coding schemes for GPRS, GPRS with CS1-4 and EGPRS. 3.1 Protocol Architecture The following figure shows the different protocols between the different network elements of a (E)GPRS networks. As it can be seen from Figure 11, the BSS network related protocols are the physical (L1/RF) and RLC/MAC layers. The RLC/MAC, LLC and SNDCP layers are (E)GPRS specific layers, but the higher layers are application dependent. HTTP or FTP TCP HTTP or FTP TCP IP IP SNDCP SNDCP GTP GTP LLC LLC UDP UDP BSSGP BSSGP IP IP NS NS L2 L2 FR FR L1 L1 RLC/MAC RLC/MAC L1/RF L1/RF Um MS DAbis BTS DAbis Abis BSC / PCU Gb SGSN Gn L2 L2 L1 L1 Gi GGSN WWW/FTP Server Figure 11 (E)GPRS Protocol Stack The protocols are communicating via Service Access Points (SAP). The Figure 12 shows the data block segmentation from IP to GSM RF. IP N-PDU SNDCP SN-DATA PDUs LLC LLC Frames RLC MAC GSM RF RLC Blocks RLC/MAC Blocks TDMA Bursts Figure 12 Data Blocks segmentation between protocols
  22. 22. 22/166 CMO SBU MS Network & Service Optimization Capability Management 3.1.1 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. Physical Layer The physical layer of the (E)GPRS networks is the standard GSM TDMA interface (with new modulation method for higher MCSs of EGPRS). Therefore the appropriate functionality of the GSM network is basic requirement to provide good (E)GPRS service. The main tasks of the physical layer are listed below: • Modulation/demodulation (GMSK and 8-PSK) • TDMA frame formatting • Bit inter-leaving • Cell selection/reselection • Tx power control • Discontinuous reception (DRx) The basic element of air interface in (E)GPRS planning is the timeslot. It lasts 0,577 milliseconds (=15/26) which corresponds to 156,25 bits. Four TDMA TSLs are needed to convey one RLC/MAC block as it can be seen in the Figure 12 above. 3.1.2 RLC/MAC Layer This subsection briefly describes the Radio Resource layer (RLC/MAC) since this layer is responsible for most of the important BSS related functionalities. 3.1.2.1 Radio Link Control The main tasks of Radio Link Control (RLC) are: • Reliable transmission of data across air interface • Segmentation/de-segmentation of data from/to LLC layer The RLC layer can be operated in both acknowledged and unacknowledged modes, and this is defined by the Quality of Service (QoS) profile within the PDP context (reliability class). 3.1.2.2 Medium Access Control The following list shows the main tasks of Medium Access Control (MAC): • Control of MS access to common air-interface medium • Flagging of PDTCH/PACCH occupancy This layer controls MS access to the common air interface and provides queuing and scheduling of the associated signaling. 3.1.2.3 RLC/MAC Header Formats All the header formats are described below.
  23. 23. 23/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 The following figure shows the downlink GPRS RLC block with MAC header. Figure 13 DL RLC/MAC format Detailed field description: Uplink State Flag (USF) field is sent in all downlink RLC/MAC blocks and indicates the owner or use of the next uplink Radio block on the same timeslot. The USF field is three bits in length and eight different USF values can be assigned, except on PCCCH, where the value '111' (USF=FREE) indicates that the corresponding uplink Radio block contains PRACH. Supplementary/polling (S/P) bit is used to indicate whether the RRBP field is valid or not. bit 4 0 1 S/P RRBP field is not valid RRBP field is valid Table 2 S/P bit Relative Reserved Block Period (RRBP) field specifies a single uplink block in which mobile station shall transmit either a Packet Control Acknowledgement message or a PACCH block to the network. The mobile station shall only react on RLC/MAC block containing a valid RRBP field.
  24. 24. 24/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. Final Block Indicator (FBI) bit indicates that the downlink RLC data block is the last RLC data block of the DL TBF. bit 1 0 1 Final block indicator Current block is not last RLC data block in TBF Current block is last RLC data block in TBF Table 3 FBI bit Power reduction (PR) fields indicate the power level reduction of the current RLC block. The coding of PR field depends on downlink power control mode – mode A and B defined in BTS_PWR_CTRL_MODE bit sent in assignment messages. Payload Type field shall indicate the type of data contained in remainder of RLC/MAC block. The encoding of the payload type field is shown below. The payload Type field is present in both downlink and uplink MAC header. bit 87 00 01 10 11 Payload Type RLC/MAC block contains an RLC data block RLC/MAC block contains an RLC/MAC control block that does not include the optional octets of the RLC/MAC control header In the downlink direction, the RLC/MAC block contains an RLC/MAC control block that includes the optional first octet of the RLC/MAC control header. In the uplink direction, this value is reserved. Reserved. In this version of the protocol, the mobile station shall ignore all fields of the RLC/MAC block except for the USF field Table 4 Payload Type field Temporary Flow Identity (TFI) field in RLC data blocks identifies the Temporary Block Flow (TBF) to which the RLC data belongs. For the downlink and uplink TFI the field is 5 bits in length and are encoded as a binary number with range 0 to 31. Block Sequence Number (BSN) field carries the sequence absolute Block Sequence Number (BSN’) modulo 128 of each RLC data block within the TBF. The BSN is 7 bits in length and is encoded as a binary number with range 0 to 127. The following figure shows the uplink RLC block with MAC header.
  25. 25. 25/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. Figure 14 UL RLC/MAC format Detailed field description: Retry (R) bit shall indicate whether the MS transmitted CHANNEL REQUEST message or PACKET CHANNEL REQUEST message one time or more than one time during its most recent channel access. The mobile station shall send the same value for the R bit each uplink RLC/MAC block of the TBF. bit 1 0 1 Retry (R) bit MS sent channel request message once MS sent channel request message twice or more Table 5 Retry bit The Stall indicator (SI) bit indicates whether the mobile's RLC transmit window can advance (i.e. is not stalled) or cannot advance (i.e., is stalled). The mobile station shall set the SI bit in all uplink RLC data blocks. bit 2 0 1 Stall indicator MS RLC transmit window is not stalled MS RLC transmit window is stalled Table 6 SI bit The Countdown Value (CV) field is sent by the mobile station to allow the network to calculate the number of RLC data blocks remaining for the current uplink TBF. The CV field is 4 bits in length and is encoded as a binary number with range 0 to 15. The TLLI Indicator (TI) bit indicates the presence of an optional TLLI field within the RLC data block.
  26. 26. 26/166 CMO SBU MS Network & Service Optimization Capability Management bit 1 0 1 Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 TLLI indicator (TI) bit TLLI field is not present TLLI field is present Table 7 TLLI indicator bit For EDGE the DL RLC/MAC header will change depends on the MCS used. The MCS7, 8 and 9 have 5 octets header (header type 1) as shown on Table 8. Bit 8 7 6 5 4 TFI RRBP ES/P BSN1 PR BSN1 BSN2 CPS 3 2 USF TFI 1 BSN1 BSN2 Octet 1 2 3 4 5 Table 8 DL RLC/MAC header for EDGE MCS 7-9 Bit 8 7 6 5 4 TFI RRBP ES/P BSN1 PR BSN1 3 2 USF TFI CPS 1 BSN1 Octet 1 2 3 4 Table 9 DL RLC/MAC header for EDGE MCS 5 and 6 (header type 2) Bit 8 7 6 5 4 3 2 1 TFI RRBP ES/P USF BSN1 PR TFI BSN1 SPB CPS BSN1 Octet 1 2 3 4 Table 10 DL RLC/MAC header for EDGE MCS 1 to 4 (header type 3) There are three header formats, because the header code rates are different for MCS1-4 and MCS5-9, and MCS5-6 have one RLC/MAC block while MCS7-9 have two RLC/MAC blocks (see Table 13). The Downlink RLC/MAC control block together with its MAC header is formatted as shown in Table 11. Bit 8 7 Payload Type RBSN PR 6 5 RRBP RTI 4 S/P 3 TFI Control Message Contents 2 USF FS 1 AC D MAC header Octet 1 (optional) Octet 2 (optional) Octet M . . . Octet 21 Octet 22 Table 11 Downlink RLC/MAC control block together with its MAC header
  27. 27. 27/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 The Uplink RLC/MAC control block together with its MAC header is formatted as shown in Table 12. Bit 8 7 Payload Type 6 5 4 spare 3 2 Control Message Contents 1 R MAC header Octet 1 Octet 2 Octet 3 . . . Octet 21 Octet 22 Table 12 Uplink RLC/MAC control block together with its MAC header The detailed description of the different header formats can be found in 3GPP 04.60. 3.1.3 Logical Link Control Logical Link Control (LLC) layer provides a reliable ciphered link between the SGSN and the MS. This protocol is independent of the underlying radio interface protocols. LLC is considered to be a sub layer of layer 2 in the ISO 7-layer model. The purpose of LLC is to convey information between layer-3 entities in the MS and SGSN. Specifically, LLC shall support: • • multiple MSs at the Um interface; multiple layer-3 entities within an MS. LLC includes functions for: • • • • • • • the provision of one or more logical link connections discriminated between by means of a DLCI; sequence control, to maintain the sequential order of frames across a logical link connection; detection of transmission, format and operational errors on a logical link connection; recovery from detected transmission, format, and operational errors; notification of unrecoverable errors; flow control ciphering LLC layer functions provide the means for information transfer via peer-to-peer logical link connections between an MS and SGSN pair. This layer can be operated in both acknowledged and unacknowledged modes, and this is defined by the Quality of Service (QoS) profile within the PDP context (reliability class).
  28. 28. 28/166 CMO SBU MS Network & Service Optimization Capability Management 3.1.4 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. SNDCP Layer Maps the network level Packet Data Units (N-PDU) on to the underlying Logical Link Control (LLC) layer. The basic functionality of SNDCP layer is listed below: • Multiplexer/demultiplexer for different network layer entities onto LLC layer • Compression of protocol control information (e.g. TCP/IP header) • Compression of data content (if used) • Segmentation/de-segmentation of data to/from LLC layer In details the SNDCP shall perform the following functions: • • • • • • • • • • 3.1.5 Mapping of SN-DATA primitives onto LL-DATA primitives. Mapping of SN-UNITDATA primitives onto LL-UNITDATA primitives. Multiplexing of N-PDUs from one or several network layer entities onto the appropriate LLC connection. Establishment, re-establishment and release of acknowledged peer-to-peer LLC operation. Supplementing the LLC layer in maintaining data integrity for acknowledged peer-to-peer LLC operation by buffering and retransmission of N-PDUs. Management of delivery sequence for each NSAPI, independently. Compression of redundant protocol control information (e.g., TCP/IP header) at the transmitting entity and decompression at the receiving entity. The compression method is specific to the particular network layer or transport layer protocols in use. Compression of redundant user data at the transmitting entity and decompression at the receiving entity. Data compression is performed independently for each SAPI, and may be performed independently for each PDP context. Compression parameters are negotiated between the MS and the SGSN. Segmentation and reassembly. The output of the compressor functions is segmented to the maximum length of LL-PDU. These procedures are independent of the particular network layer protocol in use. Negotiation of the XID parameters between peer SNDCP entities using XID exchange. IP, TCP/UDP and Application Layer The IP (Internet Protocol), TCP/UDP (Transmission Control Protocol/ User Datagram Protocol) and application layer’s functionality is described in EDGE_TCP_TWEAK_1_2 document in QP. The Internet Protocol (IP) is a network-layer (Layer 3) protocol that contains addressing information and some control information that enables packets to be routed. IP is documented in RFC 791 and is the primary network-layer protocol in the Internet protocol suite. Along with the Transmission Control Protocol (TCP), IP represents the heart of the Internet protocols. IP has two primary responsibilities: providing connectionless, best-effort delivery of datagrams through an internetwork; and providing fragmentation and reassembly of datagrams to support data links with different maximum-transmission unit (MTU) sizes.
  29. 29. 29/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. Transmission Control Protocol (TCP) provides reliable transmission of data in an IP environment. TCP corresponds to the transport layer (Layer 4) of the OSI reference model. Among the services TCP provides are stream data transfer, reliability, efficient flow control, full-duplex operation, and multiplexing. With stream data transfer, TCP delivers an unstructured stream of bytes identified by sequence numbers. This service benefits applications because they do not have to chop data into blocks before handing it off to TCP. Instead, TCP groups bytes into segments and passes them to IP for delivery. TCP offers reliability by providing connection-oriented, end-to-end reliable packet delivery through an internetwork. It does this by sequencing bytes with a forwarding acknowledgment number that indicates to the destination the next byte the source expects to receive. Bytes not acknowledged within a specified time period are retransmitted. The reliability mechanism of TCP allows devices to deal with lost, delayed, duplicate, or misread packets. A time-out mechanism allows devices to detect lost packets and request retransmission. TCP offers efficient flow control, which means that, when sending acknowledgments back to the source, the receiving TCP process indicates the highest sequence number it can receive without overflowing its internal buffers. Full-duplex operation means that TCP processes can both send and receive at the same time. User Datagram Protocol (UDP) is a connectionless transport-layer protocol (Layer 4) that belongs to the Internet protocol family. UDP is basically an interface between IP and upper-layer processes. UDP protocol ports distinguish multiple applications running on a single device from one another. Unlike the TCP, UDP adds no reliability, flow-control, or error-recovery functions to IP. Because of UDP's simplicity, UDP headers contain fewer bytes and consume less network overhead than TCP. UDP is useful in situations where the reliability mechanisms of TCP are not necessary, such as in cases where a higher-layer protocol might provide error and flow control. UDP is the transport protocol for several well-known application-layer protocols, including Network File System (NFS), Simple Network Management Protocol (SNMP), Domain Name System (DNS), and Trivial File Transfer Protocol (TFTP). The UDP packet format contains four fields; these include source and destination ports, length, and checksum fields. Application-layer protocols are one piece of a network application. For example the Web's application layer protocol is HTTP, and defines format and sequence of messages, application layer protocols for Push to Talk over Cellular (PoC) are RTP and SIP. Application-layer protocol defines: • The types of messages exchanged, for example, request messages and response messages
  30. 30. 30/166 CMO SBU MS Network & Service Optimization Capability Management • • • 3.2 Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 The syntax of the various message types, such as the fields in the message and how the fields are delineated The semantics of the fields, that is, the meaning of the information in the fields Rules for determining when and how a process sends messages and responds to messages RLC/MAC Coding Schemes While the symbol rate is the same for GMSK and 8-PSK modulation the bit rate is different since one GMSK symbol contains only 1 bit but one 8-PSK symbol contains 3 bits altogether. So the differentiations of RLC/MAC data rate of the different coding schemes are based on convolutional coding and puncturing. The CS1 and CS2 Coding Schemes (CS) are used for GPRS with PCU (PCU, PCUS, PCU-T, PCU-B). If PCU2 (PCU2-U, PCU2-D) is implemented the CS3 and CS4 will be used as well. Modulation and Coding Schemes (MCS) are used for EGPRS both in GMSK and 8PSK modulations. GPRS Coding Schemes (CSs) For error protection each RLC data block is encoded using one of the available channel coding schemes. ETSI has specified four coding schemes of which Nokia supports coding scheme CS-1 and CS-2 only with PCU1, while PCU2 supports all the four CSs (see the figure below). S11.5 with PCU2 CS1 181 9.05 CS2 268 13.4 CS3 312 15.6 CS4 PCU1 Payload (bits) per RLC block Data Rate (kbit/s) 428 21.4 Error Correction Coding Scheme Data 3.2.1 More Data = Less Error Correction Figure 15 Coding Schemes in GPRS Each of the coding schemes has been developed based on a compromise between error protection and the amount of user data carried. Coding scheme CS-1 has the lowest user data rate, but the highest error protection. CS-4 has the highest data rate but no error protection on the user data.
  31. 31. 31/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 The following figure shows the segmentation of an RLC block with MAC header in case of different CSs to/from the GSM TDMA frames. CS-1 CS-1 RLC/MAC Block Size: MAC CS-2 CS-3 57 57 57 6 6 ~2/3 ~3/4 456 588 676 0 132 220 interleaving 57 57 57 57 Data rate (kbit/s): 9.05 RLC/MAC Block Size: MAC BCS USF CS-4 16 1/2 puncturing 16 3 Precoded USF: length: 57 312 40 rate a/b convolutional coding 456 bits CS-3 268 181 Block Check Sequence: BCS +4 USF CS-2 BCS Size: 13.4 15.6 428 16 Precoded USF: 12 Data rate (kbit/s): 21.4 20 ms Figure 16 Coding Scheme segmentation in GPRS The detailed segmentation procedure for CS1 and CS2 can be seen in the following figures. USF 3 Header & Data 181 BCS 40 224 bits 1/2 rate convolutional coding + 4 tail bits 6 456 bits 181bits/20ms = 9.05kbit/s Figure 17 RLC/MAC segmentation for CS1
  32. 32. 32/166 CMO SBU MS Network & Service Optimization Capability Management USF Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Header & Data BCS 268 6 16 294 bits 1/2 rate convolutional coding 12 588 bits Puncturing (132 bits) 12 456 bits 268 bits/20ms = 13.4kbit/s Figure 18 RLC/MAC segmentation for CS2 When CS1-4 option is on, Dynamic Abis pool and (E)GPRS territories are created and when a TBF is allocated to a TRX which supports EDAP then all GPRS coding schemes (CS1 – CS4) are available for data transfer according to the parameters pcu_cs_hopping and pcu_cs_non_hop. If these parameters indicate Link Adaptation, the LA algorithm determines for each TBF separately which coding scheme (CS1 – CS4) is used. The detailed segmentation procedure for CS3 and CS4 can be seen in the following figures. USF 6 Header & Data BCS 312 16 338 bits 1/2 rate convolutional coding 12 676 bits Puncturing (220 bits) 12 456 bits 268 bits/20ms = 13.4kbit/s Figure 19 RLC/MAC segmentation for CS3
  33. 33. 33/166 CMO SBU MS Network & Service Optimization Capability Management USF Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Header & Data 12 BCS 428 16 428bits/20ms = 21.4 kbit/s Figure 20 RLC/MAC segmentation for CS4 CS3 and CS4 is using modified LA algorithm (more details are available in Section 7.6.2. Coding schemes CS3 and CS4 are supported only by PCU2. It is application software feature requiring a separate license. To ensure successful BCSU switch-over it is not possible to enable CS3 & CS4 if there are PCU1 units on the same slot as PCU2 in any of the BCSUs. 3.2.2 EGPRS Modulation and Coding Schemes (MCSs) The EGPRS standard defines nine coding schemes MCS1 to MCS9, providing different throughputs depending on the amount of redundancy implemented in each coding scheme. In EGPRS MCSs the user data from higher layers and the RLC/MAC header are having different code rates. The header code rate is more robust for having the header even in very bad radio conditions. That is why there are “bad header, bad data” and “valid header, bad data” counters. The different data rates per timeslot are presented below: Scheme Code rate Header Modulation RLC blocks Raw Data Code rate per Radio within one Block Radio Block (20ms) Family BCS MCS-9 1.0 0.36 2 2x592 A MCS-8 0.92 0.36 2 2x544 A MCS-7 0.76 0.36 2 2x448 B 44.8 MCS-6 0.49 1/3 1 592 544+48 A 29.6 27.2 MCS-5 0.37 1/3 1 448 B 8PSK 2x12 Tail HCS Data rate kb/s payload 2x6 59.2 54.4 8 12 6 22.4 MCS-4 1.0 0.53 1 352 C 17.6 MCS-3 0.80 0.53 1 296 272+24 A 14.8 13.6 GMSK MCS-2 0.66 0.53 1 224 B 11.2 MCS-1 0.53 0.53 1 176 C 8.8 NOTE: the italic captions indicate the padding. Table 13 Coding scheme performance versus Eb/No. The MCSs are divided into different families A, B and C. Each family has a different basic unit of payload: 37 (and 34), 28 and 22 octets respectively. Different code rates
  34. 34. 34/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 within a family are achieved by transmitting a different number of payload units within one Radio Block. The family concept is used for retransmission only, so the retransmitted RLC/MAC block’s MCS can be the initial MCS or an MCS inside the family. For families A and B, 1 or 2 or 4 payload units are transmitted, for family C, only 1 or 2 payload units are transmitted (see Figure 21 below). MCS-3 Family A 37 octets 37 octets 37 octets 37 octets MCS-6 MCS-9 MCS-3 34+3 octets Family A padding 34+3 octets MCS-6 34 octets 34 octets 34 octets 34 octets MCS-8 MCS-2 Family B 28 octets 28 octets 28 octets 28 octets MCS-5 MCS-7 MCS-1 Family C 22 octets 22 octets MCS-4 Figure 21 MCS Families The following figure shows the RLC/MAC segmentation (convolutional coding and puncturing) to 4 normal GSM bursts.
  35. 35. 35/166 CMO SBU MS Network & Service Optimization Capability Management 3 bits USF Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 45 bits 612 bits 612 bits RLC/MAC HCS FBI E Data = 592 bits BCS Hdr. TB Rate 1/3 convolutional coding 36 bits 135 bits FBI E Data = 592 bits BCS Rate 1/3 convolutional coding 1836 bits 1836 bits puncturing puncturing TB puncturing 36 bits 124 bits 612 bits 612 bits 612 bits 612 bits 612 bits 612 bits P1 SB = 8 P2 P3 P1 P2 P3 1392 bits Figure 22 MCS9 Coding and puncturing
  36. 36. 36/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 4. Copyright 2007 Nokia Siemens Networks. All rights reserved. (E)GPRS Procedures The knowledge of (E)GPRS procedures can help to analyze the signaling traffic. So before the analysis of signaling situation in Chapter 5 the procedure of • TBF establishment • Data transfer • TBF release should be studied in details. After GPRS Attach and PDP Context Activation the next procedure is the TBF establishment with Packet Immediate Assignment (attach and PDP context activation also require TBF establishment, but that is not discussed here in this section). 4.1 TBF Establishment The TBF establishment is triggered by Channel Request (UL), Paging (DL) and Immediate Assignment (DL). 4.1.1 Channel Request and Packet Immediate Assignment On receipt of a CHANNEL REQUEST message indicating a packet access, the network may allocate a temporary flow identity and assign a packet uplink resource comprising one PDCH for an uplink temporary block flow in GPRS TBF mode. On receipt of an EGPRS PACKET CHANNEL REQUEST message, the network may allocate a temporary flow identity and assign a packet uplink resource comprising one PDCH for an uplink temporary block flow in EGPRS TBF mode or GPRS TBF mode. (3GPP 04.18-8.0) Channel Request Message: If the establishment cause in the CHANNEL REQUEST message indicates a request for a single block packet access, the network shall grant only the single block period on the assigned packet uplink resource if the network allocates resource for the mobile station. EGPRS Packet Channel Request Message: If the establishment cause in the EGPRS PACKET CHANNEL REQUEST (EPCR) message indicates a request for a two phase access, the network shall grant one or two radio blocks for the mobile station (within a Multi Block allocation) to send a PACKET RESOURCE REQUEST and possibly an ADDITIONAL MS RADIO ACCESS CAPABILITIES messages on the assigned packet uplink resource if the network allocates resource for the mobile station. Immediate Assignment Message: The packet uplink resource is assigned to the mobile station in an IMMEDIATE ASSIGNMENT message sent in unacknowledged mode on the same CCCH timeslot on which the network has received the CHANNEL REQUEST or the EGPRS PACKET CHANNEL REQUEST message. There is no further restriction on what part of the downlink CCCH timeslot the IMMEDIATE ASSIGNMENT message can be sent. Timer T3141 is started on the network side.
  37. 37. 37/166 CMO SBU MS Network & Service Optimization Capability Management 4.1.2 Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 DL TBF Assignment Reason for paging is DL user data or signaling while MS is on STANDBY state. The terminal has to be paged by the network in the STANDBY state since its position is known only on the Routing Area level. MS BSS SGSN 1. PDP PDU 2. Paging Request 3. GPRS Paging Request 4. Any LLC Frame 5. Any LLC Frame Figure 23 Paging flow chart DL TBF Assignment, MS on CCCH The DL TBF assignment is based on the following procedure (Figure 24). MS BTS BSC SGSN MS on ready state /c72084(S9) packet_immed_ass_msg P-Immediate Assignment TBF per priority 90000(S10) Sent on the PDTCH to find out the MS Timing Advance. In Nokia implementation, always sent when DL TBF Assignment is from CCCH. Not sent when DL TBF is assigned on PACCH Immediate Assignment (CCCH) If requested and available Only 1 TCH is allocated first. DL TBF Establ. 72005(S9) Max sim. DL TBF .72007(S9) EGPRS DL TBF EGPRS DL TBF UNACK 72089(S10) Possibly 72091(S10) Possibly Req 1 tsl DL 72039(S9) P-Immediate Assignment Ack Alloc 1 tsl DL 72049(S9) /c72085(S9) packet_immed_ass_ack_msg Packet Polling Request DL RLC MAC /c72077(S9) Packet Polling Request (PACCH) Packet Control Ack (PACCH) Packet Power Control/Timing Advance Packet Control Ack Packet Power Control/Timing Advance DL RLC MAC /c72077(S9) Figure 24 DL TBF Assignment, MS on CCCH Alternatively, Packet Downlink Assignmnet may be sent if more timeslots are required
  38. 38. 38/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 DL TBF Assignment when UL TBF is ongoing If there is an UL TBF ongoing, the channel request and immediate assignment is not needed. The DL TBF is allocated by sending Packet Downlink Assignment on PACCH. MS BTS BSC SGSN LLC PDU DL TBF DUR. UL /c72075(S9) New TBF is established in the same mode (GPRS, EGPRS) than the ongoing TBF. TBF per priority 90000(S10) If UL TBF is EGPRS DL TBF Establ. 72005(S9) EGPRS DL TBF 72089(S10) EGPRS DL TBF UNACK 72091(S10) Req x tsl DL 72039(S9) Packet Downlink Assignment (PACCH) DL RLC Data Block Figure 25 DL TBF Assignment when UL TBF is ongoing Max sim. DL TBF .72007(S9) Alloc x tsl DL 72049(S9) DL RLC MAC /c72077(S9) DL RLC ACK MSC1…9 /c79000(S10) or DL RLC UNACK MSC1…9 /c79001(S10)
  39. 39. 39/166 CMO SBU MS Network & Service Optimization Capability Management 4.1.3 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. UL TBF Assignment Depending on the network configuration different establishments procedures are used during the data connection. One phase access may reduce the TBF establishment time when accessing the cell and allows the system to allocate more than 1 RTSL for the UL TBF. When CCCH is in use, the Uplink Establishment offers: • GPRS: one-phase access is possible, but only 1 TSL can be allocated to the TBF. Timeslot reconfiguration would be needed for multi slot allocation • EGPRS: two-phase access is mandatory (in case of EPCR (S11, SX 4.0) implemented on CCCH the one phase access is possible as well) When PCCCH is in use, the Uplink Establishment offers: • GPRS: one-phase access is possible. Network can allocate more than one TSL to the UL TBF. The gain is obtained from the transmission side due to timeslot allocation. In CCCH case only one TSL is assigned, while in PBCCH case there can be more then one. This explains the increasing importance of the gain as the ping packet size becomes bigger. • 4.1.3.1 EGPRS: one-phase access is possible only if “EGPRS Packet Channel Request” (EPCR) is supported by the network (see Chapter 4.1.3.2). (If EPCR is not supported, then EGPRS is forced to use two-phase access even if working in the PCCCH.) Channel Request - Packet Access Procedure (CCCH / PCCH) The following tables show the packet access procedure on CCCH (3GPP 04.18) and PCCH (3GPP 04.60). The table describes the differences of the Channel Request (S10.5ED)and EGPRS Packet Channel Request (S11) functionality. All the access modes are described in unacknowledged and acknowledged mode (8>= bit or 8< bit).
  40. 40. 40/166 CMO SBU MS Network & Service Optimization Capability Management Purpose of the packet access procedure User data transfer – requested RLC mode = unacknowledged User data transfer – requested RLC mode = acknowledged and number of RLC data blocks ? 8 (note 1) User data transfer – requested RLC mode = acknowledged and number of RLC data blocks > 8 (note 1) Upper layer signalling transfer (e.g. page response, cell update, MM signalling, etc) 16/12/2008 EGPRS PACKET CHANNEL REQUEST supported in the cell EGPRS PACKET CHANNEL REQUEST with access type = 'Two-phase access' EGPRS PACKET CHANNEL REQUEST with access type = 'Short Access' or 'One-phase access' or 'Two-phase access' EGPRS PACKET CHANNEL REQUEST with access type = 'One-phase access' or 'Two-phase access' Copyright 2007 Nokia Siemens Networks. All rights reserved. EGPRS PACKET CHANNEL REQUEST not supported in the cell CHANNEL REQUEST with establishment cause = 'Single block packet access' for initiation of a two-phase access CHANNEL REQUEST with establishment cause = 'Single block packet access' for initiation of a two-phase access CHANNEL REQUEST with establishment cause = 'Single block packet access' for initiation of a two-phase access EGPRS PACKET CHANNEL REQUEST with access type = 'signalling' or CHANNEL REQUEST with establishment cause 'one-phase access' CHANNEL REQUEST with establishment cause = 'Single block packet access' for initiation of a two-phase access or CHANNEL REQUEST with establishment cause value 'one-phase access' CHANNEL REQUEST with establishment cause = 'Single block packet access' Sending of a measurement report or of a PACKET CELL CHANGE FAILURE Sending of a PACKET CHANNEL REQUEST with establishment cause = 'Single block packet access' PAUSE message (note 2) NOTE 1: The number of blocks shall be calculated assuming channel coding scheme MCS-1. NOTE 2: Upon sending the first CHANNEL REQUESTmessage the mobile station shall start timer T3204. If timer T3204 expires before an IMMEDIATE ASSIGNMENT message granting a single block period on an assigned packet uplink resource is received, the packet access procedure is aborted. If the mobile station receives an IMMEDIATE ASSIGNMENT message during the packet access procedure indicating a packet downlink assignment procedure, the mobile station shall ignore the message. Table 14 Packet Access Procedure (CCCH) Purpose of the packet EGPRS PACKET CHANNEL REQUEST EGPRS PACKET CHANNEL REQUEST access procedure supported in the cell not supported in the cell User data transfer – EGPRS PACKET CHANNEL REQUEST PACKET CHANNEL REQUEST with requested RLC mode = with access type = 'Two-phase access' access type = 'Two-phase access' unacknowledged (NOTE 2) User data transfer – EGPRS PACKET CHANNEL REQUEST PACKET CHANNEL REQUEST with requested RLC mode = with access type = 'Short Access' or access type = 'Two-phase access' acknowledged and number 'One-phase access' or 'Two-phase (NOTE 2) of RLC data blocks ? 8 access' (NOTE 1) User data transfer – EGPRS PACKET CHANNEL REQUEST PACKET CHANNEL REQUEST with with access type = 'One-phase access' or access type = 'Two-phase access' requested RLC mode = acknowledged and number 'Two-phase access' (NOTE 2) of RLC data blocks > 8 (NOTE1) Upper layer signalling EGPRS PACKET CHANNEL REQUEST PACKET CHANNEL REQUEST with transfer (e.g. page with access type = 'signalling' or PACKET access type = 'Two-phase access' or response, cell update, MM CHANNEL REQUEST with PACKET CHANNEL REQUEST with signalling, etc) corresponding access type (NOTE 2) corresponding access type (NOTE 2) Sending of a measurement PACKET CHANNEL REQUEST with access type = 'Single block without TBF report or of a PACKET establishment' (NOTE 2) CELL CHANGE FAILURE Sending of a PACKET PACKET CHANNEL REQUEST with access type = 'Single block without TBF PAUSE message establishment' (NOTE 2) (NOTE 3) NOTE 1: The number of blocks shall be calculated assuming channel coding scheme MCS-1. NOTE 2: The format to be used for the PACKET CHANNEL REQUEST message is defined by the parameter ACC_BURST_TYPE. NOTE 3: Upon the first attempt to send a PACKET CHANNEL REQUEST message the mobile station shall start timer T3204. If the mobile station receives a PACKET DOWNLINK ASSIGNMENT message before expiry of timer T3204, the mobile station shall ignore the message. Table 15 Packet Access Procedure (PCCCH) 4.1.3.2 EGPRS Packet Channel Request SI13 contains the EPCR information. PCU always includes Access Technology Request into EDGE UL assignment. Therefore MS sends Packet Resource Request
  41. 41. 41/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 (PRR) message in first allocated USF, and optionally the Additional Radio Access Capability (ARAC) message in second one. GPRS & EGPRS short access is basically same scenario as GPRS one phase access; Access Technology Request is never included in UL assignment message. MS requests one-phase access, PCU makes final decision whether used or not. (E.g. Common BCCH (multiband) and EGPRS territory in non-BCCH band => forced 2phase access). The following figure shows the flow chart of One phase access on EGPRS. One Phase/Short Access SI13 (EPCR Support) MS BSC / PCU EGPRS Packet Channel Request - one phase access or short access Decision – one-phase vs. two-phase Immediate Assignment (UL assignment) (Packet Resource Request) (Additional Radio Access capability) UL Data Block + TLLI Packet UL ACK/NACK + TLLI Packet Control ACK or UL TBF ready UL Data Block w/o TLLI … One Phase Access: If not all RAC info fits in PRR, MS sends this additional message One Phase Access: If NW has requested RAC info from MS in Immediate Assignment, MS responds with Packet Resource Request Figure 26 EGPRS one phase access on CCCH 4.1.3.3 Dynamic and Extended Dynamic Allocation on UL with and without USF4 The number of RLC/MAC blocks to transmit is controlled by the USF_GRANULARITY parameter characterizing the uplink TBF. USF Granularity 1 means that the mobile station shall transmit one RLC/MAC block. USF Granularity 4 means that the mobile station shall transmit four consecutive RLC/MAC blocks. PCU2 uses USF Granularity 4 for GPRS MSs in EGPRS territory. USF granularity 4 is useful when there is GPRS UL TBF multiplexed in the same timeslot with EGPRS DL TBF. In this case only every fourth DL data block need to be
  42. 42. 42/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 GSMK coded, and the other three blocks can be 8-PSK coded. PCU1 uses always USF granularity 1, meaning that EGPRS DL TBF does not utilize 8-PSK coding schemes while a GPRS UL TBF is transferring data on the same timeslot. The detailed description of Dynamic Allocation with and without USF4 and Extebded Dynamic Allocation with/without USF4 can be found in Section 7.7.2. 4.1.3.4 UL TBF ASSIGNMENT, MS on CCCH, 2 phase access After Channel Request and Immediate Assignment the network sends PACKET_UL_ASSIGNMENT message including Single Block Allocation or MultiBlock Allocation, indicating 2-phase access. MultiBlock Allocation may be used only if MS is EGPRS capable (e.g. network receives an EGPRS_PACKET_CHANNEL_REQ). In PACKET_UL_ASSIGNMENT, network reserves limited resources on 1 PDCH for the MS, and MS may transmit PACKET_RESOURCE_REQUEST and optionally ADDITIONAL MS RADIO ACCESSS CAPABILITIES. In PBCCH, 2-phase access can be initiated by: • Network: When sending a PACKET_UL_ASSIGNMENT it includes Single or MultiBLock Allocation, which forces the MS to send a PACKET_RESOURCE_REQ (-> 2-phase access). • MS: By requiring a 2-phase access in the PACKET_CHANNEL_REQ or EGPRS_PACKET_CHANNEL_REQ. If access is granted, the Network shall order the MS to send PACKET_RESOURCE_REQ in the PACKET_UL_ASSIGNMENT. MS BTS BSC SGSN UL TBF ASSIGNMENT, MS ON CCCH. 2 phase access. Channel Request (RACH) Establ.cause '2-ph.access' Single block Immediate Assignment (CCCH) P_Channel Required /c72082(S9) packet_ch_req P-Immediate Assignment Cmd /c72084(S9) packet_immed_ass_msg NOTE: BTS does not send Imm Ass Ack for Single block Immediate Assignment Packet Resource Request (PACCH) Including TLLI for contention resolution Packet Uplink Assignment (PACCH) Including TLLI for contention resolution Packet Resource Request UL RLC MAC /c72076(S9) Packet Uplink Assignment TBF per priority 90000(S10) DL RLC MAC /c72077(S9) UL TBF Establ. 72000(S9) Max.sim.UL TBF 72002(S9) UL TBF UNACK Max.sim.UL TBF UNACK 72010(S9) Possibly 72012(S9) Possibly More than 1 TCH can be allocated. Req X tsl UL 72034(S9) Alloc X tsl UL 72044(S9) RLC Data block RLC Data Block UL RLC CS1 /c72062(S9) Packet Uplink Ack/Nack Packet Uplink Ack/Nack (specs) DL RLC MAC /c72077(S9) Figure 27 UL TBF ASSIGNMENT, MS on CCCH, 2 phase access or UL RLC CS2 /c72064(S9) The Contention resolution was already done above. The PCU does not immediately send Packet Uplink Ack/Nack (as it does in one phase access for contention resolution) but only after a certain amount of blocks or after Final UL Data Block.
  43. 43. Copyright 2007 Nokia Siemens Networks. All rights reserved. 43/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 4.1.3.5 UL TBF ASSIGNMENT, MS on CCCH, 1 phase access Contention Resolution Before establishing an UL TBF, the network must assign a TFI to the TLLI, which identifies uniquely the MS (3GPP 04.60): • Until contention resolution the TLLI must be included in every RLC block, and if MCS9-7 is used, in both RLC blocks • TLLI shall be included in PACKET_RESOURCE_REQUEST ADDITIONAL_MS_RADIO_ACCESS_CAPABILITIES • It applies for retransmission of RLC blocks as well • NW responds with TLLI in PACKET_UL_ACK/NACK • For an EGPRS TBF the network may respond with PACKET_UL_ASSIGNMENT if resources allocated to the TBF need to be reallocated • On network side, Contention Resolution is completed when the network receives RLC block with TLLI and TFI associated to the TBF • On MS side, Contention Resolution is completed when MS receives PACKET_UL_ACK/NACK with TLLI and TFI. MS shall then stop T3166 and N3104 and MS sends a PACKET_CONTROL_ACK containing the TA index if a valid RRBP is received. MS UL TBF ASSIGNMENT, MS ON CCCH. 1 phase access. Channel Request (RACH) Establ.cause '1-ph.access' BTS BSC P-Channel Required P-Immediate Assignment Cmd (CCCH) SGSN RACH p-ch.req. /c72082(S9) packet_ch_req CCCH p- imm.ass. /c72084(S9) packet_immed_ass_msg Only 1 TCH can be allocated. UL TBF Establ. 72000(S9) Sent 6 TDMA frames before the Imm Ass goes to air. Includes the air-if TDMA frame number of the Imm Ass message Immediate Assignment (CCCH) Req 1 tsl UL 72034(S9) Max.sim.UL TBF 72002(S9) Alloc 1 tsl UL 72044(S9) P-Immediate Assignment Ack CCCH p- imm.ass. ack /c72085(S9) packet_immed_ass_ack_msg Figure 28 UL TBF ASSIGNMENT, MS on CCCH, 1 phase access The PACKET_UL_ASSIGNMENT construction contains the following information (3GPP 04.18-8.0):
  44. 44. 44/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 Copyright 2007 Nokia Siemens Networks. All rights reserved. • Temporary flow identity, TFI; • USF value, if the medium access method is dynamic allocation; or the fixed allocation bitmap, if the medium access method is fixed allocation; • Channel coding scheme for RLC data blocks; • Power control parameters; • Polling bit; • Optionally, the timing advance index (see 3GPP TS 05.10); • Optionally, the TBF starting time (note: TBF starting time is mandatory if medium access method is fixed allocation). In addition, the EGPRS packet uplink assignment construction also contains: • EGPRS modulation and coding scheme; • Information whether retransmitted uplink data blocks shall be resegmented or not; • EGPRS window size to be used within the transmission; • Optionally a request for the mobile station to send its radio access capability information.
  45. 45. Copyright 2007 Nokia Siemens Networks. All rights reserved. 45/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 4.1.3.6 EGPRS UL TBF ASSIGNMENT, MS on PCCCH with 2 phase access MS BTS EGPRS Packet Channel Request (PRACH) Establ.cause '2-ph.access' BSC SGSN PRACH p-ch req. /c91002 (S10) nbr_of_packet_channel_reqs EGPRS Packet Channel Request Packet UL Assignment DL RLC MAC /c72077(S9) Packet UL Assignment (PCCCH) /c91021(10) p_ul_ass_msgs_on_pccch Packet Resource Request (PACCH) Packet Resource Request Including TLLI for contention resolution Packet Uplink Assignment (PACCH) UL RLC MAC /c72076(S9) Packet Uplink Assignment DL RLC MAC /c72077(S9) Including TLLI for contention resolution TBF per priority 90000(S10) UL TBF Establ. 72000(S9) Max.sim.UL TBF 72002(S9) UL TBF UNACK Max.sim.UL TBF UNACK 72010(S9) Possibly 72012(S9) Possibly EGPRS TBF if there are resouces More than 1 TCH can be allocated. RLC Data block EGPRS UL TBF EGPRS UL TBF UNACK 72088(S10) Possibly 72090(S10) Possibly Req X tsl UL 72034(S9) RLC Data Block Alloc X tsl UL 72044(S9) UL RLC ACK MSC1…9 /c79002(S10) UL RLC UNACK MSC1…9 /c79003(S10) The Contention resolution was already done above. The PCU does not immediately send Packet Uplink Ack/Nack (as it does in one phase access for contention resolution) but only after a certain amount of blocks or after Final UL Data Block. or Packet Uplink Ack/Nack Packet Uplink Ack/Nack (specs) DL RLC MAC /c72077(S9) Figure 29 EGPRS UL TBF ASSIGNMENT, MS on PCCCH with 2 phase access 4.1.3.7 EGPRS UL TBF ASSIGNMENT, MS on PCCCH with 1 phase access MS UL TBF ASSIGNMENT, MS ON PCCCH. 1 phase access. BTS BSC More than 1 TCH can be requested EGPRS Packet Channel Request (PRACH) EGPRS Packet Channel Request Establ.cause '1-ph.access' QoS information. SGSN PRACH p-ch req. /c91002 (S10) nbr_of_packet_channel_reqs UL TBF establ. 72000(S9) EGPRS TBF if there are resouces Max.sim.UL TBF 72002(S9) EGPRS UL TBF 72088(S10) Possibly Req x tsl UL 72034..38(S9) Alloc x tsl UL 72044..48(S9) Packet UL Assignment Packet UL Assignment (PCCCH) DL RLC MAC /c72077(S9) /c91021(10) p_ul_ass_msgs_on_pccch Figure 30 EGPRS UL TBF ASSIGNMENT, MS on PCCCH with 1 phase access
  46. 46. Copyright 2007 Nokia Siemens Networks. All rights reserved. 46/166 CMO SBU MS Network & Service Optimization Capability Management 16/12/2008 4.1.3.8 Establishment of EGPRS UL TBF when DL TBF is ongoing The MS may request UL TBF by including a Channel Request Description IE in a Packet Downlink Ack/Nack message MS BTS New TBF is established in the same mode (GPRS, EGPRS) than the ongoing TBF. BSC SGSN EGPRS Packet_DL_Ack/Nack(Channel Request Description) MAC UL RLC /c72076(S9) UL TBF DUR. DL /c72074(S9) TBF per priority 90000(S10) UL TBF Establ. 72000(S9) Max.sim.UL TBF 72002(S9) UL TBF UNACK Max.sim.UL TBF UNACK 72010(S9) Possibly 72012(S9) Possibly EGPRS UL TBF 72088(S10) EGPRS UL TBF UNACK 72090(S10) Possibly Req X tsl UL 72034(S9) Packet Uplink Assignment UL RLC Data Block (PACCH) Alloc X tsl UL 72044(S9) DL RLC MAC /c72077(S9) UL RLC ACK MSC1…9 /c79002(S10) Figure 31 Establishment of EGPRS UL TBF when DL TBF is ongoing or UL RLC UNACK MSC1…9 /c79003(S10)
  47. 47. 47/166 CMO SBU MS Network & Service Optimization Capability Management 4.2 Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 (E)GPRS Data Transfer After TBF establishment the data transfer signaling is conveyed on PACCH. 4.2.1 (E)GPRS Data Transfer DL MS BTS BSC SGSN DL Data Packets DL TBF ASSIGNMENT Gtp_packets_sent_in_dl /c3001 Downlink Data Packets Downlink Data Packets (PDTCH) DL RLC block counter Gtp_data_in_bytes_sent_in_dl /c3003 The SGSN encrypts each DL packet according to parameters negortiated in PDP context activation NSCV_passed_data_in_bytes /c3017 bytes_in_of_vjhc_in_sndcp /c3008 Header compr bytes_out_of_vjhc_in_sndcp /c3009 Packet Downlink Ack/Nack (PACCH) PCU controls how often the ack should come (polling in DL data block). It is about every 18 blocks but gets adapted to radio conditions. bytes_in_of_v42bis_in_sndcp /c3010 bytes_out_of_v42bis_in_sndcp /c3011 Flowrate per priority /c90005/90006(S10) 1sec sampling (retransm.not incl.) Packet Downlink Ack/Nack UL RLC MAC /c72076(S9) Downlink Data Packets If NACK received and ack mode used Downlink Data Packets (PDTCH) DL RLC retransm CS1 /c72068(S9) or DL RLC retransm CS2 /c72069(S9) After TBF released DL TBF release counter group Figure 32 (E)GPRS Data Transfer DL 4.2.2 (E)GPRS Data Transfer UL Data compr
  48. 48. 48/166 CMO SBU MS Network & Service Optimization Capability Management MS Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 BTS BSC SGSN UL TBF ASSIGNMENT DL dummy control block "First data blocks" (PDTCH) There is a dummy DL MAC block before each UL data block DL RLC MAC /c72077(S9) "First data blocks" (PDTCH) UL RLC block counter Flowrate per priority /c90005/90006(S10) 1sec sampling Packet Uplink Ack/Nack (PACCH) Packet control ack (PACCH) LLC frames Packet Uplink Ack/Nack (FAI=1 when last) The LLC frame is already ciphered DL RLC MAC /c72077(S9) LLC ack (window 1-16) Packet control ack PCU controls after how many blocks the ack is sent. It is about every 20 blocks but can be adapted to radio conditions. UL RLC MAC /c72076(S9) UL TBF release counter group RLC blocks per priority 90001(S10) Gtp_packets_sent_in_ul /c3000 Gtp_data_in_bytes_sent_in_ul /c3002 Also if priority changed Header compr. bytes_in_of_vjhc_in_sndcp /c3008 bytes_out_of_vjhc_in_sndcp /c3009 Data compr. bytes_in_of_v42bis_in_sndcp /c3010 bytes_out_of_v42bis_in_sndcp /c3011 Figure 33 (E)GPRS Data Transfer UL
  49. 49. 49/166 CMO SBU MS Network & Service Optimization Capability Management 4.3 Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 Mobility with Cell-reselection The following mobility related signaling flowcharts are show in this chapter: • • Inter PCU cell-reselection (intra BSC) • RA/LA Update (intra PAPU) • 4.3.1 Intra PCU cell-reselection RA/LA Update (Inter PAPU or inter SGSN) Intra PCU Cell-Reselection MS BTS1 BTS2 BSC SGSN DL TBF ASSIGNMENT, MS ON CCCH, via BTS 1 DL Data Packets DL Data Packets DL Data Packets (PDTCH) The SGSN encrypts each DL packet according to parameters negortiated in PDP context activation PCU buffers LLC pdu's in RLC ACK-mode until all RLC blocks of the LLC pdu are acknowledged. The MS notices a need for a cell change (measurement strategy in 05.08). The MS stops receiving the DL Data Packets and tunes to the new frequency. While doing the neighboring measurement, the MS also checks for a possible RA change; if the cell change results in RA change, a RA update is performed instead of a cell update. (reliability class 1-3) In RLC UNACK-mode PCU buffers until all RLC blocks of LLC pdu are sent. UL TBF ASSIGNMENT, MS ON CCCH, via BTS 2 03.60:: "LLC frame of any type, including MS identity" 03.60:: "LLC frame of any type", BSS adds CGI 08.18: If MS is in UL data transfer it starts UL TBF in the new cell to transfer data. Cell Update is performed, too. Queued BSSGP signalling, e.g. pages, shall not be affected by Flush. These will thus go wasted if Cell Change happens. DL flush /c72059(S9) UL flush /c72058(S9) Flush-LL Ack DL Data Packets DL TBF ASSIGNMENT, via BTS 2 DL Data Packets DL Data Packets (PDTCH) In Flush-LL Ack the PCU tells whether the queued data packets were deleted or forwarded to new BVCI Figure 34 Intra PCU Cell-reselection Flush-LL PDU( Old BVCI+MS TLLI) The SGSN does not wait for Flush-LL ack before it forwards new DL Data Packets towards new BVCI If new BVCI is given in Flush-LL, and the new BVCI is served by the same NSE, the queued data packets are forwarded to the new BVCI. In the Intra-PCU case the NSE is the same, since In the Nokia implementation each PCU represents one and only one Network Service Entity (NSE).
  50. 50. Copyright 2007 Nokia Siemens Networks. All rights reserved. 50/166 CMO SBU MS Network & Service Optimization Capability Management 4.3.2 Inter PCU Cell-reselection (Intra BSC) MS 16/12/2008 Cell1 Cell2 BSC SGSN DL TBF ASSIGNMENT, MS ON CCCH, via BTS 1 DL Data Packets DL Data Packets DL Data Packets (PDTCH) The MS notices a need for a cell change (measurement strategy in 05.08). The MS stops receiving the DL Data Packets and tunes to the new frequency. While doing the neighbouring measurement, the MS also checks for a possible RA change; if the cell change results in RA change, a RA update is performed instead of a cell update. The SGSN encrypts each DL packet according to parameters negortiated in PDP context activation PCU buffers until RLC/MAC ack (relaibility class 1-3) UL TBF ASSIGNMENT, MS ON CCCH, via BTS 2 03.60:: "LLC frame of any type, including MS identity" 03.60:: "LLC frame of any type", BSS adds CGI Related to cell1 DL flush /c72059(S9) UL flush /c72058(S9) Flush-LL PDU( Old BVCI+MS TLLI) Flush-LL Ack DL Data Packets DL TBF ASSIGNMENT, via BTS 2 DL Data Packets DL Data Packets (PDTCH) In Flush-LL Ack the PCU tells whether the queued data packets were deleted or forwarded to new BVCI Figure 35 Inter PCU Cell-reselection (Intra BSC) In Nokia implementation, the inter-PCU cell change is also a inter-NSE cell change, thus the PCU destroys queued data packets after a Flush that follows inter-PCU cell change. Thus if PCU is sending DL data when MS makes an inter PCU cell change, data is probably lost and retransmissions rely on the LLC layer acknowlegements
  51. 51. 51/166 CMO SBU MS Network & Service Optimization Capability Management 4.3.3 Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 RA/LA Update (intra PAPU) MS BSS SGSN 1. Routeing Area Update Request 2. Security Functions 3. Routeing Area Update Accept 4. Routeing Area Update Complete Figure 36 RA/LA Update (intra PAPU) MS BTS First System information message(BCCH) Channel Request (RACH) Cell reselection data Outage Immediate Assignment (CCCH) BSC New SGSN First System information message [1]. P_Channel Required P-Immediate Assignment Cmd Location area Update [2]. Location update request (SDDCH) Location update request SECURITY FUNCTIONS AS SET BY THE OPERATOR Location Update Accept Location Update Accept Caneel Release (SDCCH) Routing area Update [3]. Routing Area Update Request (PDTCH) Routing Area Update Request Routing Area Update Request Routeing Area Update Accept DL TBF ASSIGNMENT Routing Area Update Accept Routing Area Update Accept (PDCCH) Routing Area Update complete (PDCH) Routing Area Update complete Figure 37 RA/LA Update (intra PAPU) in BSS network
  52. 52. Copyright 2007 Nokia Siemens Networks. All rights reserved. 52/166 CMO SBU MS Network & Service Optimization Capability Management 4.3.4 RA/LA Update (Inter PAPU or inter SGSN) MS BSS 16/12/2008 new SGSN old SGSN GGSN HLR 1. Routeing Area Update Request 2. SGSN Context Request 2. SGSN Context Response 3. Security Functions 4. SGSN Context Acknowledge 5. Forward Packets 6. Update PDP Context Request 6. Update PDP Context Response 7. Update Location 8. Cancel Location 8. Cancel Location Ack 9. Insert Subscriber Data 9. Insert Subscriber Data Ack 10. Update Location Ack 11. Routeing Area Update Accept 12. Routeing Area Update Complete Figure 38 RA/LA Update (Inter PAPU or inter SGSN) In case of inter-PAPU RA replace SGSN with PAPU. The flow chart for RA/LA Update from the radio part point of view is included below:
  53. 53. 53/166 CMO SBU MS Network & Service Optimization Capability Management Copyright 2007 Nokia Siemens Networks. All rights reserved. 16/12/2008 MS BTS BSC New SGSN UL TBF ASSIGNMENT, MS ON CCCH 1-ph.access Start T3330, 15s (max.5 tries) Routeing Area Update Request (PDTCH) Including TLLI for contention resolution Routeing Area Update Request UL RLC block counter Including TLLI for contention resolution Packet Uplink Ack/Nack Packet Uplink Ack/Nack (PACCH) DL RLC MAC /c72077(S9) Routeing Area Update Request Including TLLI for contention resolution Including TLLI for contention resolution Packet control ack (PACCH) UL RLC MAC /c72076(S9) Packet control ack UL TBF release counter group New SGSN sends context req to old SGSN. Old SGSN sends response and starts tunneling data to new SGSN . New SGSN sends ‘Update PDP context request’ to GGSN. New SGSN informs HLR about SGSN change by sending ‘Upate location’. HLR sends ‘Cancel location’ to old SGSN. SECURITY FUNCTIONS AS SET BY THE OPERATOR Routeing Area Update Accept DL TBF ASSIGNMENT Routeing Area Update Accept Routeing Area Update Accept Start T3350, 6s (max.5 tries) DL RLC block counter Packet Downlink Ack/Nack (PACCH) Packet Downlink Ack/Nack UL RLC MAC /c72076(S9) DL TBF release counter group Figure 39 RA/LA Update (Inter PAPU or inter SGSN) in BSS network 1/2 MS BTS BSC New SGSN UL TBF ASSIGNMENT Routeing Area Update Complete (PDTCH) Including TLLI for contention resolution Routeing Area Update Complete Including TLLI for contention resolution UL RLC block counter Routeing Area Update Complete Packet Uplink Ack/Nack (PACCH) Including TLLI for contention resolution Packet Uplink Ack/Nack Including TLLI for contention resolution DL RLC MAC /c72077(S9) Succ_inter_sgsn_ra_updat /c1019 UL TBF release counter group Figure 40 RA/LA Update (Inter PAPU or inter SGSN) in BSS network 2/2 4.4 TBF Release PACKET TBF RELEASE message is sent on the PACCH by the network to the mobile station to initiate release of an uplink or downlink TBF.

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