APUG_V01.01

Wireless Service Provider Solutions

GPRS Access NetworkParameters User GuidePE/DCL/DD/0136 12.01/EN Preliminary July 2000411–9001–0136

< 119 >< 136 >:GPRS Access Network Parameters User Guide

Wireless Service Provider Solutions

GPRS Access Network Parameters UserGuideDocument number: PE/DCL/DD/0136

411–9001–0136Document status: PreliminaryDocument issue: 12.01/ENProduct release: GSM/BSS V12Date: July 2000

Copyright 1996–2000 Nortel Matra Cellular and Nortel Networks, All Rights Reserved

Printed in France

NORTEL NETWORKS AND NORTEL MATRA CELLULAR CONFIDENTIAL:

The information contained in this document is the property of Nortel Networks and/or Nortel Matra Cellular. Except asspecifically authorized in writing by Nortel Networks and Nortel Matra Cellular, the holder of this document shall keepthe information contained herein confidential and shall protect same in whole or in part from disclosure anddissemination to third parties and use for evaluation, operation and maintenance purposes only.

You may not reproduce, represent, or download through any means, the information contained herein in any way or inany form without prior written consent of Nortel Networks and Nortel Matra Cellular.

The following are trademarks of Nortel Networks: *NORTEL NETWORKS, the NORTEL NETWORKS corporate logo,the NORTEL Globemark, HOW THE WORLD SHARES IDEAS.

All other brand and product names are trademarks or registred trademarks of their respective holders.

Publication HistoryNortel Networks Confidential iii

GPRS Access Network Parameters User Guide

PUBLICATION HISTORY

SYSTEM RELEASE : GSM/BSS V12

July 2000

This version is based on the internal document Access Network Parameters UserGuide (version 01.02) completed in July 2000.

Publication History Nortel Networks Confidentialiv

PE/DCL/DD/0136411–9001–0136

Preliminary 12.01/EN July 2000 GSM/BSS V12

PAGE INTENTIONALLY LEFT BLANK

Table of contentsNortel Networks Confidential v


About this document ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Applicability ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Audience ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Prerequisite ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Related Documents ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Applicable document ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reference document ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

How this document is organized x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1 Classification of parameters per object 1–1. . . . . . . . . . . . . . . . . . . . . .

2 GPRS algorithms and mechanisms 2–1. . . . . . . . . . . . . . . . . . . . . . . . . .

2.1 Introduction 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2 GPRS overview 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2.1 GPRS architecture 2–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2.2 GPRS protocol stack 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.2.3 Mobility management 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3 Uplink temporary block Flow 2–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3.1 Establishment of uplink temporary block flow 2–6. . . . . . . . . . . . . . . . . . . . . .

2.3.2 Uplink transfer establishment during downlink transfer 2–9. . . . . . . . . . . . . .

2.3.3 Release of uplink temporary block flow 2–10. . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3.4 Loss of communication procedures for uplink transfer 2–13. . . . . . . . . . . . . .

2.4 Downlink temporary block flow 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.4.1 Establishment of downlink temporary block flow(access without paging) 2–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.4.2 Downlink TBF establishment during uplink transfer 2–17. . . . . . . . . . . . . . . . .

2.4.3 Release of downlink temporary block flow 2–19. . . . . . . . . . . . . . . . . . . . . . . .

2.4.4 Loss of communication procedures for downlink transfer 2–21. . . . . . . . . . . .

2.5 RLC/MAC features 2–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.5.1 Countdown Procedure 2–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.5.2 Sliding Window 2–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.6 Reselection algorithms 2–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.6.1 Overview 2–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.6.2 Cell reselection in Ready state 2–30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of contents Nortel Networks Confidentialvi

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2.7 MS power control 2–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.7.1 Overview 2–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.7.2 Open Loop Control 2–32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.8 DRX–mode 2–34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.9 Timing advance 2–36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3 OMC–R algorithms parameters 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1 Call establishment parameters 3–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.2 Countdown procedure parameters 3–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.3 Radio link failure parameters 3–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.4 Cell selection and reselection parameters 3–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.5 DRX mode parameters 3–13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.6 Power control parameters 3–14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.7 Timeslot sharing parameters 3–19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.8 Dual–band cell parameters 3–22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.9 TDMA selection parameters 3–23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.10 Sliding window parameters 3–24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.11 Block allocation parameters 3–26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.12 Other access network parameters 3–29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3.13 Reserved parameters 3–31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4 PCUSN OAM algorithm parameters 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . 4.1 Network service parameters 4–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.2 BSSGP parameters 4–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.3 Frame relay parameters 4–12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 Appendix A: main procedures between the MS and the PCU 5–1. . 5.1 Proc_1: establishment of uplink TBF 5–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.2 Proc_2: establishment of uplink TBF during a downlink transfer 5–2. . . . . . . . . . . . . . .

5.3 Proc_3: release of an uplink TBF 5–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.4 Proc_4: release of an uplink TBF with a lost of communication 5–4. . . . . . . . . . . . . . .

5.5 Proc_5: establishment of a downlink TBF 5–5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.6 Proc_6: failure of downlink TBF establishment 5–6. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5.7 Proc_7: Establishment of downlink TBF during an uplink transfer 5–7. . . . . . . . . . . . . .

5.8 Proc_8: release of a downlink TBF 5–8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6 Abreviations and definitions 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.1 Abreviations 6–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6.1.1 Definitions 6–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

List of figuresNortel Networks Confidential vii


Figure 2–1 GPRS Architecture 2–2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–2 GPRS Protocol Stack Description 2–3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–3 MM State Model of MS ( with SIM card) 2–4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–4 Main procedures to transfer data from MS to PCU. 2–6. . . . . . . . . . . . . . . . . . . . .

Figure 2–5 A successful uplink access. 2–7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–6 Establishment of an uplink TBF during a downlink TBF. 2–9. . . . . . . . . . . . . . . . . .

Figure 2–7 Example of Uplink TBF Release 2–11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–8 Release of an Uplink TBF with lost of the communication 2–12. . . . . . . . . . . . . . . .

Figure 2–9 Establishment of Downlink TBF 2–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–10 Downlink TBF Establishment failure 2–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–11 Establishment of Downlink TBF during an Uplink transfer 2–18. . . . . . . . . . . . . . . .

Figure 2–12 Example of Downlink Release 2–21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–13 Description of Sliding Window at a RLC endpoint transmitter 2–26. . . . . . . . . . . . .

Figure 2–14 Description of Sliding Window at a RLC endpoint receiver 2–28. . . . . . . . . . . . . . . .

Figure 2–15 The occurrence of the CCCH channels 2–35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 2–16 Example of continuous timing advance 2–37. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–1 maxRach part on the Uplink Establishment Transfer 3–3. . . . . . . . . . . . . . . . . . . .

Figure 3–2 Parameters of MS Output Power. 3–15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–3 Traffic example of uplink power control 3–17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–4 Traffic example of uplink power control 3–18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 3–5 Impact of AllocBitmap on TBF Establishment duration 3–27. . . . . . . . . . . . . . . . . . .

List of figures Nortel Networks Confidentialviii

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About this documentNortel Networks Confidential ix


ABOUT THIS DOCUMENTThis user guide describes the Nortel GPRS access network algorithms andparameters from an engineering point of view.

This document contains extensive Nortel GPRS parameters setting know–how.Information coming from experiments, studies, simulations are also related in it.

This version is a complement of the Manual < 36 > BSS Parameter User Guide(Release V12).

Applicability

This document applies to Gate 2 soft release of the PCU available for the trials andis compliant with the V12.4 BSS release.

Audience

ABPUG is mainly aimed at all persons needing exhaustive descriptions of the GPRSparameters.

Prerequisite

In order for this document to be fully profitable, readers should have basicknowledges of the GPRS system functioning.

Related Documents

Applicable document

PRJ/DOM/CLA/NNNN GPRS Engineering test plan

Reference document

[R1] PE/DCL/DD/0036 BSS Parameters User Guide

[R2] PE/DCL/DD/0007 BSS Operating Principles

[R3] PE/DCL/DD/0124 BSS Dictionary of Parameters

[R4] PE/DCL/DD/0125 Observation Counter Dictionary

About this document Nortel Networks Confidentialx

PE/DCL/DD/0136411–9001–0136


How this document is organized

The classification of the parameters by object is provided in Chapter 1.

Chapter 2 describes the GPRS Nortel access network algorithms and recommendsways to use them efficiently. All the algorithms and mechanisms are compliantwith the Gate 2 release.

All parameters used in the algorithms are described in Chapter 3. The parametersconsidered in this document are managed by the OMC–R or NMS. They areconveyed in the Air interface, Abis interface, Agprs interface between the MS andthe PCU.

For each parameter, the following essential fields are described:

Class

Object

Default value

Range Value

Recommended Value

Engineering rules

Some engineering rules given in this document will be improved from the field testsand from the GPRS Network Dimensioning Simulator (CT9500) results.

In Chapter 4, simulations results are presented as well as impact studies for someparameters.

Chapter 5 gives the main exchange between the MS and the PCU.

In Chapter 6, the signification of all the abbreviations used in this document andsome key–definitions are explained.

Classification of parameters per objectNortel Networks Confidential 1–1


1 CLASSIFICATION OF PARAMETERS PER OBJECT

Bts:

V12.4

Parameter Object Class a b c

bsCvMax bts 3 X X X

btsSensitivity bts 3 X X X

radioAllocator bts 3 X X X

gprsCellAllocation bts 3 X X X

gprsPermittedAccess bts 3 X X X

maxRACH bts 3 X X X

panDec bts 3 X X X

panInc bts 3 X X X

panMax bts 3 X X X

nAvgT bts 3 X X X

nAvgW bts 3 X X X

N3103 bts 3 X X X

reserved3 (T3168) bts 3 X X X

reserved4 (T3192) bts 3 X X X

gprsPreemption bts 3 X X

maxDwAssign bts 3 X X X

gprsPreemptionProtection bts 3 X X

minNbrGprsTs bts 3 X X

btsSensitivityInnerZone bts 3 X

longTbfLossThroughput bts 3 X

longTbfSizeThreshold bts 3 X

maxBsTransmitPowerInner-Zone

bts 3 X

maxDnTbfPerTs bts 3 X

maxUpTbPerTs bts 3 X

drxTimerMax bts 3 X

T3172 bts 3 X

msCapWeightActive bts 2 X

Classification of parameters per object Nortel Networks Confidential1–2

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V12.4

cbaClassObjectParameter

nbrFreeTchBeforeAnticipation bts 3 reserved parameter

nbrFreeTchToEndAnticipation bts 3 reserved parameter

maxUpTbfP1P2Threshold bts 3 reserved parameter

speechOnHoppingTs bts 3 reserved parameter

maxDnTbfP1P2Threshold bts 3 reserved parameter

nAvgl bts 3 Not used

Bsc:

V12.4


bscGprsActivation bsc 3 X X X

Transceiver:

V12.4


blockErrorRate transceiver 3 X X X

codingScheme transceiver 2 X X X

gprsPriority transceiver 2 X X X

maxNbrPUDWithoutVChange(N0002Max)

transceiver 2 X X X

N3105Max transceiver 2 X X X

upAckTime transceiver 3 X X X

maxSize transceiver 3 X

dLPwrValue transceiver 3 reserved parameter

maxNbrPDAAssig transceiver 2 Not used

maxNbrRLCEmptyBlock(N0001Max)

transceiver 2 Not used

dwAckTime transceiver 3 Not used

Classification of parameters per objectNortel Networks Confidential 1–3


Channel:

V12.4


channelType channel 2 X X X

GprsNsProv:

V12.4

Parameter Attribute Criticity a b c

nsBlockTimer GprsNsProv None X X X

nsBlockRetries GprsNsProv None X X X

nsUnblockRetries GprsNsProv None X X X

nsResetTimer GprsNsProv None X X X

nsResetRetries GprsNsProv None X X X

resumeTimer GprsNsProv None X X X

resumeRetries GprsNsProv None X X X

nsTestTimer GprsNsProv None X X X

nsAliveTimer GprsNsProv None X X X

nsAliveReries GprsNsProv None X X X

GprsPcBssgpProv:

V12.4


bvcBlockRetries GprsPcBssgpProv None X X X

bvcUnblockRetries GprsPcBssgpProv None X X X

bvcResetReqTimer GprsPcBssgpProv None X X X

bvcResetReqRetries GprsPcBssgpProv None X X X

suspendTimer GprsPcBssgpProv None X X X

suspendRetries GprsPcBssgpProv None X X X

raCapabilityUpTimer GprsPcBssgpProv None X X X

raCapabilityUpRetries GprsPcBssgpProv None X X X

Classification of parameters per object Nortel Networks Confidential1–4

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V12.4

cbaCriticityAttributeParameter

flowControlMaxRate GprsPcBssgpProv None X X X

tsflowCntlBucketSize(tsBmax)

GprsPcBssgpProv None X X X

tsLeakRate GprsPcBssgpProv None X X X

msFlowCntlBucketSize GprsPcBssgpProv None X X X

FrAtmDlciSpProv:

V12.4


maximumFrameSize (n203) FrAtmDlciSpProv None X X X

rateEnforcement (re) FrAtmDlciSpProv None X X X

committedInformationRate (cir) FrAtmDlciSpProv None X X X

committedBurstSize (bc) FrAtmDlciSpProv None X X X

excessBurstSize (be) FrAtmDlciSpProv None X X X

measurementInterval (t) FrAtmDlciSpProv None X X X

accounting (ac) FrAtmDlciSpProv None X X X

GPRS algorithms and mechanismsNortel Networks Confidential 2–1


2 GPRS ALGORITHMS AND MECHANISMS

2.1 Introduction

This chapter describes major GPRS algorithms using OMC–R algorithmparameters, both on the PCU and the MS side.

2.2 GPRS overview

In order to have a better understanding of all the algorithms and the mechanismsdescribed in this document, an GPRS overview is presented below.

2.2.1 GPRS architecture

GPRS is primarily intending to support data applications, which generates burstytraffic (ON/OFF pattern), where packet switched transmission is obviously a moreefficient transportation means. The application of the packet oriented transmissionscheme on the air–link, results in a better utilization of the scarce radio resourcesfor typical Internet applications. The kind of Traffic has an important impact on theparameter values and on the choice of algorithms.

The improvements are gained from the provision of a packet oriented data servicefor GSM, which

allows reduced connection set–up times

supports existing packet oriented protocols like IP

provides and optimizes usage of radio resources.

To introduce GPRS in the existing GSM infrastructure, additional network elementsare added to the GSM architecture. This structure is depicted in Figure 2–1.

GPRS algorithms and mechanisms Nortel Networks Confidential2–2

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BSS

GSMNSS

GPRSNSS

PSTN/ISDN

IP. X 25SGSN

HLR

PCU

GGSN

G

GPRSBSS

Datafill

Figure 2–1 GPRS Architecture

Since the existing GSM network provides only circuit–switched services, two newnetwork nodes are defined to give support for packet switching: the Serving GPRSSupport Node (SGSN) and the Gateway GPRS Support Node (GGSN).

The SGSN is responsible for the communication between the mobile station (MS)and the GPRS network. It serves the mobile station (MS) and maintains the mobilitycontext.

The GGSN provides the interface to external packet data networks or the Internet,but also to GPRS networks of other operators. It routes incoming packets to theappropriate SGSN for a particular mobile station.

The GSM Base Station Subsystem (BSS) is used as a shared resource of bothcircuit–switched and packet–switched network elements to ensure backwardcompatibility and keep the required investments for the introduction of GPRS at asustainable level.

In order to distinguish GSM and GPRS architecture, the following name arecommonly used:

Access Network: this is the GPRS BSS, made up the BTS, BSC and PCUelements.

Core Network: this is the GPRS NSS, made up the SGSN and GGSNequipments.



2.2.2 GPRS protocol stack

TLLI

MS BSS

TFI

Application

IP

SNDCP

LLC

RLC

MAC

GSM RF

TID

BSSGP

Networkservice

L1 bis

SNDCP

LLC

IP

L1

GTP

UDP/TCP

L2

SGSN

Relay

IP

L1

GTP

UDP/TCP

L2

IP/ X.25

SAPI

NSAPI

ApplicationÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ

Application part

Um Gb Gn GiGGSN

LLC relay

BSSGP

Networkservice

L1 bis

RLC

MAC

GSM RF

Figure 2–2 GPRS Protocol Stack Description

The SGSN may allocate TMSI for visiting mobile subscriber using GPRS, whichare referred to as Packet–TMSI or P–TMSI.

Then each active MS (READY or STANDBY) is identified by the Temporary LinkLevel Identity, TLLI, inside the SGSN and the access network at the LLC level.LLC shall be independent of the underlying radio interface protocols in order toallow introduction of alternative GPRS radio solutions with minimum changes tothe core network.

In the SNDCP layer, the NSAPI (Network Service Access Point Identifier),allocated dynamically by the MS, at the PDP Context Activation, identify a specificPDP type which precise the IP version and PDP address pair. This transmissionfunctionality maps network–level onto the characteristics of the underlyingnetwork.

The Tunnel Identity, TID, used by the GTP, identifies a PDP context in the IPbackbone (between SGSN and GGSN). TID consists of an IMSI and a NSAPI.


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The TFI (Temporary Flow Identity) is the unique identification of a TBF, used bythe MS and the BTS/PCU.

Most of access network parameters and algorithms described in this document arerelated with RLC/MAC. This layer contains two functions: the Radio Link Controlfunction provides a radio–solution–dependent reliable link thanks to the SlidingWindow procedure. The Medium access Control function controls the accesssignaling (request and grant) procedures for the radio channel. It also proposes theCountdown Procedure in order to optimize the resources at the end of a TBF.

2.2.3 Mobility management

IDLE

READY

STANDBY

GPRSDetach(t3322)

PDUtransmission

Cell updatesNo need of paging

RA updatesPaging

GPRSAttach(t3330)

READYTimer

(t3314)expiry

STANDBYTimerexpiry

Figure 2–3 MM State Model of MS ( with SIM card)

Before an MS is able to send data to a corresponding host, it has to be attached toan SGSN. Thus, an attachment procedure (GPRS Attach) between the MS and theNetwork is carried out and a TLLI is assigned to the MS.

There are three Mobility Management states related to a GPRS subscriber and eachstate describes the level of functionality and information allocated.

In IDLE state, the MS is not yet attached to the GPRS MM. Therefore a GPRSAttach procedure shall be perform.



In READY state, the MS is attached to GPRS MM and is known with accuracy ofa cell. The MS may receive and transmit data for all relevant services type. If theREADY Timer (MS or SGSN one) expires, the MS will move to STANDBY state.

In STANDBY state, the subscriber is attached to GPRS MM and is known inaccuracy of routing area (RA). Therefore the MS performs GPRS Routing Areaupdate and GPRS cell selection and re–selection locally.

At this point if the subscriber wants to request an E–mail message or a Web page,a PDP context must be activated before. If the STANDBY Timer (MS or SGSNone) expires in this state, the MM contexts both in MS and in SGSN independentlyreturn to IDLE state and may be deleted.


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2.3 Uplink temporary block Flow

In GPRS, access procedures are not the same in uplink as in downlink. The signalingis asymmetric. Here below are the main steps from the incoming LLC frames to thePDTCH transfer for an uplink TBF.

First LLC frameincoming

Call admission

Segmentation

RLC buffer

Slidingwindow

TRANSFER TO PCU

Figure 2–4 Main procedures to transfer data from MS to PCU.

2.3.1 Establishment of uplink temporary block flow

This section describes the allocation for an uplink transfer (no transfer is currentlyin progress with this MS). Nortel implementation concerns the Fixed Allocation(Bitmap) mechanism for uplink flow establishment (as opposed to the USFmechanism). The uplink transfer establishment is performed in two.

Uplink TBF establishment first phase: on CCCH

On receipt of the first LLC frame in the buffer of the RLC/MAC layer, the MS mustsend a RACH (“Packet Channel Request” message) to the BTS. The BTS makesa first treatment to send a Channel Required message to the PCU.



Thus during all this phase, the PCU and the MS communicate through the BTS. Thatmeans, that the BTS modifies the message at its level. The messages between theBTS and the PCU are using the Abis GSL interface. See the description in theFigure 2–5 below.

StartT3168

MS

RACH (CCCH)

IMM. Assign. (AGCH)

Channel Required Channel Required

IMM. Assign. Command IMM. Assign. Command

FIRST PDTCH

PACKET RESOURCE REQUEST

PACKET UPLINK ASSIGNMENT

BTS BSC PCU

MAX_RACHfilter

Allocator filter(TFI & resources limits)

Figure 2–5 A successful uplink access.

On reception of the Channel Required message the PCU responds according to theOMC parameter maxRach, which is the maximum RACH accepted by the PCU persecond. In the Air interface, an Immediate Assignment (AGCH) or an ImmediateAssignment Reject is sent. The PCU responds on the same timeslot on which it hasreceived the RACH.


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If the BTS can not send the “Immediate Assignment” message (traffic too loaded),the BTS informs the PCU by sending a “Delete Indication” message. Thus theprocedure is discarded at this level.

If the Allocator makes the choice to reject the MS request, by sending an“immediate Assignment Reject” message, the procedure is stopped at this level.In the other case, after this point, the mobile station use PDCH channels to talk withthe PCU.

Note that the Channel Required message provides the Timing Advance (Accessdelay field), but this value is valid only during a timer which is set to 6 seconds. Thusbefore the expiration of this timer, the PCU must send the “Packet UplinkAssignment” message. If this timer elapses, the procedure is cancelled(see Paragraph 2.9 Timming Advance).

Uplink TBF establishment second phase: on PDCH

By receiving an “Immediate Assignment”, RLC/MAC knows the type of TDMA(N° TDMA) attributed, the frame number of the allocated block(TBF–STARTING–TIME) from which the MS is allowed to transmit the “PacketResource Request”. Thus, it indicates the RLC–MODE requested (RLCAcknowledged (0) or RLC unacknowledged (1)), the RLC–OCTET–COUNT(used by the allocator to compute the number of blocks allocated to close–endedTBF according to the BLER and the coding scheme; else indicates 0), its MultislotClass capability, etc… Then the MS starts timer T3168 to control the time to waitfor the “Packet Uplink Assignment” message.

If T3168 expires, the packet access procedure is reinitiated.

If the PCU does not receive the “Packet Resource Request” in the allocated singleradio block (PACCH), the procedure is canceled in the PCU side and the packetaccess procedure is reinitiated after T3168 expires.

On receipt of the “Packet Resource Request”, the allocator knows the MScapabilities and the TBF type (open–ended if RLC–OCTET–COUNT= 0; elseclose–ended). For a close–ended TBF, the PCU knows the number of user dataoctets that has to be transferred and can give only what is needed. For anopen–ended, the PCU does not know the number of user data octets that has to betransferred and the MS has to request resources in each bitmap. Therefore, theallocator can decide if it is able to allocate resources or not, by sending a “PacketUplink Assignment” or a “Packet Access Reject”.

The “Packet Uplink” Assignment message is sent by the PCU to the mobile stationto assign uplink resources (bitmap…). The TFI is provided at this level to the MS.The communication is established and the MS goes in packet transfer mode.



2.3.2 Uplink transfer establishment during downlink transfer

The mobile station may request the establishment of an uplink transfer during adownlink TBF. This consists in including a Channel Request Information Element(containing fields RLC–MODE, RLC–OCTET–COUNT and a flag to indicate thatthese fields are valid) in the “Packet Downlink Ack/Nack” message (Initiation istriggered by a request from upper layers to transfer a LLC PDU) (see Figure 2–6).

MS PCU

Allocatorfilter

(TFI &resources

limits)

PACKET DOWNLINK ACK/NACK

DOWNLINK DATA

DOWNLINK DATA

PACKET UPLINK ASSIGNMENT(S/P=1)

PACKET CONTROL ACKNOWLEDGEMENT

DOWNLINK DATA

UPLINK DATA

TBF starting timefor the uplick TBF

Figure 2–6 Establishment of an uplink TBF during a downlink TBF.

When the MS requests an uplink TBF establishment, the PCU can be in the releaseprocedure. Thus, there are two cases:

If the PCU has already sent the data block with the FBI set to 1, in that case it islike an half duplex uplink TBF establishment: the uplink TBF establishmentrequest is resent after the release of the Downlink TBF. It means that when theLLC frame will trigger at the MS side an Uplink request, the MS will keep therequest and won’t send the PACKET RESOURCE REQUEST at this presenttime but will wait for the end of the Downlink Transfer to send the UplinkChannel Request.


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If the PCU has not already sent the data block with the FBI set to 1, the uplinkTBF establishment request is taken into account (Full Duplex transfer). If it isneeded, the sending of this block is delayed until the PACKET UPLINKASSIGNMENT message is correctly acknowledged.

On receipt of a Channel Request Description information element in the PACKETDOWNLINK ACK/NACK message, the PCU may assign radio resources to themobile station on one PDCH by transmitting a PACKET UPLINKASSIGNMENT message on the PACCH, or may reject the request by sending aPACKET ACCESS REJECT message on the PACCH.

The PCU sends the PACKET UPLINK ASSIGNMENT message with allinformation for establishing the uplink TBF. The MS acknowledges this messageby sending a PACKET CONTROL ACKNOWLEDGEMENT.

If the message is not acknowledged by the MS, the PCU sends again the messageuntil it will be acknowledged or a loss of communication is detected by the downlinkTBF.

If the loss of communication is detected, an error message is sent to the SGSN andthe procedure is canceled at this point.

If the MS acknowledges the message, the TBF uplink is established.

2.3.3 Release of uplink temporary block flow

There are two kinds of release: normal or abnormal.

A normal release of an uplink TBF by the PCU occurs in the following cases:

The PCU sends an allocation to the MS with the field FINAL_ALLOCATIONset to 1.

The PCU sends a “Packet Access Reject” to the MS to indicate it has rejected theMS request.

The PCU initiates a release by sending a “Packet TBF Release” to the MS.

A normal release of an uplink TBF by the MS occurs when it has no moreRLC/MAC blocks to transfer so it initiates a countdown procedure. The MS mustbegin the countdown procedure in order to end it within the current allocation.

An abnormal release of an uplink TBF by the PCU occurs in the following cases:

Some PDCHs allocated to a TBF are no more available. This may happen whenthe BSC informs the PCU that some GPRS resources are no more available.

The PCU has lost the communication with the MS.

In the case of a normal release of an uplink TBF by the MS, the RLC/MACinitiates release of the uplink TBF by beginning the countdown process when themobile station has sent the RLC data block with CV = 0. The MS starts the TimerT3182.



If the timer T3182 expires before the reception of the “Packet Uplink Ack/Nack”message with Final Ack Indicator bit (FAI) set to ‘1’, then the TBF is released.

If the network has not received all RLC data blocks when it detects the end of theTBF, it will send the “Packet Uplink Ack/Nack” message to the mobile station.

Besides, if necessary, the PCU allocates sufficient uplink resources for the mobilestation to retransmit the required RLC data blocks. If a new bitmap is needed, theMAC PCU layer provides it to the MS to end the TBF. For any TBF, this bitmapis provided without request from the MS (see Figure 2–7).

If the network has received all RLC data blocks when it detects the end of the TBF(i.e. When CV = 0 and there are no elements in the V(B) array set to the valueNacked), it will send the “Packet Uplink Ack/Nack” message with the Final AckIndicator bit and the FINAL_ALLOCATION set to 1 and clears counter N3103(OAM parameter).

MS PCU

PDTCH (CV=0)

PACKET UPLINK Ack/Nack

PDTCH

PDTCH

PACKET UPLINK Ack/Nack (Final Ack Indicator =1)


StartT3182

TBFrelease

TBFrelease

Figure 2–7 Example of Uplink TBF Release


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On reception of the “Packet Uplink Ack/Nack” message with the Final AckIndicator bit set to 1, the MS must transmit the “Packet ControlAcknowledgement” message and releases the TBF.

If the network does not receive the “Packet Control Acknowledgement” messagein the radio block expected, it increments counter N3103 and repeats the sendingof the “Packet Uplink Ack/Nack” message with the Final Ack Indicator bit setto ‘1’, including a valid RRBP field. This procedure is repeated until the messageis acknowledged or the counter N3103 exceeds N3103Max.

The MAC starts timer T3169 when counter N3103 exceeds its limit. The PCU mayreuse the TFI resources (see Figure 2–8) when timer T3169 expires.

MS PCU

PDTCH (CV=0)

..........

StartT3182

TBFrelease

TBFrelease

PACKET Uplink Ack/Nack (Final Ack Indicator =1)


Not receivedby the MS

StartT3169

N3103Max

Figure 2–8 Release of an Uplink TBF with lost of the communication



2.3.4 Loss of communication procedures for uplink transfer

2.3.4.1 In the PCU

The loss of communication is detected by two ways:

When the RLC layer detects NN0001Max consecutive erroneous blocks for aTBF, it informs the MAC layer, which activates the RRBP field in the next“Packet Uplink Ack/Nack” message. It means that the PCU expects for a“Packet Control Acknowledgement”. If this message is acknowledged, theMAC informs the RLC of the re–establishment of the communication, else theprocedure is the same as for a MAC detection of the loss of communication.

When the MAC sends a message with the RRBP field activated (it requests anacknowledgement with a “Packet Control Acknowledgement”), and there isno acknowledgement of this message. After this point if the RLC detects the lossof communication, this detection is not taken into account by the MAC layer.

When the first control message is not acknowledged, the MAC starts the timerNT0001 and re–sends the message with a RRBP field valid.

If the MAC receives an acknowledgement of one control message the procedure isstopped at this level.

If one message is not acknowledged the message is re–sent with a RRBP field valid.

If the timer NT0001 elapses the TBF is released.

2.3.4.2 In the Mobile Station

The loss of communication is detected at the MS side by the timer T3184. Whenthe MS receives a “Packet Uplink Ack/Nack” from the PCU, it stops T3184 andit starts again.

If T3184 elapses, i.e. a “Packet Uplink Ack/Nack” has not been received in timefrom PCU, the MS shall try to reestablish the TBF by reinitiating a random accessprocedure.

If the procedure succeeds then the RLC/MAC layer shall retransmit the current LLCframe.


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2.4 Downlink temporary block flow

2.4.1 Establishment of downlink temporary block flow (access withoutpaging)

This chapter describes the allocation for a downlink transfer when the MS is in theReady state (GPRS Mobility Management) and in Packet Idle mode (there is nocurrent TBF in progress with this MS).

From the allocator point of view, the establishment of a downlink transfer with anMS in:

The STANDBY state is similar to the establishment of an uplink TBF to carry thepaging response, followed by the establishment of a downlink transfer towardsan MS in the STANDBY state.

The Ready state and Packet Transfer mode is a downlink TBF establishmentduring uplink transfer.

As for uplink transfer establishment, the downlink transfer establishment can beseen as a two phases access.



StartNT1002

MS

FIRST PDTCH

BTS BSC PCU

BSSGP–DL–Unit–DataIMM. Assign. CommandIMM. Assignment

PACKET DOWNLINK ASSIGNMENT

PACKET CONTROL ACKNOWLEDGEMENT (Over 4 bursts )

PACKET TIMING ADVANCE

Figure 2–9 Establishment of Downlink TBF

2.4.1.1 First phase on CCCH (downlink TBF)

The downlink establishment procedure using CCCH is applicable when the MS isin packet idle mode and when there is no PCCCH in the cell.

On receipt of a downlink DL–UNITDATA coming from the SGSN, the MAC layerverifies if there is no existing transfer for this mobile and asks the Allocator forresources.

If no resources are available, the PCU sends an error message to the SGSN.

If resources are available for this new downlink TBF, the PCU sends an “ImmediateAssignment” message on the Agprs GSL interface to the BTS. Then the BTS sendsan “Immediate Assignment” message to the MS. This is the only message usingCCCH in this procedure. The Allocator can allocate only one PDCH channel fordownlink transfer establishment. This PDCH is used in the second phase to allocatemore resources to the MS according to its multislot class capability and the radioresources available.


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When the MAC layer sends the Immediate Assignment Command message, itstarts the timer NT1002.

If the BTS can not send the Immediate Assignment message (traffic too loaded),the BTS informs the PCU by a “Delete Indication” message. Thus the PCU resetsthe timer NT1002 and sends an other time the Immediate Assignment message.

Compare to the uplink TBF establishment, the timing advance is not known by thePCU on the sending of the “Immediate Assignment” message. So, in order toprovide the MS with a valid timing advance, the PCU set a polling bit in the“Immediate Assignment” message in order to use the four access bursts mechanism.

Starting time is defined neither during the first phase nor during the second phaseof the downlink TBF establishment. But for the reservation of the downlink blocksin the routing table, the allocator must take into account the transmission delay andthe MS reaction time.

2.4.1.2 Second phase on PDCH (downlink TBF)

Upon receipt of the “Immediate Assignment” message, the MS must start to monitorthe PDCH specified in the message.

In the second phase, on this PDCH, the PCU sends a “Packet DownlinkAssignment” message (when the timer NT1002 elapses), with RRBP fieldactivated, to the MS to assign downlink resources.

Upon receipt of the “Packet Downlink Assignment” message, the MS (RLC/MAClayer) must respond by the “Packet Control Ack” message on four access bursts,with the RLC–MODE requested (see Figure 2–9). This message is used by theBTS to compute the timing advance.

The TFI provided in this message may be different from the TFI given in theImmediate Assignment message because the two messages can be send ondifferent TDMA.

If the “Packet Control Acknowledgement” message is not received in the blockexpected, the MAC layer repeats the sending of the “Packet DownlinkAssignment” message, with the RRBP field activated.

The case of a failure is described in the Figure 2–10.



StartNT1001

StartNT1002MS BTS BSC PCU

IMM. AssignmentIMM. Assign. CommandIMM. Assignment


PACKET CONTROL ACK.


PACKET CONTROL ACK.


PACKET CONTROL ACK.

500 ms

500 ms

NBMAXPDASSIGN.

TBFrelease

Figure 2–10 Downlink TBF Establishment failure

2.4.2 Downlink TBF establishment during uplink transfer

2.4.2.1 Description

The establishment of a downlink TBF is triggered by the SGSN. When the decisionto establish a downlink TBF is taken there are two possible cases:

The current uplink resource allocation allows the MS to establish a downlinkTBF. Thus the PCU sends directly a “Packet Downlink Assignment” messageon the PACCH to the MS to provide the downlink resources. This message isacknowledged by sending a “Packet Control Acknowledgement”.


PE/DCL/DD/0136411–9001–0136


The current uplink resource allocation, according to the MS capability, does notallow the MS to establish a downlink TBF. Thus the PCU sends a “PacketUplink Assignment” message to provide a new uplink resource allocation to theMS that allows establishing a downlink TBF. Then the PCU sends a “Packetdownlink Assignment” message to the MS to provide the downlink resources.

The two messages are acknowledged by sending a “Packet ControlAcknowledgement” (see Figure 2–11).

MS PCU

DownlinkTBF start

PDTCH

PACKET UPLINK ASSIGNMENT (bitmap i+1)

PDTCH

PDTCH


PDTCH


PDTCH


PDTCH

PDTCH

PDTCH

PDTCH

UplinkBitmap i

UplinkBitmap i+1

Figure 2–11 Establishment of Downlink TBF during an Uplink transfer

In these two cases, before beginning the downlink TBF, the MS must finish itscurrent uplink resource allocation (it means its current bitmap). The PCU must takeinto account this constraint for the TBF starting time and waits to the end of thecurrent uplink resource allocation before to send data to the MS.



When the PCU receives the TBF downlink establishment request from the SGSN,the TBF can be in the release procedure. Thus there are two cases:

If the PCU has already sent the last “Packet Uplink Ack/Nack” message(message with the Final Ack Indicator bit and the FINAL_ALLOCATION bitset to 1) of the TBF, in that case it is like an half duplex downlink TBFestablishment.

If the PCU has not already sent the last “Packet Uplink Ack/Nack” message(message with the Final Ack Indicator bit and the FINAL_ALLOCATION bitset to 1), the TBF downlink establishment request is taken into account (FullDuplex transfer) and the sending of this message is delayed until theacknowledgement of the “Packet Downlink Assignment” message is receivedcorrectly.

2.4.2.2 Failure case

If the “Packet Downlink Assignment” message is not acknowledged, the MACstarts the timer NT0001 and the message is repeated.

Each time one message is not acknowledged the message is repeated.

If a message is acknowledged, then the timer NT0001 is stopped and the procedurecontinues normally.

If the timer NT0001 elapses, the TBF uplink is released and the SGSN is informedof the failure.

If the “Packet Downlink Assignment” message is not acknowledged, the MACstarts the timer NT0001 and the message is repeated.

Each time one “Packet Downlink Assignment” is not acknowledged the messageis repeated.

If a message is acknowledged, then the timer NT0001 is stopped and the procedurecontinue normally.

If the timer NT0001 elapses, the TBF uplink is released and the SGSN is informedof the failure.

2.4.3 Release of downlink temporary block flow

There are two kinds of release: normal or abnormal.

A normal release of a downlink TBF by the PCU occurs in the following case:

The PCU has no more LLC–PDU to be transferred. In this case, it sends adownlink RLC block with the Final Block Indicator (FBI) set to 1, with a validRRBP to ask for a “Packet Downlink Ack/Nack”, then it starts the timer T3191.


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Upon receipt of the last downlink RLC block, the MS must send a “PacketDownlink Ack/Nack” with FAI=1 and start timer T3192. When T3192 expires,the MS shall release the TBF.

When the PCU receives a “Packet Downlink Ack/Nack” with FAI=1, it startsT3193. When T3193 expires, the network shall release the TBF.

An abnormal release of a downlink TBF by the PCU occurs in the following cases:

Some PDCHs allocated to a TBF are no more available. This may happen whenthe BSC informs the PCU that some GPRS resources are no more available.

The PCU has lost the communication with the MS.

In the case of a normal release of a downlink TBF by the PCU, the PCU initiatesrelease of a downlink TBF by sending an RLC data block with the Final BlockIndicator (FBI) set to the value 1 and with a valid RRBP field. The RLC data blocksent must have the highest BSN’ of the downlink TBF. The PCU may retransmit theRLC data block with the FBI bit set to the value 1. Then the PCU starts TimerT3191. If T3191 expires, the TBF is released.

If the mobile receives an RLC data block with the FBI bit set the value 1 and witha valid RRBP field, the mobile station will transmit a “Packet DownlinkAck/Nack” message in the specified uplink block. The mobile station will continueto monitor all assigned PDCHs.

If the network receives a “Packet Downlink Ack/Nack” message, and ifretransmissions are required, then the network retransmits necessary RLC datablocks.

If the mobile station has received all previous RLC data blocks, the mobile stationshall send the “Packet Downlink Ack/Nack” message with the Final AckIndicator (FAI) bit set to 1 and shall start timer T3192. The PCU shall stop T3191and shall start T3193. The network releases the TBF (see Figure 2–12) whenT3193 expires. The mobile station will stop monitoring its assigned downlinkPDCH when T3192 expires.

If the PCU has new data to transmit to the MS when receiving a “Packet DownlinkAck/Nack” message with FAI=1, the PCU must be able to establish a new downlinkTBF through the assigned PDCH, so the allocator must be able to allocate blockson this PDCH until T3192 expires. Sending a “Packet Downlink Assignment” ora “Packet Timeslot Reconfigure” on PACCH (see [R8]) does this establishment.



StopT3191

StartT3191MS PCU

TBFrelease

TBFrelease

StartT3192

StartT3193

PDTCH (FBI=1)

PACKET DOWNLINK ACK/NACK (FAI=0)

PDTCH (FBI=0)

PDTCH (FBI=0)

PDTCH (FBI=0)


Figure 2–12 Example of Downlink Release

2.4.4 Loss of communication procedures for downlink transfer

2.4.4.1 In the PCU

The PCU polls the mobile station by setting the S/P bit and providing a valid RRBPin RLC data blocks.

After sending a valid RRBP in a downlink RLC data block, if no RLC/MAC controlmessage is received in the specified block the counter N3105 is incremented. If avalid RLC/MAC control message is received the counter N3105 is reset.

If the counter N3105 reaches N3105max, the timer T3195 is started. If the timerT3195 expires the TFI resources are released.


PE/DCL/DD/0136411–9001–0136


2.4.4.2 In the MS

At the MS side, timer T3190 is used in order to detect a loss of communication indownlink transfer. T3190 is started each time the MS receives downlink resources(by “Packet Downlink Assign” or “Packet Control Acknowledgement”). It isreset each time a RLC/MAC data block is received or when new downlink resourcesare received.

When T3190 elapses, the MS shall consider that the communication is lost.



2.5 RLC/MAC features

2.5.1 Countdown Procedure

2.5.1.1 Algorithms

The mobile station will send the Countdown Value (CV) in each uplink RLC datablock to indicate to the network the absolute BSN (BSN’) of the last RLC data blockthat will be sent in the uplink TBF.

Consider this integer:

x = round [(TBC – BSN’ – 1) / NTS]

(The function round rounds upward to the nearest integer.)

Then:

CV = {x, if x � BS_CV_MAX 15, otherwise}

Where:

TBC = total number of RLC data blocks that will be transmitted in the TBF,

BSN’ = absolute block sequence number of the RLC data block, with range from0 to (TBC –1),

NTS = number of timeslots assigned to the uplink TBF, with range 1 to 8,

BS_CV_MAX is a parameter broadcast in the system information.

2.5.1.2 Countdown Procedure objective

This procedure is managed at the MS side and is only used for open–ended TBF.As uplink resources are allocated by allocation of bitmaps (one bitmap may contains24 blocks), to avoid wasting resources at the end of an uplink TBF when just fewblocks remain to be transmitted, a threshold is computed that permit to count downthe remaining blocks.

As soon as in the RLC buffer, the number of RLC blocks is below the thresholdNTS*bsCvMax, RLC/MAC can start the Countdown Procedure by sending CV= x to the allocator. Therefore, the allocator can optimize its resources bycalculating the number of blocks requested (it takes into account the BLERmeasurements in the cell) for ending the transfer. BsCvMax is the parameter, whichdetermines when the procedure can start (see Paragraph 3.2 Coutndown procedureparameters).


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2.5.1.3 Mechanism

Once the mobile station transmits a value other than 15, the mobile will not add anynew RLC data blocks to the TBF. Any data that arrives after the beginning of thecountdown procedure will be sent in a future TBF.

At the beginning of each allocation of an open–ended TBF, the MS shall eitherrequest to continue the TBF by transmitting a “Packet Resource Request”, or theMS shall begin the Countdown Procedure so that it ends within the currentallocation.

During the Countdown Procedure in RLC acknowledged mode, if re–emission ofRLC blocks is needed, the MS may obtain another bitmap to end the TBF. In thiscase, the PCU provides a new allocation without MS request. The MAC providesthis new allocation when the RLC detects this case.

2.5.2 Sliding Window

2.5.2.1 Sliding window objective

The Sliding Window procedure makes the RLC/MAC layer reliable. Thus in RLCacknowledged mode of operation, it defines the Backward Error Correctionenabling the selective retransmission of unsuccessfully delivered RLC/MACblocks.

Note those three parameters: upAckTime, maxNbrPUDWithoutVChange andT3198, are related to this procedure. These parameters have important impacts onGPRS network performances and so their value should be set very carefully(see Paragraph 3.10 Sliding window parameters).

2.5.2.2 Transmitter

Definitions

Firstly, here below is presented a short definition of important characteristics for theRLC endpoint transmitter in the Sliding Window procedure:

V(B): is an array of 128 elements indicating the acknowledgement status ofk = 64 previous RLC data blocks.

V(A): contains the BSN value of the oldest RLC data block that has not beenpositively acknowledged.

V(S): denotes the sequence number of the next RLC data block to be transmitted.

BSN: is set equal to the value of the send state variable V(S) and is 7 bits inlength.

NN0002: is a PCU Timer. It is a counter incremented each time V(A) does notchange on receipt of “Packet Ack/Nack” message. The counter NN0002 is resetwhen V(A) is changed. When the counter NN0002 reaches its maximum valuemaxNbrPUDWithoutVChange , the TBF is aborted.



T3198: is a mobile Timer. The MS shall set an instance of T3198 for each RLCdata block sent. It shall have the expiry value set to bsCvMax block periods.

PENDING_ACK: as each RLC data block transmitted, the correspondingelement in V(B) is set to the value PENDING_ACK before the reception of the“Packet Ack/Nack” message.

ACK: is the value of the elements acknowledged by the “Packet Ack/Nack”message.

NACKED: is the value of the elements not acknowledged by the “PacketAck/Nack” message.

INVALID: when an element in the V(B) array falls outside of the active transmitwindow, i.e. [V(A) 3 BSN 3 V(S)], the element will be set to the value INVALID.

STALL CONDITION: the mobile station will indicate a transmit window stallcondition when [V(S) = V(A) + k]. Upon detecting a transmit window stallcondition, the mobile station will set the Stall indicator (SI) bit in all uplinkRLC data blocks until the stall condition ceases to exist.

Description

In RLC acknowledged mode, RLC/MAC layer considered as a RLC endpointtransmitter has an associated acknowledge state array V(B) as it is described in theFigure 2–13.


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ACK

ACK

PENDING_ACK

NACKED

PENDING_ACK

NACKED

ACK

PENDING_ACK

NACKED

ACK

ACK

ACK

PDTCH(BSN = V(A))

PACKET ACK/NACK

Statevariableupdating

V (S)

V (A)

k

2

3

1

State arrayV(B)

Figure 2–13 Description of Sliding Window at a RLC endpoint transmitter

The values of V(B) are updated from the values received from its peer in thereceived block bitmap (RBB) of the “Packet Ack/Nack” message(see Figure 2–14).

On receipt of the “Packet Ack/Nack” message, the transmitter will first send theoldest RLC data block indexed relative to V(A).

Then:

If [V(S) < V(A) + k] modulo 128 and RLC data blocks have a correspondingelement in V(B) with the value NACKED, the oldest block with a correspondingelement set to NACKED will be transmitted and the corresponding element inV(B) will be set to the value PENDING_ACK.



If [V(S) < V (A) + k] modulo 128 and no RLC data blocks have a correspondingelement in V(B) with the value NACKED, the RLC data block with BSN indexedrelative to V(S) will be transmitted and the corresponding element in V(B) willbe set to the value PENDING_ACK.

If [V(S) = V(A) + k] modulo 128, the sending side will transmit the oldest RLCdata block whose corresponding element in V(B) has the value PENDING_ACK,then the next oldest RLC data block, etc. If all RLC data block whosecorresponding element in V(B) has the value PENDING_ACK has beentransmitted once, the process will be repeated beginning with the oldest RLCdata block. The process of transmitting the oldest RLC data blocks whose valuein V(B) has the value PENDING_ACK will continue until all RLC data blocksare acknowledged (or the counter NN0002 reachesmaxNbrPUDWithoutVChange at the PCU side).

If there are no further RLC data blocks available for transmission, the sendingside will transmit the oldest RLC data block whose corresponding element inV(B) has the value PENDING_ACK, then the next oldest block. If all RLC datablocks whose corresponding element in V(B) has the value PENDING_ACKhave been transmitted once, the process will be repeated beginning with theoldest RLC data block. The process is repeated until all RLC data blocks areacknowledged (or the counter NN0002 reaches maxNbrPUDWithoutVChangeat the PCU side).

2.5.2.3 Receiver

Definitions

Firstly, here below is presented a short definition of important characteristics for theRLC endpoint receiver in the Sliding Window procedure:

V(N): is an array of 128 elements indicating the receive status of k= 64 previousRLC data blocks.

V(R): denotes the BSN of the next RLC data block expected to be received.

V(Q): denotes the sequence number of the oldest RLC data block not wellreceived.

BSN: is set equal to the value of the send state variable V(S) and is 7 bits inlength.

NN0002: is a PCU Timer. It is a counter incremented each time V(Q) does notchange on receipt of “Packet Ack/Nack”. The counter NN0002 is reset whenV(Q) is changed. When the counter NN0002 reaches its maximum valueNN0002max, the TBF is aborted.

T3198: is a mobile Timer. The MS shall set an instance of T3198 for each RLCdata block sent. It shall have the expiry value set to BS_CV_MAX block periods.


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RECEIVED: is the value of the corresponding element in V(N) when a RLCdata block is received with BSN such that [V(Q) ≤ BSN ≤ V(R)] modulo 128.

SSN: is assigned the value of the receive state variable V(R) at the RLC receiver.

INVALID: when an element in the array V(N) falls outside of the active receivewindow, i.e. [V(Q) ≤ BSN ≤ V(N)], the element will be set to the value INVALID.

Description

In RLC acknowledged mode, RLC/MAC layer considered as a RLC endpointreceiver has an associated receive state array V(N) as it is described in theFigure 2–14.

RECEIVED

RECEIVED

RECEIVED

RECEIVED

RECEIVED

RECEIVED

RECEIVED

RECEIVED

RECEIVED

PDTCH

Statevariableupdating

V (R)

V (Q)

1

3

PACKET ACK/NACK

2

Figure 2–14 Description of Sliding Window at a RLC endpoint receiver



When an RLC data block is received with BSN such that [V(Q) ≤ BSN < V(R)]modulo 128, the corresponding element in V(N) is set to the value RECEIVED.

The “Packet Ack/Nack” message sent by the RLC endpoint receiver contains astarting sequence number (SSN) and a received block bitmap (RBB).

At the RLC transmitter, for each bit in the RBB whose corresponding BSN valueis within transmit window, if the bit contains the value 1, the correspondingelement in V(B) indexed relative to SSN will be set to the value ACKED.

If the bit contains the value 0 and if at the MS side the instance of timer T3198corresponding to BSN is expired, the element in V(B) will be set to the valueNACKED. If the bit contains the value 0 (and the instance of timer T3198 is notexpired at the MS side), the element in V(B) will not be modified. A bit within theRBB whose corresponding BSN is not within the transmit window, will beignored.

The RBB is assigned the k elements whose indices in the receive state array V(N)at the receiver range from [V(R) –1] modulo 128 to [V(R) – k] modulo 128. Foreach bit in the bitmap, the bit is assigned the value 1 if the corresponding elementin V(N) indexed to SSN has the value RECEIVED. The bit is assigned the value 0if the element in V(N) has the value INVALID.

When sending a “Packet Ack/Nack” message initiated by the RLC entity, if V(Q)has not been changed at the PCU side since the previous “Packet Ack/Nack”message was sent, then the counter NN0002 is incremented. If V(Q) has beenchanged since the previous “Packet Ack/Nack” message was sent the counterNN0002 is reset. When NN0002 reaches NN0002max at the PCU side, the PCUaborts the TBF.


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2.6 Reselection algorithms

The mobility within GPRS is managed at two different levels:

At network level, it is managed by the SGSN that determines the location of themobile.

At air interface level, the MS that makes the decision to move between cells.

2.6.1 Overview

Unlike GSM, there is no Handover procedure defined for GPRS. The transitionbetween cells is performed through Cell Reselection procedure.

Four modes are defined in GSM specifications:

NC0: Normal MS control. The MS shall perform autonomous cell reselection.

NC1: MS control with measurement reports. The MS shall send measurementreports to the network. The MS shall perform autonomous cell reselection.

NC2: Network control. The MS shall send measurement reports to the network.The MS shall not perform autonomous cell reselection.

RESET: the MS shall return to the broadcast parameters. Only sent on PCCCH orPACCH.

The parameter values NC1 and NC2 only apply in Ready State. In Standby State,the MS shall always use normal MS control.

2.6.2 Cell reselection in Ready state

Cell reselection is the same than for GSM using C2, with the same list of neighborcells and the same radio parameters. At least every 5 seconds, the MS shall calculatethe value of C1 and C2 for the serving cell and re–calculate C1 and C2 values fornon serving cells (if necessary). The MS shall then check whether:

The path loss criterion (C1) for current serving cell falls below zero for a periodof 5 seconds. This indicates that the path loss to the cell has become too high.

The calculated value of C2 for a non–serving suitable cell exceeds the value ofC2 for the serving cell for a period of 5 seconds, except:

• In the case of the new cell being in a different location area, or for a GPRS MSin a different routing area, or always for a GPRS MS in Ready State, the C2value for the new cell shall exceed the C2 value of the serving cell by at leastCELL_RESELECT_HYSTERESIS (dB) (defined by the BCCH data fromthe current serving cell) for a period of 5 seconds.

• In case of a cell reselection occurring within the previous 15 seconds, the C2value for the new cell shall exceed the C2 value of the serving cell by at least 5dB for a period of 5 seconds.



This indicates that it is a better cell.

In order to minimize the impact of the introduction of the GPRS in an existing GSMnetwork, it is recommended not to modify the current value ofCellReselectHysteresis used for voice (recommended value for urban area is 6 dB).

A high value would keep the link for a long time hence some communications wouldhave a high BLER due to an important load of the cell. The throughput would thendecrease because of the retransmission at RLC/MAC layer. On the other hand a lowvalue would ease the ”Cell Reselection ping–pong” in data mode.

When a reselection occurs, the MS terminates its TBF in the previous cell, executesa cell reselection, and establishes a new TBF in the new cell. Note that for themoment a cell reselection of a GSM cell for a GPRS MS is possible. So, in this case,the loss of buffered data is unavoidable, as the establishment of a new TBF in thenew cell is impossible.


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2.7 MS power control

2.7.1 Overview

Power control, only done in uplink, is important for spectrum efficiency as well asfor power consumption in a cellular system. For good spectrum efficiency, qualitybased power control is required. Power control for a packet oriented is morecomplicated than for a circuit switched connection, since there is no continuousconnection but an ON/OFF data traffic, where ON periods can be very short.

As for GSM, Power Control algorithm is implemented in the BSS with two maingoals:

Reduce the overall interference level.

Reduce the battery consumption at the mobile side.

The RF output power P to be used by the MS on each individual uplink PDCH is:

P = min {Γ0 − ΓCH – α* (C + 48), PMAX}

Where:

ΓCH is an MS and channel specific power control parameter, sent to the MS in anRLC/MAC control message.

Γ 0 = 39 dBm for GSM900

= 36 dBm for DCS1800

α is a system parameter, broadcast on PBCCH or optionally sent to MS in anRLC/MAC control message.

C is the normalized received signal level at the MS. It is mean of the receivedsignal level of the four normal bursts that compose the block.

PMAX is the maximum allowed output power in the cell, represented by thefollowing parameters:

• GPRS_MS_TXPWR_MAX_CCH if PBCCH exists,

• MS_TXPWR_MAX_CCH otherwise.

The α and ΓCH parameters are provided to the PCU by the BSC in the power controlparameters of the “TDMA Config Request” message of the Agprs OAM interface.

When the MS receives new ΓCH or α values, the MS shall use the new value toupdate P two radio blocks after the end of the last timeslot of the message blockcontaining the new value.

2.7.2 Open Loop Control

A pure open loop is achieved by setting α = 1 and keeping ΓCH constant in thecell. We take the BTS power reduction Pb, due to power control, equal to 0 sincethere is no downlink power control in Gate 2.



The output power will be:

P = min (Γ0 − ΓCH – C – 48, PMAX)

The value ΓCH is calculated by the PCU to achieve an uplink sensitivity with a fixeddownlink transmit power. The computation is done as follows to give a target valuefor the received signal, SSb = BtsSensitivity, at the BTS.

The received signal strength at the MS:

C = SSm = PBTS – Pb – L.

Where:

PBTS = BTS maximum output power on PDTCHs (as BTS power control is notimplemented in V12.4, PBTS = bsTxPwrMax on BCCH).

L = Path Loss.

Pb = 0.

Due to Pb = 0, the C value (normalized signal strength) is:

C = PBTS – L.

The MS output power is:

P = Γ0 – ΓCH – C – 48 = Γ0 – ΓCH – PBTS + L – 48.

The received signal strength at the BTS is:

SSb = P – L = Γ0 – ΓCH – PBTS – 48.

So, the constant value of ΓCH is:

ΓCH = Γ0 – PBTS – SSb – 48

Which can be written:

ΓCH = Γ0 – bsTxPowerMax – BtsSensitivity – 48

The ΓCH parameter is constant on a cell basis but computed by the PCU through theBSC parameter BtsSensitivity (OAM Agprs interface) which is the minimumpower needed for BTS decoding.


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2.8 DRX–mode

DRX (sleep mode) will be supported when the MS is in Packet Idle Mode. DRX isindependent from MM states Ready and Standby (see [R13]).

In DRX mode, during Packet Idle Mode, the MS shall only listen the paging blocksbelonging to the paging group (BS_PA_MFRMS).

During Transfer non–DRX mode period, the MS shall listen to all the CCCHchannels (see Figure 2–15). Thus, the establishment of a downlink TBF durationwill decrease if the downlink request is sent during the Transfer non–DRX modeperiod.

In each cell, the network defines an upper limit for the duration of the period innon–DRX mode to be applied by the MS following the transition from the PacketTransfer Mode to the Packet Idle Mode (see [R8]).

There are three cases when the MS shall enter non–DRX mode:

Upon transition from the Packet Transfer Mode to the Packet Idle Mode, an MSshall enter the Transfer non–DRX mode period. The duration of this period isdetermined by the minimum value of the NON_DRX_TIMER parameter,requested in the GPRS attach procedure, and the drxTimerMax parameter,broadcast in the cell.

When the mobile station receives a new value of the DRX_TIMER_MAXparameter, the mobile station is not required to consider the new value until the nexttime it enters Packet Idle Mode.

An MS, operating in NC2 mode, shall enter the NC2 non–DRX mode periodwhen it sends a NC measurement report. The duration of this period is defined bythe NC_NON_DRX_PERIOD parameter.

When initiating the GMM procedures for GPRS attach and routing area updateprocedures, the MS shall enter the GMM non–DRX mode period. This periodends when either the messages “GPRS Attach Accept”, “GPRS AttachReject”, “Routing Area Update Accept” or “Routing Area Update Reject”is received by the mobile station. This period also ends after timeout whenwaiting for any of these messages.

Otherwise, the MS may be in DRX mode.

To sum–up, MS remains in Transfer non–DRX mode period after any TBF is ended,during:

min (NON_DRX_TIMER, drxTimerMax [of the serving cell]

The MS in DRX mode has a DRX period, which is defined by the GSM parameters:BS_PA_MFRMS. Thus the paging group definition based on BS_PA_MFRMSshall be used.



The DRX period defined by BS_PA_MFRMS has an important impact on thedownlink TBF establishment.

The Gate 2 release of Nortel’s GPRS product does not support the non–DRX mode.

DRX mode Packet transfer mode Non–DRX mode DRX–mode

BS_PA_MFRMS

CCCH channelsbelonging to thepaging Group

All CCCHchannels

BS_PA_MFRMS BS_PA_MFRMS BS_PA_MFRMS BS_PA_MFRMS

CCCH channelsbelonging to thepaging Group

Figure 2–15 The occurrence of the CCCH channels


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2.9 Timing advance

The TAI defines the PTCCH sub–channel used by the MS for the continuous timingadvance.

The TAI is allocated by the PCU and the timing advance is computed by the BTS.

The MS sends an access burst in the assigned PTCCH (specified by the TAI). Thisburst is used by the BTS to compute the timing advance. The BTS updates the timingadvance values in the next TA–message following the access burst.

If the TAI and Timing advance timeslot are present in the assignment message, theMS shall immediately begin operation of the Continuous Timing Advanceprocedure at the point in time denoted by the TBF starting time if present, otherwiseafter the reaction time.

The TAI is coded on 4 bits, so on a Timing advance timeslot we can have a maximumof 16 MS.

The following table (see Figure 2–16) gives an example of the continuous timingadvance. Each row represents a 52–multiframe.

If present, the TBF_STARTING_TIME, given in the assignment message, definesthe frame number from which the MS is allowed to start the continuous timingadvance procedure.

The four access bursts is supported, so it means that for the first phase of thedownlink TBF establishment (on CCCH), the TAI is not provided by the allocator.The TAI is provided in the second phases of access in uplink and downlink.



B0

Uplink

B1 B2 0 B4 B5 B6 1 B7 B8 B9 2 B10 B11 B12 3

Downlink TA_message 1 TA_message 1

TAI = 0 TAI = 152–multiframe number n

B0 B1 B2 4 B4 B5 B6 5 B7 B8 B9 6 B10 B11 B12 7

TA_message 1 TA_message 1

TAI = 2 TAI = 352–multiframe number n+1

B0 B1 B2 8 B4 B5 B6 9 B7 B8 B9 10 B10 B11 B12 11



B0 B1 B2 12 B4 B5 B6 13 B7 B8 B9 14 B10 B11 B12 15



B0 B1 B2 16 B4 B5 B6 17 B7 B8 B9 18 B10 B11 B12 19



B0 B1 B2 20 B4 B5 B6 21 B7 B8 B9 22 B10 B11 B12 23



B0 B1 B2 24 B4 B5 B6 25 B7 B8 B9 26 B10 B11 B12 27



B0 B1 B2 28 B4 B5 B6 29 B7 B8 B9 30 B10 B11 B12 31



Uplink

Downlink

Uplink

Downlink

Uplink

Downlink

Uplink

Downlink

Uplink

Downlink

Uplink

Downlink

Uplink

Downlink

Figure 2–16 Example of continuous timing advance


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OMC–R algorithms parametersNortel Networks Confidential 3–1


3 OMC–R ALGORITHMS PARAMETERSFor each of the following parameters, the name, class, description, range and defaultvalues are given. When available, recommended values as well as engineering rulesare specified.

Parameters class definitions are given below:

Class 0: Class 0 attributes can only be set before the BSC application database isbuilt. The system is effectively reconfigured after the BSC database is built inresponse to a Built BDA command.

Class 1: Class 1 attributes can only be set when the related BSC object is locked.

Class 2: Class 2 attributes can only be set when the object is locked and the parentBSC object is unlocked.

Class 3: Class 3 attributes can only be set when the parent BSC object isunlocked. The system is immediately reconfigured and there is no impact on thesystem operations.

3.1 Call establishment parameters

maxDwAssign Class 3 (gprsBtsExtendedConf) V12

Description : Maximum number of Immediate Assignment Downlinkmessages per second. Used to configure signaling block.

Range value : [1 to 49]Object : bts

Type : DP , Optimization

Default value : 8

Recommended value : Simulation (8)

Comments : In uplink, maxDwAssign blocks per second are reservedfor Packet Control Acknowledgement messages and, indownlink, maxDwAssign blocks per second are reservedfor Packet Downlink Assignment messages.

maxNbrPDAAssig Class 2 (gprsTranscvLockExtendedConf) V12

Description : Maximum number of repetition of Packet DownlinkAssignment message

Range value : [1 to 10]Object : transceiver

OMC–R algorithms parameters Nortel Networks Confidential3–2

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Default value : 5

maxRach Class 3 V12

Description : Maximum number of RACHs (Random Access Channel)accepted by the PCU per second (only considered foruplink transfer)

Range value : [0 to 49] blocks

Object : bts

Default value : 0

Recommended value : 15

Engineering Rules : The higher the maxRach the higher the number ofChannel Request per second is accepted, with a risk ofPCU overload.

Besides, if maxRach is too low, the establishment timemay be increased.



MS PCU

MAXRACHfilter

RACH (CCCH)

IMM. ASSIGN.

P.RESOUR. REQ.

P. UL. ASSIGN.

Figure 3–1 maxRach part on the Uplink Establishment Transfer

Comments : *In uplink, 16 blocks per second are reserved for PacketResoure Request messages while, in downlink, up tomaxRach blocks can be allocated for Packet UplinkAssignment messages (empty or pre–reserved blocks forPacket Uplink Assignment messages but unused).

**Only values between 0 and 15 will be considered. Ifgreater then 15 is taken into account.

***The load (traffic in uplink) and the radio conditions(BLER) in the cell must be evaluated in order to estimatethis value.

Moreover, the correlation with several parameters must betaken into account. Indeed after the expiration of manycounters and timers, an abnormal release with randomaccess is performed. Therefore, if one of these parametersis under–estimated, the RACH access will often be usedand maxRach must increase.


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reserved3 (T3168) Class 3 (gprsBtsExtendedConf) V12

Description : Wait for the reception of the uplink assignment aftersending a Packet Resource Request message.

This T3168 timer is used on the MS side to define when tostop waiting for Packet Uplink Assignment message aftersending a packet resource request message.



Default value : 5

Recommended value : See Engineering Rules

Engineering Rules : The radio conditions (BLER for signalling messages) mustbe taken into account to set the value of the timer.

• For very good radio conditions: BLER (for signallingblocks) < 2%, à T3168 = 0.5 s

• For good radio conditions: 2% < BLER (for signallingblocks) < 5%, à T3168 = 1 s

• For bad radio conditions: 5% < BLER (for signallingblocks) < 10%, à T3168 = 2 s

Comments : It corresponds to parameters gprsTimerWaitPUAM.

Values from 0 to 7 correspond to (in milliseconds):

• 0 = 500,

• 1 = 1000,

• 2 = 1500,

• 3 = 2000,

• 4 = 2500,

• 5 = 3000,

• 6 = 3500,

• 7 = 4000.

T3172 Class 3 (gprsBtsExtendedConf) V12

Description : Value of the timer started by the mobile on reception of aPacket Access Reject message (in seconds)

Range value : [1 to 255]



Object : bts

Default value : 5


Comments : Packed Access Rejected messages are not managed yet.


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3.2 Countdown procedure parameters

bsCvMax Class 3 V12

Description : Number of packets left to transmit from which the MScounts those packets


Object : bts

Default value : 1

Recommended value : >10

Engineering Rules : Used by the PCU for the resources allocation management.

Timer T3198 on the MS side shall have the expiry value setto bsCvMax block periods.

This timer is started each time the MS transmits a RLC datablock. At the expiration of it, the MS is allowed to acceptnegative acknowledgement for the RLC data block consid-ered.

• In one hand, the higher the value the lower theefficiency of the Sliding Window procedure.

• In the other hand, the lower the value, the higher the riskto waste bandwidth by re–transmitting blocks which donot have the time to be received by the PCU.

The delay propagation between the MS and the PCU hasto be evaluated to ensure that the value of the timer isgreater. According an R&D estimation, the round tripdelay is around 200 ms and so the delay between the BTSand the PCU is around 100 ms.

The timer T3198 shall have the expiry value set tobsCvMax blocks periods.

As a result, T3198 must be over 100 ms and bsCvMaxover 10.



3.3 Radio link failure parameters

maxNbrRLCEmptyBlock Class 2 (NN0001Max) V12

Description : Maximum number of consecutive RLC erroneous blocks


Object : transceiver


Default value : 10

N3105max Class 2 (gprsTranscvLockExtendedConf V12

Description : Maximum number of consecutive RLC data blocks sent byPCU with a valid RRBP and not having beenacknowledged by the MS




Default value : 4


Comments : The network shall increment counter N3105 for each radioblock, allocated to that mobile station with the RRBP field,for which no RLC/MAC control message is received. IfN3105 = N3105max, the network shall release the down-link TBF internally and start timer T3195 (defaultvalue=5s). When T3195 expires, the network may reusethe TFI.

panDec Class 3 (pan) V12

Description : Counters used in case of block acknowledgment time out.The MS’s counter N3102 is decremented by panDec eachtime the timer for packet uplink ack/nack expires.


Object : bts

Default value : 0


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Engineering Rules : The evolution of V(A) is directly linked to the BLER pres-ent in the Cell. Therefore, PAN values depend on the Cellload and on the Radio environment.

It is better to take a high panMax just as panInc value mustbe bigger than panDec value in order to avoid the accesson CCCH and on BCCH.

The following proposition: panInc = 2*panDec can beconsidered.

Comments : At each cell reselection the mobile station shall set thecounter N3102 to the value defined by the optional broad-cast parameter panMax. Whenever the mobile stationreceives a Packet Ack/Nack that allows the advancementof V(S), the mobile station shall increment N3102 by thebroadcast value panInc, however N3102 shall neverexceed the value panMax. Each time T3182 (defaultvalue=5s) expires the mobile station shall decrementN3102 by the broadcast value panDec. When N3102 =<0is reached, the mobile station shall perform an abnormalrelease with cell reselection.

panInc Class 3 (pan) V12

Description : Counters used in case of block acknowledgment time out.The MS’s counter N3102 is incremented by panInc eachtime a packet uplink acknowledgment which allow thetransmit window to go forward, has been received.


Object : bts




Engineering Rules : The evolution of V(A) is directly linked to the BLER pres-ent in the Cell. Therefore, PAN values depend on the Cellload and on the Radio environment




panMax Class 3 (pan) V12

Description : Counters used in case of block acknowledgment time out.Maximum value of the counter N3102 set by the mobile ateach cell reselection.


Default value : 0


Engineering Rules : The evolution of V(A) is directly linked to the BLER in theCell. Therefore, PAN values depend on the Cell load andon the Radio environment.


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3.4 Cell selection and reselection parameters

cellReselectHysteresis Class 3C3

Description : Hysteresis to reselect towards cell with different LocationArea

Range value : [0 to 14, by steps of 2] dB

Object : bts

Default value : 6


Recommended value : 4 dB (rural), 6 dB (urban)

Engineering Rules : A high value prevents the MS from making frequent loca-tion updates and may also prevent an MS from performingadequate location updates, thus risking not receiving calls.The level variation of the signal is more important in anurban context, so a higher value of hysteresis should be set.To avoid frequent location updates, there is also a timerforbidding the reselection of the previous server cell. Fora reselection with change of location area, the value is 15seconds (GSM recommendation).

Comments : This is a GSM parameter.

gprsCellActivation Class 3 V12

Description : Flag used to activate the GPRS at cell level (to allow theGPRS MSs to access)

Range value : [disabled / enabled]Default value : disabled

Recommended value : enabled


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gprsPermittedAccess Class 3 V12

Description : It defines the Routing Area Color of the cell. If the mobilestation revecives different values of the RA COLOURfield from different cells, the mobile station must interpretthe cell re–selection information as if the two cellsbelonged to different routing aeras.


Default value : 0

Recommended value : Not Applicable



3.5 DRX mode parameters

drxTimerMax Class 3 V12

Description : Maximum value allowed for mobile stations to requestnon–DRX mode after packet transfer mode

Range value : [0 to 7] seconds

Object : bts

Default value : 0 s


Engineering Rules : After the transfer mode, the mobile remains in non DRXmode during min (NON_DRX_TIMER, drxTimerMax).The recommended value set to 7 (maximum value) meansthat the value taken into account will be the mobile’s one(NON_DRX_TIMER).

Comments : Before V12.4c, the mobile directly switch to DRX modeafter leaving the transfer mode.


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3.6 Power control parameters

btsSensitivity Class 3 V12

Description : Minimum power needed for BTS decoding. Thisparameter has an influence on the power control efficiency.


Default value : 0

Recommended value : 25 (see Manual Manual < 36 > BSS Parameter User Guide)

Engineering Rules : The power control algorithm used is Open Loop Control.

A pure open loop is achieved by setting α = 1 and keepingΓCH constant.

The constant value of ΓCH is:

ΓCH = Γ0 – PBTS – BtsSensitivity + 48

where PBTS is is the BTS transmit power on PDTCH. Sincedownlink power control is not implemented yet, PBTS isequal to bsTxPwrMax.

According to the GPRS Engineering test plan, the lowestthe amplitude of the signal is, the highest the BER is.

The sensitivity of BTS is mainly impacted by:

• Ambient noise (urban noise due to cars, other radiosystems,..)

• Internal noise of the BTS, and its noise factor

• Modulation bandwidth of the radio signal (in GSM it is271 kHz)

• C/I environment, and Rayleigh’s fading

Normally, since the radio modulation and coding are thesame for GSM and GPRS, the sensitivity of the BTSshould not vary.

Measurements have already been performed, and they allshowed a sensitivity (S8000) (with particular conditions)of –110 dBm.



However, they do not have any consequences on the Bts.They are used by the PCU to calculate ΓCH. Then ΓCH isforward to the MS and it allows the MS to calculate its out-put power (See Figure 3–2 below). Thus with ΓCH the MScan calculate its output power.

Comments : The value x set on the OMC–R MMI corresponds to–x dBm.

BSC

PCUMS

P

BTS

BtsSensitivityMaxBsTransmitPower

Γ CH ( BtsSensitivity,MaxBsTransmitPower)

1

23

Figure 3–2 Parameters of MS Output Power.

According to a RF study, the following results can be con-sidered:

• Low ΓCH values mean little or No Power Control

• Medium ΓCH values mean Power Control at high signal

• High ΓCH values mean lots of Power Control

nAvgl Class 3 (gprsAvgParam) V12

Description : Signal strength filter used for MS output power control

It specifies the “interference signal strength filter” constantfor power control.


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Default value : 0

nAvgT Class 3 (gprsAvgParam) V12


It specifies the “signal strength filter period” for powercontrol in packet transfer mode.


Default value : 0


Engineering Rules : The used power control algorithm is Open Loop Control.

In packet idle mode, the MS measures its own paginggroup on PPCH. It does measurements per nAvgW multi-frames and continuously updates C. Meanwhile, the BSSmeasures the interference of the PDCHs, which are candi-dates for the transfer phase. The BSS continuously updatesthe ΓCH values (see Figure 3–3) to be used for the firsttransfer period of nAvgT multiframes. This is transferredto the MS in the PACKET UPLINK ASSIGNMENT.

In packet transfer mode, the MS measures all RLCblocks on the PDCH carrying the PACCH and filters theobtained CBLOCK. The MS updates the C value everynAvgT multiframes. The BSS measures all RLC blocks onthe used PDCH. The BSS updates the MS specific ΓCH val-ues and transfers them to the MS when needed (i. e. whenthe interference level has changed). The BSS updates theΓCHvalue every nAvgT multiframes if necessary(see Figure 3–4).

• The smaller the periods the higher the flexibility for thePower Control.

• However important period smoothes the output powerfrom the MS. A too strong variation of power maycreate interference.

Comments : The propose recommended value is to optimize uplinkpower control algorithm for Mitsubishi mobiles.



MS uses Pa MS uses Pb MS uses Pc

Non transfer phase

Ca Cb Cc CdCj’Ci’

Transfer phase

T AVG_W T AVG_W T AVG_T T AVG_T T AVG_T

Cd

Figure 3–3 Traffic example of uplink power control

nAvgW Class 3 (gprsAvgParam) V12


It specifies the “signal stength filter period” for powercontrol in packet idle mode.


Default value : 0


Engineering Rules : The used power control algorithm is Open Loop Control.

In packet idle mode, the MS measures its own paginggroup on PPCH. It does measurements per nAvgW multi-frames and continuously updates C. Meanwhile, the BSSmeasures the interference of the PDCHs, which are candi-dates for the transfer phase. The BSS continuously updatesthe ΓCH values (see Figure 3–3) to be used for the firsttransfer period of nAvgT multiframes. This is transferredto the MS in the PACKET UPLINK ASSIGNMENT.

In packet transfer mode, the MS measures all RLCblocks on the PDCH carrying the PACCH and filters theobtained Cblock. The MS updates the C value every nAvgTmultiframes. The BSS measures all RLC blocks on theused PDCH. The BSS updates the MS specific ΓCH valuesand transfers them to the MS when needed (i. e. when the


PE/DCL/DD/0136411–9001–0136


interference level has changed). The BSS updates theΓCHvalue every nAvgT multiframes if necessary (seeFigure 3–4).

• The smaller the periods the higher the flexibility for thePower Control.

• However important period smoothes the output powerfrom the MS. A too strong variation of power maycreate interference.

Comments : The propose recommended value is to optimize uplinkpower control algorithm for Mitsubishi mobiles.

MS uses Pa MS uses Pb MS uses Pc

Non transfer phase

Ca Cb Cc CdCj’Ci’

Transfer phase

T AVG_W T AVG_W T AVG_T T AVG_T T AVG_T

Cd

Figure 3–4 Traffic example of uplink power control



3.7 Timeslot sharing parameters

channelType Class 2 C4

Description : Type of logical channel supported by a radio time slot

Range value : [tCHFull (traffic) / sDCCH (traffic) / mainBCCH /mainBCCHCombined (with SDCCH) /bcchSdcch4CBCH / sdcch8CBCH / cCH (V12) /pDTCH (V12)]

Object : channel

Default value : None


Recommended value : pDTCH

gprsPreemption Class 3 (gprsBtsExtendedConf) V12

Description : Allows the Cell to refuse the GSM preemption if the GPRSresources are not sufficient to the minimum of Bandwidthshare for each MS.

Range value : [yes / no]Object : bts


Default value : False

Comments : No recommended value is specified since it this parameterdepends on the resources dimensioning strategy.

gprsPreemptionProtection Class 3 (gprsBtsExtendedConf) V12

Description : Protection timer used by the BSC in order to reduce theload in case of PCU TDMA TS status NACK messagereception during a preemption procedure. This message issent by the PCU

Range value : [1 to 60] second(s)Object : bts

Default value : 10



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gprsPriority Class 2 (gprsTranscvLockExtendedConf) V12

Description : Priorities that can be affected to the TDMA

Range value : [p1 / p2]Object : transceiver

Default value : p1


Comments : Only 1 GPRS TDMA until drop 1.3 at least.

No recommended value is specified since it this parameterdepends on the resources dimensioning strategy.

minNbrGprsTs Class 3 (gprsBtsExtendedConf) V12

Description : Minimum number of TS dedicated to GPRS in your cell


Default value : 0

Comments : It ensures a minimum of GPRS timeslots in the Cell.

No recommended value is specified since it this parameterdepends on the resources dimensioning strategy.

msCapWeightActive Class 2 V12

Description : It specifies whether the Weight Fair Allocation algorithmis actived or not

Range value : [yes / no]Object : bts

Default value : yes

Recommended value : yes

radioAllocator Class 2 V12

Description : radio allocator type used in the cell

Range value : [voice + dataCircuit, voice + dataCircuit + packetData]



Object : bts

Default value : voice + dataCircuit


Recommended value : voice + dataCircuit + packetData


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3.8 Dual–band cell parameters

btsSensitivityInnerZone Class 3 (gprsBtsExtendedConf) V12

Description : Minimum power needed for BTS decoding in the innerzone of a dual–band cell


Object : bts

Default value : 0



Engineering Rules : This parameter should be set according to GSM dual–bandcell parameters (see Manual < 36 > BSS Parameter UserGuide).

Comments : The value x set on the OMC–R MMI corresponds to–110+x dBm.

maxBsTransmitPowerInnerZone Class 3 (gprsBtsExtendedConf) V12

Description : Maximum level of BTS transmission power in the innerzone of a dual–band cell


Default value : 10



Engineering Rules : This parameter should be set according to GSM dual–bandcell parameters (see Manual < 36 > BSS Parameter UserGuide).

Comments : The value x set on the OMC–R MMI corresponds to–110+x dBm.



3.9 TDMA selection parameters

codingScheme Class 2 V12

Description : Channel coding scheme that the Mobile Station shall usewhen transmitting data on the uplink

Range value : [cs1, cs2]


Default value : cs1

Recommended value : cs2

Engineering Rules : It has a direct impact on the RLC/MAC throughput. In factcs1 is better than cs2 to convey RLC blocks in a reliableway. However in a good radio conditions cs2 provide ahigher throughput than cs1.

• Using cs1, whatever the profile considered, BLER willnot exceed 6% on the whole region already coveredwith acceptable voice quality.

• Using cs2, whatever profile considered, it will be verydifficult on certain cells / regions to ensure GPRScoverage with acceptable user throughput, as maximumBLER will exceed 10%.

Percentage of area covered with acceptable BLER:

• Using cs1, whatever profile considered, acceptableBLER can be offered on a large part of the region (morethan 92% covered with BLER better than 0.1).

• Using cs2, whatever profile considered, some areas willsuffer from very high BLER and then limitedthroughput (typically GPRS calls at cell boundaries).


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3.10 Sliding window parameters

dwAckTime Class3 (packetAckTime) V12

Description : Time (multiple of 20 ms) defining the period for theacknowledgments for downlink transfers



Default value : For 1+1 mobiles, one block per ”bitmap” (every 24 blocks)is reserved for Packet downlink acknolewdgement. Twoblocks per “bitmap” are reserved for other mobiles.

Type : DP

maxNbrPUDWithoutVchange Class 2 (NN0002Max) gprsTransvLockExtendedConf V12

Description : Maximum number of PACKET UPLINK (resp.DOWNLINK) ACK/NACK consecutively sent (resp.received) without V(R) (resp. V(Q)) is changed.




Default value : 10


Comments : Recommended value comes from trials results.

N3103Max Class 3 (gprsBtsExtendedConf) V12

Description : Maximum number of repetition of a Packet UplinkAck/Nack message


Object : bts

Default value : 0




upAckTime Class3 (packetAckTime) V12

Description : Time (multiple of 20 ms) defining the period for theacknowledgments for uplink transfers



Default value : 1

Type : DP


Engineering Rules : Values can be set between 2 and 23, which means uplinkacknowledgements are sent at most 1 block out of 2 and atleast once per bitmap.


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3.11 Block allocation parameters

blockErrorRate Class 3 (allocBitmap) V12

Description : Block error rate in the cell used by the PCU to buildallocation bitmap. This parameter is used to estimate thenumber of blocks to add in the bitmap allocation (for closeended TBF) due to retransmission caused by degradedradio conditions.

Range value : [0 to 127] blocks [0, 100]%Object : transceiver


Default value : 0

Recommended value : 24, Engineering rule (10)

Engineering Rules : This parameter should be set according to the radio charac-teristics of the considered cell.

maxSize Class 3 (allocBitmap)

Description : Maximum size of the allocation bitmap provided to the MS





Engineering Rules : In one hand, the higher the size of the bitmap the higher theconnection establishment duration (a channel request hasto wait at least one bitmap size before being introduced inthe next bitmap).



Bitmap current:Bitmap i

Bitmap fixed:Bitmap i+1

Bitmap in changing:Bitmap i+2

Request TBF

Resources allocated

Figure 3–5 Impact of AllocBitmap on TBF Establishment duration

On the other hand, the smaller the bitmap size the lower thethroughput (a new bitmap has to be requested more often).

So a trade–off has to be found between the connectionestablishment duration and the throughput.

Comments : For V12.4a&b, the bitmap size is fixed and equal to 24.

maxDnTbfPerTs Class 3 (gprsBtsExtendedConf) V12

Description : Maximum number of downlink TBF per TDMA on atimeslot basis


Default value : 8



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maxUpTbfPerTs Class 3 V12

Description : Maximum number of uplink TBF per TDMA on a timeslotbasis


Object : bts

Default value : 8




3.12 Other access network parameters

bscGprsActivation Class 3 V12

Description : Flag used to activate the GPRS at BSC level

Range value : [disabled / enabled]Default value : disabled

Recommended value : enabled

longTbfLossThroughput Class 3 (gprsBtsExtendedConf) V12

Description : Loss of throughput for long TBF in percentage of allocatedbandwidth. Prioritize normal transfer over long datatransfer.

Range value : [1 to 100] in %Object : bts


Default value : 0

longTbfSizeThreshold Class 3 (gprsBtsExtendedConf) V12

Description : Threshold for long TBF size, in Kbytes. This parameter isused in the functionality which penalize long TBF.



Default value : 100

reserved4 (T3192) Class 3 (gprsBtsExtentedConf) V12

Description : Wait for release of the TBF after reception of the finalblock.

This timer T3192 is used on the Mobile Station side todefine when the Mobile Station has received all the RLCdata blocks. When the timer expires the Mobile Stationreleases the resources associated with the TBF and beginsto monitor its paging.



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Object : bts


Default value : 5

Engineering Rules : In one hand the higher the value set to this timer, the higherthe risk of Blocking Rate due to the fact that the MS keepsits TFI and it remains on the TS allocated.

On the other hand, the higher the value set to this timer, thelower the risk of the establishment using access on CCCH.Therefore it can decreases the load on CCCH and also theestablishment time.

The value of this timer has to take into account the kind oftraffic in the cell. Therefore the typical call profiles in thecell has to be considered. Indeed it is worth to set an impor-tant value only if the downlink traffic pattern is consistingof successive ON periods with a short mean delay betweentwo ON periods.

Comments : This parameter corresponds to parameters gprsTimer-WaitRLC. Values from 0 to 7 correspond to (inmilliseconds):

• 0 = 500,

• 1 = 1000,

• 2 = 1500,

• 3 = 2000,

• 4 = 2500,

• 5 = 3000,

• 6 = 3500,

• 7 = 4000.



3.13 Reserved parameters

dLPwrValue Class 3 V12

Description : Attribute reserved for future use

Range value : [0 to 3] corresponding to 0 to 6 dB/8 to 14 dB/16 to22 dB/24 to 30 dBm


Default value : 0

maxDnTbfP1P2Threshold Class 3 (gprsBtsExtendedConf) V12



Default value : 16

maxUpTbfP1P2Threshold Class 3 (gprsBtsExtendedConf) V12



Default value : 16

nbrFreeTchBeforeAnticipation (gprsBtsExtendedConf) Class 3 V12


Range value : [0]Object : bts

Comments : It is part of gprsBtsExtendedConf.

nbrFreeTchToEndAnticipation Class 3 V12


Range value : [0]Object : bts

Comments : It is part of gprsBtsExtendedConf.


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speechOnHoppingTs Class 3 (gprsBtsExtendedConf) V12


Range value : [true, false]Object : bts

Default value : false

PCUSN OAM algorithm parametersNortel Networks Confidential 4–1


4 PCUSN OAM ALGORITHM PARAMETERSIn this chapter are listed the parameters related to PCUSN and, more precisely, tothe Gb interface. Those parameters are managed by the PCUSN OAM.

The criticity field indicates the impact of a parameter setting change on the networkservice. If the field criticity is equal to None, then the parameter value update isdynamic and no service interruption is undergone.

4.1 Network service parameters

nsAliveRetries (GprsNsProv) V12

Description : This attribute specifies the times the NS–ALIVE messagecan be retried if NS–ALIVE ACK is not received beforethe nsAliveTimer expires.


Default value : 10

Criticity : None

nsAliveTimer (GprsNsProv) V12

Description : This attributes specifies the timer to guard the NetworkService Virtual Connection (NS–VC) ALIVE procedure.This the time intervall between an NS–ALIVE andNS–ALIVE ACK.


Default value : 3

Criticity : None

Engineering Rules : The timer must be provisioned to a value that is greaterthan the maximum expected round trip delay of a ProtocolData Unit (PDU). The default value is the one provided inthe GPRS specifications.

PCUSN OAM algorithm parameters Nortel Networks Confidential4–2

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nsBlockRetries (GprsNsProv) V12

Description : This attributes specifies the number of times theNS–BLOCK message can be retried if NS–BLOCK ACKis not received before nsBlockTimer expires.


Default value : 3

Criticity : None

nsBlockTimer (GprsNsProv) V12

Description : This attributes specifies the timer to guard the NetworkService Virtual Connection (NS–VC) BLOCK andUNBLOCK procedures. This the time intervall between anNS–BLOCK and NS–BLOCK ACK, or between anNS–UNBLOCK and NS–UNBLOCK ACK.


Default value : 3

Criticity : None

Engineering Rules : The timer must be provisioned to a value that is greaterthan the maximum expected round trip delay of a ProtocolData Unit (PDU). The default value is the one provided inthe GPRS specifications.

nsResetRetries (GprsNsProv) V12

Description : This attribute specifies the times the NS–RESET messagecan be retried if NS–RESET ACK is not received beforethe nsResetTimer expires.


Default value : 5

Criticity : None



nsResetTimer (GprsNsProv) V12

Description : This attributes specifies the timer to guard the NetworkService Virtual Connection (NS–VC) RESET procedure.This is the time intervalle between an NS–RESET andNS–RESET ACK

Range value : [1 to 120] secondsDefault value : 3

Criticity : NoneEngineering Rules : The timer must be provisioned to a value that is greater

than the maximum expected round trip delay of a ProtocolData Unit (PDU). The default value is the one provided inthe GPRS specifications.

nsTestTimer (GprsNsProv) V12

Description : This attribute specifies the periodicity of the NetworkService Virtual Connection (NS–VC) TEST procedurewhich is the initiation of the NS–ALIVE Protocol DataUnit.


Criticity : NoneEngineering Rules : The range is the value provided in the GPRS

specifications. Increasing the timer value results in longertime before the test procedure is re to executed, whichmeans the NS–VC could be dead but the software mightfind it out late. They could be a loss of packets.

nsUnblockRetries (GprsNsProv) V12

Description : This attributes specifies the number of times theNS–UNBLOCK message can be retried ifNS–UNBLOCK ACK is not received beforensBlockTimer expires.

Range value : [3 to 15]Default value : 3

Criticity : None


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resumeRetries (GprsPcBssgpProv) V12

Description : This attribute specifies the maximum number of times thePacket Control Unit (PCU) can send the RESUME PDUin case a RESUME ACK is not received before theresumeTimer expires.


Default value : 3

Criticity : None

resumeTimer (GprsPcBssgpProv) V12

Description : This attribute specifies the timer to guard the RESUMEprocedure. The Packet Control Unit (PCU) sends aRESUME Protocol Data Unit (PDU) to the Serving GPRSSupport Node (SGSN) and starts the resumeTimer. ThePCU stops the timer upon reception of a RESUME–ACK(NACK) PDU from the SGSN. If the timer expires, thePCU retries the RESUME procedure.


Default value : 5

Criticity : NoneEngineering Rules : The range is the value provided in the GPRS specification.

The timer must be provisioned to a value that is greaterthan the maximum expected round trip delay of a ProtocolData Unit (PDU).



4.2 BSSGP parameters

bvcBlockRetries (GprsPcBssgpProv) V12

Description : This attributes specifies the maximum number of times thePacket Control Unit (PCU) can send the BVC–BLOCKProtocol Data Unit (PDU) in case a BVC–BLOCK ACKis not received before the bvcBlockUnblockTimerexpires.


Criticity : None

bvcBlockUnblockTimer (GprsPcBssgpProv) V12

Description : This attribute specifies the timer to guard the blocking andunblocking procedures. The Packet Control Unit (PCU)sends a BVC–BLOCK (UNBLOCK) Protocol Data Unit(PDU) to the serving GPRS Support Node (SGSN) andstarts the bvcBlockUnblockTimer. The PCU stops thetimer upon reception of a BVC–BLOCK (UNBLOCK)ACK PDU from the SGSN. If the timer expires, the PCUretries the BVC–BLOCK (UNBLOCK) procedure.



than the maximum expected round trip delay of a ProtocolData Unit (PDU).

bvcResetReqRetries (GprsPcBssgpProv) V12

Description : This attributes specifies the maximum number of times thePacket Control Unit (PCU) can send the BVC–RESETProtocol Data Unit (PDU) in case a BVC–RESET ACK isnot received before the BvcResetReqTimer expires.



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Criticity : None


Engineering Rules : If BvcResetReqRetries is set to 5, the time for the distantto send to send the BVC–RESET ACK will be (5+1) *10= 60 seconds, which according to IOT tests, is enough.

bvcResetReqTimer (GprsPcBssgpProv) V12

Description : This attribute specifies the timer to guard theBVC–RESET procedures. The Packet Control Unit (PCU)sends a BVC–RESET Protocol Data Unit (PDU) to theserving GPRS Support Node (SGSN) and starts thebvcResetReqTimer for a BVC. The PCU stops the timerupon reception of a BVC–RESET ACK PDU from theSGSN. If the timer expires, the PCU retries theBVC–RESET procedure.


Default value : 60

Criticity : None

Engineering Rules : The timer must be provisioned to a value that is greaterthan the maximum expected round trip delay of a ProtocolData Unit (PDU).

bvcUnblockRetries (GprsPcBssgpProv) V12

Description : This attributes specifies the maximum number of times thePacket Control Unit (PCU) can send theBVC–UNBLOCK Protocol Data Unit (PDU) in case aBVC–UNBLOCK ACK is not received before thebvcBlockUnblockTimer expires.


Default value : 3

Criticity : None



flowControlMaxRate (GprsPcBssgpProv) V12

Description : This attribute specifies the minimum interval betweensending consecutive Flow Control PDU for a given BSSGPRS Virtual Connection (BVC) or for a Mobile Station(MS).

Range value : [100 to 10000] milliseconds

Default value : 1000

Criticity : NoneEngineering Rules : Changing the value can affect the flow control function at

the PCU level with the Logical Link Control (LLC) framesdiscarded due to overflow of the MS or BVC buckets.

Comments : This parameter should be lower thanmsFlowControlThTimer (see SGSN parameter).

msFlowCntlBucketSize (GprsPcBssgpProv) V12

Description : This attribute specifies the Mobile Station (MS) maximumbucket size.

Range value : [0 to 655355] *100 bits/s

Default value : 90

Criticity : None


Engineering Rules : The default value assumes 6 Logical Link Control (LLC)frames in the bucket. The unit is 100 bit/s. A recommendedvalue for the maximum size of the bucket would be 320,based on the waiting factor of 30 seconds and consideringthat if data are older than 30 seconds, they become useless.The higher the value, the more CPU load is saved.


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raCapabilityUpRetries (GprsPcBssgpProv) V12

Description : This attributes specifies the maximum number of times thePacket Control Unit (PCU) can send theRA–CAPABILITY–UPDATE Protocol Data Unit (PDU)in case a RA–CAPABILITY–UPDATE ACK is notreceived before the raCapabilityUpTimer expires.


Criticity : None

raCapabilityUpTimer (GprsPcBssgpProv) V12

Description : This attribute specifies the timer to guard theRA–CAPABILITY–UPDATE procedure. When thePacket Control Unit (PCU) sends aRA–CAPABILITY–UPDATE Protocol Data Unit (PDU)to the serving GPRS Support Node (SGSN) and starts theraCapabilityUpTimer. The PCU stops the timer uponreception of a RA–CAPABILITY–UPDATE ACK PDUfrom the SGSN. If the timer expires, the PCU retries theRA–CAPABILITY–UPDATE procedure.




resumeRetries (GprsPcBssgpProv) V12

Description : This attribute specifies the maximum number of times thePacket Control Unit (PCU) can send the RESUME PDUin case a RESUME ACK is not received before theresumeTimer expires.


Criticity : None



resumeTimer (GprsPcBssgpProv) V12

Description : This attribute specifies the timer to guard the RESUMEprocedure. The Packet Control Unit (PCU) sends aRESUME Protocol Data Unit (PDU) to the Serving GPRSSupport Node (SGSN) and starts the resumeTimer. ThePCU stops the timer upon reception of a RESUME–ACK(NACK) PDU from the SGSN. If the timer expires, thePCU retries the RESUME procedure.


Default value : 5

Criticity : None

Engineering Rules : The range is the value provided in the GPRS specification.The timer must be provisioned to a value that is greaterthan the maximum expected round trip delay of a ProtocolData Unit (PDU).

suspendRetries (GprsPcBssgpProv) V12

Description : This attributes specifies the maximum number of times thePacket Control Unit (PCU) can send the SUSPENDProtocol Data Unit (PDU) in case a SUSPEND ACK is notreceived before the suspendTimer expires.


Default value : 3

Criticity : None

suspendTimer (GprsPcBssgpProv) V12

Description : This attribute specifies the timer to guard the SUSPENDprocedures. The Packet Control Unit (PCU) sends aSUSPEND Protocol Data Unit (PDU) to the serving GPRSSupport Node (SGSN) and starts the suspendTimer. ThePCU stops the timer upon reception of a SUSPEND ACK(NACK) PDU from the SGSN. If the timer expires, thePCU retries the SUSPEND procedure.



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Default value : 5



tsFlowCntlBucketSize (tsBmax) (GprsPcBssgpProv) V12

Description : This attribute specifies the maximum bucket size (Bmax)for a BSS GPRS Virtual Connection (BVC) Flow Controlprocedure. The value is the BVC Max Bucket size for aBVC with 1 time slot. The PCU calculates the actual BVCMax Bucket size for the configuration by multiplying thisprovisioned value by the number of time slot in the cell,dinamically given by the Base Station Controller (BSC).

Range value : [0 to 655355] *100 bytesDefault value : 200

Criticity : None


Engineering Rules : The default value has been estimated based on themsFlowCntlBucketSize default value, with 8 mobiles indownlink transfer. The unit is 100 bytes.

From V12.4c, tsFlowCntlBucketSize should be set tomsFlowCntlBucketSize * 8.

Before, tsFlowCntlBucketSize = msFlowCntlBucket-Size



tsLeakRate (GprsPcBssgpProv) V12

Description : This attribute specifies the leak rate parameter for a BVCwith 1 time slot. The PCU calculates the actualBVC leakrate for the configuraton, by multiplying the provisionedvalue by the number of time slots in the cells, dynamicallygiven by the BSC.

Range value : [0 to 655355] *100 bits/sDefault value : 100

Criticity : None

Engineering Rules : The default value assumes a CS1 mobile station, with athroughput of 10000 bit/s, with assumption that the flowis statiscally regular in the cell. The unit is 100 bit/s.


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4.3 Frame relay parameters

accounting (ac) (FrAtmDlciSpProv) V12

Description : This attribute allows the operator to control accounting forthis DLCI. To enable accounting data collection and recordgeneration, the value of this attribute must be onand at leastone of the accountCollection reasons in the FrAtm Cacomponent must be set.

Range value : [on / off]Default value : off

Criticity : None

committedBurstSize (bc) (FrAtmDlciSpProv) V12

Description : This attribute specifies the committed burst size (Bc). Itrepresents the amount of data that a network agrees totransfer under normal conditions over a measurementinterval when rate enforcement is in effect. Data markedDE=1 is not accounted for in the committed burst size.When rate enforcement is not in effect, this attribute isignored.

Range value : [0 to 50000000] bit


Criticity : NoneEngineering Rules : The committedInformationRate must have a value of 0

when rate enforcement is in effect and committedBurst-Size has a value of 0.



committedInformationRate (cir) (FrAtmDlciSpProv) V12

Description : This attribute specifies the committed information rate(CIR). It represents the rate at which the network agrees totransfer information under normal conditions when rateenforcement is in effect. When rate enforcement is not ineffect, this attribute is ignored. Determination of the actualCIR is based on committedInformationRate,committedBurstSize and a measurement interval. Themeasurement interval is determined internally whencommittedInformationRate has a non to zero value.Otherwise, it is based on measurementInterval which mustbe explicitly provisioned.

Range value : [0 to 50000000] bits/s


Criticity : None

Engineering Rules : The committedBurstSize must have a value of 0 whenrate enforcement is in effect and committedInformation-Rate has a value of 0.

excessBurstSize (be) (FrAtmDlciSpProv) V12

Description : This attribute specifies the excess burst size (Be). Itrepresents the amount of uncommitted data that thenetwork will attempt to deliver over a measurementinterval when rate enforcement is in effect. Data markedDE=1 by the user or by the network is accounted for here.committedInformationRate, committedBurstSize, andexcessBurstSize cannot all be zero when rate enforcementis in effect.

Range value : [0 to 50000000] bit


Criticity : None

Engineering Rules : The default value assumes 6 Logical Link Control (LLC)frames in the bucket. The unit is 100 bit/s. Decreasing thevalue may lower the throughput on the Gb interface. Thehigher the value, the more CPU load is saved.


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maximumFrameSize (n203) (FrAtmDlciSpProv) V12

Description : This attribute specifies the maximum number of octetswhich may be included in the information field. The FrameRelay header and CRC octets are not included in thisdefinition. This attribute corresponds to the dN1 parameterdescribed in the Vendor Forum Specification.

Range value : [1 to 8187] octetsDefault value : 2100

Criticity : None

measurementInterval (t) (FrAtmDlciSpProv) V12

Description : This attribute specifies the time interval over which ratesand burst sizes are measured when rate enforcement is ineffect. When rate enforcement is in effect and bothcommittedInformationRate and committedBurstSizehave values of zero, this attribute must have a non to zerovalue.

When rate enforcement is not in effect or whencommittedInformationRate and committedBurstSizehave non–zero values, this attribute is ignored.

Range value : [0 to 25500] milliseconds

Default value : 0

Criticity : None

Comments : When committedInformationRate and committed-BurstSize have non to zero values, the time interval isinternally calculated. In this situation, measurementInter-val is ignored, and it does not represent the time interval.



rateEnforcement (re) (FrAtmDlciSpProv) V12

Description : This attribute specifies whether rate enforcement is ineffect for this user data link connection. WhenrateEnforcement is on, the CIR and De=1 traffic will bemeasured and enforced. When rateEnforcement is off, allframes from the user are accepted and no modifications tothe frame with respect to the De bit will be made.

Range value : [on / off]Default value : on

Criticity : None


PE/DCL/DD/0136411–9001–0136



Appendix A: main procedures between the MS and the PCUNortel Networks Confidential 5–1


5 APPENDIX A: MAIN PROCEDURES BETWEEN THEMS AND THE PCU

5.1 Proc_1: establishment of uplink TBF

StartT3168

MS

RACH (CCCH)

IMM. Assign. (AGCH)

Channel Required Channel Required

IMM. Assign. Command IMM. Assign. Command

FIRST PDTCH

PACKET RESOURCE REQUEST

PACKET UPLINK ASSIGNMENT

BTS BSC PCU

MAX_RACHfilter

Allocator filter(TFI & resources limits)

Appendix A: main procedures between the MS and the PCU Nortel Networks Confidential5–2

PE/DCL/DD/0136411–9001–0136


5.2 Proc_2: establishment of uplink TBF during a downlinktransfer

MS PCU

Allocatorfilter

(TFI &resources

limits)

PACKET DOWNLINK ACK/NACK

DOWNLINK DATA

DOWNLINK DATA

PACKET UPLINK ASSIGNMENT(S/P=1)


DOWNLINK DATA

UPLINK DATA

TBF starting timefor the uplick TBF



5.3 Proc_3: release of an uplink TBF

MS PCU

PDTCH (CV=0)

PACKET UPLINK Ack/Nack

PDTCH

PDTCH

PACKET UPLINK Ack/Nack (Final Ack Indicator =1)


StartT3182

TBFrelease

TBFrelease


PE/DCL/DD/0136411–9001–0136


5.4 Proc_4: release of an uplink TBF with a lost ofcommunication

MS PCU

PDTCH (CV=0)

..........

StartT3182

TBFrelease

TBFrelease



Not receivedby the MS

StartT3169

N3103Max



5.5 Proc_5: establishment of a downlink TBF

StartNT1002

MS

FIRST PDTCH

BTS BSC PCU



PACKET CONTROL ACKNOWLEDGEMENT (Over 4 bursts )

PACKET TIMING ADVANCE


PE/DCL/DD/0136411–9001–0136


5.6 Proc_6: failure of downlink TBF establishment

StartNT1001

StartNT1002MS BTS BSC PCU



PACKET CONTROL ACK.


PACKET CONTROL ACK.


PACKET CONTROL ACK.

500 ms

500 ms

NBMAXPDASSIGN.

TBFrelease



5.7 Proc_7: Establishment of downlink TBF during an uplinktransfer

MS PCU

DownlinkTBF start

PDTCH

PACKET UPLINK ASSIGNMENT (bitmap i+1)

PDTCH

PDTCH


PDTCH


PDTCH


PDTCH

PDTCH

PDTCH

PDTCH

UplinkBitmap i

UplinkBitmap i+1


PE/DCL/DD/0136411–9001–0136


5.8 Proc_8: release of a downlink TBF

StopT3191

StartT3191MS PCU

TBFrelease

TBFrelease

StartT3192

StartT3193

PDTCH (FBI=1)


PDTCH (FBI=0)

PDTCH (FBI=0)

PDTCH (FBI=0)


Abreviations and definitionsNortel Networks Confidential 6–1


6 ABREVIATIONS AND DEFINITIONS

6.1 Abreviations

A ETSI generic name for BSS–NSS interface

Abis ETSI generic name for BSC–BTS interface

Agprs NORTEL specific name for BSC–PCU interface

ARQ Automatic ReQuest for retransmission

BCCH Broadcast Control CHannel

BLER Block Error Rate

BSC Base Station Controller

BSS Base Sub–System

BTS Base Transceiver Station

BSSGP Base Station System GPRS Protocol.

CCCH Common Control Channel

CS–x Coding Scheme x

CV Countdown Value

DL DownLink

FBI Final Block Indicator

Gb ETSI generic name for PCU–SGSN interface

GGSN Gateway GPRS Support Node

Gi ETSI generic name for GGSN–PDN interface

Gn ETSI generic name for SGSN–GGSN interface

GPRS General packet radio service

GSL Gprs Signalling Link

GTP Gprs Tunneling Protocol

IP Internet Protocol

LA Location Area

LAC Location Area Code

LAI Location Area Identity

Abreviations and definitions Nortel Networks Confidential6–2

PE/DCL/DD/0136411–9001–0136


LAPD Link Access Protocol on D channel

LLC Logical Link Control

MAC Medium Access Control

MM Mobility Management

MS Mobile Station

NS Network Service

NSAPI Network Service Access Point Identifier

NSS Network and Switching Subsystem

O&M Operation and Maintenance

OAM Operation Administration Maintenance

OML OAM Link

PACCH Packet Associated Control Channel

PBCCH Packet Broadcast Control Channel

PCCCH Packet Common Control Channel

PCM Pulse Coded Modulation

PCU Packet Control Unit

PDCH Packet Data Channel

PDN Packet Data Network

PDP Packet Data Protocol

PDU Packet Data Unit

PDTCH Packet Data Traffic Channel

PLMN Public Land Mobile Network

PSI (1–5) Packet System Information Type 1 to 5

QoS Quality of Service

RA Routing Area

RAC Routing Area Code

RAI Routing Area Identity

RACH Random Access Channel

RLC Radio Link Control

Abreviations and definitionsNortel Networks Confidential 6–3


RR Radio Resources

RRM Radio Resources Management

RSL Radio Signaling Link

SAPI Service Access Point Identifier

SI Stall Indicator

SGSN Serving GPRS Support Node

SNDCP SubNetwork Dependent Convergence Protocol

TA Timing Advance

TAI Timing Advance Index

TBF Temporary Block Flow

TCP Transmission Control Protocol

TDMA Time Division Multiple Access

TFI Temporary Flow Identity

TID Tunnel IDentity

TLLI Temporary Link Level Identity

TRX BTS Transceiver entity

TS Time Slot

UL UpLink

USF Uplink State Flag

WAP Wireless Application Protocol

6.1.1 DefinitionsBlock period: is the sequence of four timeslots on a PDCH used to

convey one radio block.

CV (Countdown Value): indicates in which state the countdown procedure is.

Multislot Class: indicates the UL and DL capabilities of the MobileStation.

ON period: one ON period corresponds to the transfer ofinformation (web page, email, etc) at the GPRSapplication layer (above IP/X25).

OFF period: one OFF period corresponds to the time between twoON periods.

Abreviations and definitions Nortel Networks Confidential6–4

PE/DCL/DD/0136411–9001–0136


PBCCH: used to broadcast System Information. If there areGPRS common channels in the cell, then PBCCH ispresent. Alternatively, the BCCH can be used. Thebasic idea of PBCCH is to broadcast for GPRS MS allthe information needed, that is information related topacket as well as general GSM information. However,the MS needs to monitor BCCH for synchronisation,identification of the cell.

PDCH: is a physical channel dedicated to packet data traffic.

Packet idle mode: In packet idle mode, the mobile station is not allocatedany radio resource on a PDCH. It listens to the BCCHand the CCCH.

Packet transfer mode: In packet transfer mode, the mobile station is preparedto transfer LLC PDUs on packet data physical. Themobile station is allocated radio resource on one ormore packet data physical channels for the transfer ofLLC PDUs.

RLC–MODE: indicates the RLC Mode (Acknowledged orNon–acknowledged).

RLC–OCTET–COUNT: indicates the type of TBF (open–ended orclose–ended) and eventually the number of bytes totransmit.

RR connection: is a physical connection established between a MS andthe network to support the upper layers exchange ofinformation flows. An RR connection is maintained andreleased by the two peer entities.

SI (Stalled Indication): indicates if the window is stalled.

TBF (Temporary Block Flow): the radio resources allocations are called TBF in GPRS.One TBF is allocated to a GPRS subscriber during theGPRS transfer duration. A TBF corresponds to a setof radio TS (belonging to the same TDMA) allocated tothat subscriber and for each TS (in uplink), a bitmapdescribing the way the subscriber is allowed to transmitits data on that TS, in the time.

TBF–STARTING–TIME: indicates when the Bitmap is usable.

TBF abort: The term “abort” as applied to TBF is used when theTBF is abruptly stopped without using the Release ofTBF procedures.

TBF release: The term “release” as applied to TBF is used when theTBF is stopped using one of the Release of TBFprocedures.

TFI: the number that identifies the TBF.

Timing Advance: delay used to compensate propagation time betweenthe MS and the BTS.

Transaction: is all the duration of one connection for one service.

Index of parametersNortel Networks Confidential i


Aaccounting (ac), 4–12

BblockErrorRate, 3–26

bscGprsActivation, 3–29

bsCvMax, 3–6

btsSensitivity, 3–14

btsSensitivityInnerZone, bts, 3–22bvcBlockRetries, 4–5

bvcBlockUnblockTimer, 4–5

bvcResetReqRetries, 4–5

bvcResetReqTimer, 4–6

bvcUnblockRetries, 4–6

CcellReselectHysteresis, 3–11

channelType, 3–19

codingScheme, 3–23

committedBurstSize (bc), 4–12

committedInformationRate (cir), 4–13

DdLPwrValue, 3–31

drxTimerMax, 3–13

dwAckTime, 3–24

EexcessBurstSize (be), 4–13

FflowControlMaxRate, 4–7

GgprsCellActivation, 3–11

gprsPermittedAccess, 3–11

gprsPreemption, 3–19

gprsPreemptionProtection, 3–19gprsPriority, 3–20

Index of parameters Nortel Networks Confidentialii

PE/DCL/DD/0136411–9001–0136


LlongTbfSizeThreshold, 3–29

MmaxBsTransmitPowerInnerZone, bts, 3–22

maxDnTbfP1P2Threshold, 3–31

maxDnTbfPerTs, 3–27

maxDwAssign, 3–1

maximumFrameSize (n203), 4–14

maxNbrPDAAssig, 3–1

maxNbrRLCEmptyBlock, 3–7

maxNbrWithoutVchange, 3–24

maxRach, 3–2

maxSize, 3–26

maxUpTbfP1P2Threshold, 3–31

maxUpTbfPerTs, 3–27

measurementInterval (t), 4–14

minNbrGprsTs, 3–20

msCapWeightActive, 3–20

msFlowCntlBucketSize, 4–7

NN3103Max, 3–24

N3105max, 3–7

nAvgl, 3–15

nAvgT, 3–16

nAvgW, 3–17

nbrFreeTchBeforeAnticipation, 3–31

nbrFreeTchToEndAnticipation, 3–31

nsAliveRetries, 4–1

nsAliveTimer, 4–1

nsBlockRetries, 4–2

NsBlockTimer, 4–2

nsBlockTimer, 4–2

nsResetRetries, 4–2

nsResetTimer, 4–3

nsTestTimer, 4–3

nsUnblockRetries, 4–3

Index of parametersNortel Networks Confidential iii


PpanDec, 3–7

panInc, 3–8

panMax, 3–9

RraCapabilityUpRetries, 4–8

raCapabilityUpTimer, 4–8

radioAllocator, 3–20

rateEnforcement (re), 4–15

reserved3, bts, 3–4

reserved4, bts, 3–29

resumeRetries, 4–4, 4–8

resumeTimer, 4–4, 4–9

SspeechOnHoppingTs, 3–32

suspendRetries, 4–9

suspendTimer, 4–9

TT3172, 3–4

tsFlowCntlBucketSize (tsBmax), 4–10

tsLeakRate, 4–11

UupAckTime, 3–25

Index of parameters Nortel Networks Confidentialiv

PE/DCL/DD/0136411–9001–0136



Nortel Networks Wireless SolutionsGPRS ACCESS NETWORK PARAMETERS USER GUIDE

Copyright 1996–2000 Nortel Matra Cellular and Nortel Networks,All Rights Reserved

NORTEL NETWORKS AND NORTEL MATRA CELLULARCONFIDENTIAL:

The information contained in this document is the property of NortelNetworks and/or Nortel Matra Cellular. Except as specifically authorizedin writing by Nortel Networks and Nortel Matra Cellular, the holder of thisdocument shall keep the information contained herein confidential andshall protect same in whole or in part from disclosure and disseminationto third parties and use for evaluation, operation and maintenancepurposes only.

You may not reproduce, represent, or download through any means, theinformation contained herein in any way or in any form without priorwritten consent of Nortel Networks and Nortel Matra Cellular.

The following are trademarks of Nortel Networks: *NORTELNETWORKS, the NORTEL NETWORKS corporate logo, the NORTELGlobemark, HOW THE WORLD SHARES IDEAS.All other brand and product names are trademarks or registredtrademarks of their respective holders.

Publication ReferencePE/DCL/DD/0136 411–9001–013612.01/ENJuly 2000Printed in France

For more information, please contact:

For all countries, except USA:

Documentation Department1, Place des Frères MontgolfierGUYANCOURT78928 YVELINES CEDEX 9FRANCEEmail : [email protected] : (33) (1) 39–44–50–29

In the USA:

2221 Lakeside BoulevardRichardson TX 75082USATel: 1–800–4 NORTEL1–800–466–7838 or (972) 684–5935

Internet Address:

http://www.nortelnetworks.com

APUG_V01.01

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