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User Description, GPRS/EGPRS ChannelAdministration

USER DESCRIPTION

E

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© Ericsson AB 1999–2004 — All Rights Reserved

Disclaimer

No part of this document may be reproduced in any form without the writtenpermission of the copyright owner.

The contents of this document are subject to revision without notice due tocontinued progress in methodology, design, and manufacturing. Ericsson shallhave no liability for any error or damage of any kind resulting from the useof this document.

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User Description, GPRS/EGPRS Channel Administration

Contents

1 Introduction 1

2 Glosary 1

2.1 Concepts 1

2.2 Abbreviations and acronyms 4

3 Capabilities 6

4 Technical Description 6

4.1 General 6

4.2 Service oriented Allocation of Resources on the Abisinterface (SARA) 8

4.3 Configuration of dedicated PDCHs in Packet SwitchedDomain (PSD) 10

4.4 Handling of Packet Data traffic 15

4.5 Channel selection in Cicuit Switched Domain (CSD) 19

4.6 Return of PDCHs to Cicuit Switched Domain (CSD) 22

4.7 Main changes in Ericsson GSM system R10/BSS R10 24

5 Engineering guidelines 24

6 Parameters 26

6.1 Main controlling parameters 26

6.2 Parameters for special adjustments 26

6.3 Value ranges and default values 28

7 References 29

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1 Introduction

GPRS/EGPRS packet data sessions are scheduled over the air interface asTemporary Block Flows (TBFs). When a TBF shall be set up in order to supporta certain service for a mobile user, transmission resources will be reserved onone or more Packet Data Channels (PDCHs). The PDCHs can have differentcapabilities. They may support only the low speed coding schemes CS-1 toCS-2, which will only require 16 kbits/s Abis connections per timeslot, or alsoCS-3 to CS-4 and/or EGPRS which will require 64 kbits/s Abis per timeslot.The PDCH reservation will be made taking into account the Mobile Station’s(MS) capabilities (Multislot Class, and support for EGPRS). PDCHs are chosenfor the reservations also in accordance with the requested Quality of Service)(QoS) Class for the service. The QoS attributes are negotiated with the CoreNetwork (the node SGSN).

To be able to reserve GPRS/EGPRS channels for an MS, they must first beallocated as PDCHs. PDCHs may be fixed allocated as dedicated PDCHsor they may be allocated temporary as on-demand PDCHs. The allocationof dedicated PDCHs will be made by the system according to operatorrequest (ordered number of dedicated PDCHs). On-demand PDCHs will beautomatically allocated by the system when more resources for Packet Datatraffic are needed. PDCHs will be allocated according to certain rules (bestchannels are allocated first).

Several other features impact on the GPRS/EGPRS Channel Administrationfeature see references to other User Descriptions Section 7 References onpage 29.

2 Glosary

2.1 Concepts

B-PDCH A Packet Data Channel (PDCH) used for the transferof GPRS CS-1 to CS-2.

B-TCH Traffic Channel (TCH), which in the PSD is capable ofcarrying GPRS CS-1 to CS-2.

CHGR A Channel Group (CHGR) is a group of frequencieswithin one cell. CHGRs are operator controlled andfacilitate control over groups of frequencies in a cell.

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CHGR-0 contains BCCH and is defined automatically atcell definition.

Channel setindicator

The channel set indicator says if new channels are tobe established or if the old channels should be kept.The channels may be kept at a resource level upgrade.

CSD The Circuit Switched Domain (CSD) is where the circuitswitched calls are handled (speech, data, signalling).

EDGE Enhanced Data rates for GSM Evolution (EDGE) is astandardized set of improvements to the GSM radiointerface. It defines a new modulation method (8-PSK)and new radio protocols that bring higher maximumdata rates and increased spectral efficiency. EDGE isapplicable to both GPRS traffic (EGPRS) and circuitswitched traffic.

EGPRS Enhanced GPRS (EGPRS) supports the GMSKand 8-PSK modulation methods and defines nineModulation and Coding Schemes (MCSs). MCS-1 toMCS-4 are modulated with GMSK and MCS-5 to MCS-9are modulated with 8-PSK. EGPRS supports net bitrates up to 59.2 kbps per timeslot.

E-PDCH A Packet Data Channel (PDCH) used for the transfer ofEGPRS and GPRS CS-1 to CS-4.

E-TCH Traffic Channel (TCH), which in the PSD is capable ofcarrying EGPRS and GPRS CS-1 to CS-4.

G-PDCH A Packet Data Channel (PDCH) used for the transferof GPRS CS-1 to CS-4.

GPRS GPRS is a feature that makes it possible to sendpacket data over the GSM network with GMSK codingschemes (CS-1 to CS-4). GPRS supports net bit ratesup to 20.0 kbps per timeslot.

GPRS Attach An MS shall perform a GPRS Attach to the network inorder to obtain access to the GPRS/EGPRS services.

GPRS Networkoperation mode

The network may provide coordination of paging forCircuit Switched (CS) and Packet Switched (PS)services in different ways depending on if the Gsinterface is present or not. See Section 4.3.6 on page14 “Allocation of the Master PDCH” for a detailedexplanation of the different operation modes. Thisconcept is valid also for EGPRS.

GPRS pagingmessage

This message is used to page an MS supportingGPRS/EGPRS.

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GSM 900 bands There are two sub-bands within the GSM 900:

• P-GSM band: sub-band with frequency range890-915 MHz uplink and 935-960 MHz downlink.

• G1-GSM band: sub-band with frequency range880-890 MHz uplink and 925-935 MHz downlink.

G-TCH Traffic Channel (TCH), which in the PSD is capable ofcarrying GPRS CS-1 to CS-4.

Idle rank value The idle rank value gives an indication of how wellone TCH group fulfils the allocation request for a newchannel set to be used as on-demand PDCHs. The IdleRank Value is then compared with other TCH groups inorder to find the best TCH group. The components ofthe Idle Rank Value are listed below in preference order.

1 Number of idle channels within the TCH group.

2 The highest number of consecutive idle channelswithin the TCH group.

3 The distance from the largest set of consecutiveidle channels to the other idle channels within theTCHGRP.

4 The position of the largest set of idle consecutivechannels.

For example, consecutive channels on TN5 toTN7 is ranked higher than consecutive channelson TN2 to TN4.

Master PDCH A PDCH carrying the Packet Broadcast Control Channeland the Packet Common Control Channel. PS trafficcan also be carried on the Master PDCH. The MasterPDCH is a dedicated PDCH.

MS multislot class MS capability to handle multiple time slots. The multislotclasses 1-29 are defined. They are all supported butclasses 11–12 and 19–29 are handled as class 10. Seereference 6 on Page 29.

PCU Unit in the BSC responsible for all PDCH allocatedchannels.

PS capable TCH Channels capable of carrying PS connections.

PSD The Packet Switched Domain (PSD) where theGPRS/EGPRS connections are handled . The PSDis dependent on the CSD to provide it with channelsusable for PS connections.

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PSD idle list A list of on-demand PDCHs not carrying traffic.

PSET A set of PDCHs possible to use together for aTemporary Block Flow (TBF). A PSET can contain upto eight on-demand and/or dedicated PDCHs. It iscomplete when no more PDCHs is possible to allocatein the TCHGRP due to the number of deblocked TCHs.Maximum one PSET can be allocated on the sameTCHGRP.

Selection indicator The selection indicator indicates whether dedicated oron-demand PDCHs are to be allocated.

TAI individual The PDCH, among the PDCHs used by a TBF, that ischosen to carry the TAI.

TBF A Temporary Block Flow (TBF) is a logical connectionbetween the BSS and the MS. A TBF is set up whenthere is data to send at the BSS or MS side.

TBF limit The parameters in the uplink or downlink direction forwhen new on-demand PDCHs shall be requested.The limits correspond to the average amount of TBFson all PDCHs in a cell. They are however calculatedseparately for E-,G- and B-PDCHs. Thus if the TBFlimit is exceeded for any type of PDCHs, then newon-demand PDCHs will be requested from the CSD.

TCHGRP All deblocked channels are grouped into TCHGRPs.TCHs within the group shall be located in the same cellor subcell, and be of the channel type TCH. The TCHswithin a TCHGRP shall also have the same frequencycapabilities. Non frequency hopping channels shallhave the same Training Sequence Code (TSC) andARFCN. Frequency hopping channels shall have thesame TSC, Hopping Sequence Number (HSN) andMobile Allocation Index Offset (MAIO) . A TCHGRPcan contain maximum one PSET. PDCHs can only beallocated on TCHGRPs with PS capable TCHs.

2.2 Abbreviations and acronyms

8-PSK 8-Phase Shift Keying

ARFCN Absolute Radio Frequency Channel Number

BCCH Broadcast Control Channel

CHGR Channel Group

CS Circuit Switched

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CSD Circuit Switched Domain

EGPRS Enhanced GPRS

GBR Guaranteed Bit Rate

GMSK Gausian Minimum Shift Keying

GPRS General Packet Radio Service

GSL GPRS Signalling Link

HSN Hopping Sequence Number

MAIO Mobile Allocation Index Offset

MS Mobile Station

PBCCH Packet Broadcast Control Channel

PCCCH Packet Common Control Channel

PCU Packet Control Unit

PDCH Packet Data Channel

PS Packet Switched

PSD Packet Switched Domain

PSET PDCH Set

QoS Quality of Service

RP Regional Processor

SARA Service oriented Allocation of Resources on the Abisinterface

SGSN Serving GPRS Support Node

TAI Timing Advance Index

TBF Temporary Block Flow

TCH Traffic Channel

TCHGRP Traffic Channel Group

THP Traffic Handling Priority

TFI Temporary Flow Identity

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TN Timeslot Number

TRU Transceiver Unit

TSC Training Sequence Code

USF Uplink State Flag

3 Capabilities

The capability of this feature is to allocate and reserve PDCHs. All PS capableTCHs may be used for dedicated or on-demand PDCHs.

4 Technical Description

4.1 General

In order to support GPRS/EGPRS, multiple channels can be allocated forPacket Switched (PS) connections. Channels are allocated for GPRS/EGPRStraffic from the Circuit Switched Domain (CSD) as Packet Data Channels(PDCHs). These PDCHs will then belong to the Packet Switched Domain(PSD). Multislot and PS capable TCHs are used for PDCH allocation.

In a cell, PDCHs will coexist with traffic channels for CS. The Packet ControlUnit (PCU) is responsible for all PDCH allocated channels.

In the PSD, several PS connections can share the same PDCH. One PSconnection is defined as a Temporary Block Flow (TBF) and is either uplink ordownlink. An MS can have up to two TBF at the same time, one uplink andone downlink.

When a TBF is to be set up for a MS, a reservation is put on one or morePDCHs. PDCHs are allocated in sets of PDCHs (PSET) and only PDCHs inthe same PSET can be used for a MS. Before a reservation can take place,one or more PDCHs must be present in the PSD.

There are two situations in which a set of PDCHs can be allocated forGPRS/EGPRS:

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• Allocation of dedicated PDCHs

The operator sets the number of dedicated PDCHs in a cell. ThesePDCHs are allocated from the CSD to the PSD, and will be dedicated forGPRS/EGPRS traffic only.

• Allocation of on-demand PDCHs

On-demand PDCHs are allocated from the CSD only when there is need formore PDCHs for PS traffic.

After allocation of PDCHs, the PDCHs can be reserved to carry packet datatraffic.

• PDCH reservation

Resources are provided for PS connections by PDCH reservation. PDCHsare reserved for a TBF, uplink or downlink, in accordance with the MScapabilities (MS multi-slot class, support for EGPRS and frequency bandcapabilities).

The on-demand PDCHs are only temporary allocated for GPRS/EGPRS andare returned to the CSD when they have had no reservations for a certain time,or whenever CS needs them. The following two situations can occur:

• Deallocation of idle on-demand PDCHs

PDCHs that are not reserved for GPRS/EGPRS traffic, are put in a PSD idlelist. After a limited time in the PSD idle list, the PDCHs are deallocated fromthe PSD and returned to the CSD.

• Deallocation of on-demand PDCHs due to pre-emption

If there is a shortage of traffic channels in the CSD, a request for PDCHpre-emption is sent to the PSD, in the case there are any on-demand PDCHin the cell. A suitable PDCH may be returned to the CSD, depending onthe PDCHPREEMPT setting.

The number of dedicated PDCHs can be decreased by the operator:

• Deallocation of dedicated PDCHs

The dedicated PDCHs that are removed by operator command are notreturned to the CSD immediately, but will be marked as on-demand PDCHs.If the PDCHs to be marked as on-demand do not carry PS traffic they areput in the PSD idle list.

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Each PSET can contain up to eight on-demand and/or dedicated PDCHs.PDCHs are allocated as a PSET on the very same TCHGRP using anydeblocked TCH.

As a maximum a PSET consists of up to eight PDCHs, but in some cases lesschannels are allocated as PDCHs to a PSET. Either it is not possible to allocatechannels as PDCHs, for example some TCH are busy with CS traffic, or someBPCs are configured as BCCH or SDCCH, see Figure 1 on page 8 . OnlyPDCHs in the same PSET can be used for the same PS connection and foreach MS the multislot class determines which PDCHs that can be used.

PSET 1

P T P T P T P P

B S T T P P P P

B = BCCHP = PDCHS = SDCCHT = TCH

PSET 2

Figure 1 Allocation of PSET

4.2 Service oriented Allocation of Resources on the Abisinterface (SARA)

In order to support higher data rates for PS traffic (CS-3 to CS-4) and EGPRS itis not sufficient with 16 kbits/s per TCH on Abis. G-TCHs and E-TCHs need 64kbits/s on Abis, which is handled by the SARA functionality.

The following parameters can be set at cell configuration:

NUMRE-QCS3CS4BPC is set per CHGR, and is used to set the wanted amount

of BPCs for a CHGR to be G-TCHs.

NUMREQEGPRS-BPC

is set per CHGR, and is used to set the wanted amountof BPCs for a CHGR to be E-TCHs.

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TN7BCCHis set per cell, and is used to define if TN7 is allowed tocarry EGPRS on the BCCH frequency. Note that theparameter will affect all TN7 in CHGR-0 if FrequencyHopping is used.

If there is not enough capacity on Abis to use 64 kbits/s connections for all the64 kbits/s capable timeslots in a Transciever Group, then the EGPRS capableTRUs have higher priority for 64 kbits/s Abis connections than the only GPRS(CS-1 to CS-4) capable TRUs.

At CHGR configuration the network will configure as many EGPRS capableBPCs as possible, in the basic TN priority order 6, 5, 7, 4, 3, 2, 1, 0 on thesame carrier before configuring EGPRS capable BPCs on another carrier.If frequency hopping is used the carrier with the highest prioritized MAIO isconfigured as EGPRS capable first. In order to utilize all possible EGPRScapable timeslots, if limited, for all MAIOs within a CHGR, the TN priority ordermay be different when E-TCHs are configured on certain MAIOs. The GPRS(CS-1 to CS-4) capable BPCs will be configured when all the EGPRS capableBPCs have been configured.

Example: If 24 BPCs are requested, where 9 are to support both GPRS (CS-1toCS-4) and EGPRS and 4 are to support only GPRS (CS-1 to CS-4) for a nonhopping CHGR-1, it would look like:

Table 1

TN0 TN1 TN2 TN3 TN4 TN5 TN6 TN7

f0 E-TCH E-TCH E-TCH E-TCH E-TCH E-TCH E-TCH E-TCH

f1 B-TCH B-TCH B-TCH G-TCH G-TCH G-TCH E-TCH G-TCH

f2 B-TCH B-TCH B-TCH B-TCH B-TCH B-TCH B-TCH B-TCH

Note that for CHGR-0, the network will not configure 64K Abis for the BCCHor SDCCH timeslots.

Note: According to 3GPP specifications 8–PSK (EGPRS) is not allowed to beused on TN7 on the BCCH frequency if the maximum 8–PSK output power inthe cell is lower than the maximum GMSK output power. To avoid that situationthe parameter TN7BCCH can be set to GPRS. When TN7BCCH=GPRS, TN7on the BCCH frequency will not carry EGPRS traffic, i.e. E-TCH will not beconfigured on TN7 for that carrier. TN7 can however be configured as a G-TCHif all the other BPCs in CHGR-0 are configured as G-TCH or E-TCH.

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4.3 Configuration of dedicated PDCHs in Packet SwitchedDomain (PSD)

4.3.1 General

In order to secure resources for GPRS/EGPRS, the operator can configureup to eight dedicated PDCHs per cell by setting the parameter FPDCH. Thededicated PDCHs are only available for GPRS/EGPRS traffic.

The dedicated PDCHs in a cell can either be placed on non hopping TCHs onthe BCCH frequency as a first choice, last choice or as no preference accordingto the parameter PDCHALLOC.

4.3.2 Adding dedicated PDCHs

When the operator requests an increased number of dedicated PDCHs, aPSET where these PDCHs will reside is selected. There can be up to eightdedicated PDCHs in a cell and a PSET can accommodate up to eight PDCHs.Maximum two PSETs can be selected to add dedicated PDCHs to. The firstPSET to be selected is called the primary dedicated PSET, and the secondPSET to be selected is called the secondary dedicated PSET.

The primary dedicated PSET will always be placed in accordance with theparameter PDCHALLOC. A secondary PSET is allocated when the primaryPSET is allocated on a TCHGRP with less deblocked TCHs than the requestednumber of PDCHs.

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Primary PSET

Secondary PSET

T T T T T DP DP T

B S DP DP DP DP

B = BCCHDP = Dedicated PDCHS = SDCCHT = TCH

DPDP

Figure 2 Allocation of eight dedicated PDCHs when PDCHALLOC is set tofirst

Before any dedicated PDCHs are added in a cell, a check is made to seeif it is possible to add more dedicated PDCHs in the RP handling the cell.An RP can handle several cells, but a cell can only be handled by one RP.The check is made against the parameters ONDEMANDGPHDEV andONDEMANDGPHDV64.

The parameter ONDEMANDGPHDEV is a limit of the minimum number ofB-PDCHs reserved for on-demand PDCHs for each RP (16 kbits/s GSLsub-devices), i.e. for all the cells handled by each RP. This is to make sure thatthe total number of possible PDCHs in an RP is not allocated as dedicatedPDCHs. If this would be the case, no on-demand PDCHs can be allocated inany of the cells handled by that RP and the cells without dedicated PDCHs willnot be able to handle any PS traffic at all.

The parameter ONDEMANDGPHDV64 is the corresponding limit of theminimum number of E-PDCHs and G-PDCHs reserved for on-demandE-PDCHs or G-PDCHs for each RP (64 kbits/s GSL devices), i.e. for all thecells handled by each RP. All GSL devices in a RP (both 64 kbits/s and 16kbits/s), which are reserved for on-demand PDCHs belong to the same poolof resources.

Before any dedicated E-PDCHs, G-PDCHs or B-PDCHs are added in thecell, a check is made if the on-demand PDCHs capacity will still exceed bothoperator thresholds (ONDEMANDGPHDV64 and ONDEMANDGPHDEV) afterthe allocation the dedicated PDCHs. In that case the requested number ofdedicated E-PDCHs, G-PDCHs or B-PDCHs are allocated in the cell, otherwisean attempt to move a cell from this RP shall be made. The selected cell to

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be moved is the cell with the largest amount of GSL resources occupied bydedicated PDCHs and with the least number of TBF.

When adding a dedicated PDCHs to the PSD, the following actions are made:

1 If there is a primary PSET containing less than the requested numberof PDCHs, and it is possible to upgrade it according to the amount ofdeblocked E-TCH/G-TCH/B-TCH, then this PSET is selected for addingdedicated PDCHs to. If there are suitable on-demand PDCHs in theprimary PSET, then those on-demand PDCHs are marked as dedicated, upto the number the operator has requested. If there are no suitable or notenough on-demand PDCHs in the primary PSET, then PDCH channels areallocated from the CSD towards the number the operator has requested,see Note below and Section 4.5.1 on page 19 .

2 If the primary dedicated PSET was not possible to upgrade fully accordingto the request, but there exist a secondary dedicated PSET which is notcomplete, and it is possible to upgrade it according to the amount ofdeblocked E-TCH/G-TCH/B-TCH, then that PSET is selected for addingdedicated PDCHs to. If there are on-demand PDCHs in the secondaryPSET, then those on-demand PDCHs are marked as dedicated up to thenumber the operator has requested. If there are no suitable or not enoughon-demand PDCHs in the secondary PSET, then PDCH channels areallocated from the CSD towards the number the operator has requested,see Note below and Section 4.5.1 on page 19 .

3 If no dedicated PSET exist, but the most suitable TCHGRP for allocatinga primary PSET (see Section 4.5.1 on page 19) is already in use in thePS domain as a set of on-demand PDCHs, then an attempt to transformthis PSET into a primary dedicated PSET is initiated. The on-demandPDCHs in the PSET shall be transformed to dedicated PDCHs, up tothe number the operator has requested. If there are no suitable or notenough on-demand PDCHs in the PSET according to the operator request,then PDCH channels are allocated from the CSD towards the number theoperator has requested, see Section 4.5.1 on page 19 .

4 If no dedicated PSET exists and if no on-demand PSET, which is possibleto upgrade, belongs to the best TCHGRP for allocating a primary PSETon, then an attempt to create a new primary dedicated PSET is made.ThePSET, has to be in accordance with the strategy for non hopping PDCHson the BCCH frequency, according to parameter PDCHALLOC. PDCHchannels are allocated from the CSD up to the number the operator hasrequested, see Note below and Section 4.5.1 on page 19 .

5 If the request for dedicated PDCHs cannot be fulfilled in the primaryPSET, and no secondary PSET exists, but the most suitable TCH groupfor allocating a secondary PSET (see Section 4.5.1 on page 19) is alreadyin use in the PS domain as a set of on-demand PDCHs, then an attemptto transform this PSET into a secondary dedicated PSET is initiated. Theon-demand PDCHs in the PSET shall be transformed to dedicated PDCHstowards the number the operator has requested. If there are no suitableor not enough on-demand PDCHs in the PSET according to the operator

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request, then PDCH channels are allocated from the CSD up to the numberthe operator has requested, see Note below and Section 4.5.1 on page 19 .

6 If the request for dedicated PDCHs cannot be fulfilled in the primaryPSET, and no secondary PSET exists, and if no on-demand PSET, whichis possible to upgrade, belongs to the best TCH group for allocating asecondary PSET on, then an attempt to create a new secondary dedicatedPSET is made. PDCH channels are allocated from the CSD up to thenumber the operator has requested, see Note below and Section 4.5.1on page 19 .

Note: In the transformation of on-demand PDCHs to dedicated PDCHs, thetimeslot number priority order 6–5–7–4–3–2–1–0 is normally used.However if TN7 support less coding schemes than any of TN0 to TN4,then TN7 will be transformed after the TNs which support more codingschemes.

4.3.3 Fixed PDCH Addition Timer (FAT)

Channels chosen for allocation of dedicated PDCHs may be impossible toallocate immediately, since they are busy with CS calls. Pre-allocation ofdedicated PDCHs will then take place, which means that the channels will notbe allocated for new CS calls. The status of these channels will be periodicallychecked (FAT interval). When any of these channels has been found idle, it willbe allocated as a dedicated PDCH and the pre-allocation status will cease.

4.3.4 Periodic Check for best Primary Dedicated PSET

Depending on application parameter PSETCHKPERIOD the periodic checkmay be activated. A periodic check whether a better TCHGRP exists for theallocation of a primary dedicated PSET will then be performed. If a betterTCHGRP is found (see allocation criteria in Section 4.5.1 on page 19), then thePDCHs in the current primary PSET will be marked as on-demand PDCHs anda new primary PSET will be allocated in the best TCHGRP. As a consequencethe secondary PSET (if existing) may be removed or re-allocated differently.

4.3.5 Removing dedicated PDCHs

When the operator orders a decrease in the number of dedicated PDCHs in acell, a PSET is selected from where the dedicated PDCHs are to be removed. Ifthere is a secondary dedicated PSET, then that PSET is selected. Otherwisethe primary dedicated PSET is selected.

In the selected PSET, a number of dedicated PDCHs are marked as beingon-demand PDCHs, in order to decrease the number of dedicated PDCHs inthe cell according to the requested number of dedicated PDCHs.

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If the secondary PSET was selected and there were too few dedicated PDCHsin that PSET to fulfil the request, the primary dedicated PSET is selected inorder to complete the request.

Timeslots are removed in the reversed order they have been allocated.

4.3.6 Allocation of the Master PDCH

A Master PDCH may be allocated in a cell to carry the packet broadcastchannel and the packet common control channel, the PBCCH and the PCCCH.The Master PDCH will also carry packet data traffic. The Master PDCH is adedicated PDCH and can only be set up if there are dedicated PDCHs in thecell.

Whether the Master PDCH is allocated or not when at least one dedicatedPDCH is configured, is dependent on the chosen GPRS network operationmode (also valid for EGPRS), parameter GPRSNWMODE. The GPRS networkoperation mode I requires the optional Gs interface between the MSC and theSGSN, while the GPRS network mode II and III should be chosen when theGs interface is not present.

• If network mode I is chosen, there are two choices; either no MasterPDCH will be allocated in the cell even if there are dedicated PDCHs,GPRSNWMODE = 0, or a Master PDCH is allocated when there arededicated PDCHs, GPRSNWMODE = 1. The network sends CS pagingmessage for a GPRS-attached MS, either on the same channel as theGPRS paging channel (i.e. the packet paging channel or the CommonControl Channel, CCCH, paging channel), or on a GPRS/EGPRS trafficchannel. This means that the MS must only monitor one paging channel,and that it receives CS paging messages on the packet data channel whenit has been assigned a packet data channel.

• If network mode II is chosen, GPRSNWMODE = 2, no Master PDCH will beallocated in the cell even if there are dedicated PDCHs. Common controlsignalling are performed on CCCH for both CS and PS. This means thatthe MS must only monitor the CCCH paging channel, but that CS pagingcontinues on this paging channel, even if the MS has been signed a packetdata channel.

• If network mode III is chosen, GPRSNWMODE = 3, a Master PDCH willbe allocated in the cell when there are dedicated PDCHs. The networksends CS paging message for a GPRS-attached MS on the CCCH pagingchannel, and sends a GPRS paging message on either the packet pagingchannel (if allocated in the cell) or on the CCCH paging channel. Thismeans that an MS that wants to receive pages for both CS and PS mustmonitor both paging channels if the packet channel is allocated in the cell.The network performs no paging coordination.

If a Master PDCH is allocated in the cell, one of the dedicated PDCHs that issuccessfully allocated on the primary dedicated PSET becomes the MasterPDCH in the cell. The primary dedicated PSET is allocated in accordance with

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the chosen strategy for non hopping TCH on the BCCH frequency, parameterPDCHALLOC, see Section 4.5 Channel selection in Cicuit Switched Domain(CSD) on page 19.

4.4 Handling of Packet Data traffic

4.4.1 General

When resources are needed for PS connections, PDCHs are reserved for thoseTBF. PDCHs are reserved in accordance with the MS type (EGPRS or GPRS)and the multislot class. If the feature Multiband cell is used also the frequencyband capabilities of the MS may be considered. See reference 9 on Page30. Each PDCH can carry traffic for more than one connection at a time, bothuplink and downlink. There is a limit of 32 TFI per PSET and direction. Besidesthere is a limit of 6 USF per PDCH on uplink traffic using MPDCH and 7 USFper PDCH for non MPDCH channels.

4.4.2 PDCH reservation

General

At channel request for a GPRS/EGPRS user, channels in a PSET are selectedwhere the PDCH reservations will be made for the TBF. If the MS already hasPDCHs reserved for a TBF in the opposite direction, new reservations aremade on the same PSET in accordance with the MS multislot class, (whichdoes not always mean that channels are reserved on the maximum number ofPDCHs according to the class), as well as the QoS requirements. The PDCHreservations are continuously supervised and any TBF may be upgraded (onthe same PSET) in order to fulfill the QoS requirements and/or the MS multislotclass.

Channel reservations are made according to the following:

• MS type (EGPRS or GPRS), frequency capabilities, and multislot class

• QoS attributes of the packet data session to be set up

• Available channel resources (E-, G- and B-PDCHs)

• Channel load from ongoing traffic

A TBF will generally be reserved on channels that will provide as much capacity(bandwith) as possible. If GPRS/EGPRS Quality of Service handling is on,the interaction between packet data sessions with different weights mustbe regarded, since ongoing packet data traffic will be scheduled over the airinterface according to their relative QoS weights. QoS class interactive hasgenerally higher weight than the background class and there can be differentTraffic Handling Priorities (TPHs) within the Interactive class. See reference 5on Page 29.

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Depending on the mobile capabilities, test reservations will be performed fordifferent types of TBFs. There are:

E-TBF reservations which can only use E-PDCHs

G-TBF reservations which can only use E-PDCHs and G-PDCHs

B-TBF reservations which can use all PDCHs

All types of TBFs which are applicable for a certain MS (according to the MStype) will be tested if PDCHs of the proper type are allocated in the cell. Thetype of TBF (E-, G, or B) that will be chosen depends on the capacity eachtype of reservation can provide.

If GPRS/EGPRS Quality of Service handling is on, QoS weights must also beregarded, and the weights are fetched from QoS in relation to the TBF request.See reference 6.

Quality of Service class Streaming

The streaming class has the highest priority. It will regard the GuaranteedBitRate attribute, which has been negotiated with the SGSN node. Only onestreaming TBF will be reserved per PDCH. The rest of the PDCH capacity maybe used for Interactive Class or Background Class TBFs, if possible, in order tofulfill the GBR for the Streaming TBF.

Quality of Service class Interactive

With a TBF request for an EGPRS capable MS three weights are received,these weights correspond to the three possible TBF-modes (E-TBF, G-TBF andB-TBF). With a TBF request for a GPRS only capable MS two weights arereceived (G-TBF and B-TBF). These weights are received from QoS for TrafficClass Interactive.

Quality of Service class Background

If the TBF request indicates Traffic Class Background, the weight will becalculated by this function as:

weight = 0.1 * (the lowest of the current interactive weights within the cell).

If no interactive weight is existing in the cell, the weight 1 is used as the lowestcurrent Interactive weight in the cell.

If GPRS/EGPRS QoS is off, all TBF requests are considered as Traffic ClassBackground and will thus be given the same weight.

Selection of all possible combinations of PSET and possible TBF-mode

One PSET may have up to three possible TBF-modes depending on therequested TBF-mode and the types of PDCH resources in the PSET.

In the case an EGPRS TBF (E-TBF) is requested then:

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a In a PSET containing at least one E-PDCH as the most capable, then E-,G- and basic GPRS TBF (B-TBF) is tested.

b In a PSET containing at least one G-PDCH as the most capable, then G-and B-TBF is tested.

c In a PSET containing only B-PDCHs, only B-TBF is tested.

In the case an GPRS TBF (G-TBF) is requested then:

a In a PSET containing at least one E-PDCH or at least one G-PDCH as themost capable, then G- and B-TBF is tested.

b In a PSET containing only B-PDCHs, only B-TBF is tested.

PDCHs which are not possible to use in a PDCH-reservation are notconsidered. An example is a PDCH with no available USFs, which thereforemay not be part of an Up Link PDCH-reservation. The reservation must also bedone according to the MS multislot class and MS type. If the MS capabilitiesare not known at reservation time, only one B-PDCH will be reserved. For allthe combinations above all unnecessary combinations are removed.

Test Reservations

Test Reservations are performed on all combinations selected in the previouspart selection of all possible combinations of PSET and Possible TBF-mode.The Test Reservation algorithm ranks all meaningful reservation patternswithin each selected combination and among all selected combinations. Thereservation that will give the highest bandwith for a TBF in accordance with theQoS scheduling (if QoS is active) and the capabilities of the different PDCHsthat may be reserved, will be ranked highest.

Reservation

A PDCH-reservation will be made on the best test reservation pattern (highestrank) and with the selected TBF-mode.

Upgrade of PDCH reservation

The reservations of TBFs on PSETs are continuously supervised in order tocheck if it is possible to upgrade any reservation according to the MS multislotclass.

• Upgrade will be made, if possible, in accordance with the MS multislotclass when more PDCHs are available compared to when the previousreservation was made.

• Upgrade of a TBF reservation is only possible within the PSET where theinitial reservation was made.

Dynamic downlink/uplink PDCH reservation

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This feature can be activated/deactivated by parameter DYNULDLACT. It isdeactivated by default.

• If the traffic load is indicated to be mainly uplink, an uplink upgrade can beperformed if possible.

• Since as many as possible downlink PDCHs of the PSET were reservedin the downlink direction during the initial reservation, it may then benecessary to first execute a downgrade of the downlink reservation inorder to achieve a possible uplink upgrade in accordance with the MSmultislot class.

Re-Reservation of PDCH Reservation

A TBF reservation that do not fulfill the GBR for streaming or is not reservedon as many timeslots as possible according to the MS multislot class may bere-reserved.

• A re-reservation attempt will be made if an upgrade is not possible or notenough in order to reach GBR or to handle as many timeslots as the MSmultislot class admits. (EIT excluded).

• TBF reservations on heavy loaded PDCHs may be subject forre-reservation, with the purpose to even out the load on the availablePDCHs.

• A request for new on-demand PDCHs may be part of the re-reservationstrategy if the existing PSETs do not fulfill the requirements for thereservation. Only the needed number of PDCHs will be requested fromthe CSD.

4.4.3 Request for on-demand PDCHs from the CSD

On-demand PDCHs are requested from the CSD when:

• There are no PDCHs in a cell and a GPRS/EGPRS MS requests channels.

• MS reservations were made up to one of the TBF limits (uplink or downlink)in average for the PDCHs in a cell. This is checked individually for PDCHscapable of supporting E-, G-, and B-TBFs.

• MS reservations are made on less PDCHs than the MS is capable ofaccording to its multislot class.

• An MS has been reserved using a lower TBF mode than the MS can handleaccording to its capabilities. (For instance an EGPRS mobile has beenreserved in B-TBF mode).

Note: This case is not valid for upgrade of running TBFs or for re-reservation,since change of TBF mode of a running TBF is not allowed accordingto 3GPP standard.

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If the PSET is not complete, an attempt is made to upgrade the PSET.Otherwise, if there are no incomplete PSET, an attempt is made to allocate anew PSET of up to four PDCHs. The new on-demand PDCHs are for future use.

4.5 Channel selection in Cicuit Switched Domain (CSD)

4.5.1 General

In the allocation request from the PCU, the cell, channel set indicator andselection indicator are provided. In the case of adding channels to a PSET, thenumber of already allocated channels is also provided.

If the feature Multi Band Cell is used, the frequency band capabilities of themobile are considered (if known) if the allocation of new PDCHs is done in orderto serve a certain mobile (re-reservation of PDCHs on another PSET or initialPDCH setup). See User Description, Multi Band Cell

Also if E-GSM is used the frequency band capabilities of the mobile (P-band orG1 band) are considered (if known) if the allocation of new PDCHs is done inorder to serve a certain mobile.

General PDCH allocation as a new PSET, (not for individual mobile support),can be performed only in the BCCH frequency band if the parameter MBCRACis set to 0 (default value). To allow general allocation of PDCHs in other bandsin a cell must MBCRAC be set to 1 see Page 26.

Dedicated PDCHs are always allocated according to the MBCRAC setting.

Extension of an already existing on-demand PSET is however generally allowedregardless of the MBCRAC setting.

The non BCCH band is generally preferred if other constrictions not prevent this.

The MBCRAC setting is applicable also if E-GSM is used. The GSM 900P-band and the G1 band are handled in the same way as other different bandsin a multi band cell.

If the feature Packet Data in Overlaid Subcell is used, PDCHs will be allocatedin any of the subcells which are allowed according to the parameter SCALLOCsee Page 27. The allocation algorithms will also consider if any subcell ispreferred according to this parameter. If the feature Packet Data in OverlaidSubcells is not in use, PDCH allocation is only possible in underlaid subcells.See User Description, Overlaid/Underlaid Subcells.

Among the multislot and PS capable TCHs, a TCHGRP is selected accordingto what type of allocation is requested. If the allocation request is addingchannels to an existing PSET, the TCHGRP where the already allocatedchannel(s) belong is selected. If a new channel set is requested, PS capableTCHs are selected depending on if the selection criteria is dedicated PDCHsor on-demand PDCHs.

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Only TCH groups that are non-hopping or belong to CHGRPs with parameterBCCD set to yes, see User Description, Frequency Hopping, are consideredfor the primary PSET.

4.5.2 Selection of dedicated PDCHs

When the selection indicator is set to allocation of dedicated PDCHs, therequested number of channels are selected within the allowed frequency bandand subcell(s) according to the following algorithm:

1 In the case of adding PDCHs to a PSET, then select the TCHGRP wherethe other PDCHs in the PSET are located. Then proceed to step 14.

2 For the primary PSET Select the TCHGRPs that fulfil the operator chosenstrategy regarding non hopping TCH on the BCCH frequency, according toparameter PDCHALLOC.

3 Among these TCHGRPs, select the TCHGRPs that have the highestnumber of deblocked E-TCHs (idle or busy).

4 Among these TCHGRPs, select the TCHGRPs where the E-TCHs havethe highest TNs.

5 Among these TCHGRPs, select the TCHGRPs that have the highestnumber of deblocked G-TCHs (idle or busy).

6 Among these TCHGRPs, select the TCHGRPs that have the highestnumber of deblocked B-TCHs (idle or busy).

7 Among these TCHGRPs, select the TCHGRPs that have TN6 idle.

8 Among these TCHGRPs, select the TCHGRPs that have the highestnumber of idle TCH among TN4 to TN7.

9 Among these TCHGRPs, select the TCHGRPs that have the highestnumber of idle TCH among TN0 to TN3.

10 If the function Idle Channel Measurements is active, select among theseTCHGRPs the TCHGRPs with the lowest interference level. (This refers tothe channel with the highest interference level within the TCHGRP.)

11 If frequency hopping is used, select among these TCHGRPs the TCHGRPshopping over as many frequencies as possible.

12 Select a non BCCH frequency band first, and the BCCH band as secondchoice if the prerequisites mentioned above will admit this.

13 If Packet Data in Overlaid subcell is used, select among these TCHGRPsthe TCHGRPs in the preferred subcell according to the parameterSCALLOC.

14 Among these TCHGRPs, select the first found TCHGRP and allocate asmany as requested or as many as possible, if less, PDCHs.

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Note: The normal TN allocation order is 6, 5, 7, 4, 3, 2, 1, 0. However, ifTN7 support less coding schemes than any of TN0 to TN4, thenTN7 will be allocated after the TNs which support more codingschemes. If only one PDCH was requested and if TN7 support lesscoding schemes than any of TN0 to TN4, the allocation order startswith TN5 before TN6 instead. First E-TCHs are allocated. If thereare not enough deblocked E-TCHs compared to the requestednumber of channels then the search continues for G-TCHs in thepreferred TN order. If there are not enough deblocked E-TCHsand G-TCHs compared to the requested number of channels thesearch continues for B-TCHs.

4.5.3 Selection of on-demand PDCHs

When the selection indicator is set to allocation of on-demand PDCHs, therequested number of channels are selected within the allowed frequency bandand subcell(s) according to the following algorithm:

1 In the case of adding PDCHs to a PSET, then select the TCHGRP wherethe other PDCHs in the PSET are located. Then proceed to step 10.

2 Among these TCHGRPs, select the TCHGRPs that have the best idlerank value of idle E-TCH.

3 Among these TCHGRPs, select the TCHGRPs that have the best idlerank value of idle G-TCH.

4 Among these TCHGRPs, select the TCHGRPs that have the best idlerank value of idle B-TCH.

5 Select the TCHGRP that fulfil the operator chosen strategy regardingnon hopping TCH on the BCCH frequency, according to parameterPDCHALLOC.

6 If the function Idle Channel Measurements is active, select among theseTCHGRPs the TCHGRPs with the lowest interference level. (This refers tothe channel with the highest interference level within the TCHGRP.)

7 If frequency hopping is used, select among these TCHGRPs the TCHGRPshopping over as many frequencies as possible.

8 Select a non BCCH frequency band first and the BCCH band as secondchoice if the prerequisites mentioned above will admit this.

9 If Packet Data in Overlaid subcell is used, select among these TCHGRPsthe TCHGRPs in the preferred subcell according to the parameterSCALLOC.

10 Among these TCHGRPs, select the first found TCHGRP and allocate fouror as many as possible, if less, PDCHs.

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Note: If the request was for a new PSET, then first E-TCHs are allocatedand the allocation starts from the highest TN in the group of idleconsecutive E-TCHs. If there are less than 4 idle consecutive E-TCH,then the remaining E-TCHs are allocated as close as possible to thelargest set of consecutive idle E-TCHs. If there are not enough idleE-TCHs compared to the requested number of channels then thesearch continues for G-TCHs in the preferred order. If there are notenough idle E-TCHs and G-TCHs compared to the requested numberof channels the search continues for B-TCHs. The same search criteriais used if there is no idle E-TCHs but idle G-TCHs and/or B-TCHsexists. If the allocation request stated that there must exist at least oneidle E-TCH or at least one idle G-TCH in the TCH group, then channelsare only allocated in this case. If the request was that channelsshould be added to a PSET the channels shall be allocated so that aslarge consecutiveness as possible is achieved. Idle E-TCHs shall beallocated first, secondly idle G-TCHs and as a last priority B-TCHs.

4.6 Return of PDCHs to Cicuit Switched Domain (CSD)

4.6.1 General

The on-demand PDCHs can be returned to the CSD in two ways, either whenthey have been idle for a limited time or whenever CS needs them. They arethen returned in reversed priority order (first B-PDCHs, G-PDCHs and thenE-PDCHs as last choice). Dedicated PDCHs that are removed by operatororder will not be returned to the CSD directly, but will be marked as on-demandPDCHs, see section Section 4.3.5 on page 13 .

4.6.2 Deallocation of idle on-demand PDCHs

On-demand PDCHs that become idle in both directions, are linked into the PSDidle list after which the timer PILTIMER is started. When the timer expires fora PDCH, the PDCH is deallocated in the PSD and returned to the CSD. Thetimer PILTIMER is restarted for all PDCHs in a PSET if a reservation is puton one or more PDCHs in the PSET.

The value range of the PILTIMER is 1 s. to 3600 s. When the PILTIMER is setto a low value, the idle on-demand PDCHs will only stay in the PSD idle list fora short time before they are deallocated in the PSD and returned to the CSD.This implies more allocations and deallocations of PDCHs and requires moreCP capacity.

On the other hand a low value of the PILTIMER will make the allocation ofon-demand PDCHs more dynamic in the cells handled by the same RP. Thecells, handled by the same RP, share the maximum number of possible PDCHsand by deallocating idle on-demand PDCHs the possibility to allocate PDCHsfor other cells, handled by the same RP, will increase. When setting thePILTIMER, the number of RP handling cells in the PCU, the number of cellsand the CP capacity should be taken into consideration.

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4.6.3 Deallocation of on-demand PDCHs due to pre-emption

When there is a shortage of channels in the CSD, a request for PDCHpre-emption is sent to the PSD in case there are any on-demand PDCHsin the cell. The pre-emption procedure can be controlled by the parameterPDCHPREEMPT. Thus the operator can choose to allow either pre-emption of:

• Only idle PDCHs

• Only non essential PDCHs (not carrying TAI) and idle PDCH

• Only on-demand PDCHs that are not marked as ‘used for streaming’ orare non-essential

• Only on-demand PDCHs that are not marked as ‘used for streaming’

• All PDCHs

If pre-emption of busy PDCHs are allowed, the operator can also decide ifPDCHs carrying TAI can be pre-empted, which will cause the whole packet datadata session connected to the pre-empted TAI to stop.

If the PDCHPREEMPT parameter allows pre-emption of all types of on-demandPDCHs (idle or busy), an on-demand PDCHs to be returned is selected asfollows:

1 If there exist any idle on-demand PDCHs, then select those PDCHs andproceed to 5.

2 Select the on-demand PDCHs that are chosen as TAI individual for theleast number of TBF.

3 Among those on-demand PDCHs, select B-PDCHs firstly, G-PDCHssecondly and E-PDCHs as last choice.

4 Among those on-demand PDCHs, select the PDCHs having the leastnumber of PDCH reservations.

5 Among those on-demand PDCHs, select the on-demand PDCHs residingon the PSETs with the least dedicated PDCHs.

6 Among those on-demand PDCHs, select the PDCHs residing on the PSETcontaining the fewest PDCHs.

7 Among those on-demand PDCHs, select the PDCHs residing on the PSETswith the least deblocked E-TCHs.

8 Among those on-demand PDCHs, select the PDCHs residing on the PSETswith the fewest E-PDCHs.

9 Among those on-demand PDCHs, select the PDCHs residing on the PSETswith the least deblocked G-TCHs.

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10 Among those on-demand PDCHs, select the PDCHs residing on the PSETswith the fewest G-PDCHs.

11 Among those on-demand PDCHs, select the PDCHs residing on the PSETswith the least deblocked B-TCHs.

12 Among those on-demand PDCHs, select the PDCHs in reversed priorityorder (B, G and last E-PDCHs).

13 Among those on-demand PDCHs, select the first found PDCH after searchin reversed TN order (0-1–2–3–4–7–5–6).

If only non essential PDCHs (not carrying TAI) and idle PDCHs are allowedfor pre-emption, then start on 2 above, but do only regard PDCHs notcarrying TAI. Then follow the list from 3 until 13.

If only idle PDCHs are allowed for pre-emption, then start on 1and select allidle PDCHs, then follow the list from 5 until 13.

4.7 Main changes in Ericsson GSM system R10/BSS R10

The following new functionality affecting the GPRS/EGPRS channel allocationstratagy have been introduced:

• Improved upgrade of TBF reservation (both uplink and downlink)

• TBF re-reservation

• Dynamic downlink/uplink PDCH reservation (de-activated by default)

• QoS Class Streaming

• Packet Data in Overlaid Subcell

• Multiband Cell

5 Engineering guidelines

The recommended parameter value of PILTIMER (20 s) is chosen as acompromise between keeping the number of reserved on-demand PDCHs low,thereby reducing the number of engaged GSL devices, and still admit goodperformance of traffic throughput and delay. A lower setting of the PILTIMERvalue (down to 1 s) may significantly further reduce the number of engaged GSLdevices in case of pure PS traffic in the cell. Instead on-demand PDCHs mustbe allocated more often, which may cause increased delays for some types of

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PS traffic. In case of mixed CS and PS traffic in a cell, the reduction of engagedGSL devices due to very low PILTIMER settings is negligible, so such settingsare recommended only in case of shortage of GSL devices in combination withpure PS traffic. A higher value of PILTIMER than the recommended may slightlyincrease the throughput performance to the cost of more engaged GSL devices.

The parameters TBFDLLIMIT and TBFULLIMIT have a default value of 2.A low value will ensure sufficient channel allocation for PS traffic when CStraffic is low, thereby maintaining an adequate transmission rate. A high valuemay cause lower transmission rate per MS, since several MS may share thesame PDCH, but on the other hand it will reduce the risk of preemption if CStraffic is high. The default value is chosen in order to get a reasonable fastPS transmission with a limited risk of preemption. If the cell normally hasovercapacity for GPRS/EGPRS, it may be an adequate choice to set theseparameters to 1, thus improving the data transmission rate in general permobile station.

The default value of FPDCH is 0. This will give as many channels as possiblefree for CS allocation. This may be an optimal solution if the GPRS/EGPRStraffic is low whereas the CS traffic is close to congestion and if CS serviceis prioritized, but if it is important to guarantee GPRS/EGPRS service in thecell under such conditions FPDCH may be set to 1, thus avoiding allocationattempts of a new PSET for every cell update. If the GPRS/EGPRS traffic issignificant it may be a better choice to set FPDCH to 4 to ensure adequatecapacity for multi-slot mobile stations.

If EGPRS is used it is recommended to allocate at least 4 dedicatedE-PDCHs on the non hopping BCCH CHGRP. This will be achieved by settingNUMREQEGPRSBPC (for CHGRP number 0) to the value 4.The parameterPDCHALLOC should then be set to “first and FPDCH to 4.

The preference parameter PDCHALLOC, which determines whether nonhopping TCHs on the BCCH frequency are first choice or not for allocation ofPDCHs, has some interaction with the corresponding parameter for allocationof CS channels CHALLOC, see User Description, Channel Administration. IfPDCHALLOC is set to “first”, and PDCHs are allocated using non hoppingTCHs on the BCCH frequency, then the probability to also get CS channelsthere will decrease even if CHALLOC also is set to “first”. This is due to thefact that TCHs adjacent to the TCHs allocated as PDCHs are reserved for PSas a first choice, since they could be part of a larger PSET together with thePDCHs already allocated. CS channels will be allocated there only if thereare no other idle TCHs left in the cell.

In order to maintain acceptable GPRS/EGPRS performance on on-demandPDCHs, it is recommended to only allow pre-emption of non essentialon-demand PDCHs (not carrying TAI). This is achieved by setting thePDCHPREEMPT parameter to 1. Pre-emption of a PDCH carrying TAI willcrash the on-going TBF, but pre-emption of other PDCHs will only reduce thedata throughput.

See Page 9 regarding setting of the parameter TN7BCCH.

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6 Parameters

6.1 Main controlling parameters

FPDCH is a preference parameter for number of dedicated PDCHs, set per cell.

PDCHALLOC is a preference parameter for allocation of non hopping TCHon the BCCH frequency, set per cell.

PILTIMER is a parameter for time-out of idle on-demand PDCHs, set in stepsof 1 s. and per BSC.

6.2 Parameters for special adjustments

DYNULDLACT is a parameter for activating/deactivating the feature dynamicdownlink/uplink PDCH reservation, set per BSC. Default value is off.

GPRSNWMODE is a parameter to choose the GPRS network operation mode,set per BSC.

• GPRSNWMODE=0 is chosen if the Gs interface between the MSC and theSGSN is present. A Master PDCH will not be allocated.

• GPRSNWMODE=1 is chosen if the Gs interface between the MSC andthe SGSN is present. A Master PDCH will be allocated when setting thenumber of dedicated PDCHs larger than zero.

• GPRSNWMODE=2 is chosen if the Gs interface between the MSC and theSGSN is not present. A Master PDCH will not be allocated.

• GPRSNWMODE=3 is chosen if the Gs interface between the MSC and theSGSN is not present. A Master PDCH will be allocated when setting thenumber of dedicated PDCHs larger than zero.

MBCRAC defines whether it can be assumed that all GPRS/EGPRS MSsare capable of all frequency bands that may be used in the same cell or if thenetwork has to evaluate each MS and its frequency band capability separately.It is set per BSC. Default value is 0. See also User Description, Multi Band Cell.

• MBCRAC = 0 is chosen if not all GPRS/EGPRS MSs are assumed to becapable of all frequency bands that may be used in the same cell. Generalon-demand PDCH allocation for a new PSET (not for individual mobilesupport) as well as allocation of dedicated PDCHs, can be performed onlyin the BCCH band.

Extension of an already existing on-demand PSET is however generallyallowed regardless of the MBCRAC setting.

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Channel allocation or reservation for an individual MS will only take placein the BCCH frequency band unless the frequency capabilities of the MSis known. However, the MS may be placed also in other frequency bandson on-demand PDCHs if the frequency capabilities of the MS are knownand will allow this.

• MBCRAC =1 is chosen if all GPRS/EGPRS MSs are assumed to becapable of all frequency bands that may be used in the same cell. GeneralPDCH allocation, can be performed also in other frequency bands than theBCCH band. Channel allocation or reservation for an individual MS cantake place in any frequency band if the frequency capabilities of the MSis not known. However, the frequency capabilities of the MS will be takeninto account if known.

NUMREQCS3CS4BPC is set per CHGR, and is used to set the wanted amountof BPCs for a CHGR to be G-TCHs.

NUMREQEGPRSBPC is set per CHGR, and is used to set the wanted amountof BPCs for a CHGR to be E-TCHs.

ONDEMANDGPHDEV is a parameter for minimum number of B-PDCHs (16kbits/s devices) reserved for on-demand PDCHs per RP, set per BSC.

ONDEMANDGPHDV64 is a parameter for minimum number of E-PDCHs andG-PDCHs (64 kbits/s devices) reserved for on-demand PDCHs per RP, setper BSC.

PDCHPREEMPT is a parameter (three bit binary value), set per BSC, thatcontrols the possibility for CS traffic to pre-empt different kind of PDCHs.

B0 B1 B2 Description

0 0 0 All on-demand PDCHs are possible to pre-empt

1 0 0 Only non-essential on-demand PDCHs are possibleto pre-empt

0 1 0 Only idle on-demand PDCHs are possible pre-empt

1 1 0 Only on-demand PDCHs that are not marked as‘used for streaming’ or are non-essential are possibleto pre-empt

0 0 1 Only on-demand PDCHs that are not marked as‘used for streaming’ are possible to pre-empt

PSETCHKPERIOD is a parameter for periodic check of optimal allocation of theprimary dedicated PDCHs, set per BSC. The value 0 means no periodic check.

SCALLOC is a parameter, set per cell, which makes it possible to restrictGPRS/EGPRS to a certain subcell when a subcell structure is defined for thecell. The possible values are:

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• UL – The allocation of PDCHs is restricted to the underlaid subcell. This isthe default value for the parameter.

• OL – The allocation of PDCHs is restricted to the overlaid subcell.

• BOTH,UL – It is possible to allocate PDCHs in both subcells. However,the underlaid subcell is preferred.

• BOTH,OL – It is possible to allocate PDCHs in both subcells. However, theoverlaid subcell is preferred.

TBFDLLIMIT is a preference parameter, set per BSC, for the number of averagesimultaneous TBFs per PDCH. The total number of TBFs is calculated as meanvalues counting the TBFs on all the PDCHs in the cell capable of supportingeach TBF mode. This means that checks against the limit in downlink directionare performed in priority order for each of the following combinations of PDCHsB capable (=E+G+B)), G capable (=E+G), and E capable (=E). New on-demandPDCHs are requested from CSD when the limit has been reached and it ispossible to acquire new PDCHs.

TBFULLIMIT is a preference parameter, set per BSC, for the number of averagesimultaneous TBFs per PDCH. The total number of TBFs is calculated as meanvalues counting the TBFs on all the PDCHs in the cell capable of supportingeach TBF mode. This means that checks against the limit in uplink direction areperformed in priority order for each of the following combinations of PDCHs: Bcapable (=E+G+B)), G capable (=E+G), and E capable (=E). New on-demandPDCHs are requested from CSD when the limit has been reached and it ispossible to acquire new PDCHs.

TN7BCCH is set per cell, and is used to define if TN7 is allowed to carryEGPRS on the BCCH frequency. Note that the parameter will affect all TN7 inCHGR-0 if frequency hopping is used.

6.3 Value ranges and default values

Ericson’s GSM System R10 parameters

Table 2

Parameter name Defaultvalue

Recommendedvalue

Valuerange

Unit

DYNULDLACT 0 (off) — 0,1(0=off,1=on)

FPDCH 0 — 0 to 8

GPRSNWMODE 2 — 0 to 3

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Table 2

MBCRAC 0 (off) — 0,1(0=off,1=on)

NUMREQCS3CS4BPC 0 — 0 to 128

NUMREQEGPRSBPC 0 — 0 to 128

ONDEMANDGPHDEV 20 20 1 to 256

ONDEMANDGPHDV64 5 — 0 to 63

PDCHALLOC no pref-erence

no preference first, last,no prefer-ence

PDCHPREEMPT 0 — 0, 1, 2, 3,4

PILTIMER 20 20 1 to 3600 s.

PSETCHKPERIOD 5 — 0 to 60 min.

SCALLOC UL — UL, OL,BOTHUL,BOTH,OL

TBFDLLIMIT 2 2 1 to 8

TBFULLIMIT 2 2 1 to 6

TN7BCCH GPRS — GPRS/EG-PRS

7 References

1 User Description, Channel Administration2 User Description, Overlaid/Underlaid Subcells3 User Description, Idle Channel Measurements4 User Description, Frequency Hopping5 User Description, GPRS/EGPRS Quality of Service6 3GPP TS 45.002 Multiplexing and multiple access on the radio path

(Release 4)7 User Description, EGPRS Link Quality Control8 User Description, GPRS Link Adaptation

2944/1553-HSC 103 12/4 Uen K 2004-02-09


9 User Description, Multi Band Cell

30 44/1553-HSC 103 12/4 Uen K 2004-02-09

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