03_rn20113en14gln0_egprs

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1 © Nokia Siemens Networks RN20113EN14GLN0

BSSPAR2: Chapter 3(E)GPRS

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Legal Notice

Intellectual Property Rights

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Individuals can use the Nokia Siemens Networks training material for their own personal self-development only, those same individuals cannot subsequently pass on that same Intellectual Property to others without the prior written agreement of Nokia Siemens Networks .

The Nokia Siemens Networks training material cannot be used outside of an agreed Nokia Siemens Networks training session for development of groups without the prior written agreement of Nokia Siemens Networks.

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Course Objectives

• Aim of BSSPAR 2 is to present enhanced EGPRS features and their parameters

• Focus on PCU2 new features and their parameters

• Explain PCU vs. PCU2 differences related to functionality and parameters

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Table of content

• PCU2 feature list (11.5)• GPRS LA CS3-4 (S11.5)• HMC and EDA (S12)• NCCR(S12)• NACC(S12)• (E)GPRS Extended cell (S13)• Multipoint Gb Interface (S13)• Gb flow over FR control• PCU Pooling (S13)• Packet Data Optimization Package (S13)• GPRS/EDGE support for PGSM/EGSM BTS (S14)• Downlink Dual Carrier (S14)

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Packet Control Unit 2Requirements

Overview

Functionality

Parameters

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PCU2

• SW Requirements:

• PCU2s can be installed to any Nokia GSM/EDGE BSC– PCU2-D, PCU3-E: BSC3i

– PCU2-U: other BSC types

– PCU2-E: BSC3i

– The existing PCU1s are replaced with PCU2s

• The preferred configuration can be selected flexibly– The BCSUs can be equipped with 0, 1, or 2 PCU2 plug-in units according to the functionality and

packet switched traffic handling capacity needs

– Mixed configurations with PCU1s are supported -> flexible and on need based equipping of PCU2s

• PCU2 is activated with a license key

• SW upgrade is enough to implement later PCU2 releases (PCU2 Rel. 2 in BSS12)

PCU2 Rel.1

S11.5BSC

Software release requiredNetwork element

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PCU2

In S11.5 one application software product requires PCU2 as a mandatory HW requirement

• GPRS CS3 & CS4

The following S12 application SW products require second generation PCU2 HW

• Dual Transfer Mode (DTM)

• Extended Dynamic Allocation (EDA)

• High Multislot Classes (HMC)

The following functionalities are not applicable with PCU2 in the BSC since S13:

• Enhanced QoS (EQoS)

• Support for PBCCH/PCCCH

• GPRS support for InSite BTS

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PCU2Task management

• Restructured task management of PCU2 moves RLC and Scheduler functionalities to digital signaling processor (DSP)

• External 16MB DSP memory for each DSP supports RTT improvement

PowerQuicc (PQ) processors are used

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PCU1 vs. PCU2 capabilitiesPCU PCU-S PCU-T PCU-B PCU2-U PCU2-D PCU2-E PCU2-E

BSS 10.5 ED & BSS 11Max BTSs 64 64 64 2*64 N/A N/A N/A N/AMax TRXs 128 128 128 2*128 N/A N/A N/A N/AMax SEGs 64 64 64 2*64 N/A N/A N/A N/AMax radio TSLs 256 256 256 2*256 N/A N/A N/A N/AMax Abis channels at 16kbps 256 256 256 2*256 N/A N/A N/A N/AMax Gb channels at 64kbps 31 31 31 2*31 N/A N/A N/A N/A

BSS 11.5Max BTSs 64 64 64 2*64 128 2*128 N/A N/AMax TRXs 128 128 128 2*128 256 2*256 N/A N/AMax SEGs 64 64 64 2*64 64 2*64 N/A N/AMax radio TSLs 256 256 256 2*256 256 2*256 N/A N/AMax Abis channels at 16kbps 256 256 256 2*256 256 2*256 N/A N/AMax Gb channels at 64kbps 31 31 31 2*31 31 2*31 N/A N/A

BSS 14Max BTSs 64 64 64 2*64 128 2*128 256 384Max TRXs 128 128 128 2*128 256 2*256 512 1024Max SEGs 64 64 64 2*64 64 2*64 128 256Max radio TSLs 256 256 256 2*256 256 2*256 512 1024Max Abis channels at 16kbps 256 256 256 2*256 256 2*256 512 1024Max Gb channels at 64kbps 31 31 31 2*31 31 2*31 2*31 4*31

Number of logical PCUs on board 1 1 1 2 1 2 1 1BSC Type BSCE BSCE BSCE BSC3i BSC2i BSC3i BSC3i BSC3i 3000

BSC2 BSC2 BSC2BSCi BSCi BSCiBSC2i BSC2i BSC2i

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EGPRS

GPRS

USF Granularity 4 with PCU2

Uplink state flag (USF) Granularity 4 enables higher use of 8-PSK in DL, as well as during GPRS TSL sharing in UL

Example

• An EGPRS mobile is receiving data in the DL direction

• A new GPRS connection is established in the UL into the same TSL

►GPRS mobile in the same TSL cannot decode 8-PSK

►the EGPRS connection needs to be downgraded to GMSK modulation

No need to downgrade with USF4

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USF Granularity 4 with PCU2

Benefit• Optimizes the multiplexed scheduling of GPRS and EGPRS users and in its best

2,8 folds the EGPRS users’ throughput in case of time slot sharing

ULGPRS MS

DLEGPRS MS

GMSK

USF granularity 1 with PCU 1

In shared TSL one radio block in UL with GPRS results in one GMSK EGPRS block in DL

8-PSK 8-PSK

GMSK

DLEGPRS MS

USF granularity 4 with PCU 2

8-PSK 8-PSK

GMSK

In shared TSL one radio block in UL with GPRS results in 1/4 GMSK EGPRS block in DL

ULGPRS MS

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USF4DL TSLs in (E)GPRS/GPRS multiplexing

Originally 4 DL 8-PSK TSLs (TSL 4-7), but now TSL 6 and 7 are GMSK modulated, because of USF is pointed to GPRS MS

USFUSF……

USFUSFRadio Block 4

USFUSFRadio Block 3

USFUSFRadio Block 2

USFUSFRadio Block 1

76543210

USFUSF……

Radio Block 4

Radio Block 3

Radio Block 2

USFUSFRadio Block 1

76543210

Originally 4 DL 8-PSK TSLs (TSL 4-7), but now TSL6 and 7 are GMSK modulated, because of USF is pointed to GPRS MS

USF 4 not

in useUSF 4 not

in use

USF 4

in useUSF 4

in use

GMSK

GMSK

GMSK

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PCU2Parameters

Scheduling step size

In PCU2, the new bucket round-robin (BRR) scheduling algorithm replaces the priority-based scheduling used in PCU1

PCU1/ Priority based scheduling:

DL HIGH PRIORITY SSS

DL NORMAL PRIORITY SSS

DL LOW PRIORITY SSS

UL PRIORITY 1 SSS

UL PRIORITY 2 SSS

UL PRIORITY 3 SSS

UL PRIORITY 4 SSS

PCU1/ Priority based scheduling:

DL HIGH PRIORITY SSS

DL NORMAL PRIORITY SSS

DL LOW PRIORITY SSS

UL PRIORITY 1 SSS

UL PRIORITY 2 SSS

UL PRIORITY 3 SSS

UL PRIORITY 4 SSS

PCU2/ BRR scheduling:

BACKGROUND TC SCHEDULING WEIGHT FOR ARP 1



PCU2/ BRR scheduling:




Converted values:

512106

511125

610154

79203

88302

97601

WeightSSSWeightSSS

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PCU2Parameters

Extended uplink TBF scheduling rate

PCU1:

• UL_TBF_SCHED_RATE_EXT defines the next block period when a TBF in the extended mode is given a transmission turn

• A TBF in the extended mode cannot though have better residual capacity than it would in the normal mode

In PCU2:

• POLLING_INTERVAL_BG defines the time in block periods during which the TBF in the extended state cannot have transmission time

• The parameter is the same for all traffic classes. After the POLLING_INTERVAL has elapsed, the TBF is returned to scheduling and it gets a transmission turn when the scheduler decides so

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PCU2Parameters

Delayed downlink TBF polling rate

In PCU2, POLLING_INTERVAL_BG defines the time in block periods how often the MS is polled during the delayed downlink TBF release. The parameter is the same for all traffic classes.

In PCU1, the time cannot be adjusted with any parameter.

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PCU2Parameters

Link Adaptation

The GPRS Link Adaptation (LA) algorithm is different in PCU1 and PCU2 but the EGPRS LA algorithm is the same.

PCU1: The coding scheme selection is based on the BLER estimate. BLER is estimated for each TBF based on the successfully and unsuccessfully transmitted/received RLC data blocks.

PCU2: The coding scheme selection is based on the channel quality measurements made by the RLC receivers. In downlink data transfer it is the RXQUAL value received from the MS and in uplink data transfer it is the BEP measurement received from the BTS.

• PCU1: LA works only in the RLC acknowledged mode (unack mode: CS1)

• PCU2: LA works both in the RLC acknowledged and RLC unacknowledged modes

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PCU2Parameters

GPRS Link Adaptation

LA parameters in PCU1:

•DL ADAPTATION PROBABILITY THRESHOLD•DL BLER CROSSPOINT FOR CS SELECTION HOP•DL BLER CROSSPOINT FOR CS SELECTION NO HOP•UL ADAPTATION PROBABILITY THRESHOLD•UL BLER CROSSPOINT FOR CS SELECTION HOP•UL BLER CROSSPOINT FOR CS SELECTION NO HOP

LA parameters in PCU2:

•DL CODING SCHEME IN ACKNOWLEDGED MODE•DL CODING SCHEME IN ACKNOWLEDGED MODE•UL CODING SCHEME IN ACKNOWLEDGED MODE•DL CODING SCHEME IN UNACK. MODE•UL CODING SCHEME IN UNACK. MODE•ADAPTIVE LA ALGORITHM

The LA parameters are not directly comparable and they are therefore not converted in the upgrade.

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MS-1 MS-1

PCU2DAP sharing

MS1 MS2

MCS-6 MCS-6

PCU12 x 16 kbit/s DAP sub TSL booked for MS1

2 x 16 kbit/s DAP sub TSL booked for MS2

PCU2No DAP resources booked for MS1

4 x 16 kbit/s DAP sub TSL booked for MS2

MS-2 MS-2

MS1 MS2

MCS-1 MCS-9

MS-2 MS-2 MS-2 MS-2

MCS-6 -> MCS-1/MCS-9

Master TSLs

TSL XY

MS-1 MS-1MS-1MS-1 MS-1 MS-1

Rotation of the DAP resources between MS-1 and MS-2

Rotation of the DAP resources between MS-1 and MS-2

Slave TSLs

Master TSLs

Master TSLs

Slave TSLs

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PCU2 Support in BSC

• Mixed configurations:– General rule: In the same slot capacity

and features are handled according the weakest unit (PCU, PCU-S)

– CS3&CS4 can be activated only when there is PCU2 on each BCSU on the same slot

– PCU2 can replace a faulty PCU as a spare part

– If there are PCU2 units on the same slot in every BCSU, then PCU cannot replace a faulty PCU2

BCSU 0 PC

U-S

PC

U2-D

BCSU 1 PC

U-S

PC

U2-D

BCSU 2 PC

U2-D

PC

U2-D

PCU 1 functionality

PCU2 functionality

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GPRS LA CS3-4

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GPRS Link Adaptation Algorithm (CS3-4)Introduction and Parameters• Coding schemes CS-3 - CS-4 are

supported if PCU2 is implemented

• The Coding Schemes CS-3 and CS-4 can be used in GPRS-enabled TRXs, which are EGPRS-capable.

• coding schemes CS3 and CS4 enabled (CS34)

– With this parameter you define whether the Coding Schemes CS-3 and CS-4 capability is enabled in the BTS. ▪ Range: Coding schemes CS3 and CS4

are disabled (N) (0), Coding schemes CS3 and CS4 are enabled (Y) (1). Default: Adaptive LA algorithm is enabled (Y) (1)

• adaptive LA algorithm (ALA)– With this parameter the operator can

define if the used GPRS Link Adaptation algorithm is adaptive or not. ▪ Range: Adaptive LA algorithm is

enabled (Y) (1), Adaptive LA algorithm is disabled (N) (0). Default: Adaptive LA algorithm is enabled (Y) (1)

0

10

20

30

40

50

60

0 5 10 15 20 25 30 35C/I [dB]

Th

rou

gh

pu

t [k

bit

/s]

EGPRS

CS-1 & 2

CS-1...4

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GPRS Link Adaptation Algorithm (CS3-4)Parameters• The LA algorithm is applied to measure the signal quality for each TBF in terms of RXQUAL.

It describes the channel quality with the accuracy of eight levels (0-7). RXQUAL is measured for each received RLC radio block.

• PCU uses two 2-dimensional tables for the LA operation (ACKS/NACKS and DL/UL separately)

– The values in the tables are initially based on the simulations

– Fixed values used if adaptive LA algorithm (ALA)= ‘N’

– If ALA = ‘Y’, the table is updated based on ack/nack of RLC/MAC blocks▪ Ack of RLC/MAC block the LA can allow lower RxQual value even with the same CS as a requirement

▪ Nack of an RLC/MAC block can lead to higher RxQual value even with the same CS as a requirement

CS4

CS3

CS2

CS1

76543210

xx

xx

xx

xx

RXQUAL ->

Coding schemes

The setup of the table is an example.

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GPRS Link Adaptation Algorithm (CS3-4)Parameters

• DL Coding Scheme in Acknowledged Mode (DCSA)

• UL Coding Scheme in Acknowledged Mode (UCSA)– Defines the initial CS in acknowledge mode in downlink/uplink

direction.▪ Range: CS1 (0), CS2 (1), CS3 (2), CS4 (3), LA with initial CS1 (4), LA with

initial CS2 (5), LA with initial CS3 (6), LA with initial CS4 (7).

▪ Default: CS2 (1)

Remark: The parameter values 2,3,6 and 7 are valid only for Nokia MetroSite, Nokia UltraSite and Nokia Flexi EDGE

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GPRS Link Adaptation Algorithm (CS3-4)Parameters

• DL Coding Scheme in Unacknowledged Mode (DCSU)

• UL Coding Scheme in Unacknowledged Mode (UCSU)– Define the initial CS in unacknowledged mode downlink/uplink

direction.▪ Range: CS1 (0), CS2 (1), CS3 (2), CS4 (3), LA with initial CS1 (4), LA with

initial CS2 (5), LA with initial CS3 (6), LA with initial CS4 (7).

▪ Default: CS2 (1)

Remark: The parameter values 2,3,6 and 7 are valid only for Nokia MetroSite, Nokia UltraSite and Nokia Flexi EDGE

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High Multislot Class andExtended Dynamic Allocation

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High Multislot Class

• 3GPP release 4 or earlier MSs are limited to combined DL/UL TSL sum of 5

• 3GPP release 5 (TS 45.002) introduces new MS multislot classes which allow sum of DL/UL TSL of 6

– New maximum allocation configurations : ▪ Downlink + uplink: 5+1 and 4+2

– With Extended Dynamic Allocation Application Software▪ Downlink + uplink: 3+3 and 2+4

• HMC activation– PCU2 and HMC license are needed.

0

50

100

150

200

250

300

350

GPRS GPRS CS3/4 EDGE

kb

it/s S11.5

S12

Peak downlink throughput

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DA/EDA Allocation

• Dynamic Allocation: Multislot MS needs to monitor Uplink State Flag (USF) on each timeslot allocated in Uplink direction.

• Extended Dynamic Allocation: Multislot MS monitors Uplink State Flag (USF) until it receives it on one timeslot

• EDA activation– PCU2 and EDA license is needed.

– EDA can be activated with ZW7M command

USF gives permission to send in the corresponding uplink slot during the next block period

USF gives permission to send in the corresponding uplink slot during the next block period

USF gives permission to send in the corresponding and all the later allocated uplink slots during the next block period.

USF gives permission to send in the corresponding and all the later allocated uplink slots during the next block period.

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

T

USF USF

T

0 1 2 3 4 5 6 7

0 1 2 3 4 5 6 7

T

USF

TT T

0

50

100

150

200

250

300

350

GPRS GPRS CS3/4 EDGE

kb

it/s S11.5

S12

Peak uplink throughput

A mobile may reduce its transmission power as a function of the number of UL timeslots it uses. The more timeslots a mobile uses in UL, the more it may reduce its transmission power. Therefore, transmission powerreduction may affect EDA connections more than DA connections.

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MS power reduction

• MS may reduce uplink transmission power when multiple uplink timeslots are allocated

– Applied to dynamic allocation and extended dynamic allocation

– Applied to GSMK and 8-PSK modulation

– Applied to all frequency bands

• The reduced MS transmission power is taken into account together with the expected quality of the radio path when

– Selecting the number of uplink timeslots, and

– Selecting the initial channel coding scheme for a new connection

6.04

4.83

3.02

01

Permitted nominal reduction of maximum output power (dB)

Number of uplink timeslots

02.04.06.04

00.82.84.83

001.03.02

00001

MS Multislot Profile 3




Nbr of UL TSLs

3GPP release 4 3GPP release 5

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MS power reduction

• The number of UL TSLs is determined by estimating which allocation will give the best UL throughput

• The highest throughput is not always reached by the highest number of allocated UL TSLs

• This is due to MS power reduction and scheduling inflexibility

• During radio connection the PCU adapts the allocation of DL and UL timeslots based on the monitored amount of DL and UL data traffic

• The signal quality limits for different UL timeslot configurations can be modified by the Mean BEP Limit and RX Quality Limit parameters.

– In determining these limits, the appropriate signal quality - as typically required by applications used in the network - must be considered together with the power reduction characteristics of different mobile stations.

– The limits should be set so that the signal quality remains acceptable even when the MS applies maximum power reduction.

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Network Controlled Cell Re-selection

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(E)GPRS mobility

• Network Control Mode (NCM) defines how cell re-selection is performed:– Network Control Mode = 0 (NC0): the MS will perform an autonomous cell reselection.– Network Control Mode = 2 (NC2): the MS sends neighbors cell measurements to the

network and the network commands the MS to perform cell re-selection -> Network Controlled Cell Re-selection▪ NCM is modified with MML command ZEEM.

• The GSM idle mode functionality is used for (E)GPRS cell (re)-selection, if NC0 is implemented.

– C1 and C2 parameter setup is taken into account in (E)GPRS cell selection and re-selection process

• HYS parameter– the HYS parameter is used for all the cell changes, if a TBF is ongoing– In case of standby mode (TBF is not established), the HYS parameters is used on RA

border only

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Network Controlled Cell Re-selection (NCCR)Introduction

• NCCR cell re-selection criteria:– Power budget will push EGPRS capable MSs to EGPRS cells and

non-EGPRS capable MSs to non-EGPRS capable cells.

– Quality Control trigger NCCR when the serving cell transmission quality drops even if the serving cell signal level is good.

– Coverage based ISNCCR selects 3G network as soon as it is available or when GSM coverage ends, depending on operator choice.

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Network Controlled Cell Re-selection (NCCR)General parameters• NCCR applicability

– NCCR control mode (NCM)– WCDMA FDD NCCR enabled (WFNE)

• MS reporting– NCCR idle mode reporting period (NIRP) (default: 15.36s (5))– NCCR transfer mode reporting period (NTRP) (default: 0.48s (0))

• Averaging– NCCR rxlev transfer mode window size (NRTW) (default: 5)– NCCR rxlev idle mode window size (NRIW) (default: 5)– NCCR number of zero results (NNZR) (default: 2)

• Return to old cell and penalty– NCCR return to old cell time (NOCT) (default: 10s)– NCCR target cell penalty time (NTPT) (default: 10s)– NCCR neighbor cell penalty (NNCP) (default: 6s)

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EGPRS MS moving from serving GSM cell to neighbouring EGPRS cell and

vice versa

Network Controlled Cell Re-selection (NCCR)Power Budget

Negative power budget margin value:• Network will order the EGPRS MS to select neighbouring

cell around the location A.=> EGPRS MS would be pushed to EGPRS capable cell.

• This is done although the average received signal level from the EGPRS capable cell is lower than on from the regular cell.

• In opposite direction: EGPRS MS moves away from EGPRS capable cell and approach to non EGPRS capable cell the cell-reselection would be triggered in location B.=> EGPRS MS is held longer on EGPRS capable cell.

Positive power budget margin value:• GPRS MSs are kept in regular cells as long as possible to

reserve EGPRS resources for EGPRS MSs.• Network will order the GPRS MS to select neighbouring

cell around the location A.=> GPRS MS is kept in the GSM cell longer.

• When GPRS MS move away from EGPRS capable cells and approach to non-EGPRS-capable cells the cell-reselection is triggered in location B.

Ave

rage

RXL

EV f

rom

GSM

cel

l Average RXLEV from ED

GE cell

Distance between cells

EDGE capable cellGSM capable cell

Power budget margin

AB

GPRS MS moving from serving GSM cell to neighbouring EGPRS cell and vice versa

Ave

rage

RXL

EV f

rom

GSM

cel

l Average RXLEV from

EDG

E cell



Power budget margin

AB

Ave

rage

RXL

EV f

rom

GSM

cel

l Average RXLEV from

EDG

E cell



Power budget margin

AB

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Network Controlled Cell Re-selection (NCCR)Power Budget• PBGT(n) = (AV_RXLEV_NCELL(n) - AV_RXLEV_SERV ) + (MS_TXPWR_MAX_CCH -

MS_TXPWR_MAX_CCH (n) ) - TO(n) * (1 - L(n))– TO(n) = TEMPORARY_OFFSET_NCCR(n) * H(PENALTY_TIME_NCCRS(n) - T(n))– L(n) = 0 if PRIORITY_CLASS(n) = PRIORITY_CLASS(s) , and 1 if PRIORITY_CLASS(n) <> PRIORITY_CLASS(s)

• HCS(n) = AV_RXLEV_NCELL(n) - HCS_THR(n) - TO(n) * L(n)

• PRIORITY_CLASS defines the HCS (hierarchical cell structures) priority for the cells. 0 is the lowest and 7 is the highest priority

• AV_RXLEV_NCELL(n) > GPRS rxlev access min (PRXP) (n) + Max(0, Pa)– Pa = GPRS_MS_TXPWR_MAX_CCH(n) – P– P is the MS maximum GMSK RF output power on the band of the cell n.

• PBGT(n) > PBGT_margin(n)

Parameters: NCCR EGPRS PBGT margin (EPM) NCCR GPRS PBGT margin (GPM) NCCR other PCU cell offset (NOPO) HCS signal level threshold (HCS) Priority class (PRC) GPRS temporary offset (GTEO) GPRS penalty time (GPET)

EDGE capable cell

GPRS capable cell

EGPRS MS working in EGPRS

mode

GPRS MSEGPRS MS

working in EGPRS mode

EDGE capable cell

GPRS capable cell

EGPRS MS working in EGPRS

mode

GPRS MSEGPRS MS

working in EGPRS mode

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Network Controlled Cell Re-selection (NCCR)Power Budget Parameters• GPRS RXLEV ACCESS MIN (GRXP)

– With this parameter the operator can define the minimum power level an MS has to receive before it is allowed to access the cell.▪ Range: -110...-47 dBm, step 1 dBm▪ Default: -105 dBm

• GPRS MS TXPWR MAX CCH (GTXP1)– With this parameter the operator can define the maximum transmission power

level a mobile station can use when accessing a packet control channel in the cell for GSM 900/800 bands.▪ Range: 5-39 dBm, step 2 dBm▪ Default: 33 dBm

• GPRS MS TXPWR MAX CCH 1X00 (GTXP2)– With this parameter the operator can define the maximum transmission power

level a mobile station may use when accessing a packet control channel in the cell for GSM 1800/1900 bands.▪ Range: 0-36 dBm, step 2 dBm▪ Default: 30 dBm

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Network Controlled Cell Re-selection (NCCR)Quality Control (QC)• The purpose of QC is to monitor and detect degradation periods in service

quality, and to perform corrective actions to remove the servicedegradation.

• The QC maintains statistics about – BLER filtering for each TBF

▪ For BLER sample filtering, the threshold value is operator parameter maximum BLER in acknowledged mode (BLA) or maximum BLER in unacknowledged mode (BLU), depending on the RLC mode of the TBF.

– bitrate per radio block filtering for each TBF in RLC ACK mode.▪ For bitrate per radio block sample filtering, the threshold value is one of the four

operator parameters • QC GPRS DL/UL RLC Ack Throughput Threshold (QGDRT, QGURT)

• QC EGPRS DL/UL RLC Ack Throughput Threshold (QEDRT, QEURT)

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Network Controlled Cell Re-selection (NCCR)Quality Control (QC) – BLER filtering• QC shall maintain the BLER degradation duration counter for each TBF according

to the following rules:– The BLER degradation duration counter shall be incremented by 10, if ;

– the counter shall not be modified, if ;

– The counter shall be cleared (set to zero), if.

• Max BLER in the equations is based on – Maximum BLER in Acknowledged Mode (BLA)

▪ Range: 10...100 %, step 1 %. Default: 90%

– Maximum BLER in Unacknowledged Mode (BLU)▪ Range: 10...100 %, step 1 %. Default: 10%

• The QC thread shall monitor the BLER degradation duration counter, and if the counter is larger than predefined triggering levels, the corresponding corrective action is tried.

(%)_(%)_ BLERMeasuredBLERMAX <

(%)_(%)_(%)_ BLERMAXBLERMeasuredBLERMAX ≤≤

(%)_(%)_ BLERMAXBLERMeasured <

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Network Controlled Cell Re-selection (NCCR)Quality Control (QC) – BER filtering• The bitrate per radio block degradation duration counter shall be

maintained for each TBF according to the following rules:– The bitrate per radio block degradation duration counter shall be incremented

by 10, when the bitrate per radio block is below the threshold value.– The counter shall be cleared (set to zero), when the bitrate per radio block is

above or equal to the threshold value.

• The threshold values are defined by – QC GPRS DL/UL RLC Ack Throughput Threshold (QGDRT, QGURT)

▪ Range: 0...20 kbit/s, step 1 kbit/s. Default: 6 kbit/s

– QC EGPRS DL/UL RLC Ack Throughput Threshold (QEDRT, QEURT)▪ Range: 0...20 kbit/s, step 1 kbit/s. Default: 10 kbit/s

• The QC thread shall monitor the bitrate per radio block degradation duration counter. If the counter is larger than predefined triggering levels, the corresponding corrective action is tried.

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Network Controlled Cell Re-selection (NCCR)QC Parameters• The action trigger thresholds are expressed in block periods

– QC reallocation action trigger threshold* (QCATR) (default: 25)

– QC NCCR action trigger threshold (QCATN) (default:100)

• Each action shall be triggered only once for a TBF in QC for a call (UL+DL TBFs of the same phone) during one degradation period(200ms). If the degradation period ends and a new starts, new actions can be tried.

*If reallocation is initiated by QC, new resources are reserved but from different BTS than current. If no suitable new BTS found, no reallocation is done.

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Network Assisted Cell Change

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Network Assisted Cell Change (NACC)

• NACC is an enhancement for cell re-selection process

• In NACC the network is allowed to assist MSs before and during the cell change by

– Sending neighbour cell system information on PACCH to the MS in packet transfer mode on the serving cell

– Introducing the PACKET SI STATUS procedure for the cells that have no PBCCH

• NACC reduces service outage time when a GPRS MS in packet transfer mode moves between GSM cells

• Applicable in packet transfer mode for both autonomous and network-controlled cell change

• NACC has support for intra-BSC cell changes

• Not dependent on NCCR/ISNCCR

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NACC for NC0

A new mode, Cell Change Notification (CCN) is needed for a MS in NC0 mode in order to make use of NACC feature

• MS must be in Transfer Mode

• MS may enter the CCN state when it has fulfilled the cell changecriteria and has determined the target cell for the cell re-selection

In the CCN mode the MS delays the cell reselection until it has received the required system information messages of the target cell

Both the network and MS must support CCN

• The serving cell and the target neighbor cell must support CCN mode

The support for CCN implies also that it is mandatory for the mobile station to support the Packet PSI/SI Status procedures

The support for CCN implies also that it is mandatory for the mobile station to support the Packet PSI/SI Status procedures

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NACC for NC0 (Network Control)MS Autonomous Cell-reselection

MSSource

cellC1, C2 (C31 or C32) criterion triggers

Target cell

Current TBF on source cell is

aborted

(P)SI message

(P)SI message

(P)SI message

(P)SI message

All required (P)SI message received

data

Channel request

assignment

without NACC

MSSource

cellC1, C2, (C31 or C32) criterion triggers

Target cell


aborted

PACKET CELL CHANGE NOTIFICATION

PACKET NEIGHBOUR CELL DATA #1

PACKET NEIGHBOUR CELL DATA #N

data

Channel request

assignment

PACKET (P)SI STATUS

PACKET SERVING CELL DATA #1

PACKET SERVING CELL DATA #N

with NACC

Shorter outage

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NACC for NC2 (NCCR) Network-controlled cell re-selection

MSSource

cellNCCR triggers

Target cell


aborted

(P)SI message

(P)SI message

(P)SI message

(P)SI message

All required (P)SI message received

PACKET CELL CHANGE ORDER

Channel request

assignment

without NACC with NACC

MSSource

cellTarget

cell


aborted

PACKET NEIGHBOUR CELL DATA #1

PACKET NEIGHBOUR CELL DATA #N

Channel request

assignment

PACKET (P)SI STATUS

PACKET SERVING CELL DATA #1

PACKET SERVING CELL DATA #N

NCCR triggers

PACKET CELL CHANGE ORDER

Shorter outage

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NACC

• NACC is in Rel 4 of 3GPP GERAN , mandatory for R4 mobiles

• Both, autonomous and network controlled cell reselections are supported

• NACC support for MSs in RR Packet Transfer Mode only • Support intra-BSC cell changes

• Parameter for enabling:– BSC level parameter NACC enabled (NACC)

Define the usage of NACC procedures.N= disabledY= EnabledMML default: N

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Extended Cell for (E)GPRS

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Extended Cell for (E)GPRSHW/SW Requirements

SUPPORTED IN:GSM1900

YMSC

-

NokiaNetAct

OSS4.25)

SGSN-

NetActPlanner

-BSCS13

GSM800

Y

GSM900

Y

GSM1800

Y

Nokia 2nd

Gen.

N

NokiaTalk-family

N

NokiaPrimeSite

N

NokiaMetroSite

N

NokiaInSite

N

NokiaUltraSite

CX5.0

SGSNHW/FW

-

TCHW/FW

-

BTSHW/FW

Y 3)

BSCHW/FW

Y 2)

BTSMMI

-MSY 1)

BSCMMI

Y

Operating/Application

Application 4)

HW/FW DEPENDENCY:

Note(s): 1) GPRS/EGPRS mobile is needed 2) PCU2 3) EDGE TRX required 4)Extended Cell Range ASW + Extended cell for GPRS ASW 5)OSS4.2 CD set1 / OSS5 CD set 1

NokiaFlexiEdge

EP2.0

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Extended Cell for (E)GPRSIntroduction• RTSL 0 of the N-TRX configured as

BCCH/RACH/SDCCH. • E-RACH, through which access

bursts are received from the extended service area, occupies RTSL 0 of the E-TRX. E-RACH is tuned to the same frequency as the BCCH/RACH. The DL direction of the E-RACH RTSL is not used for any purpose: BCCH serves both service areas.

• RTSL 1 of the BCCH N-TRX is left unused since its reception overlaps with that of E-RACH on the same frequency.

• Six timeslots in both TRXs can be used for actual GSM/GPRS user traffic. E-RACH E-TRX

BCCH N-TRXf1

BCCH/RACH/SDCCH

Not TCH

Delayedreception

Normalreception

f1 f1 f1 f1 f1 f1 f1

TCH TCH TCH TCH TCH

f1

TCH

f2 f2 f2 f2 f2 f2 f2

TCH TCH TCH EGTCHSDCCH

in use

N-TRX

E-TRX

E-RACH EGTCH

BTS

Normal Service Area

Overlapping Area

0 kmTA=0

30 kmTA=54 (Inner Area)TA=0 (Outer Area)


ONE CELL

65 kmTA=63

Extended Service Area

BTSBTS

Normal Service Area

Overlapping Area

0 kmTA=0



ONE C

0 kmTA=0



ONE CELL

65 kmTA=63

Extended Service Area

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Extended Cell for (E)GPRSParameters

• Ext Cell GPRS Enabled (EXGENA)– Enables or disables extended cell PS capability in a segment.

▪ Range: Yes/No. Default: No

• Ext Cell Location Keep Period (EXKEEP) – Defining the period during which MS’s service area is kept in PCU’s

memory following release of (all) TBF(s) allocated for the MS. ▪ Range: 0-44 s. Default: 15 s

• Radius extension (EXT) – Conveyed to PCU, which uses the parameter when converting TA

values received from one service area into a values applicable in the other area.▪ Range: 0-35 km. Default: 0

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Extended Cell for (E)GPRSParameters

• MS distance ho threshold ext cell max (MAX)– Conveyed to PCU, which observes the parameter when determining

whether a new UL TBF should be created in the normal or the extended service area, and when determining the need for a reallocation from the normal to the extended service area: MS TA >= MAX reallocation to extended service area.▪ Range: 0-63. Default: 63

• MS distance ho threshold ext cell min (MIN)– Conveyed to PCU, which observes the parameter when determining

the need for a reallocation from the extended to the normal service area. MS TA <= MIN reallocation to normal service area.▪ Range: 0-63. Default: 2

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Extended Cell for (E)GPRSNew parameters and channel types• MS max distance in call setup (DMAX)

– Indicates how far away from the BTS a call creation attempt is still accepted. In an extended cell, parameter applied only to access requests received through E_RACH.▪ Range: 0-255 TA units. Default: 255 (Values 63-255 indicate that call creation

attempts are not restricted by MS distance.)

• RTSL type 0-7 (CH0-CH7) – A new channel type added (EGTCH).

– Range: TCHF, TCHH, TCHD, ERACH, NOTUSED, SDCCH, MBCCH, MBCCHC, MBCCB, SDCCB, MPBCCH, EGTCH

– Default: TCHF

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Extended Cell for (E)GPRSNew parameters

• Initial MCS for ext area ack/nack mode (MCEA/MCEU)– With this parameter the operator indicate the initial Modulation and

Coding Scheme (MCS) used at the beginning of a TBF for acknowledged/unacknowledged mode in the extended coverage area of an extended cell. The parameter is used in EGPRS link adaptation. This parameter is valid only for Nokia UltraSite and Nokia Flexi EDGE BTSs.▪ Range: 1-9, step 1

▪ Default: 1

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Gb flow over FR control

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BSSGP Flow Control in DL - Parameter View

PCUPAPUGbAbisUm

BTS

MS 1

Actual Cell Leak Rate

MS 2

Cell 1

MS 1

Gb MS Flow control

Gb BVC Flow control

FC_R_TSL_EGPRS(default leak rate / TSL) This together with territory size gives the default BVC level leak rate.

FC_MS_B_MAX_DEF_EGPRS

FC_B_MAX_TSL_EGPRS(Buffering capacity / TSL)

This together with territory size gives the actual BVC allocation.

FC_MS_R_DEF_EGPRS(default leak rate – at startup)

FC_R_DIF_TRG_LIMIT(triggering limit for updates of the reported Leak rate)

Access rate

IP packet

LLC frame

MS 2

Gb buffer

BSSGP/LLC

CIR check (FR)

RLC/MAC frame NS/FR

PCU DL buffer

BVC allocation

MS bucket (MS allocation)

BVC check

MS check

Leak rate

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BSSGP Flow ControlParameters• FC_R_DIF_TRG_LIMIT

– The limit value for r_dif that triggers a flow control message (r_dif>0.1). ▪ Range: 0-1000D. Default: 100D

• FC_MS_R_DEF_EGPRS– This parameter defines the default value for MS-specific leak rate. This may be used for

EGPRS capable MSes. The value is given in Bytes/s. ▪ Range: 1000-65280D. Default: 15000D

• FC_MS_B_MAX_DEF_EGPRS– This parameter defines the default value for MS-specific buffering capacity. This may be

used for EGPRS capable MSes. (5 kB).▪ Range: 2000-65280D. Default: 55000D

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BSSGP Flow ControlParameters• FC_R_TSL_EGPRS

– This parameter defines the transmission capacity of one EGPRS timeslot. This parameter is used instead of fc_r_tsl, if the segment has EGPRS capability (given in Bytes/s). ▪ Range: 1000-65280D. Default: 4500D

• FC_B_MAX_TSL_EGPRS– Buffering capacity of one EGPRS timeslot. This parameter is used instead of

fc_b_max_tsl, if the segment has EGPRS capability. (25 kB)▪ Range: 5000-65280D. Default: 25000D

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BSSGP Flow ControlGPRS

• The following parameters are used for GPRS flow control– FC_MS_R_DEF (default: 4500 (36 Kbps))

– FC_MS_R_MIN 40 (default: (320 bps))

– FC_MS_B_MAX_DEF (default: 10000 (10 kB))

– FC_R_TSL 1500 (default: (12 Kbps))

– FC_B_MAX_TSL (default: 25000 (25 kB))

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Packet Control Unit (PCU2) Pooling

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PCU2 Pooling HW/SW Requirements

SUPPORTED IN:GSM1900

YMSC

-

NokiaNetAct

OSS4.24) 5)

SGSN1)

NetActPlanner

-BSCS13

GSM800

Y

GSM900

Y

GSM1800

Y

Nokia 2nd

Gen.

N

NokiaTalk-family

(Y)

NokiaPrimeSite

N

NokiaMetroSite

(Y)

NokiaInSite

N

NokiaUltraSite

(Y)

SGSNHW/FW

-

TCHW/FW

-

BTSHW/FW

-

BSCHW/FW

Y 2)

BTSMMI

-MS-

BSCMMI

Y

Operating/Application

Application 3)

HW/FW DEPENDENCY:

Note(s): 1) Resource Distribution Function 2) PCU2, PCU LAN cabling and site LAN switches 3)PCU2 4) PCU pooling ASW + Gb over IP ASW required 4) OSS4.2 CD set1 / OSS5 CD set 1

NokiaFlexiEdge

(Y)

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• With PCU pooling, new PCU plug-in units can be added to a live BSC easily.

• A group of PCU plug-in units form a packet service entity (PSE), that is, one PSE can contain several PCU plug-in units in a BSC.

– A PSE is a logical concept that hides the physical PCU plug-in units from the logical network configuration.

– From the SGSN, a PSE looks like a single PCU.

– The operator attaches the dynamic Abis pools (DAPs) and the segments to a PSE instead of a PCU. When a new PCU is added to a PSE, the Gbinterface is configured automatically for the new PCU. The system then allocates the DAPs and segments to the new PCU, based on the measured peak GPRS/EDGE load of each cell.

Abis and Gb interface resources are used more efficiently - CAPEX Savings

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• (E)GPRS load is shared dynamically between PCUs within the PCU pool

• Feature is implemented only in PCU2 and Internet Protocol (IP) is used as transport method in the Gb interface

– Two PCUs can form a Packet Control Pool (PCP)

– There can be maximum 50 PCUsin one PCP

– In case of Multipoint Gb, there is several NSEs in PCP. Each NSE covers all PCUs in a PCP

BSC

SGSN

PCUPCUPCU

PCU Pool

NSE(PCU Pool)

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PCU2 PoolingParameters : RNW Object model

BCFBCF

BTS(SEG)

BTS(SEG)

2000

2000

PSEPSE

(W)

RARA128 S

100

TRXTRX2000

DAPDAP1600

(W)

NSENSE800 S

PCUPCU100

NSVCNSVC1600

S

S

S

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New objects:

• PSE – Packet Service Entity– PSEI

• PCU– Logical BCSU address, PCU index, PIU type and Gb interface

type.

– PCU identifier is record number of PCU file, managed by the system.

Modified objects:

• NSE– Logical BCSU address, PCU index and PIU type removed.

PCU2 PoolingParameters

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Packet Data Optimization Package

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Packet Data Optimization Package

BSS13 packet data optimization package consists of following features:

• BSS20395 PCU Utilisation Counters

• BSS20432 EDAP Usage and Blocking Counters

• BSS20835 Latency Counters

• BSS20857 1-phase Access Counter

• BSS20746 Impact and Reason of Inadequate EDAP Allocations

With accurate (E)GPRS performance index, the operator can accurately determine if optimisation or expansion is needed, resulting in improved network dimensioning

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Packet Data Optimization Package PCU Utilisation Counters

Following new counters on PCU level:PEAK GPRS CHANNELS PER PCU AVE BUSY GPRS CH ULAVE BUSY GPRS CH DLPEAK BUSY GPRS CH ULPEAK BUSY GPRS CH DL

PEAK GPRS CHANNELS counters are sampled every 20 seconds. AVE BUSY GPRS counters are sampled every 5 seconds

Provide measurement data on peak and average (E)GPRS channelusage per PCU

Improves network dimensioning. Improves visibility of the actual GPRS/EDGE performance

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Packet Data Optimization Package EDAP Usage and Blocking Counters

PCU provides new counters that measure time when EDAP load is over predefined thresholds. There are two thresholds: one for lower load and the other for higher load. Thresholds are user definable via MMI or NetAct.

Four new counters, per EDAP pool:

• TIMES OVER DL EDAP LOW THRESHOLD

• TIMES OVER DL EDAP HIGH THRESHOLD

• TIMES OVER UL EDAP LOW THRESHOLD

• TIMES OVER UL EDAP HIGH THRESHOLD

Two configurable parameters, on BSC level:

• EDAP low peak threshold. Percentage of EDAP utilisation to be tracked by low peak counter. Default 70%.

• EDAP high peak threshold. Percentage of EDAP utilisation to be tracked by high peak counter. Default 90%.

More visiblity to EDAP usage and blocking.

GPRS traffic is very fluctuating, it is useful to know how long time utilization is e.g. over 90%

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Packet Data Optimization Package Latency Counters

Counters for DL transfer latency are implemented in BSS13

Following new counters are added to EQoSmeasurement, because QoS parameters affect queuing time.

• DL LLC TRANSFER DELAY SUM

• DL LLC DELAY FRAME COUNT

The first counter counts sum of latencies and second one counts amount of measurements. Average latency can then be calculated in post-processing using these two counters.

Due to latency depends also on size of LLC PDU, following counter is also introduced with BSS13

• DL LLC DELAY MEASURED BYTES TOTAL

For many applications latency is an important indicator of end user perceived quality

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Packet Data Optimization Package 1-phase Access Counter

Four new counters

•1 PHASE UL GPRS TBF ESTABLISHMENT REQUESTS

•1 PHASE UL GPRS TBF SUCCESSFUL ESTABLISHMENTS

•1 PHASE UL EGPRS TBF ESTABLISHMENT REQUESTS

•1 PHASE UL EGPRS TBF SUCCESSFUL ESTABLISHMENTS

MS sends request on Channel Request message (for GPRS) or EGPRS Packet Channel Request (EGPRS) message on CCCH. Messages contain information whether 1-phase access is requested. Counters are updated when 1-phase establishment has succesfully progressed to a phase where assignment command is sent to the MS.

1-phase UL EGPRS TBF establishment is possible only if EPRC feature has been activated

1. Packet channel request

2. Packet uplink assignment

One phase access

1. Packet channel request

3. Packet resource request

Two phase access



Data

Data

Operator will be able to know the proportion of terminal/subscribers making a 1-phase access (instead of a 2-phase access)

Better radio resource management. Facilitates network optimisation

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Packet Data Optimization PackageImpact and Reason of Inadequate EDAP Allocations

EDAP SLAVE CH REQUESTED

• Indicates how many EDAP slave channels are requested. Updated by amount of requested slave channels at every EDAP request where also slave channels are requested. Requested number of slave channels is based on a situation just before EDAP allocation, so possible restrictions due to GPRS territory and Link Adaptation are not visible in this counter.

EDAP MISSED SLAVE CH DUE SIZE

• Indicates how many EDAP slave channels are “missed” because EDAP pool size is too small. Updated by amount of non-received slave channels.

EDAP MISSED SLAVE CH DUE OTHER

• Indicates how many EDAP slave channels are “missed” because of PCU limitations or any other reason than EDAP pool size. Updated by amount of non-received slave channels.

New counters on PCU level to show how much the requested MCS is lowered because of EDAP pool size or other reasons. Counters to be added to Dynamic Abis measurement and collected per EDAP

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Downlink Dual Carrier

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Downlink Dual CarrierIntroduction

Single carrier allocations in Downlink and UplinkSingle carrier allocations in Downlink and Uplink Up to 5 Up to 5 TSLsTSLs in DL in DL -- max MS Multislot Class capability supported by PCU2 (Class 40max MS Multislot Class capability supported by PCU2 (Class 40--45)45) Up toUp to 296 kbps (5TSLs @ MCS9)296 kbps (5TSLs @ MCS9) of theoretical peak LLC data throughputof theoretical peak LLC data throughput Service continuity for 3G highService continuity for 3G high--datadata--rates applications not ensuredrates applications not ensured

Up to BSS13Up to BSS13

Dual Carrier in Downlink Dual Carrier in Downlink -- part of 3GPP part of 3GPP Rel.7 GERAN EvolutionRel.7 GERAN Evolution

BSS14BSS14

64 kb/s64 kb/s

200 kb/s200 kb/s

500 kb/s500 kb/s

c1

c1

c2

DL TBF may be allocated on DL TBF may be allocated on 22 carrierscarriers

increased flexibility of TSL allocationincreased flexibility of TSL allocation

more efficient sharing of the system throughput

Higher number of Higher number of TLSsTLSs allocated for DL allocated for DL TBFsTBFs

up to 10 TSLs in DL

Improved user data throughput and reduced user perceived delayImproved user data throughput and reduced user perceived delay

up to 592 kbps (10TSLs @ MCS9) of theoretical peak LLC data throughput

Ensured service continuity between areas covered by 2.5G and 3G Ensured service continuity between areas covered by 2.5G and 3G RANsRANs

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Downlink Dual CarrierNew Parameters

DCENA DLDC Enabledobject: BTS

unit: -

range: 0 (N)

1 (Y)

step: 1

default: 0

This parameter determines the Downlink Dual Carrier feature status (enabled/disabled) in the BTS

Note: Setting this parameter to its default value means that feature is disabled in the BTS.

When enabling the DLDC, the following pre-requirements are checked by the system:

- DLDC license is in ON state and there is enough capacity

- EGPRS is enabled in the cell (egprsEnabled=1)

- BTS is served by PCU2

The following checking must be done by the operator:

- BTS has 2 normal area TRXs which are EGPRS enabled(gprsEnabledTrx=1) and belong to same EDAP and the same DSP

- Default GPRS Capacity (defaultgprsCapacity) is configured in such a way that the GPRS territory is split onto two TRXs; to fully exploit supported MS multislot capabilities, PS territory shouldcomprise of at least 5 TSLs on each TRX.

It is also recommended to enable the High Multislot Class feature.

After enabling/disabling the DLDC the operator must trigger updating of the PCU (new MML command) in order to get the PCU DSP resources reallocated. O&M updates to RNW database the DLDC update info to value “update needed” in order to tell the user that PCU must be updated.

HMC is a license control feature

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PUTD PCU up to date

object: BTS

unit: -

range: Update needed

Update done

step: -

default: Update needed

DLDC update info for BTS object to tell operator whether DLDC information is updated to PCU or not after DLDC modification. Only system can modify this parameter.

Note: This is not user adjustable attribute – it’s rather kind of system indicator whether the PCU update after DLDC feature activation should be done by the user or not.

PUTD PCU up to date

object: PCU

unit: -

range: Update needed

Update done

step: -

default: Update needed

DLDC update info for PCU object to tell operator whether DLDC information is updated to PCU or not after DLDC modification. Only system can modify this parameter.

Note: This is not user adjustable attribute – it’s rather kind of system indicator whether the PCU update after DLDC feature activation should be done by the user or not.

DOP DLDC offset for PCU2-E selection

object: BSC

unit: -

range: 0..80

step: 1

default: 0

With this parameter operator can change the behavior of the PCU selection algorithm in cases when DLDC is used and the pool contains both PCU2-E and PCU2-D/U type cards.

Note: The higher value of this parameter the higher preference for PCU2-E (PCU2-E cards are allowed to get higher load than other PCU2 types).

DLDC OFFSET FOR PCU2-E – is taken into account in PCU load calculations. If the value for DLDC offset for PCU2-E selection(DOP) parameter is different than 0 (meaning that PCU2-E cards are then preferred for DLDC DAPs) it is allowed that PCU2-E cards gets higher load than other PCU2 types.

BTS: With this parameter system informs user whether or not DLDC information of the BTS is updated to PCU

PCU: With this parameter system informs user whether or not DLDC information of all BTSs using this PCU is updated to PCU

Operator gives the new PCU update command which causes followingsteps to be done by system:

Territories of the whole PCU are downgraded

EDAP table is updated

Territories of the whole PCU is upgraded so that DLDC enabled BTSs are handled first

DLDC update infos are updated to “update done” value

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BTS_DLDC_TSL_BALANCE_THRESHLD

BTS DLDC TSL BALANCE THRESHOLD

PRFILE parameter

object: BSC

unit: %

range: 0..100

step: 1

default: 100

This parameter determines the threshold for triggering an intra-BTS load reallocation for a DLDC-capable MS having single carrier DL TBF when DLDC resources are available within the BTS.

Note: The DLDC intra-BTS reallocation may be triggered if three following conditions are met

- MS does not have a concurrent EDA UL TBF

- DLDC is activated in BTS

- average capacity of DL allocated TSLs ≤ average capacity of all BTS DL PS TSLs*BTS_DLDC_TSL_BALANCE_THRESHLD

Rule: The lower the value of this attribute the more stringent condition for DLDC intra-BTS reallocation. Setting this parameter to e.g. 50% means that DLDC intra-BTS reallocation will be triggered if the average capacity of DL allocated TSLs is twice lower than average free capacity of all DL PDCHs in BTS.

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Parameter name Description

egprsEnabled Enables/disables EGPRS on BTS level

gprsEnabledTrx Defines whether GPRS and EDGE capability is enabled for TRX

dedicatedgprsCapacityDetermines the GPRS dedicated territory size in BTS. The value of the dedicated GPRS capacity parameter must be smaller than or equal to the value of the default GPRS capacity parameter (defaultgprscapacity).

defaultgprsCapacity

Determines the GPRS default territory size in BTS. Before DLDC activation the default GPRS territory should be configured in such a way that the total GPRS territory is split onto two TRXs and comprises of at least 5 TSLs on each of them (to fully benefit from the highest DC MS Multislot Capabilities: 5+5 TSLsin DL). In practice (taking into account GPRS territory upgrade rules) it means that the default territory should comprise of atleast 13 TSLs.E.g.: a cell with 2 EGPRS-enabled TRXs (gprsEnabledTrx=1) in which the number of TSL that may be used as PDCH is equal to 14 (2 TSLs dedicated to BCCH and SDCCH); to allow for at least 5 PDCHs on each TRX, the defaultGPRScapacity shall be equal to roundup(13/14)=93%

maxGPRSCapacityDetermines the maximum GPRS territory size in BTS. The maximum GPRS capacity must not be less than default territory.

Radio resources must be properly configured in order to fully exRadio resources must be properly configured in order to fully exploit DLDC feature ploit DLDC feature -- the the MS allocations may be limited due to lack of resources as in sinMS allocations may be limited due to lack of resources as in single carrier modegle carrier mode

Downlink Dual CarrierRelated Parameters

egprsEnabled - all GPRS-enabled TRXs of the BTS have to be EDGE capable. The GPRS must be enabled in the segment in order to enable EGPRS in the BTS.

Default territory includes dedeicated territory

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Determines the default value for MS specific buffering capacity for Gb-interface. Simulations showed that this parameter should be set to the value of 30000 (30 kBytes).

FC_MS_B_MAX_DEF_EGPRS(PRFILE parameter)

Determines the threshold for triggering an intra-BTS TBF reallocation. In order to reduce the number of ‘unnecessary’DLDC intra-BTS load balancing reallocations it is recommended to set this parameter to the values not greater than 60%.

BTS_TSL_BALANCE_THRSHLD(PRFILE parameter)

Parameter name Description

CHA_CONC_UL_TBF_FAVOR_DIR(PRFILE parameter)

Defines which direction is favored when establishing a concurrent UL TBF. Operator may favor DL, favor UL or share resources more evenly between the directions. In order to fully benefit from DLDC it is recommended to give the preference to DL direction.

CHA_CONC_DL_TBF_FAVOR_DIR(PRFILE parameter)

Defines which direction is favored when establishing a concurrent DL TBF. Operator may favor DL, favor UL or share resources more evenly between the directions. In order to fully benefit from DLDC it is recommended to give the preference to DL direction.

Radio resources must be properly configured in order to fully exRadio resources must be properly configured in order to fully exploit DLDC feature ploit DLDC feature -- the the MS allocations may be limited due to lack of resources as in sinMS allocations may be limited due to lack of resources as in single carrier modegle carrier mode

Downlink Dual CarrierRelated Parameters

egprsEnabled - all GPRS-enabled TRXs of the BTS have to be EDGE capable. The GPRS must be enabled in the segment in order to enable EGPRS in the BTS.

In BSSGP flow control PCU delivers the actual leak rate of a specific data flow and bucket size (FC_MS_B_MAX_DEF_EGPRS) of that flow to the SGSN. SGSN adjusts its own transmission rate for that flow accordingly. Another parameter which determines the default value for MS-specific leak rate for Gb-interface does not need to be changed. Simulations showed that this parameter should be set to the value of 15000 (15kB/s).

Default leak rate and bucket size parameters are used in PCU to calculate the pre-determined Leak_Rate value which is sent further to SGSN if the relative difference (R_Dif) between the pre-determinded Leak_rate value and the actual leak rate is large enough (greater than a threshold)

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Multipoint Gb interface

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Multipoint Gb Interface

Multipoint Gb feature gives the possibility to add several SGSNs to serve the same routing area in parallel

Multipoint Gb-interface benefits:

Improved SGSN capacity utilization• Load sharing between the SGSNs in the pool as

BSC can route information to different CN nodes within the packet switched domain

Flexible capacity upgrades• Additional SGSNs can be added in the given pool

area Increased service availability • Other SGSNs may provide services in case of one

SGSN in the pool area fails or is under maintenance

Reduced network load• Enlarged service area and reduced inter-SGSN

location updates and handovers leads to reduced SS7 and GTP signalling load

Multipoint A-interface (S12)Multipoint Gb-interface (S13)

SGSN

MSC

BSC

BTS

MS

PCU

One BSC can be connected up to 8 SGSNs and 16

MSC/MSS

Multipoint Gb feature requires PCU2 and Gb over IP

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Multipoint Gb interface - Load Sharing

Load sharing

• Cells are not connected to specific SGSN, but to several of them

• PCU selects SGSN when new MS enters the network

• SGSN capacity is used more efficiently

Load sharing uses round robin algorithms

• SGSN is selected following a fixed rule, or

• SGSN is selected based on SGSNs load

SGSN1

10% load

SGSN2

70% load

SGSN3

35% load

SGSN4

60% load

SGSN assignment queue withweighted round robin algorithm

SGSN1 SGSN2 SGSN3 SGSN4

SGSN assignment queue withnormal round robin algorithm

MSMS

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Multipoint Gb interface - SGSN Upgrade and Core Network Resiliency

SGSN UpgradeSGSN upgrades can be done without interruption to ongoing traffic

• After new SGSN activation load transfer to new SGSN will be done

SGSN ResiliencyControlled SGSN shutdown

• Traffic to shutdown SGSN is prevented before maintenance time

SGSN Failure

• In case of failures in the GPRS core the network can stay operational with reduced capacity

New SGSN

SGSNLoad

SGSNLoad

SGSNLoad

SGSNLoad

SGSNLoad

SGSN failure /

SGSN under maintenance

SGSNOut of Use

SGSNLoad

SGSNLoad

SGSNLoad

SGSNLoad

SGSNLoad

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A pool area is an area within which an MS may roam without need to change the serving SGSN node

Served by one or more SGSN nodes in parallel

Pool areas may also overlap in which case a BSS has the possibility to connect to different sets of SGSNs

MS will stay attached to a SGSN for a longer period

• Faster cell reselections

• Shorter cell reselection outage times

• Less signaling

Multipoint Gb interface - SGSN Pooling

PS pool area 1

PS pool area 2

SGSN

SGSN

BSC/PCU

BSC/PCU

BSC/PCU

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GPRS/EDGE support for PGSM/EGSM BTS

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GPRS/EDGE supports the possibility to configure PGSM and EGSM frequencies in a single BTS object, if the BCCH of the segment is on the PGSM frequency band and enables (E)GPRS to use RF hopping in the PGSM900-EGSM900 configuration

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OLD Implementation• When BCCH is on PGSM and there is EGSM frequency used in the

BCCH BTS:– GPRS/EDGE cannot be used in EGSM type frequencies in the BCCH BTS

– Use of GSM900 frequencies are not allowed in any other BTS object than BCCH BTS in the same segment.

– Frequency hopping is not allowed in BCCH BTS

– GPRS/EDGE cannot be used in RF hopping TRXs, if there is EGSM frequency used in the BTS

– If GPRS/EDGE is enabled into use in EGSM900 frequency, then GPRS/EDGE service for ‘PGSM only’ MS is not guaranteed by network

– Other features that the BSC continues to prevent in this configuration are DFCA, HSCSD and features that employ super reuse TRXs.

• When BCCH is on EGSM:– GPRS/EDGE cannot be used in PGSM type frequencies in the BCCH BTS

• When BCCH is on EGSM900 or PGSM900 frequency:– GPRS/EDGE cannot be used both PGSM900 and EGSM900 frequency TRXs in GSM900

BTS, which doesn’t have BCCH TRX.

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New Implementation• When BCCH is on PGSM900 frequency and there is EGSM900

frequency used in the BCCH BTS, then operator is able to use: ▪ Overlay layer RF hopping in the BCCH BTS. There can be only PGSM or EGSM

frequencies in the MA list of the BCCH BTS. With new ‘RF hopping Allowed’ TRX parameter operator can define TRX to be non hopping, when RF hopping is used in overlay layer of the BTS.

▪ GPRS/EDGE on non-hopping PGSM900 and EGSM900 TRX(s) in the BCCH BTS. If RF hopping is used in the BTS, then customer can use GPRS/EDGE in the BCCH TRX and in the overlay layer TRXs, which has ‘False’ value defined in new RF hopping Allowed

parameter.

• When BCCH is on EGSM900 frequency, then operator is able to use GPRS/EDGE on any PGSM and EGSM frequencies in the BCCH BTS.

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