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CPO – Dimensioning Rules 19/07/2001 All rights reserved © 2001, Alcatel, Paris.

Dimensioning Rules BSC

TC

MFS

Abis interface

Ater interface

A interface



All rights reserved © 2001, Alcatel, Paris. CPO – Dimensioning Rules 19/07/2001

Overview of the BSS network

BSC

BTS TC




Grade of services

PSTN

MSC 1

MSC 2

BSC 1

BSC 2 BTS

BTS

Air interface

Abis interface A interface

MSC / MSC interface

MSC / PSTN interface

MSC / PSTN interface

A interface Air interface Abis interface

2%

2%

2%

2%

0%

0%

0,1%

0,1%

0,1%

0,1%

0,1%




BSC dimensioning rule

Architecture: general overview of the layout of BSC

TCUC

TCUC

TCUC

TCUC

TCUC

TCUC

TCUC

TCUC

AS AS

DTCC

DTCC

DTCC

DTCC

DTCC

DTCC

DTCC

DTCC

Ater TSU

Common-functions TSUCommon-functions TSU

ASMB ASMB

ASMB ASMB

Broadcast bus

AS

AS

6 xG.703

AbisI/F

2 xG.703

Ater muxedI/F

CPRC CPRC CPRC CPRC CPRC CPRC CPRC CPRC

Abis TSU

Group switch8 planes2 stages

self-routing,non-blocking

TSL

Qmuxbus

TSCATSCA

BIUABIUA





Configuration/Capacity

Configuration Traffic capacityin Erlang [1] )

No. of TRXs(FR/DR)

No. of BTSs(FR/DR)

No. of cabinets

No. of A-bis/A-ter TSUs

2 650 128/64 95/64 1 4/3

3 1100 192/96 142/96 2 6/5

4 1300 288/144 214/144 2 9/6

5 1600 352/176 255/176 3 11/8

6 1900 448/224 255/224 3 14/9

1 160 32/16 23/16 1 1/2




BTS-BSC interface dimensioning rule Abis interface

Topology/Connectivity

Definition of BSC areas and BSC site locations

BSC network : star configuration in BangkokLimitation: connectivity of the BTS to the BSC

One Abis PCM link connects only one BTS to BSC

# of Abis PCM links/BSC = # of BTS cabinetsconnected to BSC

Up to 6 Abis PCM links / Abis TSU

1 Abis TSU can handle up to 32 TRXs





Dimensioning

Take into account the whole traffic for a BSC area

Take into account the number of TRX, sites, cellsTake into account the BSC- Abis int. connectivity limitation

Link to the BSC configuration table to find the necessarynumber of BSC and their configurations




TC A925 dimensioning rule

Architecture

MT120 MT120 Four Aitf trunks

G.703 Ater itf trunk

G.703



G.703



G.703

Up to 48 boards

A925 TC

Up to 192 A interfaces Up to 48 Ater interfaces





Rack 3

Rack 2

Rack 1

Rack 3

Rack 2

Rack 1 4

BSC G2 BSC G2

A925 TC A925 TC

MSC


The A925 transcoder can be shared

between several G2 BSC but the full Atermuxinterfaces of a BSC rack must be connectedto the same A925 transcoder

up to 24 BSC can be connected to the same A925 transcoder (since a minimum of 2 Atermux is needed per BSC for redundancypurpose) A925 TC




BSC – TC interface dimensioning rule Ater interface

Dimensioning

Sum the traffic (in Erlangs) handled by all BTS connected to aBSC area.

Use (Erlangs B law)-1 to define the number of 16k channels on Ater interface (with 0.1% blocking rate).

Divide by 4 to find the number of 64k channels on Ater

interface (submultiplexing 4:1).Divide by the number of TS used for traffic (mapping of A int.)to find the number of Ater interfaces





Dimensioning

Sum the number of Ater interfaces connected to the same

MSC. 1 MT120 board provides 1 Ater trunk and 4 A trunks

Knowing that 1 TC can support up to 48 MT120 boards (with1 Ater trunk per MT120 board), divide by 48 to find thenumber of Transcoders.




TC A925 - MSC interface dimensioning rule A interface

Multiply by 4 the number of Ater interface per transcoder to

find the number of A interfaces towards the MSC.




MFS dimensioning rule

Configuration/Capacity

Configuration Nb. of equippedtelecom

subracks

Minimum GPUboards

Maximum GPUboards

Maximum Noof BSS

Maximum Noof PDCH

Standard 1 2 *) 12 **) 11 2640

Standardpre-equipped

2 2 *) 12+12 **) 22 5280

d l






The MFS is usually colocated with the transcoders and the

MSC All BSS connected to a same MFS should be connected to asame OMC-R

BSS connected to a same OMC-R can be connected to

several MFS

MFS di i i l





Dimensioning:

1 GPU board handles a single BSS

1 GPU board supports up to 240 PDCHs

BSC MFS i t f di i i l




BSC – MFS interface dimensioning rule Ater interface

Dimensioning

For CPO network, 1 Ater mux can be fully devoted tocarry the GPRS traffic (GCH and GSL traffic)

A second Ater mux is foreseen for redundancy

Total of Ater interfaces from BSC side

Sum of Ater interfaces for voice traffic+ 2 Ater interfaces for data traffic

Di i i g l




Dimensioning rules

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