Alcatel Dimensioning Rules for CS and PS traffic with BSS Software Release B9.PDF

8/11/2019 Alcatel Dimensioning Rules for CS and PS traffic with BSS Software Release B9.PDF

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Dimensioning Rules for CS and PS traffic

with BSS Software Release B9


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CONTENTS

1. REFERENCE DOCUMENTS ....................................................................................... 4

2. INTRODUCTION .................................................................................................. 4

3. DEFINITIONS...................................................................................................... 5

4. AIR INTERFACE................................................................................................... 5

5. A-BIS INTERFACE................................................................................................. 6

5.1 Number of time-slots available per A-bis Multidrop link ......................................... 6

5.2 Usage of A-bis timeslots ............................................................................... 6

5.3 Transport of Signaling on the A-bis interface ...................................................... 7 5.3.1 General.......................................................................................... 7

5.3.2 A-bis signaling multiplexing modes......................................................... 7

5.3.3 Rules for usage of signaling multiplexing ................................................. 7

5.4 Two A-bis links per BTS ................................................................................ 8

6. BSC DIMENSIONNING RULES.................................................................................... 9

6.1 BSC equipment overview............................................................................... 9

6.1.1 A9120 (G2) BSC ................................................................................ 9

6.1.2 A9130 BSC Evolution .......................................................................... 9 6.2 BSC A-bis connectivity.................................................................................10

6.2.1 Maximum number of TRXs ..................................................................10

6.2.2 Maximum number of BTSs and Cells.......................................................11

6.2.3 Mix of Full Rate and Dual Rate TRX .......................................................11

6.2.4 The particular case of cell splitting .......................................................11

6.2.5 Introduction of CS-3, CS-4 and EDGE......................................................12

6.2.6 Abis PCM links and signaling links .........................................................12

6.3 BSC A-ter connectivity ................................................................................14

6.4 CS Traffic Handling Capability .......................................................................15

6.4.1 Maximum BSC capacity figures.............................................................15

6.4.2 The moderation factor ......................................................................16

7. A-TER INTERFACE...............................................................................................16

7.1 Definitions ...............................................................................................16

7.2 Mixed A-ter CS/PS links ...............................................................................17

7.3 Ater Time slots not usable for traffic...............................................................19

7.4 Minimum number of A-ter links ......................................................................20


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1. REFERENCE DOCUMENTS-

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[1] 3DC 21006 0003 TQZZA Use of Moderation Factor for BSS traffic assessment

[2] 3DC 21016 0003 TQZZA EVOLIUM A9120 Base Station Controller Product Description

[4] 3DC 21016 0005 TQZZA EVOLIUM A9135 MFS Product Description

[5] 3GPP TechnicalSpecification 05.02

Multiplexing and Multiple Access on the Radio Path

[6] 3DC 21034 0001 TQZZA EVOLIUM G2 Transcoder Product Description

[7] 3DC 21016 0007 TQZZA EVOLIUM A9125 Compact Transcoder Product Description1

[8] 3DC 21144 0047 TQZZA GPRS Master Channels in Release B8

[9] 3DC 21144 0032 TQZZA GPRS Radio Resource Management in Release B7

[10] 3DC 21150 0323 TQZZA GSM/GPRS/EDGE Radio Network Design Process For AlcatelBSS Release B9

[11] 3DC 21019 0007 TQZZA Evolium A9130 BSC/MFS Evolution Product Description

2. INTRODUCTIONThis document provides dimensioning rules of the A9120 (G2) BSC, A9135 MFS and A9130 BSC/MFSEvolution equipments with the BSS release B9.

When not explicitly mentioned otherwise,

BSC will refer to both A9120 BSC and A9130 BSC Evolution;

MFS will refer to both A9135 MFS and A9130 MFS Evolution

It also provides the rules to dimension the interfaces in the BSS Air interface, A-bis interface, A-terinterface and Gb interface.

1 Product name may also be found with previous ALCATEL naming as A925 transcoder


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3. DEFINITIONS

A 64 kbit/s channel on the A-bis interface is called an A-bis timeslot .

A 16 kbit/s channel on the A-bis interface is called an A-bis nibble .

A transmission channel established for carrying (E)GPRS traffic is called a GCH (GPRS channel).One GCH uses one A-bis and one A-ter nibble.

In this document, EDGE may be used instead of E-GPRS, for wording simplification purpose.

4. AIR INTERFACE

The maximum number of TRX per cell is 16.

Radio configuration of GSM cells :

There is one timeslot devoted to CCCH per cell.The maximum number of SDCCH channels per cell is 88.These SDCCH channels may be static ordynamic. At least one static SDCCH (SDCCH/4 or SDCCH/8) must be positioned on the BCCH TRX,for recovery.

The maximum number of SDCCH per TRX on an EVOLIUM BTS is 24.

In a multiband cell, all SDCCH are in the primary band of the cell.

In a concentric cell, all SDCCH are in the outer zone.

All TRX can be declared as Full rate or Dual Rate TRX. Mixtures of DR TRX and FR TRX aresupported.

Packet configuration:

The maximum number of PDCH in one cell is 60.

There may be one primary master channel (PBCCH) and up to 3 secondary master channels (PCCH)in one cell, all on BCCH TRX.

In a multiband cell, all packet traffic is in the primary band of the cell.

In a concentric cell, all packet traffic is in the outer zone.

In case of cell split over two BTS, packet traffic is supported over the master sector only.


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5. A-BIS INTERFACE

5.1 Number of time-slots available per A-bis Multidrop link-

- This number depends on :

- The type of the multidrop link : Closed Loop or Open Chain,

- Whether time-slot zero (TS0) transparency 1 is used or not,

- The BTS generation.

The table below indicates the number of time-slots available per PCM link according to thepossible choices:

OPEN CHAIN MULTIDROP CLOSED LOOP MULTIDROPG1 or G2 BTS A9100 BTS (*) G1 BTS (**) G2 or EVOLIUM

BTS

WITH TS0 TRANSPARENCY 30 31 28 29

TS0 USAGE 31 31 30 30

(*) Improvement with EVOLIUM BTS: In case all BTSs of a Multidrop are EVOLIUM BTSs, and ifTS0 transparency is used, then the time-slot used for transmission supervision can be saved(because the OML of EVOLIUM BTS supports also the transmission supervision information)

(**) This column applies as soon as there is one G1 BTS in a closed multidrop.

5.2 Usage of A-bis timeslotsOn the A-bis interface, there are basic timeslots, extra timeslots, and timeslots devoted tosignalling.

One timeslot on the air interface is mapped on one basic 16kbit/s nibble on the A-bis interface.

As a consequence, each TRX corresponds to two A-bis basic timeslots. Additional extra timeslotscan be configured for the transport of packet. This makes sense when CS3/CS4 or EDGE has beenactivated. If the cell transports voice only, or GPRS up to CS-2, there is no reason to add extra-timeslots.

The number of extra timeslots per BTS is determined by the Operator. The granularity is one A-bistimeslot.

For large BTS (up to 24 TRX or important packet traffic), two A-bis links may be used. The secondA-bis link transports voice, packet and signalling traffic.

1 Time slot 0 transparency means the BSS cannot use TS0, which is reserved by the transmission equipment for O&Mpurpose. Time Slot 0 Usage means the BSS can use TS0 .


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5.3 Transport of Signaling on the A-bis interface

5.3.1 General

In addition to data, signalling has to be transported on the A-bis interface. There are two types ofinformation to be conveyed:

- RSL : Radio Signaling Link. There is one RSL per TRX

- OML : O&M link. There is one OML per BTS. The OML link is always on the first A-bis link.

When signalling multiplexing is not used, each signalling link (OML or RSL) is transported on a 64kbit/s Abis channel. This configuration is however not recommended, as it is wasting bandwidth onthe Abis interface. The following section presents the various signalling multiplexing mode offeredby the ALCATEL BSS.

5.3.2 A-bis signaling multiplexing modes

There are three types of Signaling Multiplexing:

- Static Signaling Multiplexing consists of multiplexing on one A-bis time-slot (64 kbit/s) up to 4RSLs (Radio Signaling Link) of 16 kbit/s each belonging to the same BTS. The OML uses anadditional A-bis time-slot (64 kbit/s).

- Statistical Signaling Multiplexing 64k consists of multiplexing on one A-bis time-slot (64kbit/s) up to 4 RSLs (Radio Signaling Link) of a BTS plus its OML. Each RSL and each OML has atransfer rate of maximum 64 kbit/s (but not all simultaneously).

- Statistical Signaling Multiplexing 16k : the basic nibble corresponding to the radio timeslot 0of each TRX carries the RSL of this TRX and possibly the OML of the BTS. This feature requiresthat no traffic, but only signaling (BCCH or SDCCH) is affected on timeslot 0 of each TRX. Inthis case no additional timeslot is required on the A-bis for signaling.

5.3.3 Rules for usage of signaling multiplexing

5.3.3.1 Rules for Signaling Static multiplexing on 64 kbit/s channel

Static Signaling multiplexing can only be used if all the following conditions are met:

- - Full rate only (no Dual Rate).

- - Each TRX carries 8 SDCCH channels maximum

5.3.3.2 Rules for Signaling Statistical multiplexing on 16 kbit/s channel

Statistical Signaling multiplexing 16 k can only be used if all the following conditions are met:

- EVOLIUM BTS and Micro-BTS,

- Full rate only TRX (no Dual Rate).

- Each TRX carries 8 SDCCH channels maximum


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6. BSC DIMENSIONNING RULES

6.1 BSC equipment overview

6.1.1 A9120 (G2) BSC

The G2 BSC range available with the BSS Software Release B9 is:

Configurationnumber

BSC G2 EQUIPMENT nb of cabinets

1 32 TRX-FR; 16A, 6 A-bis-ITF 12 128 TRX-FR; 24A, 24 A-bis -ITF 13 192 TRX-FR; 40A, 36 A-bis -ITF 24 288 TRX-FR; 48A, 54 A-bis -ITF 25 352 TRX-FR; 64A, 66 A-bis -ITF 3

6 448 TRX-FR; 72A, 84 A-bis -ITF 3

For more details on G2 BSC HW, please refer to the BSC product description [2].

6.1.2 A9130 BSC Evolution

Two main types of configuration are available with the BSS Software release B9 for the BSCEvolution, in one cabinet:

- Standard configuration: BSC Evolution with one telecom sub-rack

- - Rack Sharing (RS) configuration: 2 BSCs Evolution with one telecom sub-rack

equipped for each BSC.

Configuration Nb. Of equippedtelecomsubracks

Number of CCPboards (*)

Number of LIUboards

BSC-EV-200 1 2 8

BSC-EV-400 1 3 8

BSC-EV-600 1 4 16

BSC-EV-RS 600-200 1 2 6 24

BSC-EV-RS 400-400 2 6 16

BSC-EV-RS 600-400 2 7 24

BSC-EV-RS 600-600 2 8 32

(*) Spare CCP boards included

1 The 600-200 configuration should be reserved for capacity extension purposes, otherwise the 400-400configuration shall be preferred.


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Note: The A-bis connectivity is provided in section 6.2 and A-ter connectivity is provided in section6.3 .

6.2 BSC A-bis connectivity

There is a set of rules to be respected to determine the maximum amount of TRXs and BTSs thatcan be connected to a BSC.

6.2.1 Maximum number of TRXs

6.2.1.1 A9120 G2 BSC

Some rules refer to the BSC equipment as a whole, others to theA-bis Terminal Sub-Unit (A-bis TSU) capacity.

The following table gives the maximum TRX connectivity.

BSC G2 EQUIPMENT Max. Nb. of TRX-FR Max. Nb. of TRX-DR

Configuration 1 32 14Configuration 2 128 62Configuration 3 192 92Configuration 4 288 140Configuration 5 352 170Configuration 6 448 218

Note : At least one TCU in each BSC rack must be allocated in Full Rate.That is the reason why it is not possible to have more than 218 DR TRX in configuration #6.

When the maximum number of DR TRX is reached, there are still up to 4 potential FR TRX forconfigurations (1) & (2), 8 FR TRX for configurations (3) & (4), and 8 FR TRX for configurations (5)& (6).

It is not possible to mix FR TRX and DR TRX in a single TCU.

6.2.1.2 A9130 BSC Evolution

The following table gives the maximum TRX connectivity.

Configuration Max. Nb. of TRX-FR Max. Nb. of TRX-DR

BSC-EV-200 200 100BSC-EV-400 400 200BSC-EV-600 600 300

BSC-EV-RS 600-200 800 400BSC-EV-RS 400-400 800 400BSC-EV-RS 600-400 1000 500BSC-EV-RS 600-600 1200 600


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6.2.2 Maximum number of BTSs and Cells

The maximum number of BTS and cells depends whether the TRXs are configured in Full Rate or inDual Rate mode.

6.2.2.1 A 9120 BSC (G2-BSC)

Full Rate TRX Dual Rate TRX

BSC G2 EQUIPMENT max. BTSs max. Cells max. BTSs max. Cells

Configuration 1 23 32 14 14Configuration 2 95 120 62 62Configuration 3 142 192 92 92Configuration 4 214 240 140 140

Configuration 5 255 264 170 170Configuration 6 255 264 218 218

6.2.2.2 A9130 BSC (BSC-Evolution)

Full Rate TRX Dual Rate TRX

Configuration max. BTSs max. Cells max. BTSs max. Cells

BSC-EV-200 150 200 100 100

BSC-EV-400 255 264 200 200BSC-EV-600 255 264 255 264BSC-EV-RS 600-200 405 464 355 364BSC-EV-RS 400-400 510 528 400 400BSC-EV-RS 600-400 510 528 455 464BSC-EV-RS 600-600 510 528 510 528

Note: For BSC-EV-200 and BSC-EV-400, the maximum number of BTS and cells with dual Rate TRXis lower than with Full Rate, because it is equal to the maximum number of TRX with dualrate.

6.2.3 Mix of Full Rate and Dual Rate TRX

The Half-Rate Flexibility feature allows defining the number of Dual Rate TRX in each BTSsector.

6.2.4 The particular case of cell splitting

Cell splitting is available from release B7 onwards. This feature enables to share a cell between 2BTSs. This feature enables for example to extend a site, adding a new BTS without modifying thearrangement of the already existing BTS(s).


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The connection to the BSC of the A-bis links coming from these BTSs shall not follow any specificrule. For G2 BSC, the BTS can be connected to the same or to different A-bis TSUs.

However, in the particular case of Multi-band Cell usage, one must be aware that all radio

signalling is concentrated on the primary band. Thus it is recommended to mix the 900 MHz BTSsand the 1800 MHz BTSs in each A-bis TSU, so as to enable a better signalling load distribution atTCU level.

6.2.5 Introduction of CS-3, CS-4 and EDGE

6.2.5.1 A9120 (G2) BSC

Introduction of CS-3, CS-4 and EDGE has impacts on A-bis dimensioning and on the BSC TRXconnectivity.

Extra-timeslots defined on the A-bis links are cross-connected inside the BSC and consume someBSC connectivity.

Two A-bis extra timeslots are equivalent to one Full Rate TRX in terms of connectivity in theBSC.In other words, one extra timeslot is equivalent to FR TRX.

Note : the system maps extra-timeslots on any FR TCU of the A-bis TSU to which the A-bis link isconnected.

6.2.5.2 A9130 BSC evolution

The introduction of CS3, CS4 and EDGE has no impact on the BSC TRX connectivity.

For more details on Abis transmission resource dimensioning please refer to [10].

6.2.6 Abis PCM links and signaling links

6.2.6.1 A9120 BSC specific rules and A-bis TSU capacity

Each A-bis TSU includes 8 TCUs (Terminal Control Unit) and six G.703 A-bis interfaces, which allowconnecting six A-bis PCM trunks.

The table below indicates the number of A-bis TSU for each G2 BSC configuration.

BSC G2 EQUIPMENT Nb. Of A-bisTSU

Configuration 1 1Configuration 2 4Configuration 3 6Configuration 4 9Configuration 5 11Configuration 6 14


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The following rules, relative to the A-bis TSU, must be respected:

- All TRXs of all BTSs of a same A-bis multidrop are handled by a single A-bis TSU.

- Each TCU can handle 6 signaling links (LAPD), i.e. typically: (4 RSLs + 2 OMLs for 4 TRXs+ 2BTSs ) or (3 RSLs + 3 OMLs for 3 TRXs+ 3 BTSs).

- Each TCU can handle either Full Rate or Dual Rate traffic (but not both).

- Each TCU can handle 32 Traffic Channels, i.e. 4 Full-Rate TRXs or 2 Half-Rate TRXs.

- The traffic channels and the RSL of a given TRX are handled by the same TCU.

- In case of Signaling Multiplexing, all RSLs of a given 64 kbit/s A-bis time-slot are handled bythe same TCU (this rule applies for both Static and Statistical Signaling Multiplexing)

- 6 A-bis open chain multidrop links can be connected to one A-bis TSU. In case of closed loop

multidrop links, both ends of an A-bis multidrop loop must be connected to the same A-bis-TSU. Hence up to 3 A-bis closed loop multidrop links can be connected to 1 A-bis-TSU.

- In each cabinet, there is at least one TCU configured in Full Rate.

Remarks :

- It is possible to mix within a same TCU, RSLs which are multiplexed (static and/or statistical)and RSLs which are not multiplexed.

Recommendations:

- It is recommended not to dimension a BSC over 90% of its maximum connectivity.

- Leaving free some spare capacity in all A-bis TSUs will simplify further extensions.

6.2.6.2 A9130 BSC

The number of Abis-PCM links for each configuration is provided in the table below.

Configuration Max. Nb. Of Abis links

BSC-EV-200 96BSC-EV-400 96BSC-EV-600 176

BSC-EV-RS 600-200 272BSC-EV-RS 400-400 192BSC-EV-RS 600-400 272BSC-EV-RS 600-600 352

Signaling capacity : For A9130 BSC, there are up to 441 HDLC channels at 64 kbit/s dedicated totransport the Abis signaling (OML and RSL) per BSC. If signaling multiplexing is not used, themaximum number of TRX and BTS indicated in sections 6.2.1.2 and 6.2.2.2 cannot be reached.ALCATEL recommends using signaling multiplexing (see section 5.3 for details).


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6.3 BSC A-ter connectivity

6.3.1.1 A9120 G2-BSC

The maximum number of A-ter interfaces is given in the table below. This maximum number of A-ter interfaces is the total available for CS and PS services. Each A-ter link can be either fullydedicated to PS or CS, or it is also possible to split some A-ter links between CS and PS. Thedetailed information on how to split an Ater-link between CS & PS is detailed in section 7.2.

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BSC G2 EQUIPMENT Max. Nb. ofA-ter itf

Configuration 1 4Configuration 2 6Configuration 3 10Configuration 4 12Configuration 5 16Configuration 6 18

6.3.1.2 A9130 BSC Evolution

The maximum number of A-ter interfaces for PS and CS is given in the table below.

Configuration Ater CS(*) Ater PS(**)

BSC-EV-200 10 6BSC-EV-400 20 12BSC-EV-600 30 18

BSC-EV-RS 600-200 40 24BSC-EV-RS 400-400 40 24BSC-EV-RS 600-400 50 30BSC-EV-RS 600-600 60 36

(*) With BSC evolution, the A-ter links provided for CS can be used for CS and PS. These links canbe either fully dedicated to PS or CS, or it is also possible to split some A-ter links between CS andPS. The detailed information on how to split an Ater-link between CS & PS is detailed in section

7.2.- (**) With BSC evolution the Ater links provided to PS are dedicated to PS only.


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6.4 CS Traffic Handling Capability

The maximum traffic handling capacity is mainly limited by the number of A-ter interface channelsavailable for traffic

6.4.1 Maximum BSC capacity figures

6.4.1.1 A9120 G2-BSC

These figures are guaranteed with respect to the call mix specified in annex 1.

G2-BSC configuration Maximum Traffic(ERLANG)

Maximum BHCA

Configuration 1 160 Erlang 11,520Configuration 2 620 Erlang 44,640Configuration 3 1050 Erlang 75,600Configuration 4 1300 Erlang 93,600Configuration 5 1700 Erlang 122,400Configuration 6 1900 Erlang 136,800

These figures correspond to a blocking probability on the A-ter interface of 0.1%.

Note that a conf. 6 BSC can reach a 2000 Erlangs capacity with a less constraining traffic model.Also in that case, the blocking rate will reach 0.24%, instead of 0.1%.

BHCA: Busy Hour Call Attempts.

6.4.1.2 A9130 BSC evolution

The figures below are guaranteed with respect to the call mix specified in annex 1 (TCH holdingtime = 50s).

BSC-Evolution Configuration Maximum Traffic(ERLANG)

Maximum BHCA

BSC-EV-200 900 64 800BSC-EV-400 1800 129 600BSC-EV-600 2600(*) 187 200

BSC-EV-RS 600-200 3500(*) 252 000BSC-EV-RS 400-400 3600 259 200BSC-EV-RS 600-400 4400(*) 316 800BSC-EV-RS 600-600 5200(*) 374 400

(*) Limitation with B9 release. Target for further releases is 900 ERLANG per CCP for allconfigurations

BHCA: Busy Hour Call Attempts.

The BSC Evolution architecture applies a separation between user plane and control plane. Thetraffic in ERLANG represents the user plane capacity while the BHCA expresses the control planecapacity.


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6.4.2 The moderation factor

When dimensioning a network, one must check that the nominal traffic generated by the differentBTSs does not exceed the maximum traffic handling capacity of the BSC to which they are

connected.However it has been noticed that the actual traffic encountered in a BSC is generally significantlylower than the sum of traffic capacities of all connected BTS. This comes from the fact that thenominal traffic is not reached simultaneously in each cell and that all TRXs or all traffic channelsare not all necessary to handle the actual traffic.

To account for this and avoid over-estimating the number of BSCs necessary for a given network,the notion of Moderation Factor has been introduced. The Moderation Factor is defined as theratio between the actual traffic encountered in the BSC at its busy hour and the theoreticaltraffic figure. The value of the Moderation Factor can vary very significantly depending on the

network context.Except for very dense urban areas, a maximum value of 0.8 may be used. Significantly lowervalues may even be used in many cases.

It must be noted that using the Moderation Factor is also recommended for the assessment of thenumber of A-ter Interfaces and of transcoders.

More details on the Moderation Factor can be found in document [1].

7. A-TER INTERFACE

7.1 Definitions

The A-ter 1 interface is both the interface between the BSC and the TC, and between the BSC andthe MFS.

The A-ter interface may transport pure circuit, it is then called A-ter CS .

When it transports packet traffic, it is called A-ter PS .

It is possible to mix PS and CS traffic on one single A-ter link, it is then called A-ter CS/PS .

On the A-ter CS interface, a 64 kbit/s timeslot transmits information for 4 Circuit Switch calls

(whatever they use FR or HR codecs).

1 Strictly speaking, the A-ter interface is an internal G2 BSC interface it is the interface betweenthe DTC and the ASMB boards. On this interface, a 64 kb/s timeslot transmits information for asingle CS call (FR or HR).

The actual interface between the BSC and the TC is the Atermux interface.

However, in order to simplify the wording, the Atermux interface is simply called A-ter interface.


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On the A-ter PS interface, a 64 kbit/s timeslot supports 4 GCHs.

7.2 Mixed A-ter CS/PS links

The number of 64 kbit/s time-slots assigned to PS traffic (and PS signalling) is configured by theOperator at the OMC-R, with the following granularity: 4, 8, 15, 22, and 29 timeslots (full PS) perPCM, as depicted in the following table:


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PS TS 4 8 15 22 29

0

1 TCH TCH TCH TCH GCH

2 TCH TCH TCH TCHGCH






8 TCH TCH TCH GCH GCH







15 O&M O&M O&M O&M O&M

16 SS7 SS7 SS7 SS7 SS7

17 TCH TCH GCH GCH GCH







24 TCH GCH GCH GCH GCH




28 GCH GCH GCH GCH GCH




A-ter CS/PS configurations

The MFS transparently routes the 64 kbit/s timeslots used for voice towards the transcoder.

The MFS has the possibility to split the traffic on a link to the transcoder for the CS traffic and alink to the SGSN for PS traffic.

It is also possible to route both CS and packet traffic (Gb) to the transcoder. The same granularitybetween CS & PS is kept.


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The figure below displays the different types of links between the MFS and the SGSN.

Alcatel9135 MFS

T

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Gb

A-ter CS

Note: The above figure applies to both A9130 and A9135 MFS.

7.3 Ater Time slots not usable for traffic

Specific A-ter timeslots are not usable for traffic. It is the case for:

- Transmission alarm bits: Timeslot 15 of each A-ter interface is used to transport transmissionalarm bits (sub-multiplexing of TS0 alarms), and cannot be used for traffic.

- Transport of signalling

- One timeslot per A-ter link for transport of SS7 on timeslot 16.- On A-ter used for PS, one GSL may be configured. It is then transported on timeslot

28.- Transport of O&M information between BSS and OMC-R

- A9120 BSC : When this connection is performed through the A-ter Interface, and notusing an external X25 network, 2 additional timeslots must be dedicated to the O&Mlink from the BSC to the OMC-R if. In this case timeslot 31 is used on A-ter links N1& 2 .


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- A9130 BSC: The O&M information is transported to the OMC with IP over Ater. The IPtransport uses the TS 31 of the Atermux 1 to N (N is between 2 and 16, with a defaultvalue of 4: the IP bandwidth is between 128 Kbits and 1 Mbits/s with a default value of256 Kbit/s). This IP bandwidth is configurable by the operator.

- Qmux protocol (Transmission equipment supervision 1).

- In A9120 BSC rack, there is one sub-channel ( on timeslot 14 ) on the first two A-terlinks (links N 1, 2, 7, 8, 13 & 14) that is dedicated to the Qmux protocol. Three othersubchannels are used for TCH.

- In each A9130 BSC , there is one sub-channels ( on timeslot 14) on the Ater links N1, 7, 13, 19, 25 and 2, 8, 14, 20, 26 that is dedicated to the Qmux protocol(Transmission equipment supervision, two Qmux channels per cluster of 6 Ater linkone for redundancy). The three other sub-channels are used for TCH.

7.4 Minimum number of A-ter links

The minimum number of A-ter links connected to a BSS is 2.

7.5 Number of SS7 channels

The number of SS7 64 kbit/s channels required depends on the traffic mix.

There is a maximum of one SS7 64 kbit/s channel par A-ter link.

- With the Alcatel traffic mix presented in Annex 1, it is recommended to have one SS7 channel

per A-ter link.For A9120 G2 BSC there is a maximum of 16 SS7 channels . This number of channels is

sufficient to cope with the signalling load corresponding to the G2 BSC maximumcommitted capacity and BHCA from section 6.4.1.1, with the Alcatel traffic mixpresented in Annex 1, with a maximum 0,4 ERLANG per signalling channel.

For A9130 BSC-Evolution there is a maximum of 16 SS7 channels per BSC (so up to 32in case of rack-sharing configurations, with 2 logical BSC). This number of channels issufficient to cope with the signalling load corresponding to the BSC evolutionmaximum committed capacity and BHCA from section 6.4.1.2, with the Alcatel trafficmix presented in Annex 1with maximum 0,6 ERLANG per signalling channel 2.

2 As the ALCATEL BSC always balance the load on all signalling links in the BSC to MSC direction, in case of switch-over dueto the loss of one signalling link, there is no risk of overloading SS7 in the transmit direction. In the receive direction, thepossibility to allow more than 0,4 ERLANG per link set depends on the MSC strategy for load balancing in case of switchover(load balancing or N+1 redundancy or intermediate algorithm). It must also be noted that the traffic mix presented inAnnex 1 corresponds to a very high signalling load per user, and that in most cases the average signalling load per user issuch that 0,4 ERLANG per signalling link is not reached with the highest capacity.


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- With a different traffic mix than the one presented in Annex 1, the number of SS7 channelsmay be adjusted so that the average SS7 load is about 0,4 ERLANG per channel. However, theA9130 BSC-Evolution is able to cope with a signalling load up to 0,6 ERLANG per channel. TheMSC ability to cope with this load and the way used by the MSC to balance the traffic in theMSC-to-BSC direction in case of loss of one link must however be checked before allowing 0,6ERLANG per SS7 link.

7.6 Number of GSL channels

Each GPU or GP board requires at least one GSL channel.

There can be 0 or 1 GSL per A-ter link.

The required number of GSL channels depends on the traffic. The different parameters tocalculate it are given in document [10].

For security reason, it is recommended to have at least 2 GSL channels per GPU or GP board.

The maximum number of GSL per BSC is 24.

7.7 A-ter interface configuration rules

On the A-ter interface, from one up to 8 PCM can be connected to each GPU board (A9135 MFS),and up to 13 PCM 1 to each GP board (A9130 MFS). Each PCM link can be dedicated to packet trafficor shared between CS and PS traffic.

For security reasons, the time-slots assigned to PS traffic should be spread among different A-terPCMs. However, when there is enough PS traffic to fill 2 or more PCMs, there is an advantage todedicate complete PCMs to PS rather than mixing PS with CS traffic. Indeed, doing so avoidsconnecting the A9135 MFS to the Transcoder, with A-ter PCMs not fully devoted to circuit-switchedtraffic, and thus avoids wasting transcoder resource.

It is possible to set PS time-slots on all A-ter PCMs; indeed, this can be useful in the case ofconfigurations with only 2 A-ter PCMs in order to ensure better security.

However, it is recommended not to carry PS traffic on the first A-ter PCM so that it can beconnected directly to the transcoder in order to enable MFS installation without O&M interruptionon the BSC.

1 Reaching 13 Ater links per GP is possible only for MFS configurations allowing more than 13 links per GP ( max 13 Ater +3Gb. See section 9.3, on page 24 for details on MFS and GP capacity.


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8. TRANSCODER DIMENSIONING RULES

8.1 Connection to the EVOLIUM G2 TC

Each BSC rack must be connected to only one TC G2 rack. But one TC rack can be connected toseveral BSC racks.

(Please refer to the EVOLIUM G2 TC product description [6] for more details.)

8.2 Connection to the A9125 TC

It is possible to connect up to 24 BSCs on one A9125 Compact TC.

At least 2 A-ter links per BSC are required.

It is also possible to connect one BSC to different TC racks.

(Please refer to the A9125 TC product description [7] for more details.)

8.3 Minimum number of A links

The minimum number of A-ter links connected to a BSS is 2.

- - If the O&M link to the OMC-R is not conveyed by the A-ter interface, each A-ter link needs tobe connected to a minimum of one A interface link (total 2 A links).

- - If the O&M link to the OMC-R is conveyed by the A-ter interface, each A-ter link needs to beconnected to 2 A interface links (total 4 A links).


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9. MFS DIMENSIONING RULES

9.1 A9135 MFS configurations

The A9135 MFS can accommodate from 1 to 2 telecommunication sub-racks.One GPU board per sub-rack is always dedicated to the n+1 redundancy feature.

Each GPU board is connected to only one BSC.

But one BSC can be connected to several GPU (up to 6 from B7 Release onwards), depending onpacket traffic. These GPUs can belong to different MFS subracks.

All the BSCs connected to a given MFS must be connected to the same OMC-R as the MFS.

There can be more than one A9135 MFS per MSC, and one A9135 MFS can be connected to BSCs,themselves connected to different MSCs.

One MFS can be connected to several SGSN units. One GPU is connected to only one SGSN.

One A9135 MFS can control up to 22 BSCs.

One MFS can manage up to 2000 cells.

The maximum number of cell adjacencies handled by the MFS is 40000.

Both maximum (cells and adjacencies) may be reached with one sub-rack, but in this case theycannot be increased when adding a second sub-rack.

9.1.1 MFS based on DS10 systems :

From the B8 release onwards, the MFS based on DS10 systems can house up to 32 GPU boards.

Hence each A9135 MFS sub-rack can include up to 15 GPU boards plus 1 GPU board for redundancy.The granularity is 1 GPU board.

9.1.2 MFS based on AS800 systems :

The MFS based on AS800 systems can house up to 24 GPU boards.

Hence each A9135 MFS sub-rack can include up to 11 GPU boards plus 1 GPU board for redundancy.The granularity is 1 GPU board.


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9.2 A9130 MFS configurations

The A9130 MFS Evolution can accommodate from 1 to 2 telecommunication sub-racks. Each A9130MFS Evolution racks can include up to 21 GP boards plus 1 GP board for redundancy without anysubrack constraints.

Each GP board is connected to only one BSC. But one BSC can be connected to several GP,depending on packet traffic (These GPs can belong to different MFS subracks).

One A9130 MFS Evolution can control up to 21 BSCs .

All the BSCs connected to the different GPs of a same MFS must be connected to the same OMC-Ras the MFS.

There can be more than one A9130 MFS Evolution per MSC, and one A9130 MFS Evolution can beconnected to BSCs of several MSCs .

One A9130 MFS Evolution can manage up to 3000 cells.

The maximum number of cell adjacencies handled by the A9130 MFS Evolution is 60000.

Both maximum (cells and adjacencies) may be reached with one sub-rack, but in this case theycannot be increased when adding a second sub-rack

The maximum number of external links per A9130 MFS is 256.

9.3 GP/ GPU capacity

- A9135 MFS: One GPU board can support up to 16 external links (A-ter + Gb).

- A9130 MFS : One GP board can support:

- up to 16 external links (A-ter + Gb), with a maximum of 16 GP board per MFS.- When the number of GP boards in the MFS is more than 16, the number of external

links per GP is limited, so that the total number of links per MFS is not exceeded (12per GP for the maximum MFS configuration of 21 GP).


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GPRS PDCH

Max CS Max nb of PDCH perGPU (A9135)

Max nb of PDCH perGP (A9130)

CS2 240 960 CS3 220 892 CS4 204 804

EDGE PDCH

Max EGPRS MCS Max nb of PDCH perGPU (A9135)

Max nb of PDCH perGP (A9130)

MCS 1 232 856MCS 2 228 836 MCS 3 212 796 MCS 4 200 772 MCS 5 180 704 MCS 6 172 660 MCS 7 140 448 MCS 8 116 380 MCS 9 108 348

Note: For the GP board; the maximum number of PDCH is indicated for the configuration with 16links per GP.

10. GB INTERFACE

The maximum number of links from one GPU or GP board to the SGSN is 8.

10.1 Configuration rules

There are 2 ways to connect the MFS and the SGSN via the Gb interface:

- Through the Transcoder and the MSC.

- Bypassing the Transcoder and going either directly to the SGSN (through the MSC or not). Thisis the recommended solution when the traffic is sufficient to justify A-ter PCMs completelydevoted to GPRS traffic. However, depending on the hardware and software versions, this isnot always possible, because of the GPU synchronisation issues 1.

The links between the MFS and the SGSN or between the MSC and the SGSN can be direct point-to-

1 For synchronisation issues, please refer to the A9135 MFS product description [4].


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point physical connections or an intermediate Frame Relay Network can be used..

The figure below displays the different types of links between the MFS and the SGSN.

BTS

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TC

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MSC FRDN

A bis A ter A ter A

FrameRelayDataNetwork

BTS

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FrameRelayDataNetwork

Remarks:

- The links going through the MSC can benefit from the multiplexing capability of the MSC inorder to reduce the number of ports required to the frame relay network towards the SGSN.

10.2 General dimensioning rules

The peak throughput of the Gb interface is equal to the peak LLC throughput multiplied by anoverhead factor which takes into account the Gb interface overheads.

- -This overhead factor depends on the mean frame size.

- The maximum number of Frame Relay bearer channels is 120 per GPU board (theoreticalvalue). It is however interesting to reduce the number of bearer channels to 2 (for

redundancy reason) in order to take benefit from the statistical effect of using larger bearerchannels.

For more information on the method to determine the Gb peak throughput according to the trafficmix expected within the BSC area and the Gb interface overheads, please refer to [10].


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11. ANNEX 1: STANDARD TRAFFIC MODEL

For comparison reasons, the following models are standardized with: BHCA = MOC + MTC = 1BHCA : Busy Hour Call Attempt

MOC : Mobile Originating CallMTC : Mobile Terminating Call

Mean holding time (s)

Events Average ratio perCall Attempt

SDCCH TCH SCCP

MO Call 0,6 4s 50s 54s

MT Call 0,4 4s 50s 54s

Internal Handover 2 - -

External Handover 1 - 4s

Location Update 3 3s 3sIMSI Attach 0.5 3s 3s

IMSI Detach 0.5 3s 3s

Originating SMS (PtP) 0.3 3s 3s

Terminating SMS(PtP)

0.7 3s 3s

Paging (as occurredin the A interface )

G2-BSC: 70Paging/s

Paging (as occurred

in the A- interface)

BSC-Ev: 95

Paging/s

(*) In rack-sharing configuration, the maximum paging rate corresponds to the rate for two logicalBSC.

- The BSC can handle different call mixes. If a Customers traffic mix is significantly differentfrom the above Standard Traffic Model, Alcatel is prepared to study the possibility for the BSCto cope with it.

- Performances versus traffic mix are committed upon BSC load test completion.


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12. ANNEX 2: A-BIS INTERFACE CONFIGURATION

12.1 Number of time-slots required with the different Signaling Multiplexingschemes

The table below gives the number of 64 kbit/s time-slots required with the different SignalingMultiplexing schemes. The BTS is assumed to have n TRXs in total all working in Full-Rate mode,and we shall use the notation roundup(x) when a value x is to be rounded up to the next higherinteger. For G2 sectored BTS, we shall note i, j and k the number of TRXs in sector 1,2,and 3.

WithoutSignalingMultiplexing

Static-SignalingMultiplexing

Statistical-SignalingMultiplexing-64k

Statistical-SignalingMultiplexing-16k

Trafic (n TRX) 2n (2 per TRX) 2n (2 per TRX) 2n (2 per TRX) 2n (2 per TRX)

OML if EVOLIUM BTS 1 per BTS 1 per BTS 0 0OML if non EVOLIUM BTS(previous generation)

1 per Sector 1 per Sector Not applicable Not applicable

RSL if EVOLIUM BTS 1 per TRX Roundup (n/4) Roundup ( n/4)or Roundup(n/2)(*)

0

RSL if non EVOLIUM BTS (G2-BTS)

1 per TRX Roundup(i/4)+Roundup(j/4)+Roundup(k/4)

Not applicable Not applicable

Number of A-bis time-slots required according to the different Signaling Multiplexing schemes

(*) Depends on signalling load: 4 for normal signalling load, 2 for high signalling load.

12.2 Typical cases where Signaling Multiplexing is very advantageous

- With Static Multiplexing, a sectored site with 3 x G2 BTS having 4 TRXs requires:

3x[ 1+ 4x2+ roundup ( 4 / 4 )] = 30 time-slots . Hence, it is possible to connect this sitewith only one A-bis PCM (except if Closed Loop with TS0 transparency)

- With Statistical Multiplexing 64k , one EVOLIUM A9100 BTS having 3x4 TRXs requires

Normal signaling load: 3x4x2 + roundup ( 3x4/4 ) = 27 time-slots.High Signaling load: 3x4x2 + roundup ( 3x4/2 ) = 30 time-slots.

- With Statistical Multiplexing 64k , one EVOLIUM BTS A9100 having 3x2 TRXs requires:

Normal signaling load: 3x2x2 + roundup ( 3x2/4 ) = 14 time-slots.High signaling load: 3x2x2 + roundup ( 3x2/2 ) = 15 time-slots.


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t i o n .

1 A A 0 0 0 1 4 0 0 0 4 ( 9 0 0 7 ) A 4

Hence, it is possible to connect 2 such sites with only one A-bis PCM.

- With Statistical Multiplexing 16k , one EVOLIUM Micro-BTS A9110 with 2 TRX in full Rate moderequires:

2x2 = 4 time-slots.Hence, it is possible to connect 7 of such BTSs with only one A-bis PCM.

- With Statistical Multiplexing 16k , one EVOLIUM BTS A9100 with 3x1 TRX requires:

3x2 = 6 time-slots.Hence, it is possible to connect 5 such sites with only one A-bis PCM (if open chain or

closed loop with TS0 usage).

- With Statistical Multiplexing 16k , one EVOLIUM BTS A9100 with 3x2 TRXs in full-rate modeoffering CS3/CS4 and EDGE thanks to one TRX Class 4 per sector requires:

3 x (1x2 + 4x2) = 30 time-slots.Hence it is possible to connect 1 such site with only one A-bis PCM link.


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1 A A 0 0 0 1 4 0 0 0 4 ( 9 0 0 7 ) A 4

12.3 Configurations with 2 A-bis links

12.3.1 Principles

In B9, the TWIN TRX gives the opportunity to put more TRX than 12 TRX inside a single BTS rack.For this purpose, it is possible to configure a secondary A-bis link with basic A-bis nibbles in B9.

By default, the first A-bis link is filled up as much as possible, but some additional flexibility isbrought:

It is possible to limit the number of TRX in the first A-bis link :

Two parameters MAX_FR_TRE_PRIMARY and MAX_DR_TRE_PRIMARY define the maximum number ofTRX of a BTS, which are mapped on the first A-bis link (respectively for Full Rate and Dual Rate).

Dual Rate TRX are mapped first, then Full Rate TRX, then Extra A-bis timeslots.

The OML of a BTS is always mapped on the first A-bis link.

The TCH and the RSL of a TRX are grouped on the same A-bis link.

12.3.2 Example : BTS with 16 Full Rate TRX.

In the first case, MAX_FR_TRE_PRIMARY is set to 12 (default value), while on the second caseMAX_FR_TRE_PRIMARY is limited to 8.

O M L + R S L 1 - 4

T R X 1

T R X 1

T R X 2

T R X 2

T R X 3

T R X 3

T R X 4

T R X 4

R S L 5 - 8

T R X 5

T R X 5

T R X 6

T R X 6

T R X 7

T R X 7

T R X 8

T R X 8

R S L 9

- 1 2

T R X 9

T R X 9

T R X 1 0

T R X 1 0

T R X 1 1

T R X 1 1

T R X 1 2

T R X 1 2

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

First A-bis

Second A-bis

O M L + R S L 1 - 4

T R X 1

T R X 1

T R X 2

T R X 2

T R X 3

T R X 3

T R X 4

T R X 4

R S L 5 - 8

T R X 5

T R X 5

T R X 6

T R X 6

T R X 7

T R X 7

T R X 8

T R X 8

R S L 9

- 1 2

T R X 9

T R X 9

T R X 1 0

T R X 1 0

T R X 1 1

T R X 1 1

T R X 1 2

T R X 1 2

O M L + R S L 1 - 4

T R X 1

T R X 1

T R X 2

T R X 2

T R X 3

T R X 3

T R X 4

T R X 4

R S L 5 - 8

T R X 5

T R X 5

T R X 6

T R X 6

T R X 7

T R X 7

T R X 8

T R X 8

R S L 9

- 1 2

T R X 9

T R X 9

T R X 1 0

T R X 1 0

T R X 1 1

T R X 1 1

T R X 1 2

T R X 1 2

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

First A-bis

Second A-bis

MAX_FR_TRE_PRIMARY= 12


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0 0 1 4 0 0 0 4 ( 9 0 0 7 ) A 4

First A-bis

Second A-bis

O M L + R S L 1 - 4

T R X 1

T R X 1

T R X 2

T R X 2

T R X 3

T R X 3

T R X 4

T R X 4

R S L 5

- 8

T R X 5

T R X 5

T R X 6

T R X 6

T R X 7

T R X 7

T R X 8

T R X 8

T R X 3

T R X 4

T R X 4

R S L 5

- 8

T R X 5

T R X 5

T R X 6

T R X 6

T R X 7

T R X 7

T R X 8

T R X 8

O M L + R S L 1 - 4

T R X 1

T R X 1

T R X 2

T R X 2

T R X 3

T R X 3

T R X 4

T R X 4

R S L 5

- 8

T R X 5

T R X 5

T R X 6

T R X 6

T R X 7

T R X 7

T R X 8

T R X 8

O M L + R S L 1 - 4

T R X 1

T R X 1

T R X 2

T R X 2

T R X 3

T R X 3

T R X 4

T R X 4

R S L 5

- 8

T R X 5

T R X 5

T R X 6

T R X 6

T R X 7

T R X 7

T R X 8

T R X 8

T R X 3

T R X 4

T R X 4

R S L 5

- 8

T R X 5

T R X 5

T R X 6

T R X 6

T R X 7

T R X 7

T R X 8

T R X 8

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

R S L 9

- 1 2

T R X 9

T R X 9

T R X 1 0

T R X 1 0

T R X 1 1

T R X 1 1

T R X 1 2

T R X 1 2

R S L 9

- 1 2

T R X 9

T R X 9

T R X 1 0

T R X 1 0

T R X 1 1

T R X 1 1

T R X 1 2

T R X 1 2

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

R S L 9

- 1 2

T R X 9

T R X 9

T R X 1 0

T R X 1 0

T R X 1 1

T R X 1 1

T R X 1 2

T R X 1 2

R S L 1 3

- 1 6

T R X 1 3

T R X 1 3

T R X 1 4

T R X 1 4

T R X 1 5

T R X 1 5

T R X 1 6

T R X 1 6

R S L 9

- 1 2

T R X 9

T R X 9

T R X 1 0

T R X 1 0

T R X 1 1

T R X 1 1

T R X 1 2

T R X 1 2

R S L 9

- 1 2

T R X 9

T R X 9

T R X 1 0

T R X 1 0

T R X 1 1

T R X 1 1

T R X 1 2

T R X 1 2

MAX_FR_TRE_PRIMARY= 8

This second option may be used for optimizing the filling of G2 BSC TSU.

End of Document

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