Actix call setup success rate.

Grant Chivandire - Radio Planning and Optimisation Specialist

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RADIO PLANNING AND OPTIMISATION

Call Setup Analysis – A Drive Test Perspective(Presentation/Discussion)

27 July 2009

By

Grant Chivandire


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Objectives

This presentation will cover the following: System Info Messages

Types of MOC

Signaling Flow for MOC

Call Setup Failures & possible causes


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System Info Messages

Contain network parameters sent to MS through air interface

These parameters are:

Network Identity parameters

Cell selection parameters

System control parameters

Network function parameters


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System Information Messages – Idle Mode

These are sent to the MS on BCCH

SYS INFO 1

Contains RACH control information and cell channel description

These include the following:

• Cell frequency allocation (CA list)

• Maximum retransmission times (Max retrans)

• Extended transmission timeslots (Tx_interger)

• Cell Bar access (CBA)

• Common access control level (AC)

• Call re-establish permitted (RE)

• Emergency calls permitted (EC)


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SYS INFO 1 Message from ACTIX


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SYS INFO 2

Contains the following:

• Neighbour cell description

• NCC permitted

• RACH control parameters (same as in SYS INFO TYPE 1)



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SYS INFO 3


• Location Area Identity (MCC, MNC, LAC, CI)

• Control channel description (reserved Access Grant Blocks, CCCHConfiguration, IMSI Attach/Detach allowed, Paging Multiframes,T3212)

• Cell Option (Power control indication, DTX, RLINKT)

• Cell Selection (MS_TXPWR, ACCMIN, ACS, NECI)

• RACH control parameters (same as in SYS INFO TYPE 1)


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SYS INFO 4


• Cell Selection Parameters

• RACH Control Parameters

• CBCH Channel description



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System Information Messages – Dedicated Mode

These are sent to the MS on SACCH

SYS INFO 5

Contains neighbour cell BCCH frequencies (Phase 1 Mobiles)

SYS INFO 5 Bis

Contains neighbour cell BCCH frequencies which could not fit in thelimited space of TYPE 5 and belong to the same band as serving BCCH

SYS INFO 5TER

Contains neighbour cell BCCH frequencies whose band is differentfrom serving BCCH (Dual Band Mobiles)

SYS INFO 5TER Message from ACTIX


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System Information Messages – Dedicated Mode

SYS INFO 6


• Cell Identity

• LAI

• Cell option

• NCC Permitted



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Mobile Originating Call - MOC

Types

Early Assignment

The network assigns the TCH+FACCH after sending CC Call Proceedingand completes call setup on the FACCH

Late Assignment

The network does not assign the TCH+FACCH until after alerting hasstarted

Very Early Assignment

The network makes an immediate assignment to the TCH+FACCH inthe initial RR establishment and performs the entire transaction onthe FACCH

The SDCCH is not used


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Signaling Flow of MOC


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Signaling Flow – MOC (Um Interface)

Channel Request (uplink)

MS sends Channel Request message on the RACH

Message contains the following:

• Cause value – MOC

• Random reference number

Channel Request Message from ACTIX


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Signaling Flow – MOC (Um Interface) (Cont…)

Immediate Assignment (downlink)

BSC sends immediate assignment through the BTS to the MS on AGCH


• Details of the signaling channel being assigned

• Request reference details

Immediate Assignment Message from ACTIX


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Setup (uplink)

MS sends setup message to the MSC on SDCCH


• Bearer capabilities

• B-number details

Setup Message from ACTIX

NB: Authentication and Ciphering have been omitted


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Call Proceeding (downlink)

MSC send call proceeding message to MS on SDCCH informing it thatthe call setup is in progress


• Transaction ID which maybe co-related to the relevant SETUP message

Call Proceeding Message from ACTIX


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Assignment Command (downlink)

BSC sends Assignment Command to MS on SDCCH


• Details of the traffic channel being assigned

• Amount of power to be used by the MS

Assignment Command Message from ACTIX


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Assignment Complete (uplink)

MS sends Assignment Complete message to BSC on FACCH after it hasswitched to the assigned TCH

Assignment Complete Message from ACTIX


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Alerting (downlink)

MSC sends Alerting message to MS on FACCH

The MS will hear the ring-back

Alerting Message from ACTIX


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Connect (downlink)

MSC sends Connect message to MS on FACCH

This happens after the called party has answered the call

Calling MS switches over to voice on the assigned TCH

Connect Message from ACTIX


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Connect Acknowledgement (uplink)

MS sends a Connect Acknowledgement to MSC on FACCH

Call has been successfully setup

Connect Acknowledgement Message from ACTIX


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Call Setup Failure

RACH Success


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Call Setup Failure

Paging Success


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Call Setup Failure

High SDCCH Congestion Rate


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Call Setup Failure

High SDCCH Drop Rate


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Call Setup Failure

High TCH Congestion Rate


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Call Setup Failure

Disconnect Cause

Disconnect cause code

• Layer 3 message contains the cause code and description for thedisconnection

• Get more information from 3GPP TS 24.008 document

THANK YOU !

Actix call setup success rate.

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