LATE ASSIGNMENT TRIAL

Upper Optimization

Etisalat Misr

July 2010

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Introduction

Different TCH assignment approaches

Early Vs Late assignment procedures

Trial implementation phases

Phase 1 trial results

Phase 1&2 trial impact on Ater resources

ANNEX

Contents

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The presentation highlights the different assignment approaches as well as the trial results for the trial done

Introduction

Different TCH assignment approaches 3 different TCH assignment approaches are available which

are: Very Early Assignment: The network makes an immediate

assignment to the TCH+FACCH in the initial RR establishment and performs the entire transaction on the FACCH. The SDCCH is not used.

Early Assignment: The network assigns the TCH+FACCH after sending CC Call Proceeding and completes call setup on the FACCH

Late assignment: MOC: The network does not assign the TCH+FACCH until alerting to

the terminating party has started. MTC: The network does not assign the TCH+FACCH until Connect

message is sent (User answers the phone)

The above 3 strategies are cell-level core parameters which gives great flexibility in implementation

Different TCH assignment approaches Currently Early assignment is being used in Etisalat Network

although it is very clear that the Late assignment can save a lot of resources on the:

Radio Abis Ater BSC TC MSC MGW

Also great Enhancement in KPIs (CDR, voice quality and blocking) is expected due to reduction in RFLoad

In the next slides complete Late assignment procedures as well as comparison with the early assignment procedure are shown

Early Vs Late assignment procedures Early assignment in MOC side

During call setup, a TCH is assigned before the terminating side is alerted

Early Vs Late assignment procedures Late assignment in MOC side

During call setup, a TCH is assigned after the terminating side is alerted As we can see just 1 difference between the early and late assignment exists

which is the Assignment command comes after the alerting in the late assignment procedure which makes no big difference in resource saving

Assignment command Delay

Early Vs Late assignment procedures Early assignment in MTC side

During call setup, the MSC assigns the TCH+FACCH just after the call confirmed message is sent

Early Vs Late assignment procedures Late assignment in MTC side

During call setup, the MSC does not assign the TCH+FACCH until Connect message is sent via the terminating MS (User answers the phone)

The power of late assignment is clear in MTC scenario as all the ringing time is carried over SDCCH and user is assigned a TCH only after he picks up his phone

Assignment command Delay

Trial implementation phases Trial was implemented on phases as follow

Phase0, On June 24th, Late assignment was implemented on 3 cells in Upper region where one of these cells serve one of our colleagues in Luxor in order to test the impact on End-User perception. No Impact was observed for more than 1 month

Phase1, On July 5th, Late assignment was enabled on a cluster of 10 sites on SBH14 BSC whose KPIs are presented later in this presentation (Batch 1)

Phase2, On July 6th, Late assignment was enabled on another cluster of 30 sites on SBH14 BSC (Batch 2)

As expected, SD drop rate increased due to increase of SDCCH mean holding time and so on July 8th SDCCH HO was enabled on Batch 1 sites which reduced the SD Drop rate

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MTC TCH Vs MTC SDCCH Assignements

Call Setup indication (MTC non SMS) A3101C:Assignment Requests (MTC)

Phase 1 trial results By comparing the SD & TCH seizures for MTC, we can see great reduction in

TCH seizures (more than 60% reduction) This reduction represents the eliminated missed calls TCH seizures As in late assignment, the TCH seizures decreased due to the reduction in

MTC TCH seizures, it is totally incorrect to benchmark the call drop rate using the successful TCH seizures so in the rest of the slides benchmarking using the successful SD seizures for MTC & MOC will be used instead of Successful TCH seizures in the rest of the presentation

Missed Calls

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TCH and SDCCH Traffic Split

K3014:Traffic Volume on TCH (Erlang) K3004:Traffic Volume on SDCCH (Erlang)

Phase 1 trial results All MTC alerting traffic shifted from TCH to SDCCH/8 freeing up a lot of

resources TCH traffic volume reduction reached up to 13% on some days compared to

the same day in the previous week regardless the increase in the overall traffic which can be witnessed from the graph

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SD&TCH Overall Drop Rate

SD&TCH drop rate (Radio only)

Phase 1 trial results Clear improvement in SDCCH + TCH CDR Please note that:

SDCCH drops include all drops for all services (MTC, MOC, location update,…etc) Call setup indication MOC&MTC is used instead of successful TCH seizures The increase in CDR in days July 6th to July 10th is due to external interference

External interference

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SDCCH & TCH Assign congestion rate

TCH Assign congestion SD Congestion Rate

Phase 1 trial results SDCCH and TCH Congestion enhanced after action except for the days with

HW problem

HW Problem

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Ater Maximum utilization per day

Subrack No.=6 Subrack No.=7

Phase 1&2 trial impact on Ater resources Late assignment was implemented on total of 40 sites (Out of 91 on BSC) Clear reduction on Ater utilization can be noticed

ANNEX TCH drop Number (Radio Only) ='TCH total drop'-'CM333:Call Drops

due to Abis Terrestrial Link Failure (Traffic Channel)'-'CM334:Call Drops due to Equipment Failure (Traffic Channel)'-'CM335:Call Drops due to Forced Handover (Traffic Channel)'

SD Drop number (Radio only) ='CM30:Call Drops on SDCCH'-'M303:Call Drops due to Abis Terrestrial Link Failure (SDCCH)'-'M304:Call Drops Due to Equipment Failure (SDCCH)'-'M305:Call Drops due to Forced Handover (SDCCH)'

SD&TCH Drop Number (Radio Only) ='TCH drop Number (Radio Only)'+'SD Drop number (Radio only)'

SD Congestion Rate='K3001:Failed SDCCH Seizures due to Busy SDCCH' /'K3000:SDCCH Seizure Requests‘

TCH Assign congestion ='K3011A:Failed TCH Seizures due to Busy TCH (Traffic Channel)'/'Call Setup indication (MTC & MOC calls only)‘

ANNEX Call Setup indication (MTC Non SMS) ='A3030C:Call Setup Indications

(MTC) (SDCCH)'-'A3340B:Downlink Point-to-Point Short Messages on SDCCH' Call Setup indication (MTC & MOC calls only) ='A3030A:Call Setup

Indications (MOC Non SMS) (SDCCH)'+'Call Setup indication (MTC Non SMS)‘ SD&TCH drop rate (Radio only) = ('TCH drop Number (Radio

Only)'+'SD Drop number (Radio only)')/'Call Setup indication (MTC & MOC calls only)'

Thank You

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