Call Reestablishment Feature

RNC Annaba

Netas Huawei Team Sami Ali

About This Document

Overview

Feature Description

Feature Indicators

KPIs Improvement

CFG Script

Recommendations

Overview

Call Reestablishment Feature enabled on RNC Annaba on 13-May-2015.

The objective is to enhance main RNC KPIs and enhance 3G Users

experience.

All expected Improvments noticed after open the related Switches ,

Accessibility , Retainability & Mobility .

Traffic Didnt affect and keep the same trend before and after Changes .

Feature Description :

- Call reestablishment is a function by which radio links (RLs) are reestablished when a

service interruption or an access failure occurs in temporary coverage holes and in tunnels,

elevators, and buildings that cause significant signal quality fluctuation, and it can be

initiated by a UE or the RAN.

- Call reestablishment increases the radio access bearer (RAB) setup success rate, reduces

the call drop rate, and therefore improves user experience.

- The causes that can trigger call reestablishment after a service interruption or an access

failure are : RL failure- SRB reset- Air-interface process timeout-Air-interface process

overlap- PS TRB reset.

- The Processes That Can Trigger Call Reestablishment are : Soft handover Physical channel reconfiguration- Inter-RAT handover-RB setup-RB release RB reconfiguration

- Before releasing RLs due to any of the causes, the RAN detects the service interruption or

access failure and initiates call reestablishment.

Feature

Indicators

Feature indicators:

Cell Update Attempts : number of Cell Update attempts increased about 300K.

Feature indicators:

Cell Update Attempts with Cause RL Failure increased (It was Zero Before).

Feature indicators:

Cell Update Attempts with Cause Signal Radio Bearer Reset Increased

Feature indicators:

Cell Update Attempts with Cause PS Traffic Radio Bearer Reset Increased

Feature indicators:

Number of Failure Cell Update due to No Responceincreased , and it is Normal since

number of Cell Update attempts increased , and will enhance once coverage enhanced .

Feature indicators:

Number of RRC Connection releases due to Cell Update Failure increased since attempts

are increased.

KPIS

Improvement

KPIS Improvement :

Accessibility : as Appered the number of Radio Bearer Setup Failures decreased a lot

which enhance the RB Setup Success Rate

KPIS Improvement :

PS Accessibility : HSDPA RAB Failure Rate decreased from 1.5% to 1 % , And will clearly

decrease after add new Channel Elements on congested sites.

KPIS Improvement :

PS Accessibility : HSUPA RAB Failure Rate decreased from 1.3% to 0.6 % , And will clearly decrease

after add new Channel Elements on congested sites.

KPIS Improvement :

PS Accessibility : HSDPA & HSUP RAB Setup Success Rate enhanced because below failures are deccreased:

UE No replay & Radio NetworkLayer Cause.

KPIS Improvement :

CS Accessibility : CS RAB Failure Rate decreased from 2 % to 0.5 % , And will clearly decrease after add

new Channel Elements on congested sites.

KPIS Improvement :

CS Accessibility : CS RAB Setup Success Rate enhanced because below failures are deccreased:

UE No replay & Radio NetworkLayer Cause , In addition TNL Failure problem has been Solved on MGW.

KPIS Improvement :

CS Retainability : CS Drop Call Rate Clearly decreased and Became below 0.4 %

KPIS Improvement :

CS Retainability : CS Drop Call Rate decreased because the below drop Causes almost disappeared :

SRB Reset & UL Sync Causes.

KPIS Improvement :

PS Retainability : HSDPA Drop Call Rate Clearly decreased and Became below 0.4 %

KPIS Improvement :

PS Retainability : HSUPA Drop Call Rate Clearly decreased and Became below 0.5 % and will enhance

more after solving The CE Congestion.

KPIS Improvement :

PS Retainability : PS R99 Drop Call Rate was good and decreased more after enabling this feature.

KPIS Improvement :

PS Retainability : PS Drop Call Rate decreased because the below drop Causes almost disappeared :

SRB Reset & UL Sync Causes.

CFG Script

Attached is all parameters on Cell and RNC Level Changed to enable the Call

reestablshment Fetaure

Recommendations:

After expanding The network Resources (CE Second Carrier New Site) , some Timers can be modify to enhance the Service.

All possible downtilt on Overshooting cells should be applied to enhance the Cell Update

Success Rate.

NInsyncInd, NOutsyncInd Parameters can be modified Cell By cell upon the Cases.

When IUR Interfcaes configured for this RNCs , IUR related switches should be open.

The End

THANK YOU