2g case study

8/13/2019 2G Case Study

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Optimization in Nokia System

I got good tutorial from http://www.cellular-planningoptimization.com and I wanna share with you. Its

just copy from that good website of RF.

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HOSR Analysis-Tips on Nokia system-1

Possibilities :

Co or Adjacent BCCH

High TCH Blocking on target cell

Wrong TSC setting regarding BSIC allocation

Bad Neighbor Relation

HW faulty or Unbalance TRX power among a sector

Others ( Inter BSC-Inter MSC)

Preparation Data :

BCCH, BSIC planning, ND report 072

Cell Stat or TQM of HO distribution and ND report 153

Alarm (ZEOH & ZEOL) and site visit

Timing Advance 232

Adjacent Consistency Check ND060, 62 or 69

ND Report 73 to check Undefined Neighbor

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HOSR Analysis-Tips on Nokia system-2

Problem Analysis :

Check possibility Co. or Adj. Interference then change BCCH frequency.

Check neighbor traffic & TCH blocking, check possibility for traffic sharing or directed retry.

TSC value should be same with BCC, check performance HO out and incoming.

Parameter setting ADJE to make delay on worst target cell or faster HO on best target, focused on High

HO Fail. Relate parameter FMT or AUCL.

Check TRX alarm (mostly 7745 together with 7743 or 7746). Check TRX configuration.

Optimize coverage from TA distribution or update missing Neighbor from ND 73.

Check the highest handover cause: by interference, quality, level, power budget, GPRS, etc. Check for

the highest HO failure: by Blocked, Conn. Fail., Return to Old, End of HO,etc. The highest value is

possible as the highest contribution of HO fail

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SDCCH Success Rate Analysis-Nokia System-1

Possible :

Interference on BCCH frequency

SDCCH Blocking

SD Drop on Location Update

A_If, TRC or LAPD Fail

HW faulty

Excessive TA

Data Collection :

ND Report 72 to check BCCH clearance

Alarm Log

TA distribution ND Report 232

Quality and Link Balance ND Report 195 and 196.

Interference UL and ND 196


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SDCCH Success Rate Analysis-Nokia System-2

Problem Analysis :

Check possibility Co. or Adj. Interference and clear the BCCH frequency.

Check SDCCH utilization and add SDCCH if needed.

Change TRP or change SDCCH allocation on TRX with good quality based on ND 196.

Check TRX alarm (mostly 7745 together with7743 or 7746). Check TRX configuration.

Check TA distribution, coverage distribution and propose physical tune.

Optimizing parameter C2 also if Location update is the highest contributor of SD Drop.

Highest contributor: Fail on RADIO, ABIS, A_IF, TR or LAPD.

Check TRX alarm (mostly 7745 alone or together with 7743)

Check RX Lev Access Min and Max Number of Retransmission. Check RACH Rejected and SDCCH request

(fails or ghost).

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KPI Analysis on Nokia system-TCH drop-1

Possibilities :

Interference on BCCH TRX

Interference on hopping TRX(DL Interference)

External Interference (UL interference)

Bad Neighbor Relation (bad HO)


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Low Coverage

HW Faulty or TRX Power Unbalance

Other : A_If, TR or LAPD Fail

Preparation Data :

BCCH Planning, ND report 072 (DL Interference distribution)

ND Report 216, 196 and Alarm (Interference)

ND Report 204, 153, 195 ( HO fail and Path Balance)

ND Report 232 ( Coverage cell)

ND Report 163 or TQM drop per causes

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KPI Analysis on Nokia system-TCH drop-2

Problem Analysis:

Check possibility Co. or Adj. Interference. Check clean BCCH frequency.

Check DL quality Distribution and Check MAL and MAIO

Check UL quality Distribution, check UL interference Pwr Contrl setting to compensate interference.

Check % of HO fail from adjacencies, focused on High HO Fail. Check TCH_RF_HO_OLD. Check possibility

to add some neighbor. Try to prevent un proper HO and use FMT to reduce drop.

Check best serving cell, possibility HO to best serving cell (Macro or Indoor) make it faster to prevent

drop.

Check TRX alarm (mostly 7745 together with 7743 or 7746). Check TRX configuration or reset TRX if

needed.

Check TA distribution, coverage spillage and proposed physical tune.

Check and compare which one the highest: Fail on RADIO, ABIS, A_IF, TR or LAPD.

Hope itll be helpfull.

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