ghana radio optimization_initial check.pdf

7/27/2019 Ghana Radio Optimization_Initial Check.pdf

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RADIO OPTIMIZATION INITIAL CHECK 1 (9)

Prepared (also subject responsible if other) No.

S.Sinha OPT-001Approved Checked Date Rev Reference

LARRY ARTHUR 2009-02-03 Ver A

A.Find the worst cell which is contributing to the low KPI in your zonei.e. the cell which recorded high failure

B.Check the trend of that cell performance for last 2 weeks, if the failureis consistently recorded low performance, actions needs to be taken

TABLE OF CONTENTS

1 SDCCH ACCESSIBILITY ISSUE:.......................................................................... 2

1.1 CELLS WITH SDCCH FAILURE, WITH CONGESTION: ............................................... 2

1.2 CELLS WITH SDCCH FAILURE, WITHOUT CONGESTION: ......................................... 3

2 SDCCH DROP ISSUE:.............................................................................................. 4

2.1 CELLS WITH SDCCHDROP:................................................................................... 4

3 TCH ACCESSIBILITY ISSUE:............................................................................... 5

3.1 CELLS WITH TCH FAILURE, WITH CONGESTION: .................................................... 5

3.2 CELLS WITH TCHFAILURE, WITHOUT CONGESTION: ............................................. 6

4 TCH DROP ISSUE:................................................................................................... 7

4.1 CELLS WITH TCHDROP: ........................................................................................ 7

5 OTHER CHECKS: .................................................................................................... 8

5.1 CHECK NEIGHBOUR LIST, EXTERNAL CELL DEFINITION,MF LIST. ........................... 85.2 CHECK PARAMETER CONSISTENCY ......................................................................... 8

5.3 WHEN CELL IS NOT PICKING UP TRAFFIC ................................................................. 8

5.4 WHEN CELL IS NOT ORIGINATING CALL I.E. ONLY HANDLING HO TRAFFIC............. 95.5 WHEN THE CELL HAS LOW TCH UTILIZATION BUT EXPERIENCES CONGESTION ...... 9

5.6 POOR LOCATION UPDATE STATS.............................................................................. 9


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2 SDCCH Drop issue:

2.1 Cells with SDCCH Drop:

Total MIC SDCCH Drop = ( SDCCH Drop CNRELCONG )

2.1.1 Check if any neighbour cell was OOS during that period. Wait for another day ormonitor hourly stats on the same day for any action.

2.1.2 Check for possible BCCH interference if any. Check errors on SDCCH timeslot,re-configure SDCCH timeslot to another TRX

2.1.3 Try blocking the Cell and un-blocking the Cell and monitor the SDCCH Drop

2.1.4 Try shifting the SDCCH TS from one TRX to another and monitor theperformance (try finding out the faulty TRX if any)

2.1.5 Check for hardware faults / alarms, replace hardware

2.1.6 Check the MRR report and check the MAXTA and TALIM set in the cell. If themeasurements recorded in the MRR are less than the MAXTA value, optimizethe MAXTA and TALIM. There should not be SDCCH / TCH Drop increase dueto TA. [Down tilting the antenna or reducing the height of the antenna is still abetter action than optimizing these parameter for the cells which are in urban

area]

2.1.7 Check the ACCMIN and optimize / reduce the value to give less SDCCH Failure.(In general dont reduce ACCMIN below 100)

[For points 2.1.3 & 2.1.4 please take care that the BH TCH Traffic does not decrease dueto this change]

2.1.8 Check Down tilt of the antenna, carry out drive test and check if there is nocoverage issues, increase the antenna Down tilt by additional 2 for the parentcell (and the neighbour cells if possible)

2.1.9 Check SDCCH Drop due to low signal strength, down tilt antenna by additional 2

and check the TCH traffic performance. If BH TCH traffic reduces, revert backthe change, new site needed.

2.1.10 Check if there is Blocked Transcoder cards

2.1.11 SDCCH Drop also increases when there is high TCH Congestion in the cell


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3 TCH Accessibi lity issue:

3.1 Cells with TCH failure, with Congestion:

3.1.1 Check if any neighbour cells was OOS during that period

3.1.2 Check planned TRX configuration with the configured TRX and find if there is anyTRX which is OOS, replace faulty TRXs

3.1.3 Calculate the required device from the traffic carried and rectify/increase the HRthreshold to cater to the surge in the traffic. Keep in mind the BSCs supporting

AMR and BSCs not supporting AMR.

3.1.4 If HR has reached its max value, Check if there is excess SDCCH/8 allocation,calculate & remove excess SDCCH/8 and request for new capacity site

3.1.5 If HR cant be increased and TRX cant be added then activate Assignment toworst cell feature. Additionally Check AWOFFSET & ASSOC parameter.

3.1.6 If the TS of the TRX is automatically blocked by the system, will causeunnecessary congestion, check TRX performance and remove/replace faultyTRXs

3.1.7 If the Antenna height is very high or the cell is placed in the hill top, optimize theantenna height by bringing down the antenna height. This will reduce theovershoot. This action should be done if there is no coverage loss.

3.1.8 If the antenna is positioned very high and there is a neighbour cell positioned atthe same direction and still the cell is experiencing high congestion, check theMRR report & drive test report and check if the cell is overshooting. Reduce theantenna height to control the overshoot.

3.1.9 When neighbour cells are congested, this might also lead to failure while handingover to the congested cells thereby the call might get dragged and later lead todropped call. Cell congestion should be properly analysed and HR setting shouldbe optimized to reduce congestion.


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3.2 Cells with TCH Failure, without Congestion:

3.2.1 Check for possible BCCH frequency interference

3.2.2 Shift the BCCH Frequency to another TRX

3.2.3 Lock the cell and un-lock it

3.2.4 Carry out drive test in that region, Check Down tilt of the antenna, if there is nocoverage issues, increase the antenna down tilt by additional 2 for the parentcell (and the neighbour cells if possible) this is for reducing the interference.

3.2.5 Carry out drive test and check if there is cable swap, the probability for cableswap for new sites is higher. Inform BSS for cable swap correction

3.2.6 Analyse and trace the faulty TRX and replace hardware. Avoid configuringexcess TRXs in the cell. Excess TRXs increases un-necessary interference andcauses difficulty to trace the faulty TRX / TS.


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4 TCH Drop issue:

4.1 Cells with TCH Drop:

4.1.1 Check possible BCCH frequency interference

4.1.2 Check BCCH, BSIC, HSN & MAIO consistency

4.1.3 Check and add all possible missing neighbour cells, update the external cell ifany

4.1.4 Carry out drive test and control the overshoot, analyse interference

4.1.5 Check from cell availability if the transmission link fluctuates frequently, inform Txteam for rectification

4.1.6 Carry out drive test in that region, Check Down tilt of the antenna, if there is nocoverage issues, increase the antenna Down tilt by additional 2 for the parentcell (and the neighbour cells if possible)

4.1.7 Swap Y cable between two sectors and monitor if the problem gets swapped, ifso change Y Cable

4.1.8 Check active alarms like Rx Diversity alarm, VSWR Alarm, inform BSS to rectifythe fault.

4.1.9 Check and correct CGI definition mismatch in BSC and MSC

4.1.10 Check TRX utilization and if there is excess TRX, block the TRX to reduceunnecessary interference.

4.1.11 Check the mapping from TRX to the Cell. Correct TRX to Cell mapping (TRX tiedto each Cell)

4.1.12 If the cell records high TCH drop due to TA, increase the value MAXTA & TALIM

and reduce the TCH Drop due to TA. Later check the coverage impact by downtilting the antenna by additional 2


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5 Other checks:

5.1 Check neighbour list, external cell defini tion, MF list.

5.1.1 Check and add missing neighbour, check external cell definition, correct MF list

5.1.2 Remove / modify all neighbour cells with co-BCCH and co-BSIC

5.1.3 Optimize one direction neighbour

5.1.4 Check the ratio of incoming handover w.r.t. outgoing handover of all the cells. Ifthe ratio is not balanced then analyse the congestion of the neighbour cells.

5.1.5 Check the total number of handover attempt in last 7 days for each NB relation.The cells which has very few handover attempt or no attempt in both direction,analyse if the cell is a very far neighbour, check the overshoot and down tilt theantenna and remove the neighbour relation. Remove all un-wanted neighbourrelation.

5.1.6 Too many adjacencies more than 16 might reduce the sampling rate and hencevery few samples would be identified for all the neighbour cells this might lead toin-accurate best server calculation. Un-wanted neighbour relation should beremoved.

5.2 Check parameter consistency

5.2.1 Check all the parameter consistency from the DUMP file. Re-confirm theFrequency, BSIC that is allocated with the planned freq plan.

5.3 When cell is not picking up traffic

5.3.1 Check the parameter consistency, BCCH configuration, CGI definition, NCCPermit

5.3.2 Change the BCCH to another TRX, trace the faulty TRX

5.3.3 Delete and Re-define the cell in the MSC

5.3.4 Check for any active alarm and resolve the fault


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5.4 When cell is not originating Call i .e. only handling HO traffic

5.4.1 Check Cell Bar feature and deactivate

5.4.2 Follow step 5.3

5.5 When the cell has low TCH util ization but experiences congestion

5.5.1 Check actual number of TRX configured and then calculate the TCH Utilizationwith the current TCH traffic.

5.5.2 Check TCH Availability, check transmission link fluctuation

5.5.3 Check TS Blocking and TRX Blocking, change faulty TRX

5.6 Poor location update stats

5.6.1 Configure additional SDCCH/8 and monitor the cell stats

5.6.2 Optimize/increase the CRH value in steps of 2; this will reduce the frequentLocation update

5.6.3 Check if the cell is in the location border; try to re-design the LAC border (ifpossible)

ghana radio optimization_initial check.pdf

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