2g ul external interference report_version2[1]

秘密 Proprietary Confidential▲

K15 Interference Optimization


2G OSS Class A KPI Trend

Troubleshooting TCH Drop Rate and RQ Handover Success Rate 3G cooperation


Troubleshooting: Cell list which have external UL interference

Due to K15 located near the boarder of Malaysia and Thailand, EGSM900 cells of K15(4650B, 4659A) affect by UL external interference from Thailand.

BTS NAME

TCH Drop Rate

Number of idle TCH/F with

interference band 0(Num)











4650B-DG1 19.07% 2182 152 89 26996 39434 25114650B-DG2 8.29% 29 18 14761 3248 30 634659A-DG1 15.22% 1094 46 529 55049 16518 35774659A-DG2 9.83% 1658 57134 116 20 5 204659A-DG3 10.36% 68 21056 2707 16 6 25


Troubleshooting: Bad cells UL RQ & Traffic hourly KPI

UL RQ 5~7 hourly wise keep stable in whole day.


Troubleshooting: Conclusion for UL RQ & Traffic hourly KPI

Conclusion:

For those 5 bad cells, hourly UL RQ 5~7 keep stable in whole day. It means bad UL RQ KPI have nothing to do with traffic.


Troubleshooting: 4650B-DG1 off hopping-TRX1(1008)

Off hopping On hopping


Troubleshooting: 4659A-DG1 off hopping-TRX1(1005)



Troubleshooting: Off hopping test conclusion

Conclusion:

UL RQ have no changes after off hopping. It means Bad UL RQ is not due to unreasonable frequency plan.


Troubleshooting: Signal Trace 4650B-DG1

Conclusion:

We can see from screen shot that UL RQ is worse even though RXLEV is good. It means UL have interference.


Troubleshooting: P-GSM Frequency Retune on 4650B-DG1

If we retune EGSM frequency to PGSM frequency(75), the UL RQ became better. It means there is UL external interference for EGSM.

Frequency retune to 75 Fallback


Troubleshooting: P-GSM Frequency Retune on 4650B-DG1

If we retune EGSM frequency to PGSM frequency(75), the DL RQ became worse, it means frequency 75 is not clear because this area located in exclusion zone.



Troubleshooting: P-GSM Frequency Retune on 4659A-DG1

If we retune EGSM frequency to PGSM frequency 75, the UL RQ would increased. It means there is UL external interference for EGSM.

If we retune EGSM frequency to PGSM frequency 77, the UL RQ have no change. It is due to 77 is not clear.

Frequency retune to 75 FallbackFrequency retune to 77

Fallback


Troubleshooting: P-GSM Frequency Retune on 4659A-DG1

If we retune EGSM frequency to PGSM frequency 75 or 77, the DL RQ became worse, it means PGSM frequency is not clear because this area located in exclusion zone.

Frequency retune to 77

Fallback



TCH Drop Rate : Cluster Level TCH drop rate

Compare with Pre swap, TCH drop rate became better after swap. There are 5 days(29th April, 15th May, 16th May, 18th May, 31th May) TCH drop higher than usual due

to LAPD drop.


TCH Drop Rate : Cluster Level TCH drop rate

There are 5 days(29th April, 15th May, 16th May, 18th May, 31th May) TCH drop higher than usual due to LAPD drop.


TCH Drop Rate : Cluster Level TCH drop rate exclude bad cells

If exclude bad cells(EGSM of 4650B and 4659A), TCH drop rate of K15 can meet PAC target: 0.90%.


TCH Drop Rate : EGSM cells which have UL interference list

We make optimization for those bad cells. The result shows as follows.

Cell which have strong UL external interference

CR 1 details CR date CR 2 details CR date

4650B-DG1 Handover controlPBGTHOMARGIN 2013/5/2 　　

4650B-DG2Handover control

PBGTHOMARGIN 2013/5/2

4659A-DG1 Change Power :4659A-DG1 18->10;4659A-DD1 12->20; 2013/5/2

Handover controlPBGTHOMARGIN 2013/5/31

4659A-DG2Change Power:

4659A-DG2 18->10;4659A-DD2 12->20; 2013/5/2

Handover controlPBGTHOMARGIN 2013/5/31

4659A-DG3 Change Power:4659A-DG3 18->10;4659A-DD3 12->20; 2013/5/2

Handover controlPBGTHOMARGIN 2013/5/31 　

Handover change CR1

Handover change CR2


TCH Drop Rate_4650B-DG1

Handover optimized on 2th May;


TCH Drop Rate_4650B-DG2

Handover optimized on 2th May;


TCH Drop Rate_4659A-DG1

Decrease RRU power 18->10 on 2th May; Optimized handover parameter for 4659A G900 cells on 31th May;


TCH Drop Rate_4659A-DD1

Increase RRU power 12->20 on 2th May; Optimized handover parameter for 4659A G900 cells on 31th May;



Decrease RRU power 18->10 on 2th May; Optimized handover parameter for 4659A G900 cells on 31th May;



Increase RRU power 12->20 on 2th May; Optimized handover parameter for 4659A G900 cells on 31th May;



Decrease RRU power 18->10 on 2th May; Optimized handover parameter for G900 cells on 31th May;



Increase RRU power 12->20 on 2th May; Optimized handover parameter for G900 cells on 31th May;


TCH Drop Rate _ EGSM Traffic Shift Due To Handover Out

EGSM of 4650B and 4659A traffic shift due to put higher priority on Handover to neighbor cells; HOSR of EGSM 4650B and 4659A keep stable after handover parameter optimization, On 31th

May to 4th June, Handover success rate low due to 4769B PSSR issue.


TCH Drop Rate _ EGSM Traffic Shift Due To Handover Out

On 31th May to 4th June, Handover success rate low due to 4769B PSSR issue which result handover to 4769B failure;

PSSR team change jumper on 4th June and KPI recovered from 5th June.


Handover Success Rate

HOSR increased since swap, but still cannot meet PAC target: 98.50% due to handover out to bad cells.


Handover Success Rate exclude bad cells

HOSR can meet PAC target: 98.50% if we exclude the number that cells handover out to bad cells. On 31th May, low HOSR due to Transmission issues.

Date Handover attempts number Handover success number HOSR2013/5/20 333473 331620 99.44%

2013/5/21 339772 337769 99.41%

2013/5/22 346443 344443 99.42%

2013/5/23 347265 345319 99.44%

2013/5/24 306427 304452 99.36%

2013/5/25 315558 313658 99.40%

2013/5/26 314631 312862 99.44%

2013/5/27 326319 324602 99.47%

2013/5/28 333489 329753 98.88%

2013/5/29 336233 334398 99.45%

2013/5/30 343825 341473 99.32%

2013/5/31 306385 297695 97.16%

2013/6/1 305229 303261 99.36%

2013/6/2 319354 317051 99.28%


Handover Success Rate exclude bad cells

On 31th May, low HOSR due to Transmission issues.


3G cooperation

We turn OFF IRAT and giving priority to IHFO on 16th May.

We can see that 3G traffic increased.

2g ul external interference report_version2[1]

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