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The objective of the performance monitoring is to monitor RAN performance and identify
faulty, non performing or poor performing network elements, RNC, Node B’s, cells etc. RANperformance will be monitored for the following types of performance “checks” :
Accessibility, RAN accessibility at initial network access, call setup and other services establishment.
Retainability, call or other bearer service completion successes or failures.
Mobility, successes or failures whilst UE’s are transported within the network.
Integrity, call or other bearer services transmission quality, speech quality, throughput rates etc.
Performance monitoring activity identifies problematic network elements, investigates rootcauses to problems based on available input data( mainly performance statistics) andsuggests changes that needs to be made in order to correct non optimal operation ofnetwork elements.
Output
The output of the Performance monitoring activity is:
List of network elements that are faulty, non performing or poor performing, that needs to be fixed.
Suggested actions to resolve problems or non optimal operation, based on initial root cause analysis
Prerequisites/ Inputs for the Radio Performance monitoringThe following scope and information must already be agreed and in the scope of work, or similar service contract
documentation, for the service delivery and available as inputs to the Radio Performance monitoring(procedures as described in this document). The service delivery and methodologies in this document cannot be executed without this information agreed and available as input:
Scope of the project Agreed Network element level/ depth to be assessed
Geographical area set by OSS, RNC’s etc (Optional)
RAN Feature Functionality, if any specific features in or out of scope of delivery
Customer inputsInformation/ data provided to service delivery by customer based on scope of work or delivery contract/
specification.
1. List of NEs (RNCs or BTS)s to be included in performance monitoring activity
2. Agreed KPI thresholds and targets
3. Other supporting vendor documentation (on a need be basis e.g. counter and/ or KPI dictionary)
Performance monitoring method based on available tools and OSS access Direct OSS access - online assessment
PM statistics file dump - offline assessment
Note: In case of offline assessment customer parameter dump file and formats needs to have beenagreed in scope of work or service delivery contract discussions.
RNC aggregated multi RAB IRAT stats, E_CMSIRAT_SR_1 < zz %
Analysis and potential solution:
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings. System SWupgrade?
RRC blocking due to Admission: Rrc_Blocking > xz %
RRC blocking due to CE: RRC_blocking_CE_rate > xz %
c) RAB establishment failures due to blocking:
RAB blocking due to max number of connections: Cell_Conn_limit_R > zx %
RAB blocking due to code blocking: Rab_Blocking > zx %
Analysis and potential solution:
RRC/ RAB establishment failures excessive, blocking/ congestion indicated and additional capacityneeds to be added, alternatively parameterization for cell load sharing or traffic distribution. Reference
5. Root cause analysis, coverage or interference limited cell: Numbering…
a) Coverage limited cell:
Reported low average RSSI, AvgRssiAvg_BH < -95 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _Dy Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
Then UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?
More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
1. Trigger: excessive call drop rate based on aggregated cell level KPI’s: AMR:E_CCSDCR_1, NRT R99: E_CPSDCR_1
2. Root cause analysis, poor drop call performance RNC level:
a) Drop due to sync and transmission network:
Drop call rate due to sync, aggregated cell statistics, E_CCSDCR_US_1 > xx %Analysis and potential solution:
Drops due to synch indicating issues in transmission or core network.
Verify RNC, LA and RA area based changes, has there been any major system wide changes, re-homing, RNC’s added or redesigned.
Known performance issues on this RNC, transmission network?
3. Root cause analysis RNC, mobility:
a) Drops due mobility issues:
Drops due to inability to add AS neighbor, aggregated cell stats, E_CCSDCR_AN_1 > zz %
Drops due to missing neighbor, aggregated cell stats, E_CCSDCR_MN_1 > zz %
Analysis and potential solution:
Statistics indicating cells in RNC having abnormal level of drops due to active set or neighbordefinitions. Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? SW update?
1. Trigger: excessive call drop rate based on cell level KPI’s: AMR: E_CCSDCR_1, NRTR99: E_CPSDCR_1
2. Check cell and neighbor cell alarms and performance alarms
3. Root cause analysis, poor performance HW, transmission or core NW:
a) Drop due to sync and transmission network: Drop call rate due to sync, cell statistics, E_CCSDCR_US_1 > xx %
Analysis and potential solution:
Drops due to synch indicating issues in transmission, core network or WRBS HW issues.
Verify synch related alarms on WRBS. Verify RNC, LA and RA area based changes, has there beenany major system wide changes, re-homing, RNC’s added or redesigned.
Known performance issues on RNC or transmission network?
Drops due to inability to add AS neighbor, cell stats, E_CCSDCR_AN_1 > zz %
Drops due to missing neighbor, cell stats, E_CCSDCR_MN_1 > zz %
Analysis and potential solution:Statistics indicating cells in RNC having abnormal level of drops due to active set or neighbordefinitions. Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan?
5. Root cause analysis, missing neighbors:
a) Drops due to missing neighbors, WNCS statistics:
Missing neighbors leading to a dropped connection: numberOfDrops < zz (kbps)
Analysis and potential solution:WNCS report can be used to identify missing neighbors that if added could have avoided a droppedconnection. Missing neighbors with reported dropped connections, should preferably be added asneighbors.
Missing neighbors leading to a dropped connection: Rladd_fail_R_Wncs > 2 [%]Analysis and potential solution:
WNCS report can be used to identify problematic neighbor relations. Coverage and interference limitedcells should be filtered out, non-relevant, since poor coverage or excessive interference leads toperformance issues aswell.
If problem neighbor is located in different RNC or OMC, check external neighbor definitions andrelevant RNC/ system parameter settings.
If cell is in same RNC, LAC and RAC, investigate problem further, if no problem can be identified,remove neighbor from neighbor list and re-run WNCS recording and re evaluate removal.
7. Root cause analysis, capacity:
a) Drops due to capacity limitations:
Drops due to congestion, cell stats, E_CCSDCR_BLK_1 < zz %
Analysis and potential solution:
Cell seems to have a high rate of dropped calls due to congestion. Verify cell capacity and ensure there
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _DyReported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
Then UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?
More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
Performing WMRR measurements for problem cells is an additional source for trouble shooting, drops and RF relatedissues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication if it really is the RF environment thatare causing excessive dropped connections, or if the problem is at a higher level.
Correlation of these performance measurements is a good way of identifying RF related problems.
1. Trigger: excessive call drop rate based on aggregated cell level KPI’s:E_CRAB_HSASR_1 & E_CRAB_HSASR_1
2. Root cause analysis, signaling:
a) Low signaling success rate RNC’s:
Signaling success rate, total CS and PS RNC, E_CRRC_CSPS_SSR_1 < xx %Congestion or transport network related issues: pmNoOfIurTermHsCong > yy %,pmHsSevereCong(IubLink) > yy %, pmHsSevereCong(IurLink) > yy %
Analysis and potential solution:
Check core and transmission network outage and performance stats, any major networkreconfigurations?
b) Non-signaling related, continue root cause at node level.
3. Root cause analysis, availability:a) Low HS availability
Abnormally Low HS availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’sor LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? Or just inconsistent RNC
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Abnormal low throughput in an RNC should be investigated further, is there a system wide or RNCperformance issue, or are there cells in RNC with exceptional bad performance?
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC HS parameter settings.
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Verify or update neighbor lists, check external cell definitions on controller border cells.
5. Root cause analysis, low throughput:
a) Low average throughputCell HS stats, E_CHS_DLTH_1 < zz (kbps)
Cell HS stats, Rab_Blocking_Hs(UtranCell) > xx %
Analysis and potential solution:
Abnormal low throughput in a cell, is the average throughput decreased? Is there sufficient capacity,cell having blocking problems?
If cell is resource limited, increase license limits or add resources, HW elements.
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _Dy
Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
Then UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?
More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
Abnormally Low HS availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’sor LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? Or just inconsistent RNC
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Abnormal low throughput in an RNC should be investigated further, is there a system wide or RNCperformance issue, or are there cells in RNC with exceptional bad performance?
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC HS parameter settings.
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Verify or update neighbor lists, check external cell definitions on controller border cells.
6. Root cause analysis, missing neighbors:
a) Drops due to missing neighbors, WNCS statistics:Missing neighbors leading to a dropped connection: numberOfDrops < zz (kbps)
Analysis and potential solution:
WNCS report can be used to identify missing neighbors that if added could have avoided a droppedconnection. Missing neighbors with reported dropped connections, should preferably be added asneighbors.
Missing neighbors leading to a dropped connection: Rladd_fail_R_Wncs > 2 [%]
Analysis and potential solution:
WNCS report can be used to identify problematic neighbor relations. Coverage and interference limitedcells should be filtered out, non-relevant, since poor coverage or excessive interference leads toperformance issues aswell.
If problem neighbor is located in different RNC or OMC, check external neighbor definitions andrelevant RNC/ system parameter settings.
If cell is in same RNC, LAC and RAC, investigate problem further, if no problem can be identified,remove neighbor from neighbor list and re-run WNCS recording and re evaluate removal.
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _Dy
Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
When UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?
More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
Abnormally Low HS availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’sor LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? Or just inconsistent RNC
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Abnormal low throughput in an RNC should be investigated further, is there a system wide or RNCperformance issue, or are there cells in RNC with exceptional bad performance?
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC HS parameter settings.
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Verify or update neighbor lists, check external cell definitions on controller border cells.
6. Root cause analysis, missing neighbors:
a) Drops due to missing neighbors, WNCS statistics:Missing neighbors leading to a dropped connection: numberOfDrops < zz (kbps)
Analysis and potential solution:
WNCS report can be used to identify missing neighbors that if added could have avoided a droppedconnection. Missing neighbors with reported dropped connections, should preferably be added asneighbors.
Performing WMRR measurements for problem cells is an additional source for trouble shootingmobility, drops etc related to RF issues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication if it really is the RFenvironment that are causing poor cell change performance connections, or if the problem is at ahigher level.
Correlation of these performance measurements is a good way of identifying RF related problems.
Abnormally Low HS availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’sor LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? Or just inconsistent RNC
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Abnormal low throughput in an RNC should be investigated further, is there a system wide or RNCperformance issue, or are there cells in RNC with exceptional bad performance?
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC HS parameter settings.
Thresholds indicating cell is experiencing congestion, heavily loaded in general. Continue root cause toidentify what the capacity bottle neck is and ensure blocking/ capacity is addressed and prevented.
b) Licensed max number of users exceeded
Number of HS users, Hs_Users > 16 [simultanous users]
Analysis and potential solution:
If suggested threshold is exceeded, verify license, increase if possible, else add HW, HS-TX card.
License/ parameter upgrade 32, 48 or 96.c) Excessive number of users cell
If HS_Users increases( trending up) and Pint HS _ I _ DlTp _User increases (trending up) ORAvg_HS_Users_Sched_2ms_TTI increases
Analysis and potential solution:
Verify hardware configuration and consider HS-TX card upgrade.
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _Dy
Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
When UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
Performing WMRR measurements for problem cells is an additional source for trouble shootingmobility, drops etc related to RF issues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication if it really is the RFenvironment that are causing poor cell change performance connections, or if the problem is at ahigher level.
Correlation of these performance measurements is a good way of identifying RF related problems.
Abnormally Low Eul availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’sor LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan?
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Abnormal low throughput in an RNC should be investigated further, is there a system wide or RNCperformance issue, or are there cells in RNC with exceptional bad performance?
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC HS parameter settings.
Check serving and neighbor cells for abnormally Low EUL availability is an obvious performanceimpacting issue. Cell having outages regularly? HW fault?
4. Root cause analysis, signaling:
a) Low signaling success rate RNC’s:
Signaling success rate, total CS and PS RNC, E_CRRC_CSPS_SSR_1 < xx %
Congestion or transport network related issues: pmNoUlIubLimitEul , pmNoOfIurTermHsCong > yy %,pmHsSevereCong(IubLink) > yy %, pmHsSevereCong(IurLink) > yy %
Analysis and potential solution:
Check core and transmission network outage and performance stats, any major networkreconfigurations?
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _Dy
Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
Then UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
Abnormally Low EUL availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’sor LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? Or just inconsistent RNC
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Abnormal low throughput in an RNC should be investigated further, is there a system wide or RNCperformance issue, or are there cells in RNC with exceptional bad performance?
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC HS parameter settings.
Check serving and neighbor cells for abnormally Low EUL availability is an obvious performanceimpacting issue. Cell having outages regularly? HW fault?
4. Root cause analysis, signaling:
a) Low signaling success rate RNC’s:
Signaling success rate, total CS and PS RNC, E_CRRC_CSPS_SSR_1 < xx %
Congestion or transport network related issues: pmNoUlIubLimitEul , pmNoOfIurTermHsCong > yy %,pmHsSevereCong(IubLink) > yy %, pmHsSevereCong(IurLink) > yy %
Analysis and potential solution:
Check core and transmission network outage and performance stats, any major networkreconfigurations?
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Verify or update neighbor lists, check external cell definitions on controller border cells.
6. Root cause analysis, missing neighbors:
a) Drops due to missing neighbors, WNCS statistics:Missing neighbors leading to a dropped connection: numberOfDrops < zz [numb]
Analysis and potential solution:
WNCS report can be used to identify missing neighbors that if added could have avoided a droppedconnection. Missing neighbors with reported dropped connections, should preferably be added asneighbors.
Low HSUPA/ EUL RetainabilityCell level8. Root cause analysis, RF performance:
a) Coverage limited cell:
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _Dy
Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
When UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
Abnormally Low EUL availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’sor LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? Or just inconsistent RNCborder area HO parameter settings.
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Abnormal low throughput in an RNC should be investigated further, is there a system wide or RNCperformance issue, or are there cells in RNC with exceptional bad performance?
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC HS parameter settings.
Check serving and neighbor cells for abnormally low EUL availability is an obvious performanceimpacting issue. Cell having outages regularly? HW fault?
4. Root cause analysis, signaling:
a) Low signaling success rate RNC’s:
Signaling success rate, total CS and PS RNC, E_CRRC_CSPS_SSR_1 < xx %
Congestion or transport network related issues: pmNoUlIubLimitEul > zz[%], pmNoOfIurTermHsCong> yy[%], pmHsSevereCong(IubLink) > yy[%], pmHsSevereCong(IurLink) > yy[%]
Analysis and potential solution:
Check core and transmission network outage and performance stats, any major networkreconfigurations?
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Verify or update neighbor lists, check external cell definitions on controller border cells.
6. Root cause analysis, missing neighbors:
a) Drops due to missing neighbors, WNCS statistics:Missing neighbors leading to a dropped connection: numberOfDrops < zz (kbps)
Analysis and potential solution:
WNCS report can be used to identify missing neighbors that if added could have avoided a droppedconnection. Missing neighbors with reported dropped connections, should preferably be added asneighbors.
Performing WMRR measurements for problem cells is an additional source for trouble shootingmobility, drops etc related to RF issues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication if it really is the RFenvironment that are causing poor cell change performance connections, or if the problem is at ahigher level.
Correlation of these performance measurements is a good way of identifying RF related problems.
Abnormally Low EUL availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’s
or LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? Or just inconsistent RNCborder area HO parameter settings.
Abnormal mobility success rate might indicate system wide performance or configuration issue, orperformance issues related to controller border.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Abnormal low throughput in an RNC should be investigated further, is there a system wide or RNCperformance issue, or are there cells in RNC with exceptional bad performance?
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC HS parameter settings.
Check serving and neighbor cells for abnormally low EUL availability is an obvious performanceimpacting issue. Cell having outages regularly? HW fault?
4. Root cause analysis, signaling:
a) Low signaling success rate RNC’s:
Signaling success rate, total CS and PS RNC, E_CRRC_CSPS_SSR_1 < xx %Congestion or transport network related issues: pmNoUlIubLimitEul > zz[%], pmNoOfIurTermHsCong> yy[%], pmHsSevereCong(IubLink) > yy[%], pmHsSevereCong(IurLink) > yy[%]
Analysis and potential solution:
Check core and transmission network outage and performance stats, any major networkreconfigurations?
Thresholds indicating cell is experiencing congestion, heavily loaded in general. Continue root cause toidentify what the capacity bottle neck is and ensure blocking/ capacity is addressed and prevented.
Excessive EUL blocking, see next steps if licensing limit on number of users is exceeded. Considerreconfiguration of cells dependent on load on the various RAB’s.
c) EUL specific code utilization
Code utilization high for EUL, Code_util_EUL > xx [%]
Analysis and potential solution:
EUL code utilization is excessively high and needs to be addressed, possibility to reconfigure carrier?Else verify cell configuration and consider carrier upgrade, if possible.
Cell level6. Root cause analysis, RF performance 1:
a) Coverage limited cell:
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _Dy
Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
When UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
Performing WMRR measurements for problem cells is an additional source for trouble shootingmobility, drops etc related to RF issues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication if it really is the RFenvironment that are causing poor cell change performance connections, or if the problem is at ahigher level.
Correlation of these performance measurements is a good way of identifying RF related problems.
RNC aggregated multi RAB IRAT stats, E_CMSIRAT_SR_1 < zz %
Analysis and potential solution:
Low HO success rate in cell in general, verify external cell definitions and that neighbor lists are up todate.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
b) Interference limited cell:
Reported high distribution of UE’s at cell edge or at coverage border: Cell_UE_dist _Dy
Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
Then UE traffic distribution is indicating cell shrinkage during busy hour, UE’s served closer to cell in BH vs. nonbusy hour.
This might in turn indicate cell and neighbors are interference limited, UL or DL and hence soft capacity blocking.
This is verified with for example: SUP_fail , Setup failures increasing significantly in Busy hour for these cells.
Are there options of redistributing traffic to neighbor cells?More likely and effective option might be changing physical configuration to contain serving cell or neighboring cells,by changing cell coverage areas, downtilts, azimuth or antenna model changes. In order to minimize the cellbreathing effect in the area, by re-distributing RF( interference) and UE’s to better contained cells.
RNC aggregated multi RAB IRAT stats, E_CMSIRAT_SR_1 < zz %
Analysis and potential solution:
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Excessive blocking RNC wide, might lead to unnecessary large number of IFHO in order to offloadcapacity to the 2nd layer. Make sure there is sufficient capacity in area, resource upgrade necessary.
RNC aggregated multi RAB IRAT stats, E_CMSIRAT_SR_1 < zz %
Analysis and potential solution:
Low HO success rate in cell in general, verify external cell definitions and that neighbor lists are up todate.
Has there been any major parameter change to RNC’s or LA/ RA i.e. re-home, re-dimensioning or redesign of LA or RNC plan? Or just inconsistent RNC border area HO parameter settings.
Performing WMRR measurements for problem cells is an additional source for trouble shooting, drops, HO and otherRF related issues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication of the RF environment. If themeasurement statistics shows poor RF environment, it is likely the IFHO is a “rescue” HO and that the other layer RFenvironment is also at is edge, which might then cause bad performing IFHO in difficult RF environment.
PLMN and RAN level1. Trigger: Low HSDPA IFHO success rate based on aggregated cell relational KPI’s:
Pint_HS_M _ IFHO _ S _CR(Utran Relation ) & PStrHS _M _ IFHO _ S _CR(UtranRelation )
2. Root cause analysis, signaling:
a) Low signaling success rate RNC’s:
Signaling success rate, total CS and PS RNC, E_CRRC_CSPS_SSR_1 < xx %Congestion or transport network related issues: pmNoOfIurTermHsCong > yy %,pmHsSevereCong(IubLink) > yy %, pmHsSevereCong(IurLink) > yy %
Analysis and potential solution:
Check core and transmission network outage and performance stats, any major networkreconfigurations?
b) Non-signaling related, continue root cause at node level.
Abnormally Low HS availability in an RNC could indicate system wide problems and outages,transmission or core network interruptions? Has there been any major parameter change to RNC’sor LA/ RA i.e. re-home, re-dimensioning or re design of LA or RNC plan? Or just inconsistent RNCborder area HO parameter settings.
Direction gives an indication on where to look next, if it’s outgoing, the problem is likely to be in thetarget cell. Incoming faults are typical on source cell.
6. Root cause analysis, missing neighbors:
a) Drops due to missing neighbors, WNCS statistics:
Missing neighbors leading to a dropped connection: numberOfDrops < zz (kbps)
Analysis and potential solution:WNCS report can be used to identify missing neighbors that if added. Even looking at ISHO missingrelations gives an idea of what IFHO missing neighbors there might be to add.
Missing neighbors might be the reason for unsuccessful IFHO’s, non-optimal neighbor, might be moresuitable that is missing.
Missing neighbors leading to a dropped connection: Rladd_fail_R_Wncs > 2 [%]
Analysis and potential solution:
WNCS report can be used to identify problematic neighbor relations. Coverage and interference limitedcells should be filtered out, non-relevant, since poor coverage or excessive interference leads toperformance issues aswell.
If problem neighbor is located in different RNC or OMC, check external neighbor definitions andrelevant RNC/ system parameter settings.
If cell is in same RNC, LAC and RAC, investigate problem further, if no problem can be identified,
remove neighbor from neighbor list and re-run WNCS recording and re evaluate removal.Looking at Intra system neighbors and HO performance gives some leads on what is expected in termsof neighbors and neighbor performance also for IFHO.
Performing WMRR measurements for problem cells is an additional source for trouble shooting, drops, HO and otherRF related issues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication of the RF environment. If themeasurement statistics shows poor RF environment, it is likely the IFHO is a “rescue” HO and that the other layer RFenvironment is also at is edge, which might then cause bad performing IFHO in difficult RF environment.
Reported low average RSSI, AvgRssiAvg_BH < -85 dBm
UE distribution: Prop_delay_Avg, Prop_delay_Max
Analysis and potential solution:
Cell is having reported low average RSCP.Looking at Max and average propagation delay, is the cell in fringe of network coverage?
High propagation delay value indicates cell with large coverage area. If average propagation delay is less then maxpropagation delay / 2, it is typically a cell at fringe of coverage. If average is greater then max propagation delay / 2,is there a way of distributing coverage and traffic to neighbor sectors?
b) Non optimal serving area, low RSCP in fringe of coverage area:
Served traffic far field: if Prop_delay_Avg > Cell_UE_dist _norm_BH = 80 [%]
Analysis and potential solution:Statistics shows that cells served traffic is in the fringe of cell coverage area, 80% of max propagation delay for allUE’s served in cell.
This is non optimal for various reasons, power, interference, capacity etc and traffic or coverage should be optimizedin order to serve traffic closer to cell center.
Performing WMRR measurements for problem cells is an additional source for trouble shooting, drops, HO and otherRF related issues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication of the RF environment. If themeasurement statistics shows poor RF environment, it is likely the ISHO is a “rescue” HO and that the 2G networkRF environment is also at is edge, which might then cause bad performing ISHO in difficult RF environment.
Coverage statistics based on Propagation delay distribution:
Analysis and potential solution:
Using GPEH for coverage and interference analysis is a very powerful tool for detailed trouble shooting.
GPEH measurements provides per call type analysis including both event based statistics and measurements, butalso RF KPI’s as measured RSCP and propagation delay etc.
Reported potential cell breathing/ interference limited cell, based on UE distribution:Cell_UE_dist_norm_Dy - Cell_UE_dist_norm_BH > 15 [%]
Analysis and potential solution:
Metric above looks at difference of average propagation delay and normalized daily propagationdelay distribution, if UE distribution changes significantly during busy hour, average traffic closer cellcenter in busy hour. This might be an indication that cell is interference limited and experiencing softblocking, RF blocking.
Detailed cell level RSCP measurements: CPICH RSCPAnalysis and potential solution:
Performing WMRR measurements for problem cells is an additional source for trouble shooting, drops, HO and otherRF related issues.
Looking at UE reported BLER, TX pwr, EcIo and RSCP can give an indication of the RF environment. If themeasurement statistics shows poor RF environment, it is likely the ISHO is a “rescue” HO and that the 2G networkRF environment is also at is edge, which might then cause bad performing ISHO in difficult RF environment.
a) interference and prop delay, GPEH measurements:
Coverage statistics based on Propagation delay distribution:
Analysis and potential solution:
Using GPEH for coverage and interference analysis is a very powerful tool for detailed trouble shooting.
GPEH measurements provides per call type analysis including both event based statistics and measurements, butalso RF KPI’s as measured RSCP and propagation delay etc.