High BER on E1’s was removed by customer transmission but no improvement in KPIs was observed. I made a detailed analysis of site KPI’s and checked the following measurements:
Radio Link Failures on second and third sector were observed and trend showed increased radio link failures in both sectors after E1 troubleshooting:
I made a detailed analysis of Radio Link failures on TRX level and found that DCS1800 TRX in second and third sector were having increased radio link failures
Downlink Levels were observed during radio link failures and it was found that during failures the level was not OK.
I checked the Mean timing advance during radio link failures for both sectors and found out that downlink levels were not good as compared to timing advance and uplink level for both cells.
It was clearly stating some sort of hardware fault for second and third sector.
When radio Link Failure alarms are encountered due to Abnormal Releases first of all the transmission alarms (if any) on site should be cleared, Basic configuration parameters of cocentric cells and basic handover parameters of concentric cells should be checked to be correct. Site engineer should make sure that there is no complete or partial sector swap carefully.