Limited available radio frequency ARFCN owned by mobile operators would often increase challenge of RF planning and optimization. Beside difficulty when assigning frequency, one of impact of this is high handover failure due to configuring same BCCH and BSIC on the neighbor.
We can simply identify such impact by make a special query that meet such condition:
“High handover failure in one direction AND 1st tier + 2nd tier neighbor have same BCCH-BSIC”
On this situation, mobile station would be “fooled” during composing measurement report to observed cell and handover shall be wrong be triggered and possibly increases handover failure.
Wireless network optimization can be started with network configuration audit which cover inspection of high handover failure rate in one direction with above mentioned situation is met.