Pix is correct in saying that the “Brain of BTS” might not be working properly.
In NOKIA systems..the brain of BTS is
You check the ALARM in BSC for this BTS.
If you are observing HANDOVER FAILURES for this BTS in drive tests and also from the reports then…
ask the BTS engineer to ensure the correct value of DAC in BOIA.
Incorrect setting of DAC in case of Nokia BTS can result handover failures irrespective of the definitions in BSC.
Iam not remembering exactly but the alarm description is somewhat like
DIFFERENCE IN FREQUENCY REFERENCE BETWEEN BTS AND PCM.