Check sector inversion or TR inversion, meaning that one TRX of a sector is actually being transmitted on another sector’s antenna.
Are there a lot of HO ? What cause ? and in which direction ? sector 1 to sector 2, or vice versa ? What is the amount of requests and successes of HO in each way ?
The TCH and SDCCH drop are located on all TRX or just one TRX ?
What is the cause of drops ?
Is there any problem regarding TCH assignment or SDCCH assignment ?
What is the average TCH holding time, per TRX ?
If you suspect a TRX problem, just lock the faulty TRX for a while.