i don’t see where he is saying the call drops are due to control channels..? But maybe you are working together, since it looks like you know how the did their frequency planning.
no offense, but no frequency planning is perfect. It always worths a shot to check out the frequency usage of the frequency of TRX2 or TRX3.
But yes, of course, it can be linked to a TRX hardware issue. I always try to clear out the radio problems first before asking someone to go on site and change the TRX cards.
An intracell HO is a handover from one TRX to another TRX within the same cell. They are due to interference on the initial TRX, : they move the call to another TRX, trying to get a clearer frequency on this one.
(other cases for intracell HO are due to AMR – are they using AMR ?)
Intracell HO occurs within the same cell, whether it is omni or sectorized.