in the channel activation, the BSC asks the BTS to activate a certain timeslot and associate ciphering and speech codec to it.
do you think some BTS woul have a problem applying ciphering or speech codecs required by the BSC (i’m thinking about A5/3 or AMR)
you can investigate further in this direction:
– what is the content of channel activation
– why the BTS wouldn’t acknowledge this message ? which field would be a problem ?
if you have Abis failures, it would impact not only this message, but it would generate call drops, sdcch drops, etc.