During a handover, the MS receives a HO COMMAND from the BSC, describing the target cell “A”. In fact, it describes the target “TCH” (frequency = 54, bsic = 11)
Then, the MS must try to access the target TCH, by sending the access burst “HO ACCESS”, towards this TCH. If there is a cell “B” somewhere that uses the frequency 11 as BCCH frequency, with BSIC = 11, then it will decode the access burst “HO ACCESS” as a “CHANNEL REQUEST”, and it will therefore allocate a SDCCH channel.
Of course, this is a mistake, because the MS is not trying to send a CHANNEL REQUEST to cell “B”, but it is sending HO ACCESS to cell “A”.
But ok, I don’t know for sure if that can lead to some HO failures, in some weird ways, as described by m12.