peyo,
some corrections…
Baseband hopping is not necessarily moving from TRX to TRX. In alcatel, the BBH is “synthetized” : the TCH remains on the same TRX, and the frequency changes each TDMA frame.
The SACCH, FACCH and TCH are three different channels, each located on the TCH multiframe.
FACCH is stolen from TCH bursts on demand.
SACCH is regularly sent on timeslot 12 of the TCH mframe.
regards,
pix