hi RF,
for traffic channel TCH multiframes are transmitted,1TCH multiframe(120 ms) =26 TDMA frames,out of which in 24TDMA TCH frames,data is transmitted,and 1TDMA frame is used for SACCH(for power control measurements sent by MS to BTS)AND 1 tdma frame is used for IDLE neighbour RXlev measurements rpts.sent by MS in Uplink.normally after 4 SACCH frames means after 480 ms,power Decrease or increase command is given to BSS.
BR//
yogesh_rf