The MS can initiate the establishment of the Radio Resource
(RR) connection by sending a channel request message over
RACH. The BSC, in turn, assigns resources for the RR
connection by sending an immediate assignment command
to the MS over Access Grant Channel (AGCH). Immediate
assignment message as shown in Fig. 8 give packet channel
description of the obtained ARFCN. It consists of hopping
channel data, time slot number and training sequence.