8th December 2011 at 06:15
#65560
Guest
After getting immediate assignment through AGCH the MS switches to the assigned channel and activates it. By sending an SABM frame containing a „Service
Request Message“, it switches the SDCCH to the „Multiple Frame Acknowledge“mode, there by activating it. The Service Request message helps the network to recognize the service being requested by the MS. This information is used to decide
how to proceed.
Service request messages are:
· CM SERVICE REQUEST
· LOCATION UPDATING REQUEST
· IMSI DETACH
· PAGING RESPONSE
· CM REESTABLISHMENT REQUEST
Than the BTS send the acknowledgement that it has receive the service by means of UA frames.