GSM AGCH(Access Grant Channel)
This page describes GSM Access Grant Channel(AGCH).
AGCH is the channel from the network to the Mobile Subscriber (MS) in the downlink of GSM system. It carry information by which mobile will determine whether the access to the network has been allowed or denied.
It provides very useful information about which TCH/SDCCH channels mobile need to use further during communication with the network.
It uses normal burst for mapping the AGCH information as shown in the figure. In the 51 frame multi frame structure, first two time slots (TS0) in consecutive TDMA frames are occupied for FCCH and SCH and this repeats every 10 frame. The next four are reserved for BCCH and rest by CCCH (AGCH/PCH).
The structure where CCCH (AGCH/PCH) and SDCCH/SACCH maps vary based non-combined configuration and combined configuration (Low capacity cell and high capacity cell).
GSM RELATED LINKS
GSM Logical Channels
traffic channel processing
control Channel processing