The contents of the Broadcast Control Channel (BCCH)
channel are generated at the BSC and are transmitted over the
air as Radio Resource (RR) messages. A number of system
information messages are defined to carry a plethora of system
information parameters necessary for the MS, which includes
system Information (SI) 1, 2, 3, 4 and 13. Apart from these,
some other SIs (5 and 6) are transmitted on Slow Associated
Control Channel (SACCH) to those MS which have active RR
connection.