5. Random Access Channel (RACH), UL, mapp ed to CCCH, DCCH and DTCH . Again, this channel
is similar in nature to the GSM random access channel, although this one carries req uests for
service from UEs trying to access the system. By its nature the RACH is a shared channel that
any UE can access, and therefore mobiles requesting service will send a message. This is
acknowledged by the network, using the Acquisition Indicator Channel (AICH). If the RACH
request is not acknowledged, then the UE waits a random amount of time before sending
another access request.
6. Uplink Common Packet Channel (CPCH), UL, mapped to DCCH and DTCH. From its name it is
understood that this is an uplink only channel. It provides additional capability beyond that of
the