Random Access Channel
The Random Access Channel (RACH) is an uplink transport channel intended to be used to
carry control information from the terminal, such as requests to set up a connection. It can
also be used to send small amounts of packet data from the terminal to the network.
For proper system operation the random access channel must be heard from the whole desired cell coverage area, which also means that practical data rates have to be rather low, at least for the initial system access and other control procedures.
