A RADIO COMMUNICATION SYSTEM HAVING A PRIMARY STATION AND A PLURALITY OF SECONDARY STATIONS AND A METHOD OF OPERATING SUCH A RADIO COMMUNICATION SYSTEM

摘要

A radio communication system has a random access channel for the transmission of data from a secondary station to a primary station while the secondary station is not engaged in a call. A secondary station wishing to use a random access channel resource transmits a preamble encoded with a signature corresponding to the required resource. In response the primary station can transmit a positive acknowledgement (ACK) corresponding to the received preamble, indicating that a channel is available, or a negative acknowledgement (NACK), indicating that the resource is not available. A first set of signatures are used to encode ACKs and a second set of signatures are used to encode NACKs. The two sets of signatures have the property that no signature in one set is the inverse of a signature in the other set, thereby avoiding the possibility of simultaneously transmitting an ACK and a NACK with signatures that are the inverse of one another.