Abstract: A fixed wireless access communications system comprises an access point and a plurality of subscriber units. Each subscriber unit (502) contends for access to a communications channel to the access point by transmitting a contention word to the access point during a contention time slot. The contention word is predistorted to compensate for the channel impulse response of the transmission channel so that the access point can decode the contention words without using equalisation. A control unit (512), which may comprise a microprocessor, loads the predistorted contention word (a) into a memory (520) and causes the stored predistorted contention word (a) to be applied to a transmitter (508) during a contention time slot when the subscriber unit (502) wishes to request a transmission channel to transmit data to the access point.