A method of, and system for, reserving timeslots in a TDMA system of a type in which a plurality of subscriber units (CPE) use the same radio channel for transmission during different timeslots to a base station and in which the base station administers the radio channel centrally enable subscriber units to transfer, if appropriate, a transmission request to the base station in the form of a PN (Pseudo-random noise) sequence (e.g., M-sequence, preferred gold, Katsami or orthogonal gold sequence). Transmission requests from different subscriber units can be identified at the base station using the PN sequence, reception time of the PN sequence and/or phase of the PN sequence.