A method and system by which a base station in a Wireless Regional Area Network (WRAN), and more generally a transceiver in a cognitive radio (CR) system, can communicate with other transceivers to fairly share transmission and reception of scheduled use (“occupancy”) of frames on a single channel within a frame-based, on demand spectrum contention system. The method and system disclose how the base station currently occupying a channel responds to requests from other base stations for an increased share of the frames available in a subsequent superframe of the CR system. The method and system assure fair and efficient access to the transmission channel by a random number based contention process.