A method and system by which base stations in a Wireless Regional Area Network (WRAN), and more generally transceivers in a cognitive radio (CR) system, can communicate 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 a base station can acquire the scheduled use of a share of the frames available in subsequent superframes of the CR system. The method and system assure fair and efficient access to the transmission channel by using a random number based contention process.