US Patent 7916746 Media access control protocol with priority and contention-free intervals

An access contention scheme is described for use by a station in a network of stations. Access contention by a station having a frame to be transmitted includes detecting contention control information for a contention period and determining from the contention control information if the station is permitted to contend for access to a transmission medium to which the stations are connected during the contention period. When a contention control indicator is detected for a contention period, a station having a frame to transmit determines from the contention control indicator if it is permitted to contend for access to the transmission medium during the contention period.