A radio based communication system comprises a base station (1) and one or more remote stations (2) each incorporating a radio transmitter and receiver to support communication between the base station and each remote station on a down link and between each remote station and the base station on an up...http://www.google.com/patents/US5377192?utm_source=gb-gplus-sharePatent US5377192 - Radio data communication system having means for reducing collisions between contending remote stations
