A communications system (1) includes a plurality of nodes (2). Each node (2) has receiving means for receiving via an antenna (13) a signal transmitted by wireless transmitting means; transmitting means for wireless transmission of a signal via an antenna (13); and, means for determining if a signal...http://www.google.com/patents/US7061883?utm_source=gb-gplus-sharePatent US7061883 - Communications system and method
