A micro-cellular radio communications system (microsystem) is arranged to re-use radio frequency channels which are assigned for use in a cellular radio system (macrosystem) in the same vicinity. The microsystem maintains a list of each frequency channel which is in current use in any microcell of...http://www.google.com/patents/US5828963?utm_source=gb-gplus-sharePatent US5828963 - Selecting radio frequency channels for reuse in micro-cellular radio communications systems 
