Abstract: A radio communications system which is channelized and constituted in cellular array shares the spectrum with other fixed radio communications systems but complies with FCC rules as to interference to these fixed systems. It still maintains however good quality in its signals. Interference is determined by real-time field measurements of interference received from fixed stations on both forward and reverse offset channels by base stations and a mobile terminals. Such real-time measurements besides sensing the quality of a signal can be used to determine interference to the nearby microwave fixed users. In addition compensation is made for multiple users and thus no worst case compromises need be adopted as in prior systems.