A first PCS unit monitors carrier activity of other PCS units in an unlicensed frequency band adjacent to a licensed frequency band used by the first PCS unit, which has a microprocessor that compiles a history table of this other carrier activity. The first PCS unit then uses the history...http://www.google.com/patents/US5850596?utm_source=gb-gplus-sharePatent US5850596 - Method and system for making unlicensed priority transmissions
