Patent ID: RE39677

Claim:
A local multipoint distribution system comprising: a head end coupled to a plurality of base stations, each base station constituting a cell, each base station having a plurality of sector beam antennas, each sector beam antenna illuminating a predetermined sector of said cell with RF communication signals, a plurality of RF subscriber stations for each sector of a cell, each subscriber station having a high gain antenna with a narrow beam width oriented toward the sector beam antenna oriented toward its assigned sector, time division multiple access control means at each subscriber station operated such that each subscriber transmits at a time different from the other subscribers in its sector so the subscribers in a given sector do not interfere with each others transmissions, respectively, means controlling the transmitted power level such that all subscriber signals arrive at their respective base stations at about the same power level, means controlling the transmit signal timing such that all subscriber signals arrive at their respective base stations at the exclusively assigned time thereby minimizing the possibilities of mutual interference and means controlling the transmit signal frequency such that all subscriber signals operate at their proper assigned frequency and are orthogonal to all other carrier frequencies received by the base station, and wherein each subscriber station first, in order to initiate operation, is operated in a receive-mode only to detect a stable downstream frequency from a head end signal and detect any received frequency error and adjust its initial frequency of operation in accordance therewith.