Abstract: The present invention relates to transmitters (10) and receivers (30) for use in a spread spectrum radio communication system wherein transmitters generate FH-MFSK signals by adding elements of each user's Q level encoded message sample and that user's unique Q level, L-length frequency-hopping address sequence using the rules of algebra for finite fields. The receivers (a) spectrum analyze received transmissions during each chip or period of the L-length sequence to determine which Q level frequencies are received and (b) generate a set of decoded message signals by subtracting corresponding chip elements of a particular user's FH address sequence from those of the detected frequency levels using the rules of algebra for finite fields.

Abstract: The present invention relates to a transmitter, a receiver and techniques for use in a frequency-hopping, multilevel frequency shift keyed (FH-MFSK) radio system which permits the selective concurrent transmission of one or two encoded frequencies per time slot of the transmitted sequence for improving reception at a receiver experiencing interference from the system transmitters above a predetermined interference threshold level. An alternative arrangement permits all transmitters and receivers to communicate with one another by transmitting a separate one of multiple frequencies in a separate one of an equal number of multiple frequency subbands forming the system frequency band during each time slot for providing flexibility in system design. Combinations of the two arrangements can also be employed.