Multicarrier frequency hopping communications system

A multicarrier frequency hopping spread spectrum communications system comprising at least two stations each of which includes a transmitter section and a receiver section, communication between stations being via a communications channel between the transmitter section of one station and the receiver section of another station;

• characterized in that:
• the transmitter section of each station comprises
• encoding means for encoding data symbols of a signal to be transmitted, the encoding being in accordance with a constellation of code values;
• mixing means coupled to said encoding means for assigning samples of the encoded data symbols to particular ones of a predetermined series of fixed carrier frequencies, the frequency assignments being periodically mixed in accordance with a frequency hopping code;
• and
• multiplexing means coupled to said mixing means for combining the samples of encoded data symbols and their assigned carrier frequencies in accordance with an inverse Fourier transform, so as to multiplex the samples of encoded data symbols by an orthogonal frequency division modulation;
• and
• the receiver section of each station comprises:
• demultiplexing means for receiving multiplexed samples of encoded data symbols transmitted by the transmitter section of another station, and applying a direct Fourier transform to demodulate by reversing the orthogonal frequency division modulation performed on the samples of encoded data symbols in the transmitter section of said other station;
• demixing means coupled to said demultiplexing means for combining the demodulated samples of encoded data symbols in accordance with the inverse of the frequency hopping code employed in the transmitter section of said other station, thereby recovering said samples of encoded data symbols;
• and
• decoding means coupled to said demixing means for decoding the samples of encoded data symbols produced thereby in accordance with the inverse of the constellation of code values employed in the transmitter section of said other station.