Cyclic shift keying spread spectrum underwater acoustic communication

Aimed at solving the problem of low data rate of direct sequence spread spectrum underwater acoustic communication and that of complexity of the receivers of M-ary spread spectrum underwater acoustic communication, cyclic shift keying spread spectrum underwater acoustic communication is proposed based on the good characteristic of spread sequences. At the transmitter, base waveform is cyclically shifted according to the input information. At the receiver, only one correlator is used to estimate the time delay and decode. Multi-code spread spectrum based on cyclic shift is presented. Lake experiments at both middle and long range were conducted for the proposed methods. Single and two code cyclic shift keying underwater acoustic communication were realized in the range of 15 km and the bandwidth of 2 kHz. The data rate was 438 bit/s with bit error ratio around 10^-2-10^-5. The result demonstrated the bandwidth efficiency and low complexity of the proposed methods and the applicability for long range underwater acoustic communication and multi-user underwater acoustic communication network.