OFDM cyclic shift keying spread spectrum underwater acoustic communication

Aiming at solving the problems of low data transmission rate of direct sequence spread spectrum underwater acoustic communication and high complexity of the receiver design of M-ary spread spectrum underwater acoustic communication, an orthogonal frequency division multiplexing cyclic shift keying spread spectrum (CSK-OFDM) method is proposed to improve bandwidth efficiency. The bit error rate performance is analyzed under the additive white Gaussian noise channel condition in theory. The peak to the average power ratio (PAPR) of the CSK-OFDM system is theoretically proved to be upper bounded by 3 dB using Chu sequences as spreading codes. Further simulation comparison to DSSS-OFDM is provided with the multi-path channel model based on lake-trial data. Simulation results show that the CSK-OFDM method has excellent anti-multipath capability, low complexity as well as high bandwidth efficiency. Consequently, the proposed method is suitable for long-range and multi-users underwater acoustic communication.