A differential cyclic shift keying spread spectrum in underwater acoustic communication

Abstract

Cyclic shift keying (CSK) spread spectrum underwater acoustic (UWA) communication systems are seriously affected by fast-carrier phase fluctuation and time-varying UWA channels. Differential cyclic shift keying (DCSK) spread spectrum UWA communication using time reversal mirror (TRM) is proposed in this paper. Differential coding and decoding inhibit the influence of fast-carrier phase fluctuation effectively, and time-reversal mirror technology controls multipath propagation. A tracking/updating adaptive channel estimation algorithm used in this system estimates the real-time time-varying acoustic channel and save the effective estimation channel as the time-reversal mirror processing channel to ensure the reliability of processing. We verify that the system can achieve low bit error rate communication under the condition of fast-carrier phase fluctuation and channel multipath propagation by carrying out an under-ice vertical communication trial test.