Underwater digital communication using acoustic channel estimation

Sound transmitted in the ocean will often have multiple interactions with the sea surface, the bottom, and volume. Multipath propagation in underwater acoustic communication causes distortion to high-rate digital signals. In this paper, a new method for underwater acoustic communication using channel estimation is considered. The proposed method is similar to the passive phase conjugation technique. However, the probe signal is used for underwater communication channel estimation. The underwater channel impulse responses are estimated by eigenvalue decomposition algorithm. The channel vectors are in the null space of the covariance matrix of the received signal at receiver array. After waiting for the multipathed arrivals to clear, the source then transmits the data stream. The received data signals are convolved with the time-reversed channel impulse responses. The performances of the proposed method will be evaluated in various environments.