Transmit array for acoustic communications in multipath underwater channel

High data rate acoustic transmission is required for diverse underwater operations such as the retrieval of large amounts of data from bottom packages and real time transmission of signals from underwater sensors. High speed acoustic transmission over a shallow water channel characterized by small grazing angles presents formidable difficulties. The reflection losses associated with such small angles are low, causing large amplitudes in multi-path signals. When the signal is transmitted from the transmitter to the receiver, in the case of multipath in the environment, the transmitter and receiver have a higher SNR (signal-to-noise ratio) when they have array sensors rather than single sensors. In this paper, we propose a transmit array system for high data rate underwater acoustic communication. With sensor arrays, the transmitter can reduce or suppress the interference, it provides an improved desired signal level. The simulation results indicate that the proposed method outperforms over a distance of 13 km and a channel depth of only 20 meters.