Simulation of the equalizer for shallow water acoustic communication

High rate digital acoustic communication is limited by severe inter-symbol interference (ISI) associated with long range, shallow underwater channels. The ISI is caused by multi-path propagation resulting from surface and bottom reflections. To overcome the effects of intersymbol interference, an adaptive equalization method employing a mean square error (MSE) criterion is introduced. Computer simulations are carried out to verify the effectiveness of the equalization scheme for high data rate communication. Quadrature phase shift keying (QPSK) signalling is employed to make efficient use of the available channel bandwidth. Simulation results show that adaptive equalization allows reliable transmission over a distance of 20 km in an ocean depth of only 50 m and a transmission rate in excess of 8 kbits/s