Multichannel decision feedback equalization in underwater acoustic communication

Abstract

This paper studies an underwater acoustic communication system and its performance in shallow water. A channel encoder and a quadrature phase shift keying (QPSK) modulation scheme have been adopted at the transmitter, and a multichannel decision feedback equalizer (DFE) with a soft decision device has been used at the receiver. This system has been tested in a Yellow Sea experiment for transmitting an image at a range of 18.5km. A space diversity procedure is used to mitigate the performance degradation of the multichannel DFE caused by occasional impulsive noise in the receiver. In the case of two receivers, the equalizer exhibits good performance with bit error number of 319 out of 239946. After channel decoding, an image is obtained without any errant bits.