In this paper, we focus on the need for remote and robust underwater acoustic(UWA) communication in shallow sea. A set of OFDM underwater acoustic communication algorithm is designed including the techniques of Doppler estimation and compensation, channel equalization and frequency diversity. This algorithm is realized in the DSP and successfully applied on the OFDM-Modem platform. In Da- Lian shallow sea trial, the horizontal communication distance is 36 kilometers under the condition of QPSK modulation, 1/2 rate convolution code, bandwidth between 4 and 8kHz. The communication rate of the OFDM-Modem can reach 426bps and the ultimate BER is less than 10-3.
Adaptive and efficient nonlinear channel equalization for underwater acoustic communication