An Algorithm of Multi-array Turbo Equalization of Underwater Acoustic Communication

The main problems of the application of the Turbo equalizer in underwater acoustic communication are long time spread of channel and the multi-array processing. The union algorithm of time reversal and Markov Chain Monte Carlo (MCMC) equalization is proposed. Time reversal compresses the long time spread by combining multi-array signal, then the whitening filter is adopted to the solution of the noise model mismatch, at last the MCMC equalizer under optimal Maximum A Posteriori (MAP) criterion realizes the soft-in soft-out equalizer with the channel information obtained by channel estimation of soft iteration. The simulation based on the real experimental condition is conducted for the error model of truncated channel estimation. Simulation results denote that, this algorithm gets 1.6 dB Bit Error Rate (BER) performance gain, and 67% complexity loss over adaptive Turbo equalization. In the real experiment conducted in a lake, result of data processing denotes that the union algorithm of time reversal and MCMC equalizer have a superior performance over the algorithm of multichannel adaptive Turbo equalizer.