Experimental demonstration of high spectral efficiency MIMO underwater acoustic communication using adaptive passive time reversal on the continental shelf in mid latitude

High data rate in long range link is one of the most challenging tasks for underwater acoustic communication due to the bandwidth limitations and the long-strong multipath interferences of underwater acoustic channel. In this study, we report an at-sea experiments of a spatial division multiplexing multiple input multiple output underwater acoustic communication over the long communication distance of 14 km conducted in the continental shelf area of Japan. We propose a signal processing method that combines a practical equalizer and forward error correction method with the adaptive passive time reversal method, and evaluate its performance. Specifically, the effective data rate versus bit-error-rate performances with changing the signaling parameters are investigated. The experimental result shows that a robust high spectral efficiency performance of 6.4 bps/Hz can be achieved in a real sea environment.