High-Frequency Acoustic Estimation of Time-Varying Underwater Sparse Channels Using Multiple Sources and Receivers Operated Simultaneously

In this paper, the authors propose a robust underwater acoustic field estimation of the timevarying channel impulse response for simultaneous transmissions using multiple sources and multiple receivers [multi-in multi-out (MIMO)] that closely follows the rapidly time-varying nature of the underwater acoustic channel. The presented algorithm outlines a time-varying underwater channel estimation method based on the channel sparsity characteristic. The method uses the MIMO P-iterative greedy orthogonal matching pursuit algorithm and takes advantage of the sparsity of the underwater acoustic channel. This technique is compared to a trended least square estimation method presented by the authors in a previous publication. Both techniques are demonstrated in a fully controlled environment, using simulated and experimental data, and the results in each case show a significant improvement in the estimation of the channel impulse response.