Channel Estimation for OFDM Underwater Acoustic Communications via Orthogonal Approximate Message Passing

Orthogonal frequency-division multiplexing (OFDM) technique provides an efficient modulation for underwater acoustic (UWA) communications. For OFDM UWA communication systems, channel estimation is a key factor to its performance. In this study, we investigate the feasibility of Orthogonal Approximate Message Passing (OAMP) for the channel estimation of OFDM UWA communications. The Bernoulli- Gaussian (BG) prior distribution is employed to account for the sparse characteristics of UWA channels. The experimental data collected in the XM16 sea trial is adopted to evaluate the OAMP channel estimation scheme. It showed better performance than conventional methods at a lower pilot cost.