Panayırcı, ErdalAltabbaa, Mhd TahssinUysal, MuratPoor, H. Vincent2019-06-272019-06-272019431053-587X1941-04761053-587X1941-0476https://hdl.handle.net/20.500.12469/448https://doi.org/10.1109/TSP.2019.2893841In this paper a new channel estimation algorithm is proposed that exploits channel sparsity in the time domain for an orthogonal frequency division multiplexing (OFDM)-based underwater acoustical (UWA) communications systems in the presence of Rician fading. A path-based channel model is used in which the channel is described by a limited number of paths each characterized by a delay Doppler scale and attenuation factor. The resulting algorithm initially estimates the overall sparse channel tap delays and Doppler shifts using a compressed sensing approach in the form of the orthogonal matching pursuit (OMP) algorithm. Then a computationally efficient and novel channel estimation algorithm is developed by combining the OMP and maximum a posteriori probability (MAP) techniques for estimating the sparse complex channel path gains whose prior densities have complex Gaussian distributions with unknown mean and variance vectors where a computationally efficient maximum likelihood algorithm is proposed for their estimation. Monte Carlo simulation results show that the mean square error and symbol error rate performances of the OMP-MAP algorithm uniformly outperforms the conventional OMP-based channel estimation algorithm in case of uncoded OFDM-based UWA communications systems.eninfo:eu-repo/semantics/embargoedAccessUnderwater acoustic channel estimationequalizationOFDMorthogonal matching pursuitMAP estimationArticle15501565667WOS:00045799160000510.1109/TSP.2019.28938412-s2.0-85061301379Q1Q1