Angle-Domain Frequency-Selective Sparse Channel Estimation for Underwater MIMO-OFDM Systems

In this letter we propose a fully angle-domain frequency-selective sparse channel estimation algorithm for multiple-input multiple-output orthogonal frequency division multiplexing underwater acoustic communication (MIMO-OFDM UAC) systems. The algorithm is divided into two stages (finding nonzero tap positions and finding nonzero angle-domain coefficients) to reduce the computational complexity. It has been demonstrated that the 2-stage orthogonal matching pursuits algorithm provides an efficient way to estimate the under-determined frequency-selective sparse channel with reduced complexity for MIMO-OFDM UAC systems.