An improved least square channel estimation algorithm for underwater acoustic OFDM systems

Channel estimation is vital for the performance of underwater acoustic (UWA) orthogonal frequency division multiplexing (OFDM) systems. In this paper, we first analyze the conventional least square (LS) channel estimation algorithm, which is very sensitive to noise and frequency synchronization errors, and then we develop a novel LS algorithm. It utilizes the channel frequency response of one pilot symbol to revise that of the following symbol with weighted average, so that it can suppress the error diffusion that results from the former error symbol. Simulation results show that the proposed LS algorithm achieves better bit error rate (BER) and mean square error (MSE) performance compared to the conventional one.