Underwater Acoustic Communications Based on OTFS

The orthogonal time frequency space (OTFS) modulating and demodulating signal in delay-Doppler domain alleviates the multipath delay spread and Doppler spread effects simultaneously. The traditional underwater acoustic communications (UACs) do not work well, since underwater acoustic channels have inherently double dispersive characteristics (i.e., multipath propagation and ubiquitously relative mobility). In order to eliminate or reduce the effects of double dispersion existing in the underwater scenarios, this paper proposes an OTFS-based UAC scheme. We first present the background for signal preprocessing and post-processing steps of the OTFS scheme, and then introduce the OTFS-based UACs in detail. Moreover, we verify the proposed scheme can obtain the reliable performance through simulation analysis. Finally, simulation results show that the OTFS-based UAC scheme outperforms the OFDM and DFT-s-OFDM in time-varying multipath underwater acoustic channel.