Design of an UWA-OTFS Communication Receiver Based on Single-Element Two-Dimensional Virtual Passive Reversal

Orthogonal Time Frequency Space (OTFS) modulation offers a novel solution to enhance the reliability of mobile underwater acoustic (UWA) communication systems. In this study, a receiver architecture tailored for UWA-OTFS communication is presented, leveraging single-element two-dimensional virtual passive reversal (2D-VPR) technology in the delay-Doppler (DD) domain. To enhance the concentration of main lobe energy in the equivalent channel after 2D-VPR equalization, a block orthogonal matching pursuit with dynamic power weighting (BOMP-DPW) channel estimator is proposed, resulting in an order-of-magnitude reduction in the communication system's raw bit error rate (BER). Furthermore, considering the impact of signal distortion and noise, the 2D-VPR processor driven by the BOMP-DPW estimator is coupled with a minimum mean square error (MMSE) equalizer to further suppress sidelobe interference and noise. The proposed scheme was tested in the South China Sea, where data processing results confirmed that the receiver achieved reliable communication within a frequency band of 2-4 kHz, a data rate of 1.8 kbps, a maximum towing distance of 5 km, and a relative speed of 2 m/s between the transmitter and receiver.