Smart Metasurface-Enabled Adaptive Beamforming for Satellite-Assisted Maritime Communications

In satellite-assisted maritime communications, unmanned surface vessels (USVs) suffer from intensive rotational motions due to wave fluctuations, resulting in beam misalignment with the satellite and thus deteriorating the transmission performance severely. This paper initially proposes to leverage the smart metasurface at the USV to combat the rolling motion of the USV in hostile sea environments. Specifically, we design an uplink transmission framework for beam tracking and propose a rolling angle prediction model based on triple-layer long shortterm memory (TL-LSTM) to predict the instantaneous rolling angle of the USV. Then the USV-to-satellite uplink transmission rate is maximized accordingly through the joint beamforming design of the USV and the satellite based on the predicted channel state information (CSI). Simulation results demonstrate the robust accuracy of the proposed rolling angle prediction scheme under various sea conditions, while the corresponding beamforming optimization scheme is also significantly efficient in improving the USV-to-satellite transmission performance.