RIS-Aided Offshore Communications with Adaptive Beamforming and Service Time Allocation

TL;DR

This paper explores RIS-assisted offshore communication systems using adaptive beamforming and service time optimization to enhance data rates cost-effectively, employing low-cost hardware with minimal performance loss.

Contribution

It introduces a joint optimization framework for beamforming and service time allocation in RIS-aided offshore systems, utilizing low-cost RRAs instead of expensive FDAAs.

Findings

RIS significantly improves effective sum rate.

Proposed scheme with RRAs achieves near-FDAA performance.

Optimal resource allocation enhances maritime communication efficiency.

Abstract

Reconfigurable intelligent surfaces (RISs), which can deliberately adjust the phase of incident waves, have shown enormous potentials to reconfigure the signal propagation for performance enhancement. In this paper, we investigate the RIS-aided offshore system to provide a cost-effective coverage of high-speed data service. The shipborne RIS is placed offshore to improve the signal quality at the vessels, and the coastal base station is equipped with low-cost reconfigurable reflect-arrays (RRAs), instead of the conventional costly fully digital antenna arrays (FDAAs), to reduce the hardware cost. In order to meet the rate requirements of diversified maritime activities, the effective sum rate (ESR) is studied by jointly optimizing the beamforming scheme and the service time allocated to each vessel. The optimal allocation scheme is derived, and an efficient fixed-point based alternating ascent method is developed to obtain a suboptimal solution to the non-convex beamforming problem. Numerical results show that the ESR is considerably improved with the aid of the RIS, and the proposed scheme using the hardwareefficient RRAs has only a slight performance loss, compared to its FDAA-based counterpart.