Robust Max-Min Fair Beamforming Design for Rate Splitting Multiple Access-aided Visible Light Communications

TL;DR

This paper develops a robust beamforming design for RSMA-aided VLC networks with imperfect CSIT, optimizing for fairness and power constraints, and demonstrates superior performance over existing multiple access schemes.

Contribution

It introduces a novel CCCP-based beamforming algorithm with SDR and penalty methods for RSMA-VLC networks under practical power and CSIT constraints.

Findings

Proposes a new lower bound for channel capacity in RSMA-aided VLC.

Achieves better fairness and power efficiency compared to SDMA and NOMA.

Demonstrates robustness under imperfect CSIT conditions.

Abstract

This paper addresses the robust beamforming design for rate splitting multiple access (RSMA)-aided visible light communication (VLC) networks with imperfect channel state information at the transmitter (CSIT). In particular, we first derive the theoretical lower bound for the channel capacity of RSMA-aided VLC networks. Then we investigate the beamforming design to solve the max-min fairness (MMF) problem of RSMA-aided VLC networks under the practical optical power constraint and electrical power constraint while considering the practical imperfect CSIT scenario. To address the problem, we propose a constrained-concave-convex programming (CCCP)-based beamforming design algorithm which exploits semidefinite relaxation (SDR) technique and a penalty method to deal with the rank-one constraint caused by SDR. Numerical results show that the proposed robust beamforming design algorithm for RSMA-aided VLC network achieves a superior performance over the existing ones for space-division multiple access (SDMA) and non-orthogonal multiple access (NOMA).