Rate-Splitting-Based Generalized Multiple Access for Band-Limited Multi-User VLC

Abstract

In this paper, we propose a rate-splitting-based generalized multiple access (GMA) scheme for band-limited multi-user visible light communication (VLC) systems. By splitting and transmitting the input data of each user in a joint orthogonal multiple access (OMA) and non-orthogonal multiple access (NOMA) manner, the proposed rate-splitting-based GMA scheme can obtain better bandwidth utilization than OMA and suffer less severe interference than NOMA. In order to achieve the maximum sum rate over typical low-pass VLC channels, the optimal rate-splitting-based GMA scheme was first obtained through theoretical analysis and computer simulations. Subsequently, the superiority of the optimal rate-splitting-based GMA scheme over both OMA and NOMA under various channel conditions, user separations, and error propagation levels was further verified by the theoretical, simulation, and experimental results. In particular, the experimental results showed that, when the error propagation ratio was increased from 0 to 0.2, the sum rate reduction ratio was significantly reduced from 31.4% to 7.5% by replacing NOMA with the obtained optimal rate-splitting-based GMA.