Rate-Splitting Multiple Access: Unifying NOMA and SDMA in MISO VLC Channels

TL;DR

This paper explores rate-splitting multiple access (RSMA) for visible light communication (VLC), demonstrating its ability to unify and outperform existing multiple access techniques like NOMA and SDMA in VLC systems.

Contribution

It introduces RSMA to VLC, showing its potential to generalize and improve upon existing multiple access methods through system modeling and simulations.

Findings

RSMA can unify NOMA and SDMA in VLC systems.

RSMA outperforms traditional methods in weighted sum rate.

Simulation results validate RSMA's flexibility and superiority.

Abstract

The increased proliferation of connected devices requires a paradigm shift towards the development of innovative technologies for the next generation of wireless systems. One of the key challenges, however, is the spectrum scarcity, owing to the unprecedented broadband penetration rate in recent years. Visible light communications (VLC) has recently emerged as a possible solution to enable high-speed short-range communications. However, VLC systems suffer from several limitations, including the limited modulation bandwidth of light-emitting diodes. Consequently, several multiple access techniques (MA), e.g., space-division multiple access (SDMA) and non-orthogonal multiple access (NOMA), have been considered for VLC networks. Despite their promising multiplexing gains, their performance is somewhat limited. In this article, we first provide an overview of the key MA technologies used in VLC systems. Then, we introduce rate-splitting multiple access (RSMA), which was initially proposed for RF systems and discuss its potentials in VLC systems. Through system modeling and simulations of an RSMA-based two-use scenario, we illustrate the flexibility of RSMA in generalizing NOMA and SDMA, as well as its superiority in terms of weighted sum rate (WSR) in VLC. Finally, we discuss challenges, open issues, and research directions, which will enable the practical realization of RSMA in VLC.