Sum-rate maximization for downlink rate-splitting multiple access (RSMA) in visible light communication (VLC)

Visible light communication (VLC) is a short-range wireless technology that leverages visible light for data transmission while simultaneously providing illumination. While light-emitting diodes (LEDs) are commonly employed as transmitters in VLC systems, their limited bandwidth restricts the achievable data rates. As VLC systems are anticipated to play an essential role in future communication infrastructures, they must support not only high-speed data transmission but also multiple-user access. In this context, rate-splitting multiple access (RSMA) has recently received attention in VLC for combining the advantages of non-orthogonal multiple access (NOMA) and space-division multiple access (SDMA) schemes. In this study, the sum-rate maximization problem for downlink RSMA in VLC is investigated. To this end, a typical indoor environment illuminated by multiple LEDs is modeled in compliance with lighting standards. The sum-rate in downlink multiple-input single-output VLC systems employing RSMA, NOMA, and SDMA is formulated within this scenario to maximize performance considering practical system limitations. To solve these optimization problems, this study employs the artificial bee colony algorithm. Numerical results reveal that the RSMA scheme outperforms SDMA and NOMA in terms of sum-rate performance.