Multiple access methods for visible light communication

Visible light communication (VLC) is a short-range wireless optical communication method that uses visible light for both communication and illumination. Most VLC systems use light emitting diodes (LEDs) as transmitters, which limits communication speed. In this thesis, multiple access (MA) methods that also increase the sum rate for indoor VLC systems are examined and improvements are proposed for non-orthogonal multiple access (NOMA) and rate splitting multiple access (RSMA) methods. In the findings obtained in the NOMA method, various constraints such as fairness and illumination, which are not considered in many studies in the literature, are used during the calculations. The effects of these constraints on each other and the sum rate are investigated. The proposed meta-heuristic algorithms outperform traditional power allocation methods in terms of sum rate. The results for the RSMA method indicate that RSMA provides performance very close to NOMA with lower complexity. In addition, it is demonstrated that RSMA and NOMA outperform orthogonal multiple access (OMA) in terms of sum rate. The advantages and limitations of RSMA, NOMA, and space division multiple access (SDMA) in terms of sum rate under fairness constraint are shown. Finally, it is demonstrated that RSMA is superior to NOMA under imperfect channel state information (CSI).