Hybrid multi-user access scheme for a visible light communication system.

A hybrid multi-user access scheme based on orthogonal frequency-division multiple access and non-orthogonal multiple access (OFDMA-NOMA) is proposed for visible light communication (VLC) systems with a bandwidth-constrained channel. In the scheme, a novel user resource allocation method is used, to the best of our knowledge, to reduce the unfairness among different users caused by the high-frequency fading characteristic of VLC systems. Furthermore, the particle swarm optimization (PSO) is introduced to satisfy the transmitting power requirements of each user and to improve system performance. Simulation results show that, under the same VLC system conditions, the OFDMA-NOMA scheme with PSO has significant improvements in terms of user capacity and transmission rates compared to the purely NOMA scheme and the OFDMA scheme.