Symbol error rate performance analysis of non- orthogonal multiple access for visible light communications

Non-orthogonal multiple access (NOMA) is considered as one of promising radio access techniques for visible light communications (VLC) in next-generation wireless communications systems. In order to provide theoretical support for designing VLC-NOMA, we derive its analytic expressions for the symbol error rate (SER). Specifically, NOMA is first incorporated with appropriate VLC to establish a VLC-NOMA framework. Afterwards, mathematical expressions of the SER for the VLC-NOMA are developed. Moreover, numerical results are provided carefully to demonstrate that the proposed VLC-NOMA scheme outperforms than state-of-the-art orthogonal frequency division multiple access (OFDMA) one in terms of SER performance. Finally, relationships between the SER performance and the number of users, power allocation coefficient and semi-angle are well investigated, which can give us a scientific guide to devise the VLC-NOMA system for achieving better SER performance.