Optical Intelligent Reflecting Surface-Aided VLC With NOMA: Principle, Challenges, and Trends

Recently, visible light communication (VLC) has emerged as an attractive complement to radio frequency (RF) communications due to the license-free bandwidth and high data rate. Nevertheless, VLC in practice scenarios encounters challenges, such as the blockage and limited bandwidth of light-emitting diodes (LEDs). Optical intelligent reflecting surface (OIRS) and non-orthogonal multiple access (NOMA) are two potential technologies that can help VLC overcome its shortcomings. According to the principle of NOMA, the power is allocated based on the channel conditions and OIRS can reconfigure the optical channel, which inspires us to study the OIRS-aided VLC with NOMA for multi-user high speed communications. Specifically, the advantages can be categorized into three types: the reconfiguration of optical channel, the enhancement of signal quality, and the improvement of communication security. Additionally, we summarise the key technologies and challenges of NOMA-based VLC with OIRS. Finally, the open issues and trends are discussed for future research of optical wireless communications.