Optical Intelligent Reflecting Surface Configuration for NOMA-based MISO VLC Systems

Optical intelligent reflecting surfaces (OIRS) can be deployed in visible light communication (VLC) systems to provide OIRS-reflected paths for multiple light-emitting diodes (LEDs) and users via adjustable reflective characteristics, thereby significantly mitigating the signal blockage challenges in VLC. To achieve this goal, the effectiveness of OIRS in the non-orthogonal multiple access (NOMA)-based multiple-input single-output (MISO) VLC system is explored, while the system model is established considering both the line-of-sight (LoS) and the OIRS-reflected paths. Subsequently, the problem is formulated with the objective of optimizing the OIRS configuration to maximize the achievable sum data rate with the diverse constraints. To address the highly intractable and non-convex problem, a relaxed iterative optimization algorithm based on the Taylor expansion is proposed in this paper. Moreover, numerical results are provided to show the improvement of the achievable sum data rate and the effects of the proposed relaxed iterative algorithm.