Optical Beam Steerable Orthogonal Frequency Division Multiplexing (OFDM) Non-Orthogonal Multiple Access (NOMA) Visible Light Communication Using Spatial-Light Modulator Based Reconfigurable Intelligent Surface

We put forward and demonstrate a steerable optical beam visible light communication (VLC) system combining orthogonal frequency division multiplexing (OFDM) and non-orthogonal multiple access (NOMA) schemes, and utilizing a spatial light modulator (SLM)-based reconfigurable intelligent surface (RIS) for beam steering. When utilizing the SLM as RIS for optical beam steering, its operation principle, maximum achievable steering angle (i.e., field-of-view, FOV), as well as the corresponding loss should be analyzed. We theoretically and experimentally analyzed in detail the characters of SLM when acting as the RIS. Experimental results demonstrate the flexibility of both active beam control and data rate allocation for multiple users. The SLM-based RIS can independently and simultaneously control multiple beams, and significantly reduce the deploying cost of the increase in the devices for the multi-beam handling scenario. All of the specified channels under evaluation satisfy the pre-forward error correction bit-error rate limit (pre-FEC BER = 3.8 × 10-3).