Space Division Multiple Access Based on OIRS in Multi-User FSO System

Optical intelligent reflecting surface (OIRS) is a new type of passive programmable optical devices, and has the potential to expand the application scenarios of traditional optical wireless commnucation. In this paper, an OIRS-based space division multiple access (SDMA) technology is proposed, which realizes accurate SDMA by partitioning the signal input and control of the OIRS, so that a single OIRS can output multiple adjustable optical beams containing different information. By jointly considering the multi-path interference among OIRS regions, OIRS physical model, pointing error, and atmospheric attenuation, we build a mathematical model of the OIRS-based SDMA system. Based on the model, the closed-form expressions for the system BER and outage probability has been derived. It is shown through numerical results that the derivation results are accurate and there is an error floor cased by multi-path interference among OIRS regions. Based on theoretical analysis and simulation results, the effect of each parameter and system design have been discussed.