Downlink Multiple Access in Optical Mobile Communications: NOMA and OMA Comparison

Optical mobile communication (OMC) introduces optical intelligent reflecting surface (IRS) into optical wireless communication systems, which makes the channel configurable and provides possibility for supporting multiple mobile users. However, the introduction of IRS also makes the calculation of achievable rate quite difficult, and different access methods will bring variation in performance. In this paper, we analyze the rate region of IRS-aided OMC system with different access methods. It is found that orthogonal multiple access entitles larger rate region than non-orthogonal multiple access in some situations, which is quite different from conventional optical wireless communication systems without IRSs.