Performance Analysis of Hybrid RF-Reconfigurable Intelligent Surfaces Assisted FSO Communication

Optical reconfigurable intelligent surface (ORIS) is an emerging technology that can achieve reconfigurable optical propagation environments by precisely adjusting signal's reflection and shape through a large number of passive reflecting elements. In this article, we investigate the performance of an ORIS-assisted hybrid radio frequency (RF) and free space optics (FSO) communication system. By jointly considering the physical models of ORIS, RF channel, atmospheric turbulence, and pointing error, the closed-form solutions of the system's exact outage probability, asymptotic outage probability and BER have been derived. It is shown through numerical results that the derivation results are accurate and the RF-FSO links with ORISs show a slightly worse performance than the traditional RF-FSO links. However, the performance degradation introduced by ORIS is relatively small, and at the cost of this, the FSO link obtains a higher degree of beam adjustment freedom. We can also observe that both the increase of Rice factor in RF link and the decrease of pointing error in FSO link can effectively improve the system performance. Based on theoretical analysis and simulation results, the effect of each parameter and system design have been discussed.