Physical Layer Security for Intelligent Reflecting Surface-Assisted VLC/RF Hybrid Network

Driven by emerging materials technology, wireless communication system based on intelligent reflecting surface (IRS) has attracted more and more attention. However, most of current IRS-assisted physical layer security (PLS) research aims at radio frequency (RF) or visible light communication (VLC) independent networks, and few has focused on the PLS of IRS-assisted VLC/RF hybrid network which provides wide coverage via RF communication and high-data speed via VLC. In this paper, we study the PLS of IRS-assisted VLC/RF hybrid network, which works in two successive hops, and the first hop VLC link is used for transmitting information in electromagnetic sensitive environment, while the second hop RF link is used for extending the distance of the propagation by deploying IRS and relay nodes jointly. In the proposed system, there exists an eavesdropper trying to eavesdrop information from the relay. With this setup, closed-form expressions of the secrecy outage probability and strictly positive secrecy capacity of the system are derived. Simulation is carried out to verify the theoretical analysis. The simulation results show that IRS has a positive effect on improving the PLS performance.