Secrecy Sum Rate Maximization for OIRS-Aided Visible Light Communications with Confidential Messages

2026-06-02

AI Summary

This work addresses the limited secrecy rate in optical intelligent reflecting surface (OIRS)-assisted visible light communication systems under line-of-sight blockage and internal eavesdropping threats. To overcome this challenge, a novel joint optimization approach is proposed that simultaneously designs transmit precoding and the on/off states of OIRS elements. The problem is formulated as a non-convex secrecy rate maximization model with binary constraints and coupled variables. An efficient alternating optimization framework is developed by leveraging the concave–convex procedure (CCCP) and first-order Taylor approximations to handle the non-convexity. Theoretical analysis ensures convergence of the proposed algorithm, and simulation results demonstrate that the scheme significantly enhances the system’s secrecy rate, with performance gains increasing as the number of OIRS elements grows.

Abstract

This paper investigates the secrecy sum-rate (SSR) performance of optical intelligent reflecting surface (OIRS)-assisted multi-user visible light communication (VLC) systems under line-of-sight (LoS) blockages. To mitigate physical obstructions and internal eavesdropping, a joint optimization problem is formulated to maximize the SSR through the co-design of the transmission precoder and OIRS units assignment. Due to the binary constraints and coupled variables, the problem is highly non-convex. To solve it efficiently, an alternating optimization (AO) framework integrating the concave-convex procedure (CCCP) and first-order Taylor approximations is developed. Simulation results demonstrate the convergence of the proposed algorithm and show that increasing the number of OIRS reflecting units yields significant SSR gains.

Problem

• secrecy sum rate
• optical intelligent reflecting surface
• visible light communications
• line-of-sight blockage
• physical-layer security

Innovation

• Optical Intelligent Reflecting Surface (OIRS)
• Visible Light Communication (VLC)
• Secrecy Sum Rate (SSR)
• Alternating Optimization (AO)
• Concave-Convex Procedure (CCCP)