Performance Analysis of IRS-Assisted Hybrid VLC/THz Communication System

Abstract

This paper investigates the performance of a novel hybrid communication architecture that integrates visible light communication (VLC) with an intelligent reflecting surface (IRS)aided terahertz (THz) link. The proposed system aims to mitigate the severe path loss, blockage sensitivity, and alignment issues inherent in indoor communication by employing IRS-based passive beamforming and dynamic reflection control. A hardswitching mechanism is implemented, where the IRS-assisted THz link supplements the VLC link under adverse channel conditions, thereby enhancing link robustness and continuity. The VLC link is modeled using a Lambertian emission model, while the THz channel gain is characterized as a cascaded product of generalized α-μ fading and pointing error. The unified statistical representation of the composite channel is derived in closed form using multivariate Fox's-H functions, from which exact analytical expressions for the outage probability (OP) and average symbol error rate (ASER) are obtained. Numerical results reveal that the integration of IRS elements significantly improves signal reliability, spatial coverage, and link stability even under severe propagation impairments. The proposed hybrid VLC/IRSassisted THz framework demonstrates the potential of intelligent surfaces to enable energy-efficient, adaptive, and high-capacity indoor wireless communication systems for 5G and beyond networks. © 2026 IEEE.