Secrecy Performance Analysis of a VLC System with a Randomly Positioned Eavesdropper

Over recent years, visible light communications (VLC) has gained prominence as a promising alternative to traditional RF communication, offering advantages in terms of bandwidth and security. This paper investigates the physical-layer security for a practical indoor VLC system where the positions of a legitimate receiver (Bob) and an eavesdropper (Eve) are considered to be random within their circular receiving planes. For this system model, the statistics of the VLC channel gains are obtained using which, closed-form expressions for the secrecy outage probability are derived. The analytical results, validated through Monte Carlo simulations, demonstrate the impact of key system parameters, namely signal-to-noise ratio, Bob and Eve relative positions, and the target secrecy rate on the SOP performance.