Enhancing VLC Security with Time-Domain Interleaving and Optical-OFDM on Realistic Channel Models

This paper presents a novel approach to enhance the security of indoor visible light communication (VLC) systems by combining time-domain interleaving (TDI) with opticalorthogonal frequency division multiplexing (O-OFDM) and by considering a realistic channel model. While the primary purpose of TDI is to mitigate the effects of impulsive noise and multipath fading on the bit error rate (BER) performance in transmission systems, in this paper it is introduced as a method for physical layer security (PLS) in indoor VLC systems. Specifically, we consider TDI to provide secrecy by intentionally adding randomness and complexity to the transmitted signals. By interleaving the symbols in the time domain, TDI disrupts the sequential order of the symbols and introduces a level of uncertainty for any eavesdroppers attempting to intercept and decode the transmitted data. Additionally, TDI is integrated into O-OFDM, allowing the VLC system to benefit from both the inherent security of TDI and the spectral efficiency of O-OFDM. Furthermore, realistic VLC channel models are considered, which account for various factors influencing the VLC channel, including path loss, multipath reflections, and scattering, and ambient noise. Through MATLAB simulations, the performance of the proposed system under an indoor VLC scenario and different channel conditions is evaluated. The results demonstrate significant improvements in security, with reduced vulnerability to eavesdropping and information leakage.