Artificial Noise Design for SISO ACO-OFDM Against Randomly Located Eavesdroppers

We investigates the secrecy performance of single-input single-output (SISO) asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) visible light communication (VLC) wiretap systems. We propose a precoding scheme using time-domain artificial noise (AN) to maximize secrecy rate. Furthermore, we also consider the scenario where the eavesdropper's location is random and calculate the average secrecy rate using stochastic geometry methods. Numerical results validate that the proposed scheme enhances the system secrecy capacity and mitigates the increase in peak-to-average power ratio (PAPR) caused by the introduction of AN.