A New Eavesdropping-Resilient Framework for Indoor Visible Light Communication

Abstract

Visible Light Communication (VLC) is a promising technique for high-speed, low-cost wireless services with the rapid development and wide deployment of Light-Emitting Diodes (LEDs). However, the broadcast nature of the VLC makes eavesdroppers easily intercept the light communication in various settings, e.g., offices, conference rooms and airport lobbies. Although previous work put forward physical layer mechanisms to improve VLC security, they ignored the impact of light reflection and channel correlation on VLC security, which is not practical for the indoor environment. In this paper, we propose a new eavesdropping-resilient framework to defend against eavesdropping attacks under both Single Input Single Output (SISO) and Multiple Input Single Output (MISO) models. We propose a random time reversal scheme, that makes transmitted signal automatically focus on legitimate receivers while interfering the eavesdropper's channel with VLC's multipath redundancy, time reversal, and random choice technique. We analyze the impact of channel correlation on VLC security under the MISO model and find that the system secrecy capacity decreases. Therefore, we propose to use Karhunen-LoEve (KL) transform to improve the system secrecy capacity. Finally, we conduct extensive simulations to show that, our framework can make the eavesdropper's Bit Error Rate (BER) be above 0.0038, which is the threshold of Forward Error Correction (FEC), even when he tries to attack with Constant Modulus Algorithm (CMA). Furthermore, the system secrecy capacity is improved up to 3 Bit/Sec/Hz.