In this paper, we consider the secrecy of a hybrid radio frequency (RF)/visible light communication (VLC) system equipped with decode-and-forward relaying. We develop physical layer security algorithms that mitigate eavesdropping on both RF and VLC networks based on zero-forcing beamforming techniques. We evaluate the system performance in terms of secrecy capacity (SC) and outage probability (OP) for two network scenarios, namely non-cooperative (NCPS) and cooperative power saving (CPS) models. The NCPS case assumes fixed power at both source and relay while the CPS case assumes total average power shared between the source and relay. Our objective is to find the minimum power that satisfies a specific SC for both cases. Our simulation results show that CPS policy achieves higher SC and maintain lower OP compared with the NCPS one for the same amount of power. We also show that, for both cases, the hybrid RF/VLC network can improve SC compared with standalone RF or VLC networks. INDEX TERMS Beamforming (BF), decode-and-forward (DF), maximal ratio combining (MRC), optimization, physical layer security (PLS), radio frequency (RF), relaying, visible light communication (VLC).

In this paper, we study physical layer security (PLS) aspects of a hybrid radio frequency (RF)/visible light communication (VLC) system with multiple decode-and-forward relaying nodes equipped with friendly jamming capabilities. We first propose a novel joint relay-jammer selection algorithm to enhance the secrecy performance of the network. Next, we obtain beamforming vectors and the minimal power values, which satisfy the required secrecy threshold. Our simulation results show that the proposed hybrid RF/VLC scheme obtains higher secrecy capacity compared to the standalone VLC and RF technologies. Finally, we proved the proposed technique to be an eavesdropping-resilient PLS solution.

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