Physical Layer Security for Hybrid RF/VLC Relaying Communication Networks

The objective of this dissertation is to develop physical layer security (PLS) techniques for hybrid radio frequency (RF)/visible light communication (VLC) decode-and-forward (DF) relaying networks. The first section of the dissertation investigates PLS aspects in the presence of the eavesdropper located in the same room as the legitimate receiver. Physical layer security algorithms are developed to mitigate eavesdropping on both RF and VLC networks based on zero-forcing beamforming (ZF-BF) techniques. The system performance is evaluated 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. The second section of the dissertation utilizes friendly jamming techniques in improving the SC of the networks. First, a hybrid DF RF/VLC relaying network with jamming capabilities is investigated. Then the dissertation proposes a novel joint relay-jammer selection algorithm to enhance the secrecy performance of the network in order to examine PLS aspects of a hybrid RF/VLC system with multiple DF relaying nodes equipped with friendly jamming capabilities. The results reveal useful insights into how the power distribution facilitates achieving the required SC by exploiting the non-utilized power. For example, the CPS case ensures that all available power is used to achieve the given SC, which is higher than the one obtainable by the NCPS network. Moreover, the results show the relation between the achievable SC and the location of the eavesdropper. The simulation results show that the proposed scheme achieves higher secrecy capacity compared to the standalone RF and VLC technologies. Overall, the results indicate that the proposed techniques are eavesdropping-resilient PLS solutions.