IMPROVING SECRECY CAPACITY IN SUCCESSIVE RELAYING WIRELESS NETWORKS WITH SINGLE AND MULTI-LAYER TRANSMISSIONS

Abstract

This thesis considers using physical layer security (PLS) in successive relaying networks (SRN) where capacity of wireless channels are enhanced through simultaneous spectrum utilization by a source and two half-duplex relays, which in turn leads to inter-relay interference (IRI). In the proposed PLS schemes, by controlling the IRI through power adjustment unique to relay-destination channel state information, IRI and fading channels are turned into a source of secrecy. In particular, the IRI is cancelled at the destination, while the IRI increases the noise level at the eavesdropper. Single and multi-layer signaling are considered when analyzing secrecy capacity of these systems. Numerical analysis and simulations show that with conventional signaling, the proposed PLS scheme in SRN achieves higher secrecy capacity compared to the traditional half-duplex relaying system. Furthermore, multi-layer signaling shows great promise in terms of providing different levels of secrecy rates for different data streams represented by different power allocations.