Physical Layer Security In Wireless Relaying Channels Using Graph Signal Processing Methods

Abstract

this thesis describes the graph localized vertex frequency analysis to investigate the PLS in large-scale wireless communication networks. With this representation, the localized compositions of graph frequencies are determined to maximize the sum secrecy rate. In addition, a thorough secrecy analysis for a graph containing four nodes is presented by formulating optimization problems for optimal relay location and power allocation. Two low-complexity algorithms that minimize the secrecy outage probability are presented for randomize-and-forward (RF) and Decode-and-forward (DF) relaying systems, along with their computational complexity. Further, an exact outage and secrecy outage analysis is offered for an amplify-and-forward (AF) relaying four-node system. A new secure-coding scheme for DF relaying multi-input, multi-output (MIMO) cooperative systems is presented using a graph Laplacian eigenbasis. This coding scheme considers the spatial degree of freedom to design a precoder for PLS in MIMO cooperative relaying networks.