Buffer-aided relay selection for secure communication in two-hop wireless networks with limited packet lifetime

Abstract

Buffer-aided relay selection serves as one of the key approaches for achieving physical layer security (PLS) of wireless networks. Existing studies on buffer-aided relay selection mainly concentrate on the scenarios where transmitted packets have unlimited lifetime, while the more practical and important scenarios with limited packet lifetime remain largely unexplored. This paper therefore aims to study the buffer-aided relay selection for achieving PLS in two-hop wireless networks with limited packet lifetime. We first propose a novel buffer-aided relay selection scheme by carefully considering the remaining lifetimes of packets, conditions of available links and channel state information (CSI) of eavesdroppers. To model the security and reliability performances achieved by the proposed scheme, we then apply tools from the Markov chain theory to derive expressions of the secrecy outage probability (SOP) and the packet discarding probability (PDP) of the network, respectively. Finally, extensive simulation and numerical results are provided to illustrate the performances of our proposed scheme and our theoretical framework. The results show that although our scheme achieves a slightly higher SOP than the typical buffer-aided max-link relay selection scheme, it can greatly reduce the PDP of the network.