Stackelberg Game-based Secure Communication in SWIPT-enabled Relaying Systems

This paper investigates secure communication in a two-hop relaying system based on physical layer security. The relay employs time-switching simultaneous wireless information and power transfer (SWIPT) to harvest energy and receive information from the source, and then transmits the source’s information and its own information to the destination. A passive eavesdropper exists and wiretaps information transmission over both hops. Under the general system configuration, we first provide performance modeling to reveal the secrecy rate of source and relay as well as identify their utilities. Then, we analyze the hierarchical competition behaviors between the source and relay from a game-theoretic perspective. In particular, we develop a Stackelberg game-based analytical framework to determine the optimal strategies for the source and relay by deriving the Stackelberg equilibrium. Furthermore, we summarize the feasible conditions of utilizing SWIPT-enabled relaying for secure communication and propose the end-to-end transmission scheme accordingly. Extensive numerical results are presented to demonstrate the performance of the proposed SWIPT-enabled relaying system.

I. Introduction

The rapid evolution of wireless communication technologies strongly promotes the ubiquitousness of connections and diversification of application scenarios in the 5G era. In a wide range of practical applications, the lifetime of wireless devices is greatly constrained by the battery capacity, and thus there is an urgent demand for the development of effective energy charging techniques [1]. Recently, simultaneous wireless information and power transfer (SWIPT), which enables dual utilization of radio frequency (RF) signals to supply wireless information and energy access at the same time, has been regarded as a promising technique to solve the energy scarcity problem and improve the quality of service in energy-constrained wireless systems [2].