Improving Wireless Physical Layer Security via D2D Communication

This paper investigates the physical layer security issue of a device-to-device (D2D) underlaid cellular system with a multi-antenna base station (BS) and a multi-antenna eavesdropper. To investigate the potential of D2D communication in improving network security, the conventional network without D2D users (DUs) is first considered. It is shown that the problem of maximizing the sum secrecy rate (SR) of cellular users (CUs) for this special case can be transformed to an assignment problem and optimally solved. Then, a D2D underlaid network is considered. Since the joint optimization of resource block (RB) allocation, CU-DU matching and power control is a mixed integer programming, the problem is difficult to handle. Hence, the RB assignment process is first conducted by ignoring D2D communication, and an iterative algorithm is then proposed to solve the remaining problem. Simulation results show that the sum SR of CUs can be greatly increased by D2D communication, and compared with the existing schemes, a better secrecy performance can be obtained by the proposed algorithms.

I. Introduction

During the past few years, wireless data traffic has grown dramatically due to the daily increasing demand on multimedia contents [1]. Enormous data traffic demand not only results in great pressures on the existing cellular systems, but also leads to great challenges to the transmission security since more and more confidential information is transmitted via wireless communication. Hence, enhancing the security of wireless communication has become one of the research focuses in the fifth generation (5G) network design [2]. As an information-theoretic approach, physical layer security has triggered considerable research interest recently [3]–[6].