Secrecy Rate Maximization for Intelligent Reflecting Surface-Assisted Device-to-Device Communications System

Intelligent reflecting surface (IRS) is a promising technology for its capability of enhancing the desired signals and suppressing the interference. In this paper, we introduce IRS into a device-to-device (D2D) underlaying cellular system and investigate its application on physical layer security. The secrecy rate is maximized by jointly designing the received beamforming vector, power allocation and phase shift matrix. We apply the block coordinate descent (BCD) algorithm to decouple the optimization problem, and the semidefinite relaxation (SDR) technique is adopted to optimize the phase shift matrix. Simulation results show that the IRS is able to improve the system secrecy performance of the D2D underlying cellular system.