Energy Efficiency Maximization in an IRS-Assisted Dual-Functional Radar and Communication System

Abstract

Dual-functional radar and communication (DFRC) techniques are promising in the next generation wireless communication network. Intelligent reflecting surface (IRS) can improve the energy efficiency (EE) of the DFRC system, which is of crucial importance in practical application. However, there have been no studies yet in energy-efficient design in the IRS-assisted DFRC system. Thus, in this paper, the EE maximization problem is studied in an IRS-assisted DFRC system. The EE is maximized by jointly optimizing the transmit beamforming and the IRS phase shift matrix subject to the radar and communication performance constraints. In order to tackle the challenging non-convex fractional optimization problem, an alternative algorithm is proposed to decouple the optimization variables. The high-order challenging radar performance constraint is tackled by using the properties of the convex function and hermitian matrix. Simulation results demonstrate that our proposed design has fast convergence and improves the EE of the DFRC system, and that there is a tradeoff between the radar target detection performance and EE.