A Dual Function Intelligent Reflecting Surface in Integrated Radar Communication System

A novel intelligent reflecting surface (IRS) aided dual-function radar-communication (DFRC) system is proposed in this paper. IRSs are not only used to improve communication channels, but also employed as cooperative intelligent targets to enhance some objects of interest, such as vehicles and pedestrians in an intelligent transportation system. The optimal design objective function is to maximize the radar performance, while keeping the communication rate constant. The measure of radar performance is the Cramér-Rao bound (CRB) of the direction of departure (DOD), which is a special capability of a collocated antenna array multiple input multiple output (MIMO) radar. The joint optimization process comprises two steps, namely the passive optimization of IRSs and the active transmit beamforming. Due to the non-convexity of the optimization problem, a solver based on semidefinite relaxation (SDR) is proposed. Simulation experiments show the ability of the proposed optimization algorithm to balance the radar performance and the communication rate.