Joint Optimization Design for Intelligent Reflecting Surface-Aided Ambient Backscatter Communication System

Joint optimization is performed for design of Intelligent Reflecting Surface (IRS) assisted multi-antenna ambient backscatter communication (AmBC) system in this paper. Specifically, it is proposed for the first time to maximize the system average achievable rate by jointly optimizing the transmit beaming of the radio frequency (RF) source, the phase shift of the IRS and the reflection coefficient of the tag. Since the problem is non-convex, a suboptimal solution is obtained by designing an efficient alternating optimization algorithm. Simulation results demonstrate that the proposed method effectively enhances the average achievable rate and is applicable to practical ambient backscatter communication networks aided by IRS with discrete phase shifts.