Design of Robust Beamforming Algorithm for Intelligent Reflecting Surface-Assisted MISO Backscatter Communication System

This paper proposes a multivariable coupled achievable rate maximization problem in an intelligent reflecting surface (IRS) assisted multiple input single output (MISO) backscatter communication (BackCom) system based on bounded channel state information model by considering the backscatter device circuit initiation, base station transmit power and IRS phase shift constraints. The solution is obtained by relaxing variables, using S-procedure, alternating optimization and semidefinite relaxation. Moreover, a robust joint optimization algorithm (RJOA) is proposed. Simulation results show that the proposed algorithm performs higher average achievable rate and stronger robustness compared with non-robust and random IRS phase shift schemes.