MSE-Based Joint Transceiver and Passive Beamforming Designs for Intelligent Reflecting Surface-Aided MIMO Systems

In this letter, novel schemes for joint transceiver and passive beamforming design in an intelligent reflecting surface (IRS)-aided multiple-input multiple-output (MIMO) system are developed. Specifically, active beamformer at the BS, passive beamfomer at the IRS, and receive filter at the user are jointly optimized based on two realistic mean square error (MSE) criteria for signal estimation: (i) total MSE minimization and (ii) maximum per-stream MSE minimization. To tackle these challenging nonconvex problems effectively, two efficient iterative algorithms are proposed for both MSE criteria, in which the receive filter, active and passive beamformers are designed in alternating manner through solving the corresponding convex subproblems, respectively. Numerical results demonstrate better performance of the proposed schemes compared to baseline schemes in terms of the MSE and error rate performance.