Hybrid Beamforming for Intelligent Reflecting Surface Aided Millimeter Wave MIMO Systems

As communication systems that employ millimeter wave (mmWave) frequency bands must use large antenna arrays to overcome the severe propagation loss of mmWave signals, hybrid beamforming has been considered as an integral component communications. Recently, intelligent reflecting surface (IRS) proposed innovative technology can significantly improve performance through low-cost passive elements. In this paper, we study IRS-aided multiple-input multiple-output (MIMO) with architectures. We first exploit sparse-scattering structure and dimension channels develop joint design IRS reflection matrix beamformer for narrowband MIMO systems. Then, generalize broadband orthogonal division multiplexing (OFDM) modulation by leveraging angular sparsity frequency-selective channels. Simulation results demonstrate designs enhance spectral efficiency interest achieve superior over existing designs.