A Pragmatic Anti-Interference Algorithm for Hybrid Beamforming in Millimeter Wave MIMO Systems

As communication technologies advance, millimeter wave (mmWave) signals have been widely used, leading to the rise of massive multiple input multiple output (MIMO) systems. However, the huge resource consumption cost by all-digital beamforming limits its application in MIMO. Thus, the hybrid beamforming technology raise much attention since its efficiency and low cost. This letter proposes an interference suppression method for mmWave MIMO systems based on hybrid beamforming. Unlike existing approaches only considering the improvement of the receiving signal-to-interference-plus-noise ratio (SINR) and without considering the hardware limitation, this study presents a practical anti-interference algorithm by integrating analog and digital beamforming techniques. To ensure that the digital signal remains within the dynamic range of analog-to-digital converter (ADC), this method employs phase shifters of limited precision to reduce analog interference first, and then maximize the anti-interference potential of digital beamforming. Utilizing the minimum variance distortionless response (MVDR) criterion, this study introduces a new covariance matrix reconstruction algorithm at the analog stage, and the sampling matrix inversion algorithm at the digital stage. Simulation results demonstrate the effectiveness of proposed algorithm in anti-interference. This approach improves the practical applicability of hybrid beamforming in practical scenarios.