Maximizing Minimum Phase Difference Based Hybrid Beamforming for Multiuser mmWave Massive MIMO systems

In this paper, we propose a hybrid beamforming algorithm based on maximizing the minimum phase difference for millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) multiuser systems. The proposed algorithm uses the channel gain threshold and the correlation characteristic of the array response vectors to select vector sets that provide higher signal power from analog beamforming vector codebook. Then, inter-user interference is measured by the phase difference between the analog beamforming vector and the main propagation path array response vector. Additionally, the criterion of maximizing the minimum phase difference is proposed to suppress the strongest inter-user interference. Analysis and simulation results show that the proposed algorithm can provide higher system sum rate with lower computational complexity than traditional approaches.