Practical Hybrid Beamforming Schemes in Massive MIMO 5G NR Systems

Massive MIMO systems in millimiter-wave band rely on beamforming techniques to focus transmit energy in a specific direction. Hybrid beamforming, which typically includes analog wideband and digital subband components, is designed as a compromise between affordable but low precision fully analog schemes and energy-consuming, expensive fully digital approaches. In this paper, we apply a practical approach to hybrid beamforming for Single User 5G Massive Multiple-Input- Multiple-Output (MIMO) Systems. In the 5G New Radio (NR) simulator, we implement and experimentally validate dual-stage hybrid beamforming approaches based on Singular Value Decomposition of the channel matrix and Zero Forcing, while fully digital scheme is taken as a baseline. We quantify gain offered by partially and fully connected structures, various number of Radio Frequency chains and transmit antennas, in terms of throughput and Block Error Rate. Varying the number of phase shifters, we investigate the performance-complexity trade-off for resolution of the phase shifters. To adequately reflect propagation environment, the simulations were run with Clustered Delay Line CDL-A channel model with angle scaling.