Enhancing Spectral Efficiency for Clustered User Geometry in Sub-Connected Hybrid Beamforming Systems

Fifth-generation millimeter wave (mmWave) systems rely on sub-connected (SC) hybrid beamforming architecture due to low power consumption and reduced hardware complexity. In SC architecture, each RF chain is connected to a subset of antennas which limits the associated beamforming gain. Thus, designing beam patterns for SC mmWave systems that can effectively serve multiple users with high beamforming gains becomes a challenging task. Considering a clustered user geometry to model multiple users in close proximity, this work proposes a beam pattern multiplication-based precoder design to improve the overall spectral efficiency performance in mmWave systems. Simulation results demonstrate the effectiveness of the proposed design for SC mmWave systems in terms of high beamforming gain, improved spectral and energy efficiency.