Performance Investigation of Phase-over-Sampler based Hybrid Beamformer for mmWave Massive MIMO Systems

Millimeter-Wave (mmWave) technology performs a significant role in satisfying the rising data traffic demand in 5G wireless communications. Nowadays, hybrid beamforming is a buzzword in massive MIMO systems performing at the frequency range of mmWave. Hybrid beamforming is the combination of analog and digital beamforming. The traditional fully-connected phase shifters (FCPSs) based hybrid beamforming systems consume high power due to a large number of phase shifters (PSs) in its analog part and its configuration complexity. High RF losses occur in the conventional phase shifters with switch (SW) based hybrid beamformer and the overall performance of this beamformer is decreased due to high RF losses. A 3-bit resolution phase-over-samplers (POSs) with SW based hybrid beamformer with less number of POSs is proposed in this paper to minimize the power consumption and RF losses of existing hybrid beamforming system. The proposed phase-over-sampler with SW (POS-SW) based hybrid beamformer provides higher spectral efficiency (SE) and energy efficiency (EE) compared with existing FCPSs and PS-SW based hybrid beamforming schemes. The performance of the proposed POS-SW based hybrid beamformer is also compared with the existing fully-digital beamformer and found that the EE of proposed POS-SW based hybrid beamformer is better than existing fully digital beamformer. Some numerical examples are shown to analyze the performance of the proposed hybrid beamformer.