Low Power Consumption Beamforming System for Multi-beam Generation in 5G/6G Communications

In the 5th generation mobile communication, the millimeter band is used to increase capacity, and in the 6th generation mobile communication, the sub-terahertz band is considered. Since a lot of path loss occurs in a high frequency band, transmission is performed through beamforming. In the 5th generation millimeter band mobile communication system, a hybrid beamforming (BF) architecture has been proposed to reduce digital processing complexity including ADC power consumption. The hybrid beamforming system has an advantage in terms of hardware complexity when the number of beams is small. However, as the number of beams increases, the number of phase shifters increases in proportion to the number of beams, so hardware complexity greatly increases. If beamforming is performed at the digital stage, it is possible to obtain a benefit in generating multiple beams and flexible use of resources. In this paper, we propose system design criteria in order to ensure the same receiving quality for all terminals. Considering the performance limit of the PA, an appropriate increase in antennas is required according to the increase in beams. We analyze the power consumption of the hybrid beamforming system, and the full digital beamforming system with the constraint to generate the same number of beams and obtain the same Tx EIRP per beam. We show that the optimal BF system minimize power consumption with the same Tx EIRP per beam as the number of beams increases.