Hybrid Beamforming For Mm Wave MIMIO Networks

The growing demand on high data-rate wireless communications is the key promoter for wireless network evolution.Insufficient available sub-6G bandwidth becomes the primary impedient to improve wireless capacity.Therefore,next generation wireless network will inevitably rely on high-frequency millimeter-wave(mmWave)bands to provide abundant spectrum resources.However,for wireless communications operating at mmWave bands,the severe path-loss and low penetration will be the major challenge.Massive multiple-input multiple-output(MIMO)is proposed to deal with the severe path-loss problem,and hybrid beamforming is a critical technique to enhance the channel gains.This paper mainly focuses on the hybrid beamforming design for mmWave MIMO communication systems,where complete and practical designs are respectively proposed for various system models.The contributions of this paper can be summarized as follow:(1)This work first considers practical and energy-efficiency hybrid beamforming design for point-to-point mmWave MIMO systems based on low-resolution phase shifters and subconnected architectures.The hybrid precoder and combiner are jointly designed which can achieve satisfactory performance,as can be seen in MATLAB simulations.(2)Multi-user scenarios have also been considered,where uplink transmission,multicasting,and broadcasting are respectively studied.For uplink and multicast transmission,we propose to first design analog beamforming to enhance the channel gain while mitigate the interference.Then,digital beamforming is designed to further enhance the performance.For broadcast transmission,we propose an iterative algorithm for analog beamforming design.(3)Finally,we provide a novel cell-free mmWave MIMO architecture which breaks up conventional cell bounds and can achieve high orders of throughput.Moreover,a practical and complete signal processing for cloud-radio access network(C-RAN)based cell-free mmWave networks has been investigated.The results of this thesis can not only accelerate the development and evolution of mmWave communications into more intelligent directions,but also provide technique support for the researches,applications and standardization of the next generation mmWave networks.