Research On User Scheduling And Hybrid Beamforming Technique In Millimeter-wave MU-MIMO System

With the development of mobile multimedia applications and the popularization of terminal equipment,there are some hotspots in the communication area,where the system need to be provided with more efficient resource allocation and higher data transmission rates to further improve system performance.Millimeter wave band,owing to its rich frequency resources and its ease of integration of more antennas,is promising candidate for these requirements.Therefore,this study focuses on the user scheduling and hybrid beamforming technologies at millimeter wave band in multiple user multiple input multiple output(MU-MIMO)system.This study firstly introduces the basic knowledge of the existing multi-user MIMO technologies,multi-user scheduling technologies and two kinds of millimeter-wave hybrid beamforming technologies,and analyzes the basic principles and technical characteristics of each technical solution.Then it explains the specific usage and classification of each technology under different application scenarios.After that,combined with the directional characteristics of millimeter wave channel and the cluster distribution of users in limited area,the traditional spatial clustering technique is introduced into the millimeter-wave multi-user scheduling technologies,and an adaptive user scheduling scheme based on channel quality information(CQI)of matching users is proposed.Different from the fixed codebook,the system adaptively allocates different radio frequency resources and designs corresponding communication beams for each area,according to the statistics of different areas' user densities.Then,the complex multi-user scheduling problem in the system is converted into a simple user matching problem of each pre-defined beam,which can further reduce the computational complexity of the system.In addition,the proposed scheme uses the double cone matching model of beam to filter matching users,and filters some users who do not meet the matching conditions,thereby reducing the amount of feedback information and improving the system processing efficiency.At last,in the case of scheduling users fixed,this article proposes a hybrid beamforming scheme based on the data characteristics of signal-to-leakage-plus-noise-ratio(SLNR).At the base station,two precoding schemes of phase and codebook are respectively designed according to different precoding modes,which can simplify the base station-side precoding design process and computational complexity.Besides that,the simulation results show that the proposed hybrid beamforming scheme has better performance of the sum rate performance than existing algorithms.