The Research And Performance Evaluation On Beam Selection In 5G-NR Massive Mimo Multi-beam Transmission System

In the face of huge amount data communication needs,research on the 5th generation mobile communication technology(5G)has developed rapidly.The massive multiple-input multiple-out(MIMO)technology is considered as one of the key technologies of 5G.Beamforming technology compensates transmission losses of millimeter wave by providing high-directional beams.The full digital beamforming of massive MIMO brings high hardware costs,therefore,hybrid beamforming become an important candidate for complexity reduction.The introduction of hybrid beamforming has brought about a beam management mechanism.The first step of beam management is to search then select the best transmit and receive beam pair links quickly in the set of candidate beams.The topic of this paper based on 5G system-level simulation platform.In this paper,different beam selection methods are studied in the Massive MIMO simulation platform,and their performances are evaluated.Firstly,the paper studies the principle of Massive MIMO and hybrid beamforming technologies and summarized the research and standardization of NR's multi analog beam selection mechanism.Then the key technologies of communication system level simulation platform are introduced.The platform is used to evaluate the performance of different beam selection methods described later.Secondly,for the beam selection method in a multi-cell and multi-user system,a joint beam selection scheme based on the measurement of both physical layer signal-to-interference noise ratio(L1-SINR)and reference signal received power(RSRP)is proposed and the simulation performance is evaluated.Two methods for calculating L1-SINK are given in the simulation.The thresholds designed in the joint selection method are analyzed and simulated.The simulation results show that compared with the traditional method,under a suitable threshold the joint beam selection method can effectively improve 5%edge User Equipment(UE)throughput rate and slightly improve the average spectral efficiency.Finally,when the range of candidate beams become wide,the measurement of beam selection will lead to high measurement overhead complexity.A method on grouping beam selection based on two dimensions of transmission and reception is proposed in this paper.In the method a certain indicators is used as a reference for further selection.This paper proposes two types of reference indicators:the indicator with RSRP and the indicator with RSRP and L1-SINR combined.The user combines the better beams in the dimensions of transmission and reception according to reference indicator,to reduce the number of measurement beams and reduce the cost.In this way,the number of measurement beams is reduced and the measurement overhead is reduced accordingly.Two key parameters are designed in the grouping method.This paper presents a method on how to determine the parameters.Then we obtain the key parameter values under different size of candidate beam set by the method.The simulation results show that compared to the traditional selection method,the average spectral efficiency of the method does not decrease while its 5%edge user throughput of this method is improved under large candidate beam size.At the same time,the complexity overhead of the beam measurement can be effectively reduced.