Beam Training And Beam Tracking For Millimeter Wave Massive MIMO

Millimeter wave(mm Wave)massive Multiple-input Multiple-output(MIMO)communication is one of the key technologies of future wireless communication.Millimeter wave massive MIMO system can not only compensate the path loss of mm Wave signal transmission,but also fully exploit the spatial degree of freedom through beamforming technology.This paper conducts research work on beam training and beam tracking in mm Wave massive MIMO.The detailed work is included as follows.Beam training technology based on codebook is studied.A computation-aided adaptive codebook is designed,and a fast beam training algorithm based on this codebook is proposed.At each layer of the hierarchical codebook,the system first estimates the channel angle of arrival(AOA)or angle of departure(AOD)according to the beam training results from the previous layers and then adaptively designs a codeword in the current layer that can align with the estimated AOA or AOD.Benefiting from the computation resources used for the adaptive codebook design and beam alignment,the proposed algorithm can improve the success rate of beam training as well as reducing the training overhead comparing with the existing algorithms.Simulation results verify the effectiveness of the proposed algorithm.Considering the mobility of the transceiver,beam tracking can be performed based on the current beam training results.A fast beam tracking algorithm based on the overlapped codeword is proposed to improve the efficiency of beam tracking in this paper.In this algorithm,only a small number of beams need to be tested to realize beam tracking without any prior information of channel provided by other auxiliary devices.According to the energy distribution characteristics of the mm Wave beam domain channel,the algorithm uses overlapped codeword to form beams to point to the possible spatial position of the receiver for detection in turn,and dynamically adjusts the detection direction according to the detection results until both the transmitting beam and the receiving beam all aligned to the dominant path of the channel.Simulation results show that the proposed algorithm can significantly reduce the overhead of beam tracking compared with the exhaustive search algorithm and has higher accuracy of beam tracking.