Research On Hybrid Beam Forming For Millimeter Wave

With the rapid development of the society,people have the higher and higher requirements for information transmission.In the coming era of 5G communication,in order to meet the requirements of faster information transmission rate,more and more researches have been combined with millimeter wave technology.Although millimeter wave has the advantages of high frequency and wide broadband,its wavelength is extremely short due to its high frequency.So it is susceptible to different meteorological conditions when it propagated outdoors that limit its transmission distance is impossible to reach far.The emergence of large-scale antenna arrays and related technologies has alleviated this problem.However,in the MMW transceiver system integrated with large-scale antenna array,the existing search algorithm no longer meets the actual demand.At present,the antennas considered in the research literature are mostly the beamforming of one-dimensional antenna array in the single-path scenario,and there are few studies on the multi-path of millimeter wave and the beamforming of two-dimensional antenna array.In order to solve these problems,the research of millimeter wave-oriented multi-path beamforming of one-dimensional antenna array and multi-user beamforming of two-dimensional antenna array are carried out in this article.In view of previous search that only involves the main path which may cause the energy leakage above others,this article put forward an adaptive beam forming algorithm which can also keep good performance when path is scattered.An adaptive beamforming method based on the minimum transmitted power target is proposed for single-user multi-path scenarios.The transmitted power distribution vector corresponding to each propagation path is determined by the information rate,and then the pre-coding matrix is determined.For the multi-user multi-path scenario,considering the coupling between users,a multi-user joint beamforming based on Newton orthogonal matching tracking is proposed.Simulation results show that the proposed algorithm has a lower requirement for the total transmission power in multi-path and ensures that the maximum information rate is close to the ideal value.At present,there is little research on multi-user beamforming for two-dimensional antenna array and the matching success rate of existing algorithms is low.Therefore a beam search algorithm with multi-user and low complexity for two-dimensional antenna array is proposed.For three dimensional space communication which involves the horizontal angle and vertical angle,this article put forward the joint code that include main code and deputy code to reach beamforming.The main code could form some wider beams while deputy code could form some narrow beams.So in the latter beam search,we can determine the approximate scope by main code and then to findprecise matching beam by deputy code.In this way,we can get a high accuracy algorithm avoiding the deflection in traditional partial beam search.Matlab simulation shows that the algorithm can improve the beam-matching success rate and spectrum utilization greatly only by use less time.