Research On Millimeter Wave Beamforming Algorithm And Beam Management Mechanism Of High Speed Rail

The rapid development of the information industry has created new communication requirements in more and more industries in life,and people’s demands on network speed and communication quality are also increasing day by day.However,the currently used frequency band resources are already in short supply and cannot satisfy the requirements for new business expansion and higher-speed information transmission.Millimeter wave is the preferred way to solve this objective problem.It not only has extremely wide bandwidth resources,but also can realize ultra-high-speed information transmission,so the research on millimeter wave is necessary and feasible.At present,most of the high-speed railway communication systems still use the older GSM-R mobile communication system,which has low transmission efficiency and cannot meet the new business needs brought about by the development of high-speed railways and the expectations of passengers for high-quality high-speed railway communication services.New technical means are needed to improve the quality of service of high-speed rail communications,and millimeter waves can achieve higher rate information transmission due to its ultra-high bandwidth.However,although millimeter wave can bring a huge improvement in network performance,its serious propagation loss is a problem that needs to be solved urgently.This thesis dedicated to the research on the application of millimeter waves on high-speed railways.According to the high-speed railway communication system model,the frequency suitable for high-speed railway communications is selected according to the propagation characteristics of millimeter waves,and the corresponding simulation analysis of millimeter wave coverage is done.Based on this,the cell radius studied in this paper is determined.According to the environmental characteristics of high-speed railway and the propagation characteristics of millimeter wave,a suitable high-speed railway millimeter wave channel model is given.The characteristics of the array antenna are analyzed,and the influence of the number of array elements and the distance between the array elements on the antenna pattern and beam width is discussed.In the signal processing of beamforming using array antennas,the weight matrix is ??the most important factor that affects the performance of beamforming.This paper analyzes the performance of different weight optimization criteria,and determines the LCMV optimization criteria with DOA as a priori known information as the beamforming optimization algorithm studied in this paper.In the aspect of beam management,aiming at the shortcomings of the genetic algorithm dynamic beam tracking scheme,this paper proposes an improved beam tracking scheme based on training set.The scheme is based on dynamic beam tracking.The beam angle retransmitted during each beam switching is based on real-time DOA information.The transmitted beam width is selected in the generated training set,and the probability of each value in the training set being selected is calculated based on the product of the array gain and the transmit beam width.The simulation results show that the scheme proposed in this paper can improve system performance,increase stability,and reduce system overhead to a certain extent,and reduce the complexity of implementation.