Characteristic Analysis And Simulation Research On Broadband Wireless Channel For High-speed Railway

In recent years,high-speed railway develops rapidly.During the high-speed railway travel,the passengers spend much time to use a large number of mobile internet terminals,such as smart phones,tablet computers and so on,so that the demand of mobile communication data continues to increase.So,it is very important to carry out the research on broadband mobile communication system for high speed railway.High speed railway scenarios mainly have differences in the aspects of propagation scenarios,coverage,Doppler frequency shift and so on.Single frequency network scenario is a typical scenario of 3GPP for high speed railway.There were obvious differences between high-speed railway channels in SFN scenario and traditional wireless channels,mainly reflected in the following two aspects:1)Traditional wireless channel models are mostly statistical while SFN channel models are deterministic;2)the traditional channel model assumes that the channel characteristics do not change with time while the SFN channel model parameters vary with the time.As a result,the traditional channel simulation method is not completely suitable for the high speed railway wireless channel research,it is necessary to investigate the wireless channel characteristic and find new simulation methods for high-speed railway.The main content of this thesis are as follows:(1)Survey and research on the high-speed railway scenario and wireless channel modeling methods proposed by 3GPP RAN4 working group;analyze the characteristics of the SFN scenario,the leaky cable in the tunnel and the unidirectional RRH scenario.And select the SFN scenario which accounted for the largest proportion in high-speed railway scenarios as the key research,and choose single-tap and two-tap SFN channel models as the research objects;(2)Research on the simulation method of SFN channel model,and propose the non-stationary channel impulse response generation method.Realize accurate simulation of the dynamic change of channel parameters(Doppler frequency shift,multipath delay and relative power);(3)Implement the simulation of single-path and two-path SFN channel model on the LTE link simulation platform.Design the simulation case to assess the influence of Doppler frequency shift and multipath delay on LTE system performance.Investigate the influence of antenna type and angle on the system performance.Give the proposal for the antenna selection and network deployment under SFN network condition of high-speed railway;(4)Investigate the correlation matrix based MIMO channel simulation method,and analyze the main factors affecting the antenna correlation.Research on the applicability of MIMO technology in SFN scene,and propose an improved channel model solution method.The research results of this thesis can not only be applied to the LTE public network in high-speed railway scenarios,but also can be used to research the key technology,system design,equipment R&D and network deployment of the next generation high-speed railway dedicated LTE-R mobile communication system.