Research On Wireless Channel Characteristics Of Mobile-to-mobile Communication For High-speed Railway Cutting Scenarios

In wireless communication system,precise wireless channel models directly affect the wireless channel estimation and improvement in the performance indicators of wireless communication system.Due to the influence of reflection,scattering and diffraction of electromagnetic waves on electromagnetic wave transmission,and the impact of obstacles in the transmission environment on the random movement of transmitter and receiver,it is of great importance to accurately describe the wireless channel using an appropriate method.Based on the public network wireless communication fading model,the existing wireless channel fading models cannot be fully applied to the fading characteristics of high-speed railway in special scenarios.For example,the fading strength of high-speed railway in the cutting scenario is subjected to the impact of the height and width of cutting,and the vegetation on the cut slope.However,these influences cannot be well reflected in the existing wireless channel fading models which are mainly based on the Wide-Sense Stationary(WSS)assumption.However,with the increasingly fast operation of high-speed railway,wireless channels exhibit non-stationary characteristics,making the existing wireless channel models based on WSS unable to accurately describe the statistical characteristics of wireless channels.In order to further understand the relationship between high-speed railway cutting scenarios and wireless channel path loss,and apply existing wireless channel modeling methods to non-stationary wireless channels,this paper studies the wireless channel characteristics of high-speed railway in the cutting scenario,and conducts related work on the impact of random movement of mobile terminals on the non-stationary characteristics of wireless channels,including the following aspects:(1)The analysis of the large-scale fading model in the cutting scenario.Firstly,the large-scale model suitable for the cutting scenario was determined,and the measured path loss value of the Zhengzhou-Xi'an high-speed railway was selected to fit with the Hata model and the IMT-2000 vehicle-mounted model,so as to obtain the classic model type applicable to the cutting scenario.Secondly,the grey relational algorithm was used to compare the horizontal and vertical correlations between the parameters of the cutting structure and the path loss exponent,so as to obtain the range of value of the cutting structure when the path loss exponent is within an ideal range.(2)The M2 M double-cylinder Gauss-Markov model is built in the cutting scenario,and the time correlation function of the M2 M double-cylinder Gauss-Markov model is obtained through the transfer function of the improved model.Through the simulation of time correlation function,the non-stationary characteristics of the model are obtained.By changing the randomness of mobile terminal,the trend of non-stationary characteristics of wirelesschannel is obtained under different speed and anisotropy index.It is proved that the non-stationary characteristics of wireless channel are only under the condition of time-varying speed and direction.