Research On Vehicle To Vehicle Wireless Channel Modeling And Simulation For Typical Environment Of Vehicle Networking

The Internet of vehicles can effectively enhance road driving safety and traffic efficiency.It has attracted extensive attention in the fields of driverless,intelligent transportation system and so on.Vehicle to Vehicle(V2V)communication is an important part of vehicle networking technology,and its performance is directly restricted by the signal propagation environment,the establishment of V2 V communication with high reliability and low delay requires a channel model that can accurately describe the characteristics of wireless communication scenarios.However,the signal transmitting and receiving ends of V2 V communication have the characteristics of high-speed movement,and will be affected by the geometric structure of the driving environment,traffic flow density and vehicle driving direction.As a result,its propagation channel is significantly different from the traditional mobile channe,and the V2 V channel characteristics in different environments are also significantly different.Therefore,the applicability of the traditional mobile channel model in the V2 V communication environment of the Internet of vehicles is significantly reduced.In order to enhance the representation accuracy of the channel model and enrich the channel model to support scenarios in the Internet of vehicles environment.In this thesis,the corresponding three-dimensional non-stationary V2 V channel models are proposed for the two typical vehicle networking communication environments of urban streets and arch tunnels,and the channel statistical characteristics under the two environments are researched.The main work of this thesis is as follows:(1)Aiming at the difference between V2 V wireless communication and traditional mobile communication,this thesis explores the characteristics of V2 V wireless channel for Internet of vehicles.Starting from the distribution of scatterers in communication environment and wireless signal propagation path,this thesis analyzes the signal propagation characteristics of V2 V in three typical channel scenarios of Internet of vehicles,and points out the special factors to be considered in constructing wireless channel model in different scenarios;Different kinds of V2 V channel modeling methods are briefly described,and the key indexes such as model accuracy and complexity are compared.(2)A new three-dimensional non-stationary V2 V channel reference model and its corresponding simulation model for urban streets is proposed.Focusing on the multi-directional driving of vehicles in urban streets and other open spaces,and the non-independence of elevation angle and azimuth angle in the three-dimensional propagation scene of wireless signals,the proposed model uses Von Mises Fisher(VMF)joint distribution to describe the three-dimensional angle spectrum of signals.In order to characterize the non-stationary characteristics of wireless propagation scene,multi time-varying parameters caused by the movement of signal transmitting and receiving vehicles in arbitrarily direction and speed are introduced.Based on the proposed model,the mathematical expressions of channel space-time correlation function and Doppler power spectral density are derived,the effects of channel non-stationarity,moving speed of scatterers and vehicle direction on the above channel statistical characteristics are investigated;In addition,the proposed model distinguishes between moving and static scatterers in the vehicle environment,and has the ability to investigate the effects of different traffic density on the statistical characteristics of the channel.The simulation results show that the proposed channel model can capture the influence of the change of vehicle driving direction on the space correlation of the channel,and enrich the scenes that the model can support.The theoretical value is basically consistent with the measured value,the high fitting between the statistical characteristics of the simulation model and the reference model verifies the effectiveness of the proposed model.(3)A new three-dimensional nonstationary V2 V channel reference model and its corresponding simulation model for arch tunnel is proposed.Aiming at the complexity and non-stationary characteristics of wireless signal propagation in confined space environment such as tunnel scene,we use elliptic cylinder model and semi ellipsoid model to characterize the vertical wall on both sides of the tunnel and the curved wall on the top respectively.With the addition of the ground scattering radius and its distribution function,the proposed model can effectively describe the horizontal ground reflection path of wireless signal propagation.In order to realize the non-stationary modeling of the channel,we deduce and update the time-varying geometric parameters caused by the movement of the signal transceiver in the proposed model according to the time evolution process.Based on the derivation of mathematical theory,the effects of antenna array,nonstationarity and signal ground reflection path parameters on the channel statistical characteristics are researched.The general rules for the design of some vehicle antenna arrays and the control of ground reflection are also given in this thesis.We compare the numerical simulation results of the built model with the traditional model and the measured data.The results show that the built model improves the channel characterization accuracy in the tunnel environment.The fitting between the statistical characteristics of the simulation model and the reference model demostrates the correctness of the theoretical derivation and the practicability of the proposed model.The V2 V channel model proposed in this thesis is effective and practical,expands the research and application of V2 V channel model,enriches the channel model library of Internet of vehicles environment,and provides a useful reference for the design and evaluation of communication system in the typical environment of Internet of vehicles.