Based On Ray-tracing Wireless Channel Characteristics And Models In Urban Traffic Scenario

Urban traffic is one of the important scenarios of 5th Generation(5G)/Beyond 5G(B5G)mobile communication,and has the characteristics of dense personnel,intensive business and high dynamics.In this paper,three important urban traffic scenarios,such as subway carriages with huge pedestrian flow,urban roads with dynamic traffic flow and Unmanned Aerial Vehicle(UAV)ground communication scenario,are selected.Based on ray tracing technology,wireless channel characteristics are analyzed at 5G/B5 G typical frequency band,including Line of Sight(LOS)probability,path loss,shadow loss,Root Mean Square(RMS)delay spread,angle spread,channel time-varying and non-stationary characteristics.The channel model is established.The main achievements and innovations of this paper are as follows:(1)This paper studies the wireless channel characteristics in subway carriage at 40 GHz millimeter wave band,especially considering the influence of human body on radio wave propagation.The additional path loss caused by human body occlusion can be 69.01 d B higher.It is found that the channel characteristics are significantly different in different regions of the carriage due to the difference of passenger density.Therefore,this paper divides the carriage into LOS,occlusion LOS(OLOS)and non-LOS(NLOS)regions,studies the channel characteristics of different regions,and establishes the channel model.In addition,this paper studies and analyzes the channel non-stationary characteristics caused by passenger flow during passenger boarding and alighting.(2)This paper studies the Vehicle to Vehicle(V2V)wireless channel characteristics of typical urban road scenarios(Urban straight roads and intersections)at 5.9 GHz band,and establishes the channel model.It is found that the LOS probability almost decreases linearly with the increase of the distance from Transmitter(Tx)to Receiver(Rx),and the shadow loss caused by vehicle occlusion will exceed 20 d B even in a short Tx-Rx distance.In this paper,multimodal Gaussian distribution is used to describe the shadow fading under NLOS.Based on the research results of RMS angle spread,the deployment suggestions of antenna array are put forward.(3)This paper studies the wireless channel characteristics between UAV and vehicle when UAV is in different flight modes(hovering and level flight)in typical urban road scenarios at 2.4 GHz frequency band.More attention has been paid to the time-varying and stable characteristics,and the channel model has been established.It is found that due to the high position of UAV,the influence of surrounding objects on path loss is small.The rapid movement of UAV and vehicle not only leads to the rapid change of Channel Impulse Response,but also the channel is non-stationary,and there is significant birth and death of multipath.In this paper,Markov chain is proposed to describe the birth and death process of channel.The research results of this paper not only have high theoretical value,but also can provide support for 5B/B5 G wireless key technology research,communication equipment research and development and testing,network deployment and optimization,etc.,and have great application value.