Vehicular Channel Characterization Based On High-performance Ray Tracing

Communication between vehicles requires both ultra-reliable and low latency,and at the same time has high requirements for communication data rates.Millimeter wave(mm Wave)has advantages in bandwidth and strongly supports high data rate communication.Therefore,mm Wave related technologies are widely concerned in the field of vehicular networking research.Dynamic environment and high mobility are the main characteristics of vehicular communication,and the height of antennas located on communication entities such as vehicles and roadside units is relatively low.These characteristics add challenges to the research and channel modeling of vehicular communication.The deterministic channel modeling method represented by ray tracing,which calculates the propagation channels in specific locations and environments,can accurately reflect the impact of the scenario on the channel.Ray tracing is a key technology for vehicular channel modeling.Based on the high-performance ray tracing simulator developed by the State Key Laboratory of Rail Traffic Control and Safety in Beijing Jiaotong University(BJTU),the 22.1-23.1 GHz wideband vehicular channel is characterized.Typical vehicular scenario: urban scenario and highway scenario are reconstructed.The simulation parameters are configured by 3GPP TR 37.885 and the typical channel parameters are extracted.The variation rules of the extracted parameters under different road conditions are analyzed.The main contents and innovations are as follows:(1)The exact sizes of the buildings in the actual vehicular scenarios are obtained from Open Street Map,and the actual scenario models are reconstructed in Sketch Up.By referring to satellite maps,the number and specific locations of small scatterers such as traffic lights,traffic signs,and bus stations are determined,and the tree model is built on the roadside to make the outdoor scenario model more practical.(2)Considering the difference between vehicular communications and traditional cellular in terms of transceiver location,environment,fixed and mobile scatterers,the simulation process for vehicular channels is designed.30 kinds of simulation cases are divided according to different scenarios,number of lanes,antenna height,and traffic flow.12 propagation zones are divided according to whether the antenna main lobe is aligned,whether there is a direct path and the different surface of the reflecting/scattering object.The vehicular channel under various variable settings is explored.(3)Based on the ray tracing simulation results,the channel parameters such as path loss,angular spread,and Rician K-factor are extracted,the variation of the parameters under different road conditions are analyzed.Five external factors are summarized according to the propagation characteristics of the vehicular channel: urban/highway scenario,transmitting antenna height,traffic flow,within/without the main lobe of the transmitting antenna,line of sight/non-line of sight.The changes of different channel parameters are quantitatively analyzed and compared under each factor,and the impact of these factors on the vehicular channel is summarized to provide reference and guidance suggestions for mm Wave design and the deployment of vehicular systems.