高架桥场景下的射线跟踪仿真器校正及信道特性分析

Calibration of ray tracer and channel analysis for high-speed railway viaduct scenario

基于93.2GHz频段下高速铁路典型高架桥场景中的通信信道测量数据,利用射线跟踪仿真器对无线信道传播特性进行仿真,并通过与实测数据的对比进行场景结构尺寸、收发机位置、材料介电常数等仿真器基本输入参数的校正,实现路径损耗数据的平均误差为0.2dB,提升了仿真器的有效性和可靠性.利用校正后的仿真器输出结果对高架桥场景下的信道传播特性做了进一步的分析,分别对莱斯K因子、均方根时延扩展、功率时延谱以及角度扩展进行了计算.结果表明,高架桥场景的特殊结构导致随着收发机距离的增大,各多径成分与直射径成分的路程差减小,从而使多径在较小的时延范围内分布,同时由于半功率波束宽度为10°的喇叭天线的使用导致多径分量减少且集中,因此在高架桥场景下各参数数值均相对较小.除此之外,本文还利用相关性对整个场景进行了准平稳区间的划分,并计算了一个准平稳区间内各大尺度参数间的互相关性.

In this paper,ray tracer（RT）is applied to conduct simulation of the propagation in highspeed railway viaduct scenario at 93.2 GHz.Some basic input parameters such as geometrical dimensions of environment,positions of transmitter and receiver,permittivity of materials are calibrated based on the measurement results.The average error of path loss between simulation and measurement is calibrated to 0.2 dB,obtaining a reasonable improvement of the accuracy of RT.The calibrated results are employed to study propagation characteristics in viaduct scenario.Rician K-factor,root-mean-square（RMS）delay spread,power delay profile and angular spread are calculated.The typical structure of viaduct and the application of horn antennas lead to a small value of each calculated parameters at each snapshot.In addition,correlation between parameters are also analyzed in this paper.