摘要：随着人们的经济水平和通信技术水平的不断提升，人们对通信的要求质量也随之提升，人们之间的通信渐渐涉及受限的空间，比如室内，隧道，地铁，煤矿等，因此，本文提出了一种预测矩形隧道内电波传播特性的方法。首先，本文先通过对隧道内的通信现状及问题分析了隧道内信号覆盖所需的信号源和天馈系统的选择，再有，介绍跟踪射线追踪模型，射线追踪法能够准确的地预测电波的传播特性，但是其具有较高的计算复杂度，所以提出了一种能准确计算出由发射天线到接收天线主要路径而又避免计算复杂的射线跟踪过程，该方法是在几何光学原理基础上将三维反射路径转变为二维反射路径，精确计算出接收天线之间的路径，最后由基于改进的射线跟踪算法的传播模型得出隧道内带宽信道的特性，根据几个参数，时延扩散和接受功率得出最后结论：隧道的截面积越大，收发天线相距约近，其接收多径信号的平均实验扩散和均方根时延扩散就越大。62024

毕业论文关键词：射线跟踪算法；通信；信号源；天馈系统；时延扩散

Prediction modeling and Simulation of radio wave propagation characteristics in subway tunnel

Abstract：With the continuous improvement of people's economic level and the technological level of communication, people on communication quality requirements are increasing, the communication between people gradually involved in limited space, such as indoor, in tunnels, subway, such as coal. Therefore, this paper presents a method of characteristics of wave propagation prediction of rectangular tunnel. First of all, this article first through the status quo and problems of communication in the tunnel of the signal source and the antenna system in the tunnel coverage required for selection, and the tracking ray tracing model, can accurately predict the wave propagation characteristics of the ray tracing method, but its computational complexity is higher, so we put forward a can be exactly calculated by the transmitting antenna to the receiving antenna main path and avoid the computational complexity of the ray tracing process, this method is based on the principle of geometrical optics in 3D reflection path into 2D reflection path, accurately calculate the path between the receiving antenna, and finally by the characteristics of the propagation model of ray tracing algorithm improved the bandwidth of Channel Tunnel Based on the internal, according to several parameters, the time delay spread and receiving power finally draw the conclusion that the cross-sectional area of tunnel is bigger, sending and receiving Antenna is approximately close, the average experimental diffusion and RMS delay spread of the received multipath signal is greater.

KeyWords:Ray tracing algorithm; communication; signal source; antenna systems; time delay spread

目  录

第1章  绪论 5

1.1  研究隧道中无线电波传播的概述和意义 5

1.2  研究现状与水平 5

1.3  本文的主要工作 6

1.4  论文结构 7

第2章  信号源和天馈系统的选择 7

2.1  信号源 7

2.2  天馈系统 8

2.3  本章小结 9

第3章  预测电波方法的分类 9

3.1  统计方法 10

3.2  混合方法 10

3.3  射线跟踪法