摘要：21世纪是网络信息时代，人们对信息的获取要求很高，但在一些特别的空间，比如地铁上、火车隧道中、煤矿下等，这些环境导致信息无法正常传递。然而，隧道环境在我国不计其数，因为我国的主要交通运输是铁路运输是我国的最主要交通运输，关系国家经济发展的命脉，同时，为缓解人口众多与交通设施之间的矛盾，近几年我国高铁地铁建设事业发展迅速，许多城市兴建了高铁地铁，而其通信系统也要及时跟进，这就需要了解无线电波的传播特性。首先，文章分析了以往研究方法的可行性和不足，比较后确立用射线跟踪法建立预测模型。其次，介绍了射线跟踪模型，利用射线追踪法准确预测无线电波的传播特性。我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从而避免了计算较为复杂的射线追踪过程的方法，这种方法是建立在几何光学的原理上，将三位反射路径转换为二维反射路径，可以精确计算出接收天线之间的路径，最后用改进后的射线追踪算法的传播模型得出隧道内无线信道的特性，运用matlab仿真软件修改参数得到结果图，分析后得出结论：隧道内的横截面积越大，收发天线之间的距离越近，其接收多径信号的平局实验扩散和均方根实验扩散就越大。71014

毕业论文关键词：射线追踪算法 ;无线电波;传播特性;地铁隧道;通信

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

Abstrct: Twenty-first Century is the era of network information, people have high demand for information acquisition, but in a special space, such as the subway, trains, tunnels, coal mines, etc., these circumstances lead to information can not be unblocked

.As the level of people's economic level and communication technology continues to improve, such as subway, train tunnel in coal mine and so on, the traditional statistical measurement data prediction model based on failure cause these environment. However, the tunnel environment in China is too many to count the transportation in our country, mainly because of the railway transportation is the main transportation in our country, the lifeblood of national economy development at the same time, in order to alleviate the contradiction between city development and city traffic facilities, rail traffic planning and construction in China has developed rapidly in recent years, many city built subway. In order to achieve full coverage of the wireless environment of rail transportation, research on tunnel environment The propagation behavior has become particularly important. This paper studies the ray tracing prediction of radio wave propagation characteristics in the tunnel.  the shortcomings of the existing statistical models, including the simulation accuracy is not high and narrow the scope of application, need to go through the cost of manpower and material resources can be used for correction of the similar scenes; the ray tracing principle implementation mechanism based on the deterministic model. Secondly, the ray tracing model, tracking method for accurate prediction of radio wave propagation characteristics using ray ray tracing algorithm. Because the deposit emission line pided in to receive the ball, the diffraction processing is complex, a large amount of computational disadvantages, I propose a can be calculated accurately by the transmitting antenna to the receiving antenna main path so as to avoid the complex calculation method of ray tracing process, this kind of Party Method is based on the principle of geometrical optics, the three reflection path into two-dimensional reflection path, can accurately calculate the path between the receiving antenna, the improved ray tracing propagation model algorithm that characteristics of wireless channel tunnel, using MATLAB software to modify the parameters of the map, then draws a conclusion: the cross-sectional area of the tunnel is larger, the closer the distance between the transmitter and receiver, the draw experiment received  signals and RMS diffusion diffusion experiment more. Ray tracing forecasting methods has a broad application prospect in the field of radio wave propagation characteristics in subway tunnel environment.