基于射线跟踪仿真的弯曲隧道中电波传播特性研究

发布时间：2018-03-20 05:25

本文选题：弯曲隧道　切入点：额外损耗　出处：《北京交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：社会经济发展越来越快,人们的精神与物质需求越来越高,通信中进一步提高与优化用户体验是必然趋势,也是人们不断努力的目标。城市迅速扩张意味着涌入了更多的人口,交通压力是城市生活中永恒的话题,地铁、高铁等受限空间的利用为人们打造了方便快捷的生活方式。在通信领域中,受限空间不同于开放空间,电波传播特性有所改变。几十年来,已经有一些学者对直隧道进行研究,并提出了很重要的理论和模型。可是关于弯曲隧道的研究还比较少,电波在弯曲隧道中传播产生的路径损耗比电波在直隧道中传播产生的路径损耗更大,本文的创新点在于通过对这种电波在弯曲隧道中产生的额外损耗进行仿真、提取、分析和建模来研究电波在弯曲隧道中的传播特性。本文主要工作如下： (1)通过仿真的方式得到所需的直隧道和弯曲隧道内接收信号功率,分别对不同横截面形状的隧道进行仿真,如矩形横截面隧道、拱形横截面隧道(本文称为“Type1型隧道”)和马蹄形横截面隧道(本文称为“Type2型隧道”),也对不同信号的发射频率、弯曲隧道的不同曲率半径以及隧道内接收机的不同位置进行仿真,为后续电波传播特性的研究提供数据。 (2)根据仿真得到的数据计算路径损耗因子,探究隧道内不同因素对电波传播损耗的影响。发现弯曲隧道的曲率半径越小(隧道弯曲程度越大),损耗因子越大,表明隧道弯曲减少了波导效应。发现发射信号的频率越高,损耗因子越大,损耗越大。此外,论文还探讨了隧道横截面以及隧道内不同位置的接收机对损耗因子的影响。 (3)对弯曲隧道场景仿真得到的数据进行额外损耗的计算,探究隧道内不同因素对额外损耗的影响。额外损耗是一个相对概念,指电波在弯曲隧道内传播产生的损耗与相同环境下在直隧道中产生的损耗之差。根据观察到的额外损耗的特性,提出在距离上对额外损耗进行阶段分析,共分成三个阶段,为弯曲隧道的额外损耗建立更精确的模型。发现三个阶段中,弯曲隧道曲率半径越小(弯曲程度越大),额外损耗越大；在前两个阶段中,发射信号的频率越高,额外损耗越大,但在第三个阶段中没有显示出这样的特性；此外,本文还发现接收机在弯曲隧道内壁侧时,隧道内的额外损耗比接收机在弯曲隧道外壁侧时的额外损耗大。综上所述,本文从理论上提供了可应用到不同类型的弯曲隧道内电波传播的模型,从工程应用上为弯曲隧道内的网络规划提供指导。
[Abstract]:With the rapid development of social economy and the higher demand of people's spirit and material, it is an inevitable trend to further improve and optimize the user experience in communication, and it is also the goal of people's constant efforts. The rapid expansion of cities means an influx of more people, traffic pressure is an eternal topic in urban life, and the use of restricted space such as subway and high-speed rail has created a convenient and fast way of life for people. In the field of communications, Confined space is different from open space, and the characteristics of electric wave propagation have changed. Over the past decades, some scholars have studied straight tunnels and put forward very important theories and models. The path loss caused by the propagation of the electric wave in the curved tunnel is greater than that caused by the propagation of the electric wave in the direct tunnel. The innovation of this paper lies in the simulation and extraction of the extra loss caused by the electric wave in the curved tunnel. The propagation characteristics of electric waves in curved tunnels are analyzed and modeled. The main work of this paper is as follows:. The received signal power in the straight tunnel and the curved tunnel is obtained by simulation, and the different cross-section tunnel is simulated, such as the rectangular cross-section tunnel. The arch cross-section tunnel (referred to in this paper as the "Type1 tunnel") and the horseshoe section tunnel (in this paper called the "Type2 tunnel") are also simulated for different signal emission frequencies, different curvature radii of the curved tunnel and different positions of the receiver in the tunnel. To provide data for the subsequent study of the propagation characteristics of radio waves. The influence of different factors in the tunnel on the propagation loss of the electric wave is investigated according to the data obtained from the simulation. The smaller the curvature radius of the curved tunnel is, the greater the loss factor is, the larger the bending degree of the tunnel is, the greater the loss factor is. It is found that the higher the frequency of the transmitted signal, the greater the loss factor and the greater the loss. In addition, the influence of the cross section of the tunnel and the receiver at different positions in the tunnel on the loss factor is also discussed. 3) to calculate the additional loss of the data obtained from the simulation of the curved tunnel scene, and to explore the influence of different factors in the tunnel on the extra loss. The extra loss is a relative concept. The difference between the loss caused by the propagation of electric waves in a curved tunnel and that in a straight tunnel in the same environment. According to the characteristics of the observed extra loss, a phase analysis of the extra loss in distance is proposed, which is divided into three stages. A more accurate model for the extra loss of a curved tunnel is established. It is found that the smaller the curvature radius of the curved tunnel is in three stages (the greater the curvature, the greater the extra loss; the higher the frequency of the transmitted signal, the greater the extra loss in the first two phases. In the third stage, however, this characteristic is not shown. In addition, we find that the extra loss of the receiver on the inner side of the curved tunnel is greater than that of the receiver on the outer side of the curved tunnel. To sum up, this paper provides a theoretical model for the propagation of radio waves in different types of curved tunnels, and provides guidance for the network planning in curved tunnels in engineering applications.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN011

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