高速铁路中无线信道模型研究与系统性能分析

发布时间：2018-06-04 14:51

本文选题：高速铁路 + 理论模型　；参考：《北京交通大学》2016年硕士论文

【摘要】：在高速铁路通信中,由于列车的高速运行,通信环境会变得非常差。尽管我国大多数区域已经被3G网络覆盖,但仍有一些环境问题会导致信号的剧烈衰落,严重的时间和频率选择性衰落会从物理层影响信号的传输进程。无线传播信道作为通信中首要的随机因素,能直接影响系统的通信质量和性能。为了找出应对系统低性能和突发因素更好的对策,需要归纳和分析高速铁路中现有的问题,尤其是信道模型的问题。然而现有高速铁路的信道模型多为基于数据测量和建模而成的经验模型,理论上的研究十分有限。高速铁路经历场景丰富多样,描述单一场景的信道模型并不能适用。在理论上对高速铁路的无线信道的多径散射场景进行分析,选择适用于高速铁路通信系统最佳的理论模型,分析特定场景下通信系统的性能,这对高速铁路无线网的通信质量的评估和资源合理规划有战略性意义。针对高速铁路的信道模型问题,本文从理论上讨论和研究了适用于高铁通信环境的信道模型以及不同模型下通信系统的性能。本文的主要工作如下：(1)分析高速铁路信号传播的特性,引入了两种新的广义信道模型,从理论上重点介绍了两种广义信道模型对于高速铁路场景的适用性,并分析了高铁通信系统存在的其他问题。(2)应用两种广义信道模型,针对高速铁路中两种有代表性的干扰受限场景,推导出了相应系统性能指标的精确表达式,包括中断概率、误码率和信道容量。此外,在第三章中,为了进一步分析系统性能的受限因素,本文推导出了性能指标在高信噪比下的渐近表达式；在第四章中,为了进一步展示性能差异,本文推导出了选择合并式分集下系统的中断概率表达式,并通过MATLAB仿真误码率性能。值得注意的是,这些表达式都是迄今为止相关研究领域中最新的研究结果。(3)对于基于实测模型的高速铁路通信系统,本文第五章中同时考虑路径损耗和小尺度衰落,推导出了中断概率和受多普勒频移影响下的误码率表达式。经仿真平台验证,本文所推导的表达式误差均低于10-6,为形象展示计算结果的变化特性,本文还给出了表达式计算和仿真的数据曲线图像,并附较为全面的分析和说明。上述研究结果精确可靠,本研究为当代高铁通信系统的信道建模和性能评估的进一步研究做深厚的理论铺垫。
[Abstract]:In high-speed railway communication, the communication environment will become very bad because of the high-speed running of trains. Although most areas of our country have been covered by 3G network, there are still some environmental problems which will cause the signal to decline sharply, and the serious time and frequency selective fading will affect the signal transmission process from the physical layer. As the primary random factor in communication, wireless propagation channel can directly affect the communication quality and performance of the system. In order to find out better countermeasures to deal with the low performance and burst factors of the system, it is necessary to sum up and analyze the existing problems in high-speed railway, especially the problem of channel model. However, the existing channel models of high-speed railway are mostly empirical models based on data measurement and modeling, so the theoretical research is very limited. High-speed railway experience a variety of scenarios, the description of a single scenario channel model can not be applied. In theory, the multi-path scattering scene of wireless channel in high-speed railway is analyzed, and the optimal theoretical model for high-speed railway communication system is selected to analyze the performance of the communication system in a specific scenario. This is of strategic significance to the evaluation of communication quality and rational planning of resources of high-speed railway wireless network. Aiming at the channel model of high-speed railway, this paper theoretically discusses and studies the channel model suitable for high-speed railway communication environment and the performance of communication system under different models. The main work of this paper is as follows: (1) analyzing the characteristics of high-speed railway signal propagation, two new generalized channel models are introduced, and the applicability of the two generalized channel models to the high-speed railway scene is emphatically introduced theoretically. Two generalized channel models are applied to analyze the other problems existing in high-speed railway communication system. For two representative interference limited scenarios in high-speed railway, the exact expression of the corresponding system performance index, including interruption probability, is derived. Error rate and channel capacity. In addition, in chapter 3, in order to further analyze the limited factors of system performance, the asymptotic expression of performance index under high signal-to-noise ratio (SNR) is derived, and in chapter 4, in order to further show the performance difference, In this paper, the outage probability expression of the system based on selective combining diversity is derived, and the bit error rate (BER) performance is simulated by MATLAB. It is worth noting that these expressions are the latest research results in relevant research fields up to now. For high-speed railway communication systems based on the measured model, the fifth chapter of this paper considers both path loss and small scale fading. The expressions of interrupt probability and bit error rate (BER) affected by Doppler shift are derived. It is verified by the simulation platform that the errors of the expressions derived in this paper are all less than 10-6. In order to show the variation characteristics of the calculated results, this paper also gives the data curve images of the expression calculation and simulation, and gives a more comprehensive analysis and explanation. These results are accurate and reliable, and this study provides a theoretical basis for further research on channel modeling and performance evaluation of modern high-speed rail communication systems.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U285;TN929.5

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