多中心应急通信系统关键技术研究

发布时间：2018-06-28 16:37

本文选题：铁路 + 应急通信　；参考：《天津大学》2014年硕士论文

【摘要】：铁路应急通信系统走过了30多年的发展道路，为铁路抢险指挥提供了有效保障。高速铁路和客运专线建设的不断提速，铁路改革的不断深入，对铁路应急通信提出了新的要求。现有单一应急指挥中心与应急现场的应用模式已不能满足铁路应急事件抢险的需求，急需升级为多中心应急指挥系统。作者承担的铁路总公司、若干铁路局调度指挥中心通信工程设计中，都有升级改造现有应急通信系统的需求。通过对铁路应急通信系统新需求和升级方案的研究得知，，实现多中心通信功能的技术难题是声音信号的混音，实现混音有两个关键技术——重采样算法和混音算法。文中首先对音频信号处理、传输、交换过程中的几个关键概念和技术进行了简单的介绍，如声波、混音、VoIP、软交换、SIP协议、RTP协议等。其次，通过对音频信号数字化过程的分析和计算机中音频信号WAVE格式的分析，提出了音频重采样的线性算法、多项式算法，分析了两种算法的优缺点，确定了参数选择，通过计算机编程实现了多项式重采样算法并对结果进行了验证。再次，对常用的微软DirectSound环境进行了详细的分析，找出了其在铁路应急通信系统中难以使用的原因。根据DirectSound的设计思路研究了新的混音算法，对线性混音、限幅混音、平均混音和权重混音算法进行了效果分析、模拟试验，确定了权重混音作为推荐算法，通过编程实现权重混音算法并在实验环境下进行了验证。最后，介绍了多中心应急通信系统的设计过程，对混音处理模式进行了方案比选，确定了系统总体架构，具体研究了多中心铁路应急系统实现的内容并进行了模拟测试，达到了研究的预期目的，为实现多中心多用户通话组的混音功能提供了理论和技术支持。
[Abstract]:Railway emergency communication system has been developed for more than 30 years, which provides an effective guarantee for railway emergency command. With the rapid construction of high-speed railway and passenger dedicated line and the deepening of railway reform, new requirements are put forward for railway emergency communication. The existing application mode of single emergency command center and emergency scene can no longer meet the needs of railway emergency response and need to be upgraded to multi-center emergency command system. In the communication engineering design of the dispatching and command center of several railway bureaus, the author has the need to upgrade and transform the existing emergency communication system. Through the research on the new requirement and upgrade scheme of railway emergency communication system, it is known that the technical problem to realize the multi-center communication function is the mixing of sound signal, and there are two key technologies to realize the mixing: resampling algorithm and mixing algorithm. In this paper, several key concepts and techniques in audio signal processing, transmission and switching are introduced, such as acoustic wave, VoIP, SIP protocol and RTP protocol. Secondly, through the analysis of the digitization process of audio signal and the analysis of wave format of audio signal in computer, the linear algorithm and polynomial algorithm of audio resampling are put forward, and the advantages and disadvantages of the two algorithms are analyzed, and the selection of parameters is determined. The polynomial resampling algorithm is realized by computer programming and the result is verified. Thirdly, the Microsoft DirectSound environment is analyzed in detail, and the reason why it is difficult to use in railway emergency communication system is found out. According to the design idea of DirectSound, a new mixing algorithm is studied, and the effects of linear mixing, amplitude limiting mixing, average mixing and weight mixing are analyzed, and the simulation results show that the weighted mixing is the recommended algorithm. The weight mixing algorithm is realized by programming and verified in the experimental environment. Finally, the design process of the multi-center emergency communication system is introduced, the scheme of mixing processing mode is compared and selected, the overall structure of the system is determined, and the contents of the multi-center railway emergency system are studied and simulated. It provides theoretical and technical support for the realization of the mixing function of multi-center multi-user call groups.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN914

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