PDT数字对讲机测试技术的研究与实现

发布时间：2018-07-21 11:28

【摘要】：PDT协议标准是我国具有自主知识产权的集群通信系统,主要应用于公安无线通信的安全加密和全国联网的数字化建设中,向下兼容欧洲电信化标准的DMR标准,基于PDT协议的对讲机产品已经有国内厂商生产研发,但是对于PDT数字信号的测试仪还没有国内厂商研制,因此本项目主要研究PDT数字对讲机的信号测试,包括调制误差、符号偏移、幅度误差与误码率的测试。为了更好的实现PDT数字对讲机的各个模块的测试,需产生PDT数字基带测试信号,本文主要完成PDT信号的形成和信号的分析。本文主要基于整个项目架构中的数据链路层部分,对测试序列的形成、发送以及接收分析的整个流程基于软件实现,涉及信道编解码、调制解调及误码率测试分析。首先通过对通信标准和对讲机测试技术的研究,引出课题研究的工程实践价值与意义,然后对PDT通信协议三层架构进行了分析介绍,涵盖了PDT信号测试中所涉及的通信帧结构与信令结构、同步与时序、呼叫协议中的呼叫流程和4FSK调制的原理。论文研究的主体是数据传输中的信道编码算法与信道解码算法,通过对信号进行校验编码保护,保证通信传输的可靠性,为测试PDT测试指标误码率提供理论基础。编解码算法的是软件具体实现的核心算法部分,主要完成了三项关键工作,一是对于PDT协议中使用最为广泛的BPTC编码作了译码顺序的研究,针对可能出现的不能正确译码情况进行译码顺序说明;二是对于EMB校验中所用的二次剩余码的错误图样多项式进行求解分析与公式说明,并改进捕获译码算法来满足译码需求;三是对数据帧中的数据类型部分进行校验的Golay码,比较分析八种不同的译码方法,选择基于伴随式权重的译码算法,完成译码需求。通过分析各种译码的性能、算法复杂度和资源消耗,选择适合项目开发的译码算法,并给出具体的译码步骤、软件实现过程和仿真。最后,设计实现了直通模式下PDT数据链路层软件结构,完成了信道编解码软件,并进行了误码率仿真,以及BPTC码、二次剩余码和Golay码的编解码测试仿真,分析信道编码的纠错性能及在通信中的作用。因此本文的研究成果可以为后续硬件实现和点对点的实际通信性能测试提供理论支持。
[Abstract]:PDT protocol standard is a trunking communication system with independent intellectual property rights in our country. It is mainly used in the security encryption of public security wireless communication and the digital construction of the national network, and it is compatible with the DMR standard of European telecommunication standard downwards. The interphone products based on PDT protocol have already been produced and developed by domestic manufacturers. However, no domestic manufacturer has developed the testing instrument for PDT digital signal, so this project mainly studies the signal testing of PDT digital interphone, including modulation error. Symbol offset, amplitude error and bit error rate testing. In order to better realize the test of each module of PDT digital interphone, it is necessary to produce the PDT digital baseband test signal. This paper mainly completes the formation of PDT signal and the analysis of PDT signal. This paper is mainly based on the data link layer part of the whole project architecture. The whole process of test sequence formation, transmission and reception analysis is based on software implementation, including channel coding and decoding, modulation and demodulation, and bit error rate test and analysis. Firstly, through the research of communication standard and interphone testing technology, the engineering practice value and significance of the research are introduced, and then the three-layer structure of PDT communication protocol is analyzed and introduced. It covers the structure of communication frame and signaling, synchronization and timing, call flow in call protocol and the principle of 4FSK modulation in PDT signal testing. The main body of this paper is the channel coding algorithm and channel decoding algorithm in data transmission. By verifying and coding the signal to ensure the reliability of communication transmission, it provides a theoretical basis for testing the error rate of PDT test index. The coding and decoding algorithm is the core part of the software implementation, which mainly completes three key tasks. First, the decoding sequence of the most widely used BPTC code in PDT protocol is studied. The order of decoding is explained in view of the possible incorrect decoding, the second is to solve and analyze the error pattern polynomial of the quadratic residual code used in EMB check, and to improve the acquisition and decoding algorithm to meet the decoding requirements. The third is Golay code which is used to verify the data type part of the data frame. Eight different decoding methods are compared and analyzed. The decoding algorithm based on the adjoint weight is selected to complete the decoding requirements. By analyzing the performance, complexity and resource consumption of various decoding algorithms, the decoding algorithm suitable for project development is selected, and the detailed decoding steps, software implementation process and simulation are given. Finally, the PDT data link layer software structure is designed and implemented, the channel coding and decoding software is completed, and the error rate simulation, as well as the coding and decoding test simulation of BPTC code, secondary residue code and Golay code, are carried out. The error correction performance of channel coding and its role in communication are analyzed. Therefore, the research results in this paper can provide theoretical support for subsequent hardware implementation and point-to-point communication performance testing.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.54

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