LT码及其在不等差错保护方案中的研究

发布时间：2018-05-13 06:41

本文选题：数字喷泉码 + LT码　；参考：《郑州大学》2017年硕士论文

【摘要】：随着通信技术和互联网络的不断发展,急剧增长的数据规模和日趋多样的业务需求对通信系统的服务能力提出了越来越高的要求。数字喷泉码是近些年来提出的一类新型前向纠错编码方式,具有编译码原理简单、码速不受限制以及不需要反馈信息等特征,已经得到学术界的普遍重视。本文以LT码为研究对象,主要针对其编码过程中的度分布函数及其运用到不等差错保护中的方案展开研究。论文对喷泉码的基本原理进行概述,主要涉及其应用的二进制删除信道模型、编码过程以及两种译码算法—BP算法和GE算法,仿真对比了LT码在不同码字长度条件和采用不同译码方法时的译码性能。度分布函数在LT编码过程中起着关键性的作用,论文主要研究了几类常用度分布函数,其中侧重分析了一种改进型的鲁棒孤子分布。在开关度分布的构造思想下,提出一种结合二进制指数分布和改进的鲁棒孤子分布优势的新型开关度分布。仿真结果显示在开关点?=0.1时,该分布完全译码时所需的编码数据包数目最少,有效提升了LT码的译码性能,并且具有编译码复杂度和仿真时间上的优势。为了解决现有扩展窗喷泉编码方案中编译码复杂程度较高的问题,同时在确保低重要性数据的抗误码性能要求下,结合与或树分析,论文提出一种基于扩展窗喷泉码的优化方案,仿真结果表明该方案对高重要性(MIB)和低重要性(LIB)信息数据的译码恢复性能均有一定程度的提高。通过联合权重UEP-LT码和扩展窗喷泉码的优点,并利用反馈信息对LT码的编译码进程以及对未译出码字符号释放概率的显著影响,论文设计出一种带反馈的W-EWF编码方案,仿真结果显示该方案既能加强MIB信息的优先传输力度,又能保证LIB信息的译出恢复性能。
[Abstract]:With the continuous development of communication technology and Internet, the rapidly increasing data scale and increasingly diverse business requirements put forward more and more high requirements for the service capability of communication systems. Digital fountain code is a new type of forward error correction coding method proposed in recent years. It has the characteristics of simple encoding and decoding principle, unlimited code speed and no need for feedback information. In this paper, the LT code is taken as the research object, and the degree distribution function in the coding process and the scheme applied to unequal error protection are studied. In this paper, the basic principle of fountain code is summarized, including binary delete channel model, coding process and two decoding algorithms-BP algorithm and GE algorithm. The decoding performance of LT codes under different codeword length conditions and different decoding methods is simulated and compared. Degree distribution function plays a key role in the LT coding process. In this paper, several kinds of commonly used degree distribution functions are studied, in which an improved robust soliton distribution is analyzed. Based on the idea of constructing switch degree distribution, a new type of switch degree distribution combining binary exponential distribution and improved robust soliton distribution is proposed. The simulation results show that when the switching point is equal to 0.1, the minimum number of coded packets is required for the distributed complete decoding, which effectively improves the decoding performance of LT codes, and has the advantages of encoding and decoding complexity and simulation time. In order to solve the problem of high complexity of encoding and decoding in the existing extended window fountain coding scheme, and to ensure the error-resistant performance of low-importance data, combining with or tree analysis, An optimization scheme based on extended window fountain code is proposed in this paper. The simulation results show that the scheme can improve the decoding performance of MIB) and LIB-information data to some extent. By combining the advantages of weighted UEP-LT code and extended window fountain code, and utilizing the feedback information on the encoding and decoding process of LT code and the significant influence on the untranslated word symbol release probability, a W-EWF coding scheme with feedback is designed in this paper. The simulation results show that the proposed scheme can not only enhance the priority transmission of MIB information, but also guarantee the translation and recovery performance of LIB information.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911.2

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