LDPC码及应用研究

文档编号:TX411  文档字数:17086,页数:38

LDPC码及应用研究
摘  要

差错控制编码，也称为信道编码已经广泛地应用在各种通信系统和计算机系统中。并且它是移动通信系统中的关键技术之一，LDPC码是纠错码中比较出色的好码。因为LDPC码是最为接近Shannon极限的信道编码，同时也是下一代宽带移动通信系统中纠错编码的主要备选方案。
这次毕业设计主要通过对大量文献的查阅和研究，熟悉LDPC码的定义和原理；两种编码方法基于下三角矩阵的编码方法和基于近似三角矩阵的编码方法、译码算法以及它和另一种纠错码Turbo码的比较，比较它们的性能差异和译码复杂度。LDPC码在多种领域都有广泛的应用，比如DVB-S2（第二代卫星数字视频广播系统）、CMMB（中国移动多媒体广播）、压缩图像传输、图像数字水印等。通过LDPC码在图像数字水印系统中的应用来研究基于LDPC码的水印方案，这个方案主要是用于提高图像数字水印的鲁棒性，通过水印信息编码对它的原理进行比较全面的研究，从而更深入的了解LDPC码的在图像数字水印系统中的应用。
关键词：差错控制编码  LDPC码  Turbo码  图像数字水印

LDPC codes and applied research
ABSTRACT

Error-controlling codes, also called channel coding has been widely applied in various communication system and computer system. And it is the mobile communication system, one of the key technology . LDPC code is comparatively outstanding  good yards. Most closely because LDPC code is the channel coding Shannon limit, but also the next generation broadband mobile communication system error correction coding main alternatives.
The graduation design mainly through a vast amount of literature review and study, familiar with the definition and principles LDPC code; Two kind of coding method based on triangle matrix under the coding method based on approximate triangular matrices and the coding method, decoding algorithm and it and another kind of  Turbo yards of comparison, compare their performance differences and decode complexity. LDPC code in a variety of areas are widely used, For instance (the second generation DVB - S2 satellite digital video broadcast system), CMMB (China mobile multimedia broadcasting), compressed image transmission and digital image watermarking, etc. Through LDPC code in the application of digital image watermarking system based on LDPC code to research the watermarking scheme, This scheme is mainly used to raise the image watermarking robustness, Through the watermark on its principle of coding of more comprehensive study to more in-depth understanding of the digital image LDPC code watermarking system application.
Key words: Error-controlling codes  LDPC codes  Turbo code  image watermarking

目  录

摘要 Ⅰ
ABSTRACT Ⅱ
1  前言 1
1.1研究背景 1
1.2研究内容 1
1.3研究的任务及目标 2
2  差错控制编码理论 3
2.1差错控制编码基本概念 3
2.2信道模型和信道容量 6
2.3信道编码定理 7
3  LDPC码 9
3.1LDPC码的概念 9
3.1.1LDPC码的定义 9
3.1.2LDPC码的Tanner图表示 10
3.1.3非规则LDPC码 10
3.2 LDPC码的几何构造 11
3.3 LDPC码的编码方法 12
3.3.1基于下三角矩阵的编码方法
3.3.2基于近似三角矩阵的编码方法
3.4 LDPC码的译码 14
 4  LDPC码与Turbo码的比较 17
 4.1Turbo码概述 17
 4.2LDPC码与Turbo码的比较 19
5  LDPC码的应用 22
5.1LDPC码应用领域 22
5.2LDPC码在图像数字水印系统中的应用 23
5.2.1图像数字水印技术 23
5.2.2基于LDPC码的水印方案 25
6  结束语 32
参考文献 33
谢辞 34

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