【作者】 陈亮；

【导师】 张文军；

【作者基本信息】 上海交通大学 ， 通信与信息系统， 2007， 硕士

【摘要】 近年来,通信技术的发展日新月异,其中信道编码作为通信系统中不可替代的基本技术,也在理论研究和实际应用种取得了长足的进步。低密度奇偶校验码(LDPC码)的研究和实现,是继Turbo码之后在纠错编码领域的又一重大进展。LDPC码的优异性能及其在信息可靠传输和磁存储技术中的良好应用前景,已引起国际上学术界和IT业界的高度重视,成为当今信道编码领域最瞩目的研究热点。本文主要研究可变码率的LDPC码,提出了一种构造码率兼容LDPC码的全新策略,并基于此给出了多种新的构造算法及硬件实现方案。还在此基础之上提出了一种新的II型混合自动重传请求方案。本文首先简要地介绍了信道编码技术的研究背景以及发展现状,回顾了低密度奇偶校验码的发展历程;对LDPC码的经典译码与编码算法进行了总结分析,提出了指导构造的重要结论。在此基础上,对随机性构造和确定性构造两类构造方法的代表性构造方法进行分析。本文介绍了有限几何空间的理论基础和基于有限几何QC-LDPC码的构造方法,因为这类构造方法可以简单地实现在线性时间内进行编码,故而对实际复杂度受限系统有重要意义。然后还分析了基于有限几何LDPC码的缩短和扩展,这两种方法都可以用来生成不同码率的新码。本文创新地提出了一种构造码率兼容低密度奇偶校验码的新策略,并基于此给出了多种新的构造算法。新算法可以用同一个译码器来对一系列不同码率的LDPC码进行译码。本文还提出了一种可对RC-LDPC码在线性时间内进行编码的新方法。本文还创新性地利用提出的新策略地将QC-LDPC码和RC-LDPC码两种重要的实用信道编码技术结合在了一起,并着重分析研究了实现准循环RC-LDPC码的硬件结构。作为RC-LDPC码在实际系统中的应用,本文还提出了一种新的II型混合自动重传请求方案。更多还原

【Abstract】 Recently, regarded as one of the key symbols of rapid development on communication technology, channel coding has gained its splendid progress in both theoretical and practical fields. Low density parity check (LDPC) codes, which are recognized as the most significant breakthrough after Turbo codes, draws increasing attention from all over the world. Thanks to its excellent performance, LDPC codes have been widely considered as next-generation error-correcting codes for telecommunication and magnetic storage. The work in this thesis mainly focuses on the rate-compatible LDPC codes. A novel strategy to construct RC-LDPC codes is proposed. Based on it, several construction algorithms and hardware schemes are presented. A novel type II hybrid ARQ scheme by using RC-LDPC codes is also proposed.In this thesis, the background of channel coding and the development of LDPC codes are first introduced. Then after summarizing and analyzing the classic algorithms of decoding and encoding, some important conclusions are found to direct the construction of LDPC codes. Based on them, the representatives of both random construction by computer search and mathematical construction are analyzed.The theory of finite geometries and construction approaches of QC-LDPC codes based on them are introduced in this thesis. Because QC-LDPC codes can be encoded in the linear time, they are important and helpful to the complexity-limited systems. Extended and shortened QC-LDPC codes are investigated to produce the new codes at different rate codes.It is innovative to present a brand-new strategy and several novel algorithms based on it to construct RC-LDPC codes. Using the new algorithms, a sequence of RC-LDPC codes across a range of rates can be decoded by a single decoder. A novel scheme to encode the constructed RC-LDPC codes in the linear time is also proposed.QC-LDPC codes and RC-LDPC codes, two practical channel coding techniques can be combined by using presented new strategy creatively. The encoding schemes to implement quasi-cyclic RC-LDPC codes are investigated in detail.As a useful application in the practical commutation systems, a novel scheme for type-II hybrid ARQ protocols using RC-LDPC codes are proposed as well in this thesis.更多还原