几种常用纠错码的性能分析及应用研究

随着社会的发展，信息的传播起着越来越重要的作用。现代通信朝着宽带化、智能化、综合化、个人化的方面发展，传播手段如无线多媒体等新技术不断更新，但它们都面临着一个不可避免的问题，即如何不断降低误码率，提高通信质量。提高信息传输的可靠性和有效性，始终是通信工作所追求的目标。纠错码是提高信息传输可靠性的一种重要手段现代通信系统中，它被用来提高信道传输的可靠性和功率利用率，因此它可以检测并纠正信号传输过程中引入的错误，抗干扰能力强，所以纠错码的设计是保证数据可靠传输的一个重要组成部分。伴随着信息时代的到来以及微电子技术的飞速发展，今天纠错码已不再单纯是一个理论上探讨的课题了，它已成为一门标准技术而被广泛采用，它也不再是致力于专门研究的专业人员才应掌握的一门科学，而成为从事通信、计算机、电子系统工程的有关工程技术人员都必需掌握的一门技术。它在通信系统中的应用是不容忽视的。这是该毕业设计研究的意义所在。
早在20世纪中期，香农就提出并证明了著名的抗干扰信道编码定理。这一定理奠定了现代通信特别是纠错码的理论基础。近50年来，在信息技术发展和实际需要的不断推动下，人们一直在寻求实现复杂度合理的更优秀的编译码方法，去逼近Shannon理论的理想界限。在这个过程中，已经取得了许多伟大的进展，从早期的分组码、代数码，到RS码,到后来的卷积码，以及今天的Turbo ,LDPC码，所能达到的性能和Shannon限间的距离被不断缩小。这些方法也已经投入到多个领域的商用中，如卫星通信和深空通信，数据存储，数据传输，移动通信，数字音频和视频传输等。纠错码无论在理论还是在实际中都得到飞速发展。
7.3卷积码的仿真.....................................................38
附录................................................................44
几种常用纠错码的性能分析及应用研究
设计总说明
关键词
差错控制；纠错码；编译码原理；移动通信
Several commonly used error-correcting code performance analysis and in-depth study
Introduction
With the development of society, the dissemination of information plays an increasingly important role. Broadband towards modern communications, Intelligent, comprehensive, personal development, communication means, such as new technologies such as wireless multimedia constantly updated, but they are faced with an unavoidable issue of how to continually reduce the error rate and improve the quality of communication. The purpose of communication is to the other side do not know of reliable and timely transmission of information to each other, therefore, requires a communication system transmitted information must be reliable and fast, in a digital communication system in a reliable and rapid are often contradictory, if the fast, it will for sure makes the proportion of each symbol time, waveform narrowing, energy reduction, and thussubject to interference in thepossibility of error after the increase, reducing the reliability of information transmission. If he asks for a reliable, slow transfer rate is made. Therefore, how to solve a more reasonable reliability and speed of this contradiction is the right to design a communications system the key issues.
今天的纠错码已经不再单纯的是一个理论上探讨的课题了，它已成为一门标准技术而被广泛采用。在通信领域中，CRC校验已成为CCT对各类线路传输建议中必不可少的一部分；在移动通信中，纠错码Βιβλιοθήκη Baidu广泛用于模拟体制的信令传输及数字体制的整个传输，以提高传输的可靠性和节省珍贵频谱资源；在卫星通信中纠错码技术已成为用来降低对高功放的要求和减少地球站天线孔径的尺寸的经济可靠的方法，VSAT和VSAT的兴起，都是和纠错码技术的应用有关的；在电话网上的数据传输中，纠错码、差错控制技术已是使高速数据传输成为现实的关键技术。纠错码技术还广泛应用于计算机存储和运算系统中，此外，纠错码技术还应用于超大规模集成电路设计中，以提高集成电路芯片的成品率，降低芯片的成本。
该毕业设计研究的主要内容是介绍数字通信系统、纠错码的基本概念及其分类、以及几种常用纠错码的编译码原理、常用纠错码的应用领域研究及重要意义。几种纠错码包括线性分组码、循环码、BCH码、RS码、卷积码。这里对线性分组码、循环码和卷积码做了比较详细的介绍。通过对几种纠错码的分析后，我们再做进一步的研究，介绍一下纠错码在移动通信中的应用和发展。
7MATLAB简介及卷积码的仿真..........................................37
7.1MATLAB...........................................................37
7.2MATLAB在通信仿真中的应用.............................................37
第一章说明纠错码的主要意义，第二章介绍了数字通信系统及纠错码的基本概念，数字通信系统主要由四个部分构成：信源编码、信道编码、数字调制及同步运算，给出了基本的信道模型，方便理解。对于纠错码和差错控制进行了分类。接下来第三到六章是几种纠错码的研究，对其编译码原理分别进行讲解。第七章深入研究纠错码在移动通信中的应用，包括模拟移动通信系统中数字信令的BCH编码、GSM的FEC编码及窄带CDMA系统(IS-95)中的FEC编码。由于纠错码的内容非常丰富，涉及领域较广，所需数学知识较多、较深。而且篇幅、时间有限，这里不可能详细介绍所有内容，仅讨论纠错码理论中比较基本和重要的，并在实际应用中用得较多的各种码的编译码原理和方法。
Today's error-correcting codes is no longer simply a theoretical issue of explore, it has become a standard technology and are widely used. In the communications field, CRC checksum CCT has become the transmission lines of various essential part of the proposed; in mobile communications, the error-correcting codes are widely used in analog systems and digital signal transmission of the entire transmission system in order to improve the transmission reliability and to save precious spectrum resources; in the error-correcting codes in satellite communications technology has become used to reduce the high power requirements and earth station antenna to reduce the aperture size of the economic and reliable method, VSAT and VSAT rise are error-correcting codes and related technology; in a telephone-line data transmission, the error-correcting codes, error control technology is to enable high-speed data transfer key technologies to become a reality. Error-correcting code technology is widely used in computer storage and computing systems, In addition, the error-correcting code technology used in VLSI design, integrated circuit chips in order to enhance yield and reduce the cost of chips.
As early as the mid-20th century,Shannonput forward and prove the well-known anti-jamming channel coding theorem. This theorem has laid a modern communications, especially the theoretical basis for error-correcting codes. The last 50 years, in the information technology development and the continuous promotion of the practical needs, it has been seeking to achieve a reasonable complexity codec better ways to approach the ideal limits ofShannontheory. In this process, has made a lot of great progress, from early block code, on behalf of Digital, and RS codes, convolutional codes later, as well as the Turbo, LDPC codes can achieve the Shannon limit performance and be the distance between shrinking. Thesemethods have also been put into commercial areas, such as satellite communications and deep space communications, data storage, data transmission, mobile communication, digital audio and video transmission. Error-correcting codes in terms of theory or in practice have been the rapid development.