摘要随着经济和科学技术的快速发展，现代通信技术已经取得了长足的发展。信 道编码技术被广泛应用于通信，无线传输等领域。但是，随着通信性能要求的不 断提升，我们对现代通信系统的研究发展不能停止，尤其是信道编码技术。信道 编码技术的研究的目的就是降低误码率，进而提高通信质量。83942

本文首先介绍了 Turbo 码的发展历史，详细的研究了编码和译码技术，并通 过 MATLAB 实现了 Turbo 码的编码和译码的仿真。对于 Turbo 码的译码，本文 实现了 LOG-MAP 算法和 MAX-LOG-MAP 算法，并基于码率、迭代次数、交织 长度等重要参数，对译码算法进行了仿真研究。根据误码率的仿真结果，得出结 论：LOG-MAP 算法的性能比 MAX-LOG-MAP 算法优异；随着码率的增加，误 码率也随之下降；随着迭代次数的增加，Turbo 码的误码率不断降低；随着信噪 比的增加，迭代次数越大，译码性能越好；随着交织长度的增大，可靠性越高。

毕业论文关键词：Turbo 码；MATLAB 仿真；编码；译码

Abstract With the rapid development of economy and science and technology, modern communication technology has made great strides。 Channel coding techniques are widely used in the field of communications, wireless transmission and so on。 However, as the communication performance requirements continue to enhance, our research on the development of modern communication systems can be not stopped, especially in channel coding techniques。 The purpose of channel coding technology research is to reduce the error rate, thereby improving communication quality。

This paper introduces the development history of Turbo code, conducts  a detailed study of the encoding and decoding technology, and through MATLAB, this paper realizes the simulation of Turbo codes encoding and decoding。 For Turbo codes decoding, this paper achieves LOG-MAP algorithm and the MAX-LOG-MAP algorithm, and conducts the simulation of decoding, which is based on  some important parameters, such as rate, iterations, interleaving length。 According to the simulation result of the BER concluded: Performance of LOG-MAP algorithm is superior to MAX-LOG-MAP algorithm; with the increase of rate, the error rate can be decreased; with the increase of the number of iterations, the code error rate decreases; the lower SNR and the larger iterations are, the better decoding performance will get; the longer interleaving length is, the higher the reliability will get。

Keywords: Turbo code; MATLAB simulation; coding; decoding。

目录

第一章 绪论 1

1。1  课题研究的背景 1

1。2  信道编码技术的发展状况 1

1。3 信道编码的应用 2

1。4  论文章节安排结构 3

第二章 信道编码 5

2。1 信道编码的概念及分类 5

2。2 分组码和卷积码 6

2。2。1  分组码 6

2。2。2  卷积码 7

2。3  本章小节 8

第三章 Turbo 码的编码原理 9

3。1 Turbo 码的编码器组成 9

3。2 Turbo 码的删余矩阵 11

3。3 Turbo 码的交织器 13

3。4  本章小节