摘要:本文介绍了数字通信系统中一种卷积码文特比译码的软件实现算法，在Matlab环境中实现了卷积码Viterbi 译码功能。首先介绍了数字通信系统，卷积码的发展和本课题的意义。随后介绍了信道编码原理、卷积码的编译码原理以及信道，选择了三个不同的卷积码，确定了生成多项式，并给出了卷积编码器。详细阐述了卷积码的Viterbi译码算法,并详细分析影响其性能的关键参数。最后重点研究文特比译码算法在不同信道中的性能特性，以及在不同的码率和判决方式下，用Matlab对其进行仿真研究。仿真结果表明,信道、判决方式和码率对文特比译码算法都有影响。同时,经过多组数据比较发现,在误码率相同的条件下，软判决Viterbi算法与硬判决Viterbi算法相比有2dB左右的编码增益。22124
毕业论文关键词: MATLAB；信道编码；卷积码；文特比译码；二进制对称信道；加性高斯白噪声信道
Viterbi decoding algorithm performance simulation based on different channels
Abstract:This paper introduces a digital communication system convolutional codes Viterbi decoding algorithm software implementation to achieve the convolutional code Viterbi decoding functions in Matlab environment. First introduced the significance of digital communication systems, the development of convolution codes and the subject. Then introduced channel coding theory, the principle of encoding and decoding and channel convolutional codes, select three different convolutional code generating polynomial is determined, and a convolutional encoder. Elaborated convolutional codes Viterbi decoding algorithm, and the key parameters that affect the performance of a detailed analysis. Finally, focus on the Viterbi algorithm in the performance characteristics of different channels, and at different bit rates and judgments way, with the matlab simulation study. Simulation results show that the channel, the decision on the mode and rate of impact than the Viterbi decoding algorithm. Meanwhile, after a plurality of sets of data comparison, under the same conditions as the bit error rate, compared to the soft decision Viterbi algorithm with the hard decision Viterbi algorithm coding gain of about 2dB.
Keywords: Channel coding ; Convolution code ; Viterbi decoding ; Binary symmetric channel ; Additive white Gaussian noise channel
目录
1.绪论    1
1.1数字通信系统模型    1
1.2卷积码的发展    2
1.3课题意义    3
2.信道编码    4
2.1信道编码研究背景    4
2.2信道编码基本原理    4
2.3信道编码定理    5
2.4线性分组码    5
2.5循环码    6
2.6卷积码    6
3.卷积码编译码原理    8
3.1卷积码基本理论    8
3.2卷积码编码原理    8
3.3卷积码的代数结构    10
3.3.1卷积码的构成    10
3.3.2系统码形式的卷积码    12
3.3.3卷积码的矩阵描述    13
3.3.4卷积码的图描述    16
3.4文特比译码的度量    18
3.5文特比译码的基本原理    19
3.6卷积码 - Viterbi 译码流程    21
3.7文特比译码的性能    22
4.信道    24
4.1二进制对称信道    24
4.2加性高斯白噪声信道    25
5.基于Matlab的文特比译码性能仿真    28
5.1 卷积编码器设计    28
5.2 文特比译码器模块    32
5.3 文特比译码在二进制对称信道中的性能仿真    34 Matlab维特比译码算法在不同信道中的性能仿真研究:http://www.youerw.com/tongxin/lunwen_14625.html