卷积码的编解码matlab仿真.docVIP

卷积码的编解码Matlab仿真 摘要 卷积码是一种性能优越的信道编码。它的编码器和译码器都比较容易实现，同时它具有较强的纠错能力。随着纠错编码理论研究的不断深入，卷积码的实际应用越来越广泛。本文简明地介绍了卷积码的编码原理和译码原理。并在SIMULINK模块设计中，完成了对卷积码的编码和译码以及误比特统计整个过程的模块仿真。最后，通过在仿真过程中分别改变卷积码的重要参数来加深理解卷积码的这些参数对卷积码的误码性能的影响。经过仿真和实测，并对测试结果作了分析。得出了以下三个结论： （1）当改变卷积码的码率时，系统的误码性能也将随之发生变化。 （2）对于码率一定的卷积码，当约束长度N 发生变化时，系统的误码性能也会随之发生变化。 （3）回溯长度也会不同程度上地影响误码性能。 关键词:卷积码；码率；约束长度；回溯长度 Simulation and Research on Encoding and Decoding of Convolution Code Abstract Convolution code has a superior performance of the channel code. It is easy to coding and decoding. And it has a strong ability to correct errors. As correcting coding theory has a long development, the practice of convolution code is more and more extensive. In this thesis, the principle of convolution coding and decoding is introduced simply firstly. Then the whole simulation module process of encoding, decoding and the Error Rate Calculation is completed in this design. Finally, in order to understand their performances of error rate, many changes in parameters of convolution code are calculated in the simulation process. After simulation and measure, an analysis of test results is presented. The following three conclusions are draw: (1) When the rate of convolution Code changes, BER performance of the system will change. (2) For a certain rate of convolution code, when there is a change in the constraint length of N, BER performance of the system will change. (3) Retrospective length will affect BER. Key words: convolution code; rate; constraint length; retrospective length; 目 录 论文总页数：21页 1 引言 1 1.1 课题背景 1 1.2 国内外研究现状 1 1.3 本课题的意义 1 1.4 本课题的研究方法 1 2 卷积码的基本概念 2 2.1 信道 2 2.2 纠错编码 2 2.3 卷积码的基本概念 2 2.4 卷积码编码的概念 2 2.4.1 卷积编码 2 2.4.2 卷积码的树状图 3 2.4.3 卷积码的网格图 4 2.4.4 卷积码的解析表示 5 3 卷积码的译码 6 3.1 卷积码译码的概述 6 3.2 卷积码的最大似然译码 6 3.3 VITEBI 译码的关键步骤 7 3.3.1 输入与同步单元 7 3.3.2 支路量度计算 7 3.3.3 路径量度的存储与更新 7 3.3.4 信息序列的存储与更新 8 3.3.5 判决与输出单元 8 4 结论 9 4.1 卷积码的仿真 9 4.1.1 SIMULINK仿真模块的参数设置以及重要参数的意义 9 4.2 改变卷