毕业设计（论）-卷积码译码算法的研究.doc

西安石油大学毕业设计（论文）卷积码译码算法的研究摘 要：作为一种热门的前向纠错编码技术，基于Viterbi算法译码的卷积码纠错技术在数字通信系统中起着非常重要的作用。目前，卷积码的应用已经相当广泛。本文主要对卷积码的viterbi算法进行研究。首先对数字通信系统的基本结构和卷积码及其译码算法的发展过程做出了介绍，说明了卷积码的研究具有重要意义。接着又以（2, 1, 3）卷积码为例介绍了卷积码的基本概念、编码原理以及卷积编码器的3种表示方法，并重点介绍了其中的网格图表示方法。从（2, 1, 3）卷积编码的网格图可以看出在编码器编码过程中，输入码元为0或1时当前状态向下一状态转移的路径以及此时刻编码器所输出的分支字，另外网格图中的每条路径都代表着一个发送序列。最后着重介绍了viterbi译码算法。该算法是一种基于网格图的最大似然译码算法，其译码过程分为接收，计算和比较，从而选择出最接近的序列，进而得到发送的原始信息序列。另外还对viterbi译码进行MATLAB仿真，并证明了其译码结果的可靠性。关键词：卷积码；viterbi算法；MATLAB仿真Study on Decoding Algorithm of Convolutional Code Abstract: As one of the pop forward error correction technology, the convolution code technique based on Viterbi algorithm plays an important role in the digital communication system. Today, convolutional code has been widely applied in many fields. The Viterbi algorithm is mainly researched in this thesis. Firstly, the basic architecture of digital communication and the development process of coding and decoding of convolutional code are introduced, which shows the important significance of the study of convolutional code. Then, take (2, 1, 3) convolutional code for example, this paper introduces the basic concept and the principle of coding of convolutional code and 3 kinds of description of Convolution encoders. Among them, trellis diagram is introduced emphatically. From the trellis diagram of (2, 1, 3) convolutional code, we can get the path that the current state to the next state when the input symbol is 0 or 1 and the branch word output by the encoder at this moment in the encoding process of the encoder. And each path in the trellis diagram corresponds to a send sequence. Finally, the Viterbi algorithm, a kind of maximum likelihood decoding algorithm, which is based on trellis diagram is introduced emphatically. The decoding process is that when the decoder receives a sequence, it computes and compares immediately to select the most probable sequence and then obtain the sequence of information to be sent. In addition, the viterbi algorith