INTELSAT IESS 309协议中系统卷积码的软判决序列译码研究

【作者】 艾楚杰；

【导师】 张扬；

【作者基本信息】 电子科技大学 ， 信号与信息处理， 2006， 硕士

【摘要】 随着信息技术与卫星通信系统的高速发展,卫星的应用越来越广泛,涉及到通信的各个领域。但是,由于卫星信道传输距离远,容易受到各种各样的干扰,因此,如何提高传输的可靠性成为研究的热点。利用纠错码技术降低各类数字通信系统的误码率,提高通信质量,已经在世界上许多国家作为一门标准技术而广泛采用。卷积码是一种常用的纠错编码。卷积码的维特比译码方法比较常见,应用范围广泛,发展也非常成熟,因而参考文献和相关资料很多。而卷积码的序列译码方法因为其硬件复杂度高和应用范围小,并不十分流行,相关的参考文献也很少,尤其在国内,相关的研究非常少。为了实现IESS 309协议标准,在卫星数字接收机中实现卷积码的序列译码,我们深入的研究了序列译码算法,解决了序列译码器实现的过程中存在的一些问题。本文主要针对INTELSAT IESS 309协议标准中所采用的系统卷积码,仿真并编程实现其编码和译码。在协议中规定了两种译码的方式,我们主要是针对编码约束度为36的系统卷积码,采用Fano序列译码算法来实现其译码,并进行了仿真。本文所做的主要工作如下:1、针对IESS 309协议中所规定的系统卷积码,研究了一种实际的编码方法,并编程实现其编码。2、针对编码约束度比较大的卷积码,采用Fano序列译码算法来实现译码。并在原有算法的基础上进行了一些改进,主要是针对其Fano度量计算的改进,提高了译码器的工作速度。3、分析比较以往常规算法和所采用的算法的性能、误码率和优缺点。4、针对所取得的研究成果,提出了实际应用中可能存在的一些问题,并指明了下一步的研究方向。本文主要进行的研究是基础性的应用研究。取得的成果是用程序代码实现了卷积码的编码和序列译码,并获得了比较理想的编码增益,为将来的实际工程应用打下了一个坚实的基础,具有一定的实际应用价值。更多还原

【Abstract】 With the rapid development of information technology and satellite communication system, the application of satellite has increasingly extended to every field of communications. However, the satellite channel is liable to various interferences because of its long transmitting distance. Therefore, how to improve the transmitting reliability has become a hot issue. Reducing the bit-error rate in digital communication with error-correction technology and improving the quality of communication have been widely defined and used as the standard technology all over the world.Convoluntional code is a frequently used error-correction code. Viterbi decoding algorithm has been widely used and developed in full-fledge, therefore, it’s easy to find a lot of materials and references on it. However, the sequential decoding algorithm is not fully developed because of its complication and limited range of application, which lead to relatively few materials particularly in board. In order to implement the IESS 309 standard and sequential decoding for the convolutional codes in Satellite Digital Receiver, we have made a deep research in sequential decoding algorithm and solved some problems on implementing the sequential decoder for convolutional codes.The thesis mainly focuses on the encoding and decoding to the systemic convolutional code with programming language, which is prescribed in the INTELSAT IESS 309 standard. The IESS 309 standard indicates two decoding methods, we focus on the systemic convolutional code with long encoding restriction which is 36 bit and adopt the Fano sequential decoding algorithm to implement the decoder.The mainly work is as follows:1. Aiming at the systemic convolutional code prescribed in the INTELSAT IESS 309 standard we bring forward a kind of actual method and implement the encoder with programming language.2. Aiming at the convolutional code with long encoding restriction we adopt the Fano sequential decoding algorithm to implement the decoder. We mainly improve the calculation of the Fano metric on the basis of the original decoding algorithm, which enhance the decoder’s speed.3. Comparing and analyzing the performance, the BER, the advantages and更多还原