一种改进的LT码构造方法

摘要

通过分析信道信忠在参与LT码译码过程的特点,给出迭代深度的概念.在找出编码符号的抗误码性能与迭代深度关系的基础上对累积边增加法(PEG)加以改进来构造LT码,试图从Tanner图中找出优秀拓扑结构应具备的特征.与传统的PEG法相比,使用改进后的PEG法(IPEG)构造的LT码,其输入符号的度数分布严格符合Poisson分布,且度数为1的符号不发生错误,极大地提高了LT码的抗误码性能.%This paper introduces a new concept-iterative depth (ID), based on analyzing the feature of channel information in the decoding processing of LT codes with Belief Propagation (BP) algorithm. Improving Progressive Edge Growth (PEG), a construction method for LT codes, by the relation between the ID and the error robustness capability of coding-symbols. The purpose is to find the feature of good Tanner graphs for LT codes. Compared to classical PEG, LT codes using improved PEG has several merits such as the degree distribution of input nodes is strict Poisson distribution and there are no error in those nodes of degree l.This merits improve the error robustness capability of LT codes enormously.