在介绍LT码原理及其相关度分布函数的基础上,对Raptor码的编译码原理进行研究.其中预编码技术和LT码编译码技术是Raptor码的的两个核心技术.选择一套合适的预编码方案和改进LT度分布函数是改进算法的核心所在.通过研究和比较,在传统的一些纠删码中最终选择以LDGM码作为预编码方案,并根据实际应用对LT码度分布函数进行了改进.将LDGM码和改进后的LT码级联为Raptor码.这种Raptor编码技术的改进算法改善了数据传输过程中的网络丢包以及实时性的问题.
Based on the introduction of the LT code principle and its correlation distribution function,the encoding and decoding principles of Raptor code are studied.The precoding technology and the LT code encoding and decoding technology are two core technologies of Raptor code.How to choose an appropriate precoding scheme and improving the LT degree distribution function is the core of the improved algorithm. Through the research and comparison,LDGM code is selected as the precoding scheme among some traditional erasure codes,and the LT code distribution function is improved according to the practical application.The LDGM code and the modified LT code are concatenated into a Raptor code.The improved algorithm of Raptor coding improves the problem of network packet loss and real-time in the process of data transmission.