开关度分布:一种改进的LT数字喷泉编码度分布  

Switch degree distribution:an improved degree distribution for LT digital fountain code

作　　者：雷维嘉[1] 刘慧锋[1] 谢显中[1] 

机构地区：[1]重庆邮电大学个人通信研究所,重庆400065

出　　处：《重庆邮电大学学报（自然科学版）》2012年第1期34-38,共5页Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition)

基　　金：国家自然科学基金(60872037);重庆市自然科学基金(CSTC;2011jjA40006);重庆邮电大学博士启动基金(A2011-03)~~

摘　　要：LT数字喷泉编码所采用的度分布是影响译码效率的关键因素。给出了一种改进的LT数字喷泉编码的度分布,即开关度分布,它结合鲁棒孤子分布和二进制指数分布的优点,可以产生足够多的度很小的编码数据包,减少了译码器启动译码过程所需要的编码数据包的数量,而且减少了译码器成功译码时所需要的编码数据包的总数量。通过仿真给出了最佳的开关点参数。仿真显示,与鲁棒孤子度分布和二进制指数度分布相比,采用开关度分布,明显改善了译码效率。The degree distribution applied in the LT digital fountain code encoder is a key factor to the decoding efficiency.This paper presents an improved degree distribution which is called Switch Distribution.It combines the advantages of binary exponential distribution and robust soliton degree distribution.When the degree of the coded packets is chosen from Switch Distribution,it can generate enough encoded packets with small degrees.This distribution decreases the number of encoded packets when the decoding process firstly starts and decreases the number of source transmitted packets for recovering the source information successfully at the distination.We obtain the best switch point by simulation.Compared with using Robust Soliton Distribution and Binary Exponential Distribution,using Switch Distribution can greatly increase the decoding efficiency.

关 键 词：数字喷泉码 LT码 鲁棒孤子度分布 二进制指数度分布 开关度分布 

分 类 号：TN925[电子电信—通信与信息系统]