一种基于LT码的度分布优化算法  

A Degree Distribution Optimization Algorithm Based on LT Codes

作　　者：魏德宾[1,2] 李金明 潘成胜[2] WEI Debing;LI Jinming;PAN Chengsheng(College of Information Engineering,Dalian University,Dalian,Liaoning 116622,China;Communications and Networks Key Laboratory,Dalian University,Dalian,Liaoning 116622,China)

机构地区：[1]大连大学信息工程学院,辽宁大连116622 [2]大连大学通信与网络重点实验室,辽宁大连116622

出　　处：《计算机工程》2018年第9期83-88,共6页Computer Engineering

基　　金：国家自然科学基金(61301151;91338104);辽宁省自然科学基金(20170540034)

摘　　要：度分布函数是影响数字喷泉码性能的关键因素,在LT码中,当原始数据分组个数较小时,鲁棒孤波度分布(RSD)存在编译码复杂度较高、译码性能下降等问题。为此,提出一种新的截短鲁棒孤波固定度分布优化算法。对固定度分布(SD)进行调整后截短RSD,将截短后的RSD和调整后的SD相结合并做归一化处理,得到一种新的度分布。仿真结果表明,与RSD、SD度分布相比,该度分布优化算法能够降低25%~31%的译码开销,节省22%~55%的平均编译码时间,且原始数据分组个数越小,性能改善越明显。The degree distribution function is the key factor affecting the performance of digital fountain codes.The Robust Soliton Distribution(RSD)has the problems of high complexity of encoding and decoding,low decoding performance when the number of original data packets is small in LT cods.To solve this problem,a new truncated robust soliton distribution optimization algorithm is proposed.After adjusting the Stationary Distribution(SD),the RSD is truncated,and the truncated RSD and the adjusted SD phase are merged to be normalized to get a new degree distribution.Simulation results show that,compared with the RSD and SD degree distribution,the proposed algorithm can reduce the decoding overhead of 25%~31%and save the average encoding and decoding time of 22%~55%,and the smaller the number of original data groups,the more obvious the performance improvement.

关 键 词：数字喷泉码 LT码 鲁棒孤波度分布 固定度分布 卫星网络信道 译码开销 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]