基于规则变量节点度和扩展窗喷泉码的不等差错保护算法

该文提出了一种可适用于加性高斯白噪声(AWGN)信道的融合扩展窗喷泉码(Expanding Window Fountain, EWF)和规则变量节点度LT码(Regularized variable-node Luby Transform, RLT)策略的不等差错保护(UEP)算法，称为EWF-RLT编码算法。首先利用扩展窗口技术给不同重要等级的数据加窗，编码时让较高重要等级数据以更高的概率参与编码；同时，结合规则变量节点度算法，改变传统LT 码编码过程中随机选取邻居节点的编码方式，使较高重要等级的数据具有较大的最小变量节点度，改善错误平层现象。分析和仿真结果表明，该文提出的EWF-RLT算法与传统算法相比，能对较高重要等级数据进行更强的保护，提升网络传输质量；在UEP方案设计中，加入RLT码编码参数，使得该文方案更加灵活与适用。

Novel Scheme of Unequal Error Protection Based on Regularized Variable-node and Expanding Window Fountain Codes

A novel scheme named EWF-RLT codes, which produces Unequal Error Protection (UEP) for Luby Transform (LT) codes over Additive White Gaussian Noise (AWGN) channel by using a windowing technique before regularizing variable-node distribution, is proposed in this paper. Firstly, the idea of windowing the data sets according to their protection requirements is applied to allow coded symbols to make more edge connections with more important parts of the information bit stream with high probability. Then, variable-node degree distribution is exploited to improve the error floor and ensure the more important class of information bit stream have a higher minimum variable-node degree by modifying the traditional method of choosing neighbor nodes randomly in encoding. Compared with the conventional UEP scheme, what is confirmed both theoretically and experimentally is that the proposed approach can provide significant performance improvement in the most important bits class and improve network transmission performance. Furthermore, the proposed scheme introduces additional parameters in the UEP LT code design, making it more general and flexible in terms of the realization of UEP scheme.