序列矩阵表示的卷积网络编码的译码方法

从校验矩阵的角度对网络编码进行分析,给出其编译码的序列矩阵描述。这一方法可将确定型线性网络编码、随机线性网络编码以及卷积网络编码统一到同一矩阵序列结构中,为深刻理解网络编码提供一个新的视角。在此基础上,首次提出一种译码矩阵的求解方案,其复杂度为多项式时间,并给出可行性分析。还讨论了卷积网络编码的译码原理,并给出一些译码性质。最后,用例子简单说明序列矩阵描述的卷积网络编译码方法。

卢比变换码在自由空间光通信中的应用

卢比变换(LT)码是第一种具有实用价值的数字喷泉码。LT码在噪声信道中具有良好的性能,且已在自由空间光通信(FSO)中广泛应用。文章首先简要说明了LT码的基本原理,列举了LT码与其他几种FSO中常用的编码方案的优缺点。然后,概括了国内外对LT码在FSO系统中应用的研究进展,并从新型度分布和改进的译码方案两个角度详细介绍了LT码在FSO系统中应用的性能优化方案。最后,指出了现有LT码相关研究的不完善之处,对LT码在FSO中的未来研究方向提出了展望。

NEW ITERATIVE SUPER-TRELLIS DECODING WITH SOURCE A PRIORI INFORMATION FOR VLCS WITH TURBO CODES

A novel Joint Source and Channel Decoding (JSCD) scheme for Variable Length Codes (VLCs) concatenated with turbo codes utilizing a new super-trellis decoding algorithm is presented in this letter. The basic idea of our decoding algorithm is that source a priori information with the form of bit transition probabilities corresponding to the VLC tree can be derived directly from sub-state transitions in new composite-state represented super-trellis. A Maximum Likelihood (ML) decoding algorithm for VLC sequence estimations based on the proposed super-trellis is also described. Simu-lation results show that the new iterative decoding scheme can obtain obvious encoding gain especially for Reversible Variable Length Codes (RVLCs),when compared with the classical separated turbo decoding and the previous joint decoding not considering source statistical characteristics.