空间信息网络中基于LT码的分布式存储策略

针对空间信息网络(Space Information Network, SIN)节点存储资源严重受限及存储可靠性问题，该文提出一种基于LT(Luby Transform)码的分布式存储策略(Distributed Storage Strategy based on LT codes, DSSLT)。采用定向随机漫步机制，使得源数据包能够更快地遍历整个网络。在信息估计阶段利用基于ID的估计方法进行网络全局信息估计，使所有节点快速获得网络全局信息。合理的数据包选择机制使得最终编码度分布趋于期望的度分布。分析和仿真结果表明，与具有代表性的分布式存储策略相比，该方法大幅度减少了数据包传输时的随机漫步步长，同时提高了译码性能，简单易行。

Distributed Storage Strategy Based on LT Codes in Space Information Network

To solve the limited storage resource and the data storage reliability problem of Space Information Network (SIN), a novel Distributed Storage Strategy based on Luby Transform (LT) codes (DSSLT) is proposed. According to the proposed strategy, source data packets are transmitted quickly to every node in the network based on directional random walk. The ID-based estimation method is used to estimate the global information at the information estimation phase, the values are obtained without excessive random walks. The procedure of XORing packets is reasonable so that the distribution of code degree tends to the desired degree distribution. As presented by the analyses and simulations, random walk steps are greatly reduced compared with a representative distributed storage strategy, while improving the decoding performance.