【作者】 孙岳；

【导师】 王新梅；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2005， 硕士

【摘要】 2000年，Ahlswede等基于网络信息流的概念提出了网络编码的思想。通过允许网络节点进行编码，我们可以获得网络多播速率的最大流限，即，网络资源利用的理论上限，而通过传统的路由和复制并不一定能够获得该最大流限。此外通过网络编码我们可以取得节省网络带宽资源，平衡连路负载，优化能量受限网络的能量消耗等好处。现在，有关网络编码理论的研究已经引起了学术界的高度重视，网络编码已经成为网络信息理论领域最受瞩目的研究热点之一。 作者在理解网络编码理论思想的基础上，深入研究了网络编码的编译码算法；并着重研究了网络编码在预防多播网络链路失败中的应用。 本文主要完成的工作有以下几个方面： 1．基于无向网络图模型，详细介绍了网络编码的基本原理，特别是线性网络编码；并对网络编码多播与传统的IP多播进行了性能比较和分析。 2．介绍了网络编码的两种编译码算法，并对实际网络环境中如何运用网络编码进行了讨论。 3．研究了传统的网络链路失败恢复方式和基于网络编码的网络链路失败恢复方式，并从纠删码的编译码思想出发，指出如何进行网络编码来抵抗网络链路失败对网络链接可靠性的影响。 网络编码及其应用的研究现在还处于理论研究阶段。虽然通过网络编码多播可以获得很多好处，但是要在实际的网络环境中运用网络编码还存在很多问题需要解决。通过将网络编码运用于网络多播的链路失败的恢复，可有效的提高网络多播连接的鲁棒性。目前我们所做的工作还有很大的不足，仅仅定性在理论的分析，缺乏相关的定量的模拟与研究。下一步的工作将会集中在这一点的解决上，期待着有着进一步的探索。更多还原

【Abstract】 Network coding is introduced by Ahlswede in 2000, which is based on the conception of network information flow. If coding is permitted by the network vertices, the max-flow bound of network multicast can be achieved, i.e. the theoretical upper bound of netwoek resource utilization, which can not always be achieved by traditional copying and routing. Furthermore, through network coding, we can obtain the benefits of saving in bandwidth, load balancing, optimizing the energy usage of energy-limited networks and so on. Now, the research of network coding has received great interests and has become one of the most attractive fields in network information theory.This thesis investigates some aspects of netwok coding with emphasis on the application of network coding to guard against link failures of multicast network. The main results and contents are as follows.1. Based on directed graph, the basic principle of network coding is addressed, especially linear network coding, and the performance of multcast based on network coding and that of traditional IP multicast are compared.2. Two algorithms of network recoding and decoding are introduced, and implementation issues of network coding in actual environment are discussed.3. The methods of traditional link-failure recovery and that based on network coding are studied. From the idea of erasure codes, we show how to construct network codewords to withstand the effect of link failures to the robustness of the multicast information transmission.Now, the study of network coding is still in its theoretical stage. Through multicast based on network coding, many advantages can be achieved, however, if network coding is used in actual environment, there are still many issues to resolve. Through the link-failure recovery based on network coding, the robustness of multicast information transmission will greatly enhanced, but we only have little work on this title, and great effort will be done to this problem.更多还原