【作者】 杨磊；

【导师】 王匡；

【作者基本信息】 浙江大学 ， 信息与通信工程， 2011， 硕士

【摘要】 网络编码最初是为了解决如何实现组播网络的最大网络容量的问题提出的,随着研究的深入,网络编码技术与其他技术如P2P文件共享、无线网络技术的结合能够解决很多传统技术中无法解决的问题,成为众多学者的研究热点。本文首先在研究代内网络编码和代间网络编码对组播网络中重传方法性能的影响的基础上,对基于代内网络编码的重传策略进行改进,将代间网络编码技术与组播重传技术结合起来,提出代间随机重传策略和代间最小重传策略两种重传机制,进一步提升了重传算法的性能,减少重传包的数量,提高网络带宽利用率。通过与代内网络编码重传策略仿真比较,可以看出代间最小重传策略相对代内最小重传策略、代间随机重传策略相对代内随机重传策略的重传性能都得到提升。代间随机重传策略性能受有限域大小影响明显,代间最小重传策略计算复杂度较高但是性能也最优。然后通过分析应用网络编码技术如何加快P2P文件共享速度,提出了在P2P网络中应用部分时间网络编码和部分网络节点网络编码技术。部分时间网络编码技术结合P2P技术时,网络中所有下载节点的平均下载速度达到最大下载速度之后停止应用网络编码技术,通过仿真可知能够达到与完全应用网络编码技术的P2P文件共享系统相同的性能。部分节点网络编码技术结合P2P技术时,通过仿真可知部分节点在下载过程中应用网络编码即可接近所有节点应用网络编码的性能。这两种方法都能降低网络节点的计算开销。更多还原

【Abstract】 Network coding was first proposed to address how to achieve maximum network multicast network capacity issues. With recent years’research, it was shown that network coding technology combined with other technologies such as P2P file sharing, the wireless network technology can solve many problems which can not be solved by traditional technology. And it has attracted booming interest in recent years.At first, according to retransmission strategies in packet network and network coding with multi-generation mixing, we propose two new retransmission strategies:Multi-generation Random Retransmission strategy and Multi-generation Minimum Retransmission strategy, which focus on optimizing the retransmission efficiency. Compared with retransmission strategies based on intra-generation network coding, simulation results show that the retransmission efficiency has been improved and Multi-generation Random Retransmission strategy is sensitive to the encoding field size, Multi-generation Minimum Retransmission strategy has the highest complexity which is still polynomial and is the best.Then it has been shown that how the P2P content distribution system benefits from network coding in term of average download speed. And in order to minimize the costs, we propose part-time-network-coding and part-peer-network-coding. We can see that the performance of part peers in the P2P network work with the application of network coding, or all the peers stop the application of network coding after the download speed up to the maximum download speed, can reach the same performance with all the peers with the application of network coding all the time in P2P content distribution through simulation. Both of them can reduce the computational cost of the peers in the P2P network.更多还原