摘要
基于网络编码的P2P流媒体直播系统的优势之一在于多个源节点之间不需要显式的协同调度也能有效地服务于请求节点。但正是由于缺乏协同,即使编码系数的有限域足够大,仍然存在线性相关冗余数据,从而浪费了源节点的带宽。分析了这一问题产生的原因,并提出采用从tracker提供的源节点集合中选择部分节点作为活动源节点来解决该问题。活动源节点最优选择问题可以归约为0-1背包问题的变种,是NP难的,因此我们设计了一个多项式时间的近似算法来逼近最优解。通过形式化证明和模拟,我们验证了该算法的可行性。数据表明该方法能够进一步提高P2P流媒体直播系统的服务质量。
One advantage of the network coding based P2P live streaming system is that multiple source peers can serve the requests efficiently without explicit cooperation control.However,the lack of cooperation also brings redundant data due to the linear dependence,even when the Galois field of the coding coefficients is large enough.In this paper,we first analyze the causes of the redundant data.Then,we propose selecting active source peers from the source set given by the tracker to handle this problem.Active source peer selection problem can be regarded as a variant of 0-1 knapsack problem,which is NP hard,such that we design an approximation algorithm to compute the solution.Through formal proofs and simulations,we verify the validity of the algorithm,which can further improve the QoS of the P2P live streaming.
出处
《计算机系统应用》
2011年第3期64-69,共6页
Computer Systems & Applications
基金
国家高科技研究发展计划(863)(2009AA012142)
关键词
网络编码
P2P直播流媒体
活动源节点
背包问题
network coding
P2P live streaming
active source peer selection
knapsack problem
