多播网络中基于网络编码的高效丢失恢复机制

网络编码为无线网络中可靠多播通信提供了有效解决途径。该文分析了网络中编码机会的变化规律，研究了解码失败的编码数据包对网络编码性能的影响，提出了新的基于网络编码的丢失恢复算法(NCLR)。NCLR要求节点缓存解码失败的编码数据包，并反馈信息给发送节点。根据各个节点的丢包情况，NCLR通过优先传输对编码性能影响较大的数据包，并在需要重传的已编码数据包和原始数据包中选择编码组合，来充分挖掘网络中的编码机会。仿真结果表明相对于已有算法，NCLR算法可以在重传次数和丢失恢复时延方面有显著性能改善。

Efficient Loss Recovery Based on Network Coding in Multicast Networks

Network coding is a promising technique for reliable multicast in wireless networks.In this paper,the characteristics of network coding opportunities are analyzed in multicast networks.The effect of the network coded packets,which can not be decoded,on the performance of network coding is studied.Based on these analyses,a Network Coding Loss Recovery(NCLR) scheme is proposed.NCLR allows receivers to store the packets,which they can not decode,and report the reception status to the sender.According to the feedback,NCLR prioritizes the packets that can contribute more to the overall transmission performance.Moreover in NCLR,not only original packets,but also encoded packets are scheduled and coded together to fully exploit coding opportunities.Simulation results show that NCLR improves significantly the multicast performance in terms of the number of retransmissions and recovery latency compared with existing schemes.