基于机会式网络编码的多阶段重传机制

Multi-stage retransmission scheme based on opportunistic network coding

为进一步提高无线单跳网络中基于网络编码的重传机制的效率,提出了基于机会式网络编码的多阶段重传机制(multi-stage retransmission scheme,MSRS)。根据丢包分布的不同特性,MSRS将丢包恢复分为两个阶段。第一阶段对全译码特性丢包利用严格即时可解网络编码思想进行恢复,第二阶段对非全译码特性丢包利用基于缓存的网络编码进行协助恢复。MSRS分阶段恢复丢包的思想充分利用了全译码特性包的编码机会,同时也挖掘了非全译码特性包潜在的编码机会,解决了非全译码特性包编码机会利用率低的问题。仿真实验表明,MSRS相比现有基于网络编码的重传方法能有效降低重传次数,且具有更好的稳定性。

To improve the efficiency of the retransmission scheme based on network coding in wireless network, a multi-stage retransmission scheme （MSRS） based on opportunistic network coding is proposed. According to the characteristics of different lost packet distribution, the packets recovery process is divided into two stages in MSRS. First, the packet with complete decoding character （CDC-packet） can be recovered with strictly instant decodable network coding （SIDNC）. Second, the packet with the incomplete decoding character （IDC-packet） can be recovered with the assistance of cache-based network coding. MSRS makes full use of the encoding opportunity of CDC-packets, fully discovers the potential encoding opportunity of IDC-packets, improving the efficiency of the encoding opportunity of IDC-packets. The simulation results show that MSRS can effectively decrease the number of retransmission, and has better stability compared with existing retransmission methods based on network coding.