广播重传中基于多包解码的高效快速网络编码

Efficient rapid multi-packet decoding and network coding based broadcasting retransmission

针对当前基于网络编码的代表性无线广播重传(NCWBR)策略中,如果一个编码组合包包含了不止一个在某一接收节点丢失的信息包,就会导致编码包解码失败而丢弃编码包,从而引起分组重传次数增加、网络时延增大等问题.通过不丢弃解码失败的编码包,从多个这样的编码包中解码出信息包的思路,提出了广播重传中基于多包解码的高效快速网络编码(MDNCBR)策略,并通过增加'打破交叉关系就重传'的机制进一步提出了MDNCBR的改进方案(IMDNCBR).理论分析和仿真结果表明:MDNCBR及IMDNCBR策略能有效提高接收节点的解码效率,快速地确定须要重传的信息包,与NCWBR策略相比能够有效地减少丢失包的重传次数,降低传输时延和网络开销,提高传输性能.

At current wireless broadcasting retransmission approach based on network coding, NCWBR （network coding wireless broadcasting retransmission） would decline the performance of the network and increase the retransmission numbers if the same node has more than two losing packets. An approach of efficient rapid MDNCBR （multi-packet decoding and network coding based broadcast- ing retransmission） was presented according to the idea of recovering packets from the encoded pack- ets which cannot be decoded and stored in buffer. IMDNCBR （improved MDNCBR） was further put forward by using the optimization scheme, retransmitting when breaking cross relation. Theoretical a- nalysis and simulation results reveal that this way can improve the efficiency of decoding in the re- ceived nodes, and determine the packets which need to be retransmitted. Compared with NCWBR ap proach, MDNCBR and IMDNCBR can effectively reduce the retransmission numbers, transmission delay and network overhead, and improve the efficiency of transmission.