Abstract: The current applications of network coding in single-hop wireless network retransmission are based Single Sender Multiple Receiver (SSMR) scenes. Therefore, this paper proposed a retransmission mechanism named NCWRM (Network Coding Wireless Retransmission Mechanism) which can be used in multiple sender multiple receiver networks. Each node in the network can be either a sender or a receiver. The node can broadcast a coded packet which is combined by multiple lost packets in the second retransmission after packet failed in transmission and the first retransmission. Multiple recipients can simultaneously get their lost packets by decoding the coded packet, which can effectively improve the efficiency of retransmission. Theoretical analysis and simulation results show that NCWRM algorithm can significantly improve system saturation throughput, while reducing overhead and packet loss rate.

Key words: network coding, retransmission, broadcast, retransmission efficiency

摘要： 鉴于目前网络编码在单跳无线网络重传中的应用研究都是基于单发-多收场景的局限性，提出一种应用于多发-多收无线网络中的重传机制NCWRM。该重传机制中，网络节点既可以是发送方也可以是接收方，节点发送的数据包在直传和第一次重传中都失败后，第二次重传时广播发送由多个丢失数据包编码组合得到的编码包。多个接收方通过解码编码包得到丢失的数据包，从而实现一次重传获得多个丢失的数据包，可以有效提高重传效率。理论分析和仿真结果表明，NCWRM算法能够明显提高系统的饱和吞吐量，同时减小开销及丢包率。

关键词: 网络编码, 重传, 广播, 重传效率