一种基于网络编码的新型卫星网络可靠组播机制

卫星信道的天然广播及广域覆盖等特性使得基于卫星网络开展组播服务具有很强的吸引力,然而,卫星链路长时延、高误码、非对称的特点容易导致报文大量丢失和重传,使得组播可靠性难于保证。提出了一种基于网络编码的卫星网络可靠组播机制(NCM)。NCM通过在发送端主动发送原始报文的冗余编码包,可实现接收端多个丢失报文的本地恢复;同时结合传统ARQ反馈重传,当出现原始报文和编码包同时丢失时,通过重传编码包,就可恢复多个丢失报文。理论分析和仿真实验表明了该机制的可行性和有效性。

A novel reliable multicast mechanism in satellite networks based on network coding

Satellite communication channels have the properties of natural broadcasting and wide area coverage, which make it attractive to carry out multicast services in satellite networks. However, the features of long transmission delay, high bit error and non symmetrical link cause large number of message loss, making it difficult to guarantee the multicast reliability. We propose a reliable multicast mechanism named NCM based on the network coding for satellite networks. NCM can recover multiple lost packets locally at the receiving end via sending redundant coding information generated from the original data packets. At the same time, combining with the mechanism of Automatic Repeating re Quest（ARQ）, it can restore multiple lost primitive packets by retransmitting only one coded package when the original and its redundant coded messages are lost simultaneously. Theoretical analysis and simulation results validate the feasibility and effectiveness of the mechanism.