流间网络编码中的自适应通知报文发送机制

Adaptive reception reports sending mechanism in inter-session network coding

流间网络编码机制需要借助通知报文来确定编码机会,现有的机制一般采用"τ间隔通知机制",但对通知间隔τ的选取及其导致的开销并未进行分析。通过分析"τ间隔通知机制"所产生的通信开销及其对编码机会和吞吐量的影响,提出一种自适应通知报文发送机制。在自适应通知报文发送机制中,无线节点根据局部网络的流量自适应地确定发送间隔,且通知报文仅携带最近2个通知间隔侦听到的数据包信息,在保证编码机会的情况下降低通知报文中携带的信息量和通知报文的发送频度,从而降低附加开销和冲突。网络模拟器仿真实验结果表明:自适应通知报文发送机制能有效地减少通知报文发送的额外带宽开销,取得比采用"τ间隔通知机制"的流间编码机制更高的吞吐量。

The existing inter-session network coding mechanisms almost unanimously adopt u r-interval-notification7, , which is used to determine the coding opportunities, and its overhead has not been analyzed. In the current study, its communication overhead and its impacts on coding opportunity and throughput were analyzed, and an adaptive reception report sending mechanism called AR2SM （Adaptive Reception Reports Sending Mechanism） was proposed. In AR2SM, the interval of broadcasting reception reports is determined adaptively according to the traffic of local network, and the reception reports carry the packets overheard in the last 2 intervals. As a result, the size of reception report and the frequency of sending reception report were both reduced on the condition of guaranteeing the coding opportunity. According to the simulator results in network simulator, the proposed mechanism reduces the overhead of transmitting the reception reports, and achieves higher throughput than the “ T-interval-notification” mechanism.