无线mesh网络中编码感知的跨层优化机制

无线网络的广播和易于侦听的特点,使得网络编码技术能够很好地应用于无线网络中,以提高无线网络的吞吐量。通过理论分析和仿真实验发现,IEEE802.11标准的MAC层机制会使得成功竞争到信道的节点在短时间内在竞争信道方面更具优势,这会导致编码节点在短期内获得的属于不同编码流的数据包数目不均衡,从而丧失很多的编码机会。提出了一种跨层协作的优化机制,在编码节点根据编码流的队列占用情况计算编码流的优先级别,并将其发送给相应上游节点以调节MAC层参数,进而平衡编码节点中参与编码的不同流的队列占用率,增加编码机会。仿真实验结果表明,这种编码感知的跨层优化机制,能够很好地协调参与编码的流的速率,提高了整个网络的吞吐量。

A coding-aware cross-layer optimization mechanism for wireless mesh network

Due to the inherent broadcast and overhearing capabilities of wireless network, the network coding technique is very suitable for the wireless mesh network. Through the theoretical analysis and simulation results, it is observed that the MAC mechanism of the IEEE802.11 standard may make the node more competitive after accessing the channel successfully, which unbalances the amount of packets of different coding flows in the buffer of the coding node in a short period, and finally, some coding opportunities are lost. A cross-layer optimization mechanism is proposed. In the mechanism, the priorities of coding flows are calculated by using the buffer occupancy information and are sent to the upstream node, and then the corresponding upstream node adjusts its MAC parameters, which yields more coding opportunities. Simulation results show that the proposed mechanism can adjust the rate of flows whose packets can be encoded together adaptively, and improve the total throughput of network.