无线Mesh网络中一种基于剩余时延的公平调度策略

A fair scheduling policy based on delay margin in wireless mesh networks

在基于IEEE 802.11e标准的无线Mesh网络中,由于802.11e机制中保障多媒体传输服务质量的参数(如竞争窗口、传输机会等)是静态分配的,且所有支持该协议的通信节点均使用相同的参数配置,导致其更适合在一跳范围内提供较好的传输性能,不能有效地适应动态无线多跳环境下的服务质量需求。针对由于具有较大时延界限的数据流长期占用传输信道而导致具有较低时延界限数据流出现大量丢包、重传,从而影响整个网络的吞吐量及多数据流传输的公平性问题,从数据包的剩余时延出发,提出了一种公平共享的数据包调度策略,在减少数据包的重传次数的同时,提高多个数据流传输的公平性。仿真结果表明,相比原有802.11e机制,该策略具有更高的效率。

In IEEE802.11e-based wireless mesh networks,the parameters （eg.,contention windows,transmission opportunity） used in 802.11e＇s mechanism is statically assigned in order to guarantee the quality of service,which is more suitable to the communication nodes in one hop transmission with environment and not to the wireless multi-hop environment.In view of the problem that data flows with long delay bound may consume more channel time than data flows with short one so as to cause packet loss and networks performance degradation,a fair share scheme based on the residual packet delay bound,which is equally distributed among data packet,is proposed to alleviate the retransmission number and promote the fairness between data flows.Simulation results show that the proposed scheme is more effective than the original 802.11e protocol.