应用于802.11e无线局域网QoS区分的新机制

Novel MAC scheme for weighted-fair differentiated service in 802.11e WLANs

针对802.11e无线局域网中的不公平现象,即当网络负载较大时低优先级数据流的吞吐量几乎为零,提出一种新的媒体接入控制机制P-EDCA,实现按数据流权重公平的系统带宽资源分配.P-EDCA支持802.11e的多优先级队列结构,通过站点内部的队列调度机制保证各队列分组获取公平的站点发送权;通过站点之间的信道竞争机制保证各站点获取公平的信道访问机率.仿真表明,P-EDCA能够精确实现按权重、成比例的带宽资源分配.与EDCA相比,在满足高优先级数据流QoS需求的前提下,P-EDCA能够将低优先级数据流的时延降低50%.

In this paper, a novel MAC scheme referred to as P-EDCA is proposed to resolve the unfairness problem in IEEE 802. 11e WLANs （i. e. , the flows with lower priorities can not get any throughput of data transfer in cases of heavy network loads）. P-EDCA provides weighted fairness for differentiated service between the flows, and supports the stations with the 802.11e based multi-queue structure. By using the inner centralized queuing discipline, P-EDCA guarantees fair transmission opportunity between the queues within a station. And by using a contention based access method, i. e. , the DFS algorithm, fairness of channel accessing between the stations is reached. Simulation results show that weighted-fair differentiation is accurately implemented by P-EDCA with no information shared between the users. And, without decreasing the performance of higher priority flows, P-EDCA outperforms the original EDCA in terms of its QoS assurance for lower priority flows in the network.