Supporting QoS in IEEE 802.11e wireless LANs
Supporting QoS in IEEE 802.11e wireless LANs
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DOI：
10.1109/twc.2006.1687738
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发表时间：
2006-08
影响因子：
10.4
通讯作者：
Xiang Chen;Hongqiang Zhai;X. Tian;Yuguang Fang
中科院分区：
文献类型：
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作者：
Xiang Chen;Hongqiang Zhai;X. Tian;Yuguang Fang
在新兴的IEEE 802.11e MAC协议中，提出了增强型分布式信道接入（EDCA）来支持优先级QoS，但是，如果没有适当的网络控制机制，它不能保证语音和视频等实时业务所需的严格QoS。为了克服这一缺陷，我们首先建立了一个分析模型，得出一个平均延迟估计的流量在不饱和的802.11e无线局域网中的不同优先级，表明可以满足实时业务的QoS要求，如果输入流量得到适当的调节。然后，我们提出了两个有效的呼叫接纳控制方案和速率控制方案，依赖于平均延迟估计和信道繁忙率，一个指标，可以准确地代表网络状态。其关键思想是，当接受一个新的实时流，接纳控制算法考虑其对信道利用率和现有的实时流所经历的延迟的影响，确保信道不过载，不违反延迟要求。同时，速率控制算法允许尽力而为业务充分利用实时业务所留下的剩余带宽，从而实现高信道利用率
In the emerging IEEE 802.11e MAC protocol, the enhanced distributed channel access (EDCA) is proposed to support prioritized QoS; however, it cannot guarantee strict QoS required by real-time services such as voice and video without proper network control mechanisms. To overcome this deficiency, we first build an analytical model to derive an average delay estimate for the traffic of different priorities in the unsaturated 802.11e WLAN, showing that the QoS requirements of the real-time traffic can be satisfied if the input traffic is properly regulated. Then, we propose two effective call admission control schemes and a rate control scheme that relies on the average delay estimates and the channel busyness ratio, an index that can accurately represent the network status. The key idea is, when accepting a new real-time flow, the admission control algorithm considers its effect on the channel utilization and the delay experienced by existing real-time flows, ensuring that the channel is not overloaded and the delay requirements are not violated. At the same time, the rate control algorithm allows the best effort traffic to fully use the residual bandwidth left by the real-time traffic, thereby achieving high channel utilization