Dynamic Contention Window Control Mechanism to Achieve Fairness between Uplink and Downlink Flows in IEEE 802.11 Wireless LANs
Dynamic Contention Window Control Mechanism to Achieve Fairness between Uplink and Downlink Flows in IEEE 802.11 Wireless LANs
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DOI：
10.1109/twc.2008.070304
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发表时间：
2008-09
影响因子：
10.4
通讯作者：
B. H. S. Abeysekera;T. Matsuda;T. Takine
中科院分区：
文献类型：
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作者：
B. H. S. Abeysekera;T. Matsuda;T. Takine
本文考虑了 IEEE 802.11 无线 LAN 中上行链路和下行链路流之间的公平性问题，其中上行链路流在无线带宽使用方面优于下行链路流。作为解决这种不公平问题的方法，我们建议修改接入点 (AP) 的 IEEE 802.11 MAC 协议。我们的方案动态控制AP的最小竞争窗口大小，并为它们提供充足的机会来获取传输权。注意，所提出的方案不需要对无线终端处的MAC协议进行任何修改。此外，最佳最小竞争窗口大小由下行链路流的总分组速率与上行链路流的分组速率之比的显式函数给出。通过UDP和TCP流的仿真实验表明，该方案能够实现上下行流的公平性。
This paper considers a fairness issue between uplink and downlink flows in IEEE 802.11 wireless LANs, where uplink flows dominate over downlink flows in terms of wireless bandwidth usage. As a solution to this unfairness, we propose modifying the IEEE 802.11 MAC protocol at access points (APs). Our scheme dynamically controls the minimum contention window size at APs and provides an ample opportunity for them to acquire the transmission right. Note that the proposed scheme does not require any modifications in the MAC protocol at wireless terminals. Furthermore, the optimal minimum contention window size is given by an explicit function of the ratio of the total packet rate of downlink flows to the packet rate of an uplink flow. Through simulation experiments with UDP and TCP flows, we show that the proposed scheme can achieve fairness between uplink and downlink flows.