最优常数竞争窗口对WLAN的性能优化研究

Using optimal constant contention window to optimize performance of WLAN

在IEEE 802.11网络中可通过监控信道获得系统中竞争节点数目,而IEEE 802.11DCF协议的设计并没有利用这一参数。因此,首先分析了在IEEE 802.11DCF中使用常数竞争窗口的可行性,提出了DCF/CCW这一改进协议,并对其进行系统吞吐量和接入时延分析。在此基础上,提出根据网络中竞争节点数目来选择最优常数竞争窗口的optimal-DCF/CCW协议。在optimal-DCF/CCW中,各终端首先利用S-DCF算法估算网络中竞争节点的数目,据此选择所应采用的最优常数竞争窗口Wopt的值。仿真表明,与IEEE 802.11DCF相比较,opti-mal-DCF/CCW优化算法能够显著提高饱和系统性能。

In IEEE 802. 11 networks, the number of competing terminals could be estimated through monitor the channel. However, the proposed IEEE 802.11 DCF doesn＇ t utilize this information. Analyzed the feasibility of using constant contention window and proposed hence the DCF/CCW protocol. Based on the performance analyze of DCF/CCW, proposed an optimization algorithm of optimal-DCF/CCW to give the terminals an optimal constant contention window according to the estimated number of competing nodes. In optimal-DCF/CCW, each terminal firstly estimates the number of competing terminals with S-DCF al- gorithm and then selects its optimal constant contention window. Simulation results show that compare with IEEE802.11DCF, the optimal-DCF/CCW can significantly improve the system saturation performance.