非饱和状态下IEEE 802.11 DCF的性能分析

Performance analysis of the IEEE 802.11 DCF in the non-saturation state

在非饱和状态下,针对具有多业务支持能力的IEEE 802.11分布式协调功能,提出了一种简单有效的性能分析模型.该模型中引入了“虚拟时隙”以及“虚拟时隙状态”的概念,近似地将无线终端的行为在时间上离散化.以此为基础用二维Markov链对系统的性能进行了建模,利用该模型得到了平均分组传输延迟的近似闭合解,并提出了控制所有通信业务的平均分组传输延迟方法,有助于进一步研究如何对系统性能进行预测与优化.

In the case of the non-saturation state, a simple and effective analysis model is proposed for the IEEE 802.11 DCF with multiple traffic supporting. In the model, the concepts of ＂Virtual Time Slot＂ and ＂Virtual Time Slot State＂ are introduced, which discretize the behavior of a wireless terminal. Based on it, a two dimensional Markov chain is used in the model. By using the proposed model, the approximated closed form solutions of the average packet delays are obtained. Moreover, the method for controlling the average packet delays of all the traffic flows is given. The proposed model and the obtained analytical results help one to further study how to predict and optimize the system performance.