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

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.