Pre-estimation Number of Contending Nodes in an IEEE 802.11 WLAN

摘要

Performance of IEEE 802.11 distributed coordination function (DCF) is very sensitive to the number n of nodes contending the channel. And the value n can be expressed as function of frame collision probability of any given node. Each node can get the arithmetical average value of its frame collision probability by itself during its transmission. Hence it may figure out the value n, but this method cannot react in time to the changes of n. A virtual DCF algorithm, VDCF, is proposed in this paper, which can pre-estimate the number of contending nodes by means of the virtual frame collision probability before the real frames are transmitted. Simulation results show that this approach is both high accuracy and prompt reactivity to changes in the number of contending nodes.