Analysis and modeling of errors at the 802.11b link layer

In this paper, we analyze the errors observed at the link layer of an 802.11b network. Our analysis at all supported bitrates (i.e., 2, 5.5. and 11 Mbps) establishes that the error patterns are not memoryless, and therefore, they exhibit a certain level of temporal dependencies. Thus, we evaluate the suitability of a two-state Markov model to capture the channel behavior. Non-stationarity of the error patterns renders such a simplistic model inadequate, and hence, we consider higher order models. This formulates a key contribution of this paper, and that is, a hierarchical Markov model, which captures the non-stationarity of the channel while employing real-time application-specific considerations to determine state-transition probabilities.