Performance evaluation of IEEE 802.11 with stochastic reward nets

In this paper, we present a performance study to evaluate the mean delay and the average system throughput of IEEE 802.11 based wireless local area networks (WLANs). We consider the distributed co-ordination function (DCF) mode of medium access control (MAC). The current literature provides very few models to analyze the DCF performance. Existing analytical studies of the IEEE 802.11 DCF do not take into account, the effect of freezing the backoff counter at a station, due to channel capture by other stations. We present a stochastic reward net (SRN) based analytical model to evaluate the mean delay and the average system throughput of the IEEE 802.11 DCF. Our model takes into account, the effect of freezing of the backoff counter, and the maximum number of packet retrials. We validate our analytical model by comparison with simulations.