An Analytical Model for IEEE802.11 Networks Running Query-Based Applications

An emerging field of application for IEEE 802.11 are Wireless Sensor Networks (WSNs) in which the network nodes do not have significant power and cost constraints, such as Vehicular WSNs employing the "under construction" standard IEEE 802.11p. In this paper we provide an analytical evaluation of the performance of IEEE 802.11 Distributed Coordination Function (DCF) in a query-based scenario. In such scenario each node transmits a single packet to a gathering center called sink only upon the sink request. Therefore previous analyses with the assumption of data traffic saturation [8] do not apply as in our case the number of nodes competing for the channel as well and the probability of packet collision are time dependent. Our mathematical model allows the evaluation of the probability that a node succeeds when accessing the channel as a function of time, packet length and number of network nodes. We also validate the results obtained with the model through simulation.