Available Bandwidth Estimation in IEEE802.11b Network Based on Non-Intrusive Measurement

In this paper, we present a nonintrusive and time-based mechanism to estimate the available bandwidth of a node with the nodes collision and backoff stage taken into account. We first give a new definition of available bandwidth in IEEE802.11b network to reflect the collision and contention between nodes. Then, the investigated node obtains the NAV information of its neighbors within the measurement duration through CSMA/CA mechanism and stores the information into its routing buffers. Subsequently, we obtain the available bandwidth of the investigated node by calculate the ratio of its channel accessible time to the measurement duration, which should subtract the sum of NAV values of its neighbors and the backoff time itself from the measurement duration. Simulation shows the proposed scheme is accurate and can completely reflect the collision and contention between nodes