End-to-End Available Bandwidth Estimation in Multi-Hop IEEE 802.11b Ad Hoc Networks

In this paper we estimate the end-to-end capacity and available bandwidth of a path between a pair of nodes in an IEEE 802.11b ad hoc network using dispersion traces between packet pairs of different lengths. The pairs of packets that suffer the minimum delay are used to estimate the maximum achievable transmission rate as a function of packet length, for any packet length, while the variability of the dispersions is used to estimate the fraction of that capacity that is available for data transmission. To model the dependence of the variability of the dispersion traces on the true fraction of available capacity, we use a neuro-fuzzy estimator trained on data collected from a large set of real and simulated scenarios. The system is shown to provide accurate estimates (within 15% of accuracy 80% of the time on the test data), to be efficient in the use of communication resources (transmits 48 kbps during the test), and to present low computational cost (about 500 floating point operations per estimate).