A measurement study of bandwidth estimation in IEEE 802.11g wireless LANs using the DCF

Abstract

In this paper we present results from an extensive measurement study of wireless bandwidth estimation in IEEE 802.11 WLANs using the distributed coordination function. We show that a number of known iterative probing methods, which are based on the assumption of first-come first-serve scheduling, can be expected to report the fair bandwidth share of a new flow rather than the available bandwidth. Our measurement results confirm this view and we conclude that under the current probe gap and probe rate models the fair share can only be loosely related to the available bandwidth. Like a few other studies we report that packet sizes have a tremendous impact on bandwidth estimates. Unlike these studies we can, however, show that minor modifications to known methods for wired networks, such as Pathload, can solve previously indicated limitations of these methods in wireless networks. © 2008 Springer-Verlag Berlin Heidelberg.