Performance of rate-adaptive wireless-LAN

The quality of different applications over rate-adaptive Wireless Local Area Networks (WLAN) is investigated. Therefore, we extend an analytical model of rate-adaptive WLAN at bit and packet level from previous work by including TCP flows and voice over IP applications at flow level. The stations are modelled as M/G/1/B queueing systems. The final model results in a set of non-linear equations, which are solved to calculate performance metrics of these applications, such as loss rate and delay. We will show that links over WLAN are highly asymmetric in terms of delay and loss rate and that the performance depends mainly on the locations of the users and the number of these. Further we show that collisions do not play a significant role in the overall packet loss rates. We verify our findings by means of simulations. (c) 2006 Elsevier GmbH. All rights reserved.