Bandwidth Monitoring in Multi-Rate 802.11 WLANs with Elastic Traffic Awareness

We present a lightweight algorithm for the estimation of the node achievable throughput and available bandwidth in IEEE 802.11 wireless networks. We consider a multirate WLAN with access point (AP), where there may be both elastic and inelastic traffic flows. Through our algorithm and leveraging previous theoretical results, the AP can estimate: (i) the available bandwidth that a new station wishing to associate with the AP can use, (ii) the impact on the system performance of admitting the new station, (iii) the bandwidth still available (if any) for inelastic traffic. The above quantities can be effectively used for admission control in WLANs and load balancing among APs with overlapping coverages. Indeed, simulation results show that the estimates yielded by our algorithm accurately reflect the system throughput behavior when there are both elastic and inelastic flows, in the uplink and downlink directions.