Smart traffic scheduling in 802.11 WLANs with access point

In distributed systems like 802.11 WLANs, simple requirements like providing fair access to all users are hard to get by because of the random access protocol and the unpredictability of the wireless channel. The main contribution of this paper is the proposal of an LLC-layer algorithm that is implemented at both AP and WSs. The algorithm aims at guaranteeing fair access to the medium to every user, by awarding longer transmission opportunities to WSs that experienced short channel failures. At the same time, an adaptive contention window setting protects downlink traffic from the unbalancement typical of WLANs with AP. We outline the proposed solution and present a simulation study that shows the effectiveness of the new algorithm in comparison to the standard 802.11b implementation both under a TCP and a UDP traffic scenario.