With the increasing availability of flexible wireless 802.11 devices, the potential exists for users to selfishly manipulate their channel access parameters and gain a performance advantage. Such practices can have a severe negative impact on compliant stations. To enable access points to counteract these selfish behaviours and preserve fairness in wireless networks, in this paper we propose a policing mechanism that drives misbehaving users into compliant operation without requiring any cooperation from clients. This approach is demonstrably effective against a broad class of misbehaviours, soundly-based, i.e. provably hard to circumvent and amenable to practical implementation on existing commodity hardware.
We provide the first rigorous analysis of proportional fairness in 802.11 WLANs. This analysis corrects prior approximate studies. We show that there exists a unique proportional fair rate allocation and completely characterise the allocation in terms of a new airtime quantity, the total air-time. In this paper we propose a feedback-based scheme to penalise misbehaving nodes in an 802.11 network based on gains achieved due to their (mis)configuration. Only the access point (AP) is modified and the scheme requires no additional communication or cooperation from other nodes. We achieve this by failing to send MAC-level ACKs with a probability determined by the online feedback scheme. The scheme is designed so that it can incentivise nodes to configure themselves correctly and avoids the need to explicitly detect misbehaving nodes.