Traditional fair queuing algorithms designed for wired networks attempt to provide a fair allocation of the bandwidth on a shared link [8,9,24]. Previous work on Fair scheduling in wireless networks generally adopted this notion of fairness [20,22,27]. However, unlike wired links, typical wireless networks are half-duplexed in that the channel needs to be shared for both transmitting and receiving packets.
In AP-based WLANs, each AP is just a facilitator and thus the resource used by it to transmit packets destined to a client should be accounted as part of the resource used by the client or its flow. In the rest of this paper, we focus on providing fair channel time shares among competing nodes, not flows. The channel time used by a competing node is the total channel time used in both transmitting and receiving packets to and from the AP. We believe that this notion is more intuitive than the traditional notion of providing fair resource allocations among competing flows. The latter is more suitable for wired networks and ad hoc wireless networks, where there are no facilitators present (e.g. when the medium is shared by nodes in a distributed manner) or the facilitator is the only one transmitting on the medium (e.g. router scheduling packets to transmit on an output link).