In this paper we consider transport layer approaches for achieving high rate, low delay communication over edge paths where the bottleneck is a modern WLAN which can aggregate multiple packets into each WLAN frame. We show that regulating send rate so as to maintain a target aggregation level can be used to avoid queue buildup at the WLAN AP. We derive an approximate downlink throughput model for WLANs using aggregation, verify its accuracy using experimental measurements and using this determine a convex low delay rate region. This allows us to derive a low delay proportional fair rate allocation for which we present a prototype transport layer implementation.
We consider the proportional fair rate allocation in an 802.11 WLAN that supports multi-user MIMO (MU-MIMO) transmission by one or more stations. We characterise, for the first time, the proportional fair allocation of MU-MIMO spatial streams and station transmission opportunities. While a number of features carry over from the case without MU-MIMO, in general neither flows nor stations need to be allocated equal airtime when MU-MIMO is available. We consider virtualization of network capacity in 802.11 WLANs and mesh networks. We show that allocating total airtime slices to ISPs is analogous to allocating a fraction of available time-slots in TDMA. We establish that the max-min fair flow rate allocation within an ISP airtime slice can be characterized independently of the rate allocation policy employed in other slices. Building on these observations, we present a lightweight, distributed algorithm for allocating airtime slices among ISP and max-min fair flow rates within each slice. 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.