SmartAP: Practical WLAN backhaul aggregation

In light of the growing disparity between residential broadband and 802.11 speeds, Access Point (AP) backhaul aggregation has been proposed by the research community as a service whereby residential customers may enjoy higher throughput when in range of participating 802.11 APs. The fundamental assumption of these works is that 802.11 clients can be modified at driver level. However, due to the high diversity of 802.11 chipsets and drivers in the market, the cost of modifying any WiFi driver for any operating system is prohibitive, which in turn makes the solution unpractical for commercial deployment. In this paper, we propose a WLAN backhaul aggregation scheme that works with unmodified 802.11 clients. We introduce SmartAP, a single-radio 802.11 AP, that can deliver higher throughput to its off-the-shelf clients by aggregating the backhaul capacity of APs in range, even if these APs are in different radio channels. SmartAP reaches this goal without adding new radio hardware to the network. We build SmartAP with off-the-shelf hardware and evaluate its performance in a network testbed of 6-nodes with unmodified smartphones and laptops as clients. We evaluate the conditions under which SmartAP leads to gains comparable to state-of-the-art approaches with client-side modifications and we demonstrate that using a two-hop transmission to access additional backhaul capacity yields substantial benefits.