Increased AP density in enterprise WLANs leads to increasing RF interference and decreasing performance. An important step towards mitigating this problem is to construct precise RF maps in the form of a conflict graph. Prior work on conflict graph construction, mostly using bandwidth tests [17], suffers from two problems: a) It is limited to static settings and cannot support mobility, and b) It incurs significant measurement overhead and must be performed offline (e.g. overnight). An alternative to bandwidth tests is "micro-probing" [4] that operates on millisecond-level time scales. Micro-probing rapidly constructs the conflict graph even while the network is in use (i.e. online). While interesting in principle, micro-probing has only been evaluated in simulation. In this work, we empirically study micro-probing on a 40-node wireless testbed. In doing so, we not only show that micro-probing is in fact practically realizable, but also present key insights that drive the design choices for our implementation. We benchmark micro-probing against bandwidth tests and find that micro-probing is just as accurate but with up to a 400 times reduction in overhead. Finally, we argue that a successful implementation of micro-probing opens up the space for further innovations in real-time WLAN adaptation and optimization.

Rural Internet kiosks in developing countries can cost-effectively provide communication and e-governance services to the poorest sections of society. Unfortunately, a variety of technical and non-technical issues have caused most kiosk deployments to be unsustainable [1]. KioskNet addresses the key technical problems underlying kiosk failure by using robust ‘mechanical backhaul’ for connectivity [2], and by using low-cost and reliable kiosk controllers to support services delivered from one or more recycled PCs. KioskNet also addresses related issues such as security, user management, and log collection. In this paper, we describe the KioskNet system and outline its hardware, software, and security architectures. We describe a pilot deployment, and how we used lessons from this deployment to re-design our initial prototype.