Infrastructure mobility: A what-if analysis

Mobile computing has traditionally implied mobile clients connected to a static infrastructure. This paper breaks away from this point of view and envisions the possibility of injecting mobility into infrastructure. We envision a WiFi access point on wheels, that moves to optimize desired performance metrics. Movements need not necessarily be all around the floor of a home or office, neither do they have to operate on batteries, or connect wirelessly to the Internet. At homes, they could remain tethered to power and Ethernet outlets while moving in small areas (perhaps under the study table). In offices of the future, perhaps APs could move on tracks installed on top of false ceilings. This paper explores the viability of this vision and presents early measurements from various home/office environments. We find that complex multipath characteristics of indoor environments cause large fluctuations in link quality even when the antenna moves in the scale of few centimeters. Mobile APs can leverage this spatial variation by relocating to a location that is strong for its own clients and yet weak from its interferers. Experiment results show that such micro-mobility itself can offer up to 2x throughput gains. Additional opportunities may emerge, such as in energy savings, security, QoS, and even in applications such as indoor localization. While this paper explores a small fraction of the landscape of opportunities, the results have been far more promising than what we had anticipated originally.