Energy Harvesting Active Networked Tags (EnHANTs) - Measurements, Algorithms, and Prototyping
Abstract: We discuss a new type of wireless devices in the domain between RFIDs and sensor networks – Energy Harvesting Active Networked Tags (EnHANTs - http://enhants.ee.columbia.edu). Future EnHANTs will be small, flexible, and self-powered devices that can be attached to objects that are traditionally not networked (e.g., books, toys, clothing), thereby providing the infrastructure for various Internet-of-Things tracking applications. We describe the paradigm shifts associated with the underlying enabling technologies. Then, we present the results of an indoor light energy measurement campaign and of a kinetic energy study that have been conducted in order to characterize the energy availability for EnHANTs. We discuss low complexity energy-harvesting-adaptive algorithms which aim to allocate resources uniformly in respect to time. Finally, we present the design considerations for the EnHANT prototypes which harvest indoor light energy using custom organic solar cells, communicate and form multihop networks using ultralow-power Ultra-Wideband Impulse Radio (UWB-IR) transceivers, and adapt their communications and networking patterns to the energy harvesting and battery states. We also describe a small scale EnHANTs testbed that uniquely allows evaluating different algorithms with trace-based light energy inputs and discuss experimental results.
Based on joint works with M. Gorlatova, G. Grebla, J. Marasevic, R. Margolies and the groups of P. Kinget, J. Kymissis, D. Rubenstein, and L. Carloni (Columbia University).