This project proposes to lay the algorithmic foundations for ambient backscatter, a novel communication mechanism that transforms existing wireless signals (e.g., TV, cellular, and Wi-Fi transmissions) into both a source of power as well as a communication medium: thus, enabling communication without requiring additional bandwidth and/or power. Ambient backscatter networks have the potential to introduce a new practical model of communication; reduce world-wide battery usage and energy consumption of small computing devices; and reduce the human and economic costs of maintaining power.
The proposed research, if successful, can open up ubiquitous communication applications in multiple domains including Internet-of-Things, wearable and mobile devices, as well as infrastructure-free localization. As small Internet-of-Things devices are increasingly embedded in objects and environments such as thermostats, books, furniture, and even implantable medical devices; a novel primitive like ambient backscatter would enable ubiquitous communication at unprecedented scales (without batteries or wires) and in location and times that were previously infeasible (day and night, indoors and outdoors). Further, since ambient backscatter consumes orders of magnitude lower power than traditional radio communication, it can enable always-on communication for battery-operated mobile devices such as smart phones and tablets as well as wearable devices such as head-on displays and smart watches. Finally, since with ambient backscatter, battery-free devices can communicate with each other, they are aware of their context and the devices around them; this enables missing-item localization in warehouses and medical facilities that are infeasible with existing RFID technologies, without an extensive deployment of power infrastructure.
The proposed research will produce algorithms, designs, circuits, and system implementations that will enable communication and networking out of thin air. The key challenge in achieving this is that existing signals such as TV, cellular, and Wi-Fi transmissions already carry data and are fast-changing signals; transmitting additional information on top of these signals can be challenging. Further, since the proposed devices are powered using these ambient signals, circuit designs that can harvest energy from them efficiently are needed. This research will design algorithms for enabling communication without requiring additional bandwidth and/or power. This project will also design a complete network stack for this new communication primitive that will enable multiple such devices to co-exist with each other as well as with legacy receivers and leverage algorithms and techniques to enable new functionalities such as battery-free localization and demonstrate their applications in a number of domains including inventory, and healthcare.
