Ambient backscatter: wireless communication out of thin air

We present the design of a communication system that enables two devices to communicate using ambient RF as the only source of power. Our approach leverages existing TV and cellular trans-missions to eliminate the need for wires and batteries, thus enabling ubiquitous communication where devices can communicate among themselves at unprecedented scales and in locations that were pre-viously inaccessible. To achieve this, we introduce ambient backscatter, a new com-munication primitive where devices communicate by backscatter-ing ambient RF signals. Our design avoids the expensive process of generating radio waves; backscatter communication is orders of magnitude more power-efficient than traditional radio communica-tion. Further, since it leverages the ambient RF signals that are al-ready around us, it does not require a dedicated power infrastruc-ture as in traditional backscatter communication. To show the fea-sibility of our design, we prototype ambient backscatter devices in hardware and achieve information rates of 1 kbps over distances of 2.5 feet and 1.5 feet, while operating outdoors and indoors re-spectively. We use our hardware prototype to implement proof-of-concepts for two previously infeasible ubiquitous communication applications