Ambient Backscatter transforms existing wireless signals into both a source of power and a communication medium. It enables two battery-free devices to communicate by backscattering existing wireless signals.
Backscatter communication is orders of magnitude more power-efficient than traditional radio communication. Further, since it leverages the ambient RF signals that are already around us, it does not require a dedicated power infrastructure as in RFID.
Backscatter communication is orders of magnitude more power-efficient than traditional radio communication. Further, since it leverages the ambient RF signals that are already around us, it does not require a dedicated power infrastructure as in RFID.
As computing devices become smaller and more numerous, powering them becomes more difficult; wires are often not feasible, and batteries add weight, bulk, cost, and require recharging/replacement that is impractical at large scales. Ambient backscatter communication solves this problem by leveraging existing TV and cellular transmissions, rather than generating their own radio waves. This novel technique enables ubiquitous communication where devices can communicate among themselves at unprecedented scales and in locations that were previously inaccessible.
Ambient Backscatter uses existing radio frequency signals, such as radio, television and digital telephony, to transmit data without a battery or power grid connection. Each such device uses an antenna to pick up an existing signal and convert it into tens to hundreds of micro watts of electricity.It uses that power to modify and reflect the signal with encoded data. Antennas on other devices, in turn, detect that signal and can respond accordingly.
Initial implementations can communicate over several feet of distance, even with transmission towers up to 10.5 kilometers (6.5 mi) away. Transmission rates were 1K bits per second between devices situated 0.45 meters (1 ft 6 in) apart inside and 0.75 meters (2 ft 6 in) apart outside, sufficient to handle text messages or other small data sets. Circuit sizes can be as small as 1 sq. mm.
This approach would let mobile and other devices communicate without being turned on. It would also allow unpowered sensors to communicate, allowing them to be placed in places where external power cannot be conveniently supplied.
