Ambient Backscatter Communication: Principles and Applications

Ambient backscatter communication refers to communication between devices that lack their own power source or radio wave transmitters. These devices communicate by reflecting or absorbing existing ambient radio frequency (RF) signals, such as TV or cellular transmissions.

This innovative concept was recently developed by engineers at the University of Washington. Their prototype devices achieve data rates of up to 1 kbps over a distance of 2.5 feet indoors and 1.5 feet in outdoor environments. The engineers designed the complete physical layer and network stack to facilitate communication between the devices. The system relies on ambient RF radiation as both its power source and wireless communication medium.

As illustrated in the figure above, a ‘0’ is transmitted by absorbing TV signals, while a ‘1’ is transmitted by reflecting them. The design of an ambient backscatter system typically involves three key components: a transmitter, a receiver, and a harvester.

The harvester circuit extracts energy from ambient RF signals, providing power to the entire device. A device, say ‘A’, inserts additional information to be transmitted to another device, say ‘B’, over the existing, received, ambient-encoded TV signals originating from a TV tower. The devices typically operate within UHF TV frequency bands.

Ambient backscatter technology holds promise for various applications, including smart homes and wearable computing devices.

For more detailed information, you can visit the University of Washington’s website: https://abc.cs.washington.edu/

Ambient Backscatter Architecture and Working

Refer to the following resources for a deeper understanding of ambient backscatter architecture and its operation, including circuit details. The working principles of both the ambient backscatter transmitter and receiver (transceiver) circuits are explained.