what is Ambient Backscatter
Communication between devices without any power or radio waves of their own is called ambient backscatter communication. The devices communicate based on reflection or absorption of the existing TV or cellular transmissions around. This new concept is recently developed by university of washington engineers. The designed prototype ambient backscatter devices communicate at the data rates of 1 kbps upto distance of 2.5 feet and upto 1.5 feet in outdoor and indoor scenarios respectively. The complete physical layer and network stack has been designed by engineers to take care of communication between the devices.
The system utilizes existing ambient RF radiations as the source of power and also utilizes the same as wireless medium for communication between devices.
As shown in the figure, 0 is transmitted by way of absorption of the TV signals and 1 is transmitted by way of reflection of the TV signals.
In the design of ambient backscatter there are three main parts viz. transmitter,receiver and harvester. Harvester is the circuit which extracts energy from ambient RF signals to provide power to the complete board. The device say 'A' inserts additional information to be sent to the other device say 'B' over the existing received ambient encoded TV signals from TV tower. The devices work at UHF TV frequency bands
Ambient backscatter will have many applications such as smart homes, wearable computing devices and more.
This page covers basics of the system, to know more one can visit following link of the university: