Ambient backscatter uses existing
radio frequency
Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the u ...
signals, such as
radio
Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...
,
television
Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...
and
mobile telephony
Mobile telephony is the provision of wireless telephone services to mobile phones, distinguishing it from fixed-location telephony provided via landline phones. Traditionally, telephony specifically refers to voice communication, though th ...
, 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 microwatts 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 if the
transmission towers are up to away. Transmission rates were 1k bits per second between devices situated apart inside and apart outside, sufficient to handle text messages or other small data sets. Circuit sizes can be as small as 1 sq. mm.
[ Later implementation uses Wi-Fi, ]Bluetooth
Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is li ...
, FM radio and LoRa
LoRa (from "long range", sometimes abbreviated as "LR") is a physical proprietary radio communication technique. It is based on spread spectrum modulation techniques derived from chirp spread spectrum (CSS) technology. It was developed by Cycleo ...
transmissions. There exists technology to extend backscatter communication range up-to 3.4 kilometers while consuming 70 μW power at the backscatter tag.
This approach would let mobile and other devices communicate without being turned on. It would also allow unpowered sensors to communicate, allowing them to function in places where external power cannot be conveniently supplied.
In 2021, researchers integrated RF backscatter with Li-Fi
Li-Fi (commonly referred to as LiFi) is a wireless communication technology which utilizes light to transmit data and position between devices. The term was first introduced by Harald Haas during a 2011 TEDGlobal talk in Edinburgh.
Li-Fi is a ...
to achieve greater range via PassiveLiFi.
See also
* Backscatter
In physics, backscatter (or backscattering) is the reflection of waves, particles, or signals back to the direction from which they came. It is usually a diffuse reflection due to scattering, as opposed to specular reflection as from a mirror, ...
References
External links
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Ambient Backscatter: Wireless Communication Out of Thin AirTurbocharging Ambient Backscatter CommunicationAmbient Backscatter
*
*{{cite journal, doi=10.1109/TWC.2016.2635654, title=Noncoherent Detections for Ambient Backscatter System, year=2017, last1=Qian, first1=Jing, last2=Gao, first2=Feifei, last3=Wang, first3=Gongpu, last4=Jin, first4=Shi, last5=Zhu, first5=Hongbo, journal=IEEE Transactions on Wireless Communications, volume=16, issue=3, pages=1412–1422, s2cid=28878453
Wireless networking hardware
Wireless sensor network
Energy harvesting