Researchers find a way to use Wi-Fi signals as a power source

The increasing ubiquity of Wi-Fi is a blessing (unless you’re in a national park) for a number of business users. But like almost any technology it needs a power source.

Maybe not. Researchers at the University of Washington think some low-power devices may be able to run on Wi-Fi, TV or cellular radio waves. The technology is called Wi-Fi backscatter, and the initial thought is it could be used to power devices for the so-called Internet of Things that have a special receiver tag stuck on them. That’s right — the devices would be battery- and AC-free.

You can read the researchers’ paper here.

It is possible to re-use existing Wi-Fi infrastructure to provide Internet connectivity to RF-powered devices, they argue, and the paper outlines a prototype that does it using off the shelf Wi-Fi access points. Communications rates of up to 1 kbps, but only up to 2.1 meters away from the transmitter. Researchers believe the range can be extended to 20 meters.

Briefly, the tag does it by modulating the Wi-Fi channel so it conveys the 1 and 0 bits by reflecting or absorbing packets it receives.

While the bit rates in the prototype aren’t high, the researchers believe the ability to communicate at even low rates would be critical for the adoption of an RF-powered Internet of Things. According to a news report, they have filed patents on the technology

Who cares? If you believe that the IoT will be composed of billions of devices — that is, almost everything imaginable can be connected to the Internet — then a low- or-no energy technology will have to be discovered.

The research was funded in part by chipmaker Qualcomm’s Innovation Fellowship.

Howard Solomon
Howard Solomon
Currently a freelance writer, I'm the former editor of and Computing Canada. An IT journalist since 1997, I've written for several of ITWC's sister publications including and Computer Dealer News. Before that I was a staff reporter at the Calgary Herald and the Brampton (Ont.) Daily Times. I can be reached at hsolomon [@]

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