Wednesday, 01 October 2014
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Ambient backscatter promises battery-free communications

University of Washington engineers have created a new wireless communication system that allows devices to interact with each other without relying on batteries or wires for power.

Using so-called ambient backscatter, these devices can reportedly interact with users and communicate with each other without using batteries because they exchange information by reflecting or absorbing pre-existing radio signals from TV and cellular transmissions.

The researchers have built small, battery-free devices with antennas that can detect, harness and reflect a TV signal, which then is picked up by other similar devices.

Using ambient backscatter, these devices can interact with users and communicate with each other without using batteries. They exchange information by reflecting or absorbing pre-existing radio signals

Source: University of Washington

Using ambient backscatter, these devices can interact with users and communicate with each other without using batteries. They exchange information by reflecting or absorbing pre-existing radio signals

‘We can repurpose wireless signals that are already around us into both a source of power and a communication medium,’ said lead researcher Shyam Gollakota, a UW assistant professor of computer science and engineering. ‘It’s hopefully going to have applications in a number of areas including wearable computing, smart homes and self-sustaining sensor networks.’

The researchers published their results at the Association for Computing Machinery’s Special Interest Group on Data Communication 2013 conference currently taking place in Hong Kong.

‘Our devices form a network out of thin air,’ said co-author Joshua Smith, a UW associate professor of computer science and engineering and of electrical engineering. ‘You can reflect these signals slightly to create a Morse code of communication between battery-free devices.’

According to the university, smart sensors could be built and placed permanently inside nearly any structure, then set to communicate with each other. It is claimed sensors placed in a bridge could monitor the health of the concrete and steel, then send an alert if one of the sensors picks up a hairline crack. The technology can also be used for communication – text messages or emails – in wearable devices.

The researchers tested the ambient backscatter technique with credit card-sized prototype devices placed within several feet of each other. For each device the researchers built antennas into ordinary circuit boards that flash an LED light when receiving a communication signal from another device.

Researchers demonstrate how one payment card can transfer funds to another card by leveraging the existing wireless signals around them. Ambient RF signals are both the power source and the communication medium

Source: University of Washington

Researchers demonstrate how one payment card can transfer funds to another card by leveraging the existing wireless signals around them. Ambient RF signals are both the power source and the communication medium

Groups of the devices were tested in a variety of settings in the Seattle area, including inside an apartment building, on a street corner and on the top level of a parking garage. These locations ranged from less than half a mile away from a TV tower to about 6.5 miles away.

Researchers demonstrated how one payment card can transfer funds to another card by leveraging the existing wireless signals around them; ambient RF signals are the power source and the communication medium.

They found that the devices were able to communicate with each other, including the ones farthest from a TV tower. The receiving devices picked up a signal from their transmitting counterparts at a rate of 1 kilobit per second when up to 2.5 feet apart outdoors and 1.5 feet apart indoors. This is enough to send information such as a sensor reading, text messages and contact information.

It is further claimed that the new system could be built into devices that do rely on batteries, such as smartphones. It could be configured so that when the battery dies, the phone could still send text messages by leveraging power from an ambient TV signal.

The researchers plan to continue advancing the capacity and range of the ambient backscatter communication network.

 

Source: University of Washington

University of Washington engineers have created a new wireless communication system that allows devices to interact with each other without relying on batteries or wires for power


Readers' comments (8)

  • Ambient Backscatter: an amazing communication tool. Revolutionary.

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  • Transferring funds by leveraging existing wireless signals....bet the criminal fraternity will be monitoring that one

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  • Criminality aside, this is clever. It is a new concept of manipulating a small portion of the electromagnetic waves that surround us all constantly. The only analogy I can think of is the way that those of us cursed with sensitive hearing can detect the change in ambience caused by a person in a dark room. I just wish it was a British development.

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  • If there is enough power for these devices, what are the EM waves doing to our bodies? Time for more research on the effects on us and other living things?

    Otherwise a good use of power in the environment!

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  • I'm sure Nikola Tesla would be very happy to see his 1893 power by wireless ideas in action. (Possibly Hutin & LeBlanc's successors should be checking to see if their US patent 527,857 could be invoked!)
    What comes around, goes around.

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  • Cool innovative idea of communication.This can be useful in times of natural disaster or loss of communication signals.

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  • Bearing in mind prosecutions, typically of farmers. for harvesting RF energy, and possibly energy from power transmission lines, it would be interesting to know if harvesting power in this way is lawfull in England.

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  • Why are the researchers planning "... to continue advancing the capacity and range of the ambient backscatter communication network."

    when they should be joining up with sales and marketing gurus to find a real demand for this technology! Do you really need to know that you left your keys on the couch. No, not really, it's unlikely you'll pay for this. Do you really want (a cheaper method) to know that your car is where you left it... yes, I'd probably pay for that.

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