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Power cord freedom: NCSU researchers create wireless system mixing energy, high-speed data

The Broadband Report

Sep, 18 2017, 11:24 AM

“Our system is comparable in power transfer efficiency to similar wireless power transfer devices, and shows that you can design a wireless power link system that retains almost all of its efficiency while streaming a movie on Netflix.”

- NCSU's Dr. David Ricketts

RALEIGH - Imagine being able to binge videos without having to worry about draining the power of your mobile device, which doesn't have to stay plugged in. That's the advance unveiled by researchers at N.C. State - and it's freely available for private sector development.

Dr. David Ricketts, who is widely known for his work on creating 3D tracking of footballs in collaboration with Disney Research and is an associate professor of electrical and computer engineering, led the development of the new power-data mixing system based on research into WPT, or wireless power transfer.

This is NOT data over power lines as being developed by AT&T. This is a true mix of bits for data as well as energy to keep devices performing while users binge.

"It is a breakthrough for impact," Ricketts tells The Skinny. "Similar to having a phone with GPS build in, created so many amazing apps and value added features for users."

Yet as big a breakthrough that this is, especially for consumer convenience, Ricketts says NCSU isn't seeking patent coverage.

" [Y]ou can't patent GPS+Phone," he explains, noting that the "breakthrough was a conceptual one for us in that we looked at the problem differently and saw that we could make it work. 

"We are not pursuing a patent, since reducing it to practice produced a very similar  apparatus to what is being already used, but used differently than previous (how we are able to transmit both data and power)."

He adds that the private sector is welcome to adopt the system: "This technique could be used by the public now based on our paper."

The NCSU team's research was published in the IEEE Antennas and Wireless Propagation Letters.

So how does this system differ from AT&T's recent advance in delivering data via power lines?

"The AT&T system doesn't deliver wireless power, it just delivers internet, much like you get today," Ricketts points out. "They are using the power line infrastructure (poles, wires, etc.) to deliver the standard internet you  get on your phone or home. They do not deliver power to any devices,  except through the wall plug with a wire, i.e. they do not have any 
wireless power. So its just a novel way to distributed Wi-Fi like AT&T  already does with their cell towers. No power."

Power cord freedom

Ricketts points out that the NCSU research builds off wireless re-emerging as a means to deliver power and thus "free us from the power cord."

“One of the most popular applications is in wireless cell phone charging pads. As many know, these unfortunately often require almost physical contact with the pad, limiting the usefulness of a truly ‘wireless’ power source," he explained to Matt Shipman of NCSU's news service.

"Recent work by several researchers have extended wireless power to ‘mid-range’ which can supply power at inches to feet of separation. While encouraging, most of the wireless power systems have only focused on the power problem – not the data that needs to accompany any of our smart devices today. Addressing those data needs is what sets our work apart here.”

Rickets, who earned a PhD in engineering and applied science at Harvard, worked in the private sector for eight years, developing integrated circuits for mix-signal, radio frequency and power management applications. He focuses much of his research on micro- and nano-integrated circuits, systems and devices for analog and high-speed applications, his bio at NCSU notes.

In a nutshell, the abstract of the paper explains NCSU's advance in the further development of WPT.


Paper's abstract

"Wireless power transfer (WPT) has gained renewed interest due to emerging low power applications and high efficiency. Coupled with power in many applications is the need for communication, whether for regulation of power transfer or for transfer of information between source and load. Several communication methods have been proposed for use with WPT, including adjacent channel communication (non-WPT), as well as WPT based methods, such as load modulation and passive backscattering; however approaches using the WPT link have historically been low speed (< 400 kbps). In this work, we report on an ultra-high data rate (3.39 Mbps) communication method that utilizes the WPT link for both power and communication transfer, operating at 13.56 Mhz, capable of 3.39 Mbps data transfer with an efficiency reduction of only <2%."


The concepts

The Skinny asked Ricketts to explain how this new system differs.

​"Most previous systems that had wireless power used a separate radio to deliver internet (like your Wi-Fi router, but in the building or city) or simply used cable or fiber to your house (not wireless). So your laptop  gets internet from the Wi-Fi radio, but has to plug into the wall for  power (no wireless power), your tablet, etc., same thing," he points out.

In testing, the NCSU team found that "when transferring almost 3 watts of power – more than enough to power your tablet during video playback – the system was only 2.3 percent less efficient when also transmitting 3.39 megabytes of data per second," Shipman reported.

"At 2 watts of power, the difference in efficiency was only 1.3 percent. The tests were conducted with the transmitter and receiver 16 centimeters, or 6.3 inches, apart, demonstrating the ability of their system to operate in longer-distance wireless power links."

Ricketts told Shipman: “People thought that efficient wireless power transfer requires the use of narrow bandwidth transmitters and receivers, and that this therefore limited data transfer. We’ve shown that you can configure a wide-bandwidth system with narrow-bandwidth components, giving you the best of both worlds.”

Bottom line?

Ricketts tells Shipman: “Our system is comparable in power transfer efficiency to similar wireless power transfer devices, and shows that you can design a wireless power link system that retains almost all of its efficiency while streaming a movie on Netflix."

Read the paper:

The paper, “Ultra-high Data-rate Communication and Efficient Wireless Power Transfer at 13.56 MHz,” was published the journal IEEE Antennas and Wireless Propagation Letters. Jordan Besnoff, a former postdoctoral researcher at NCSU who is now at Oak Ridge National Laboratory, was lead author. Co-author is Morteza Abbasi, a research assistant professor at NC State.





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