MIT researchers create smart surface to improve wireless signal strength

Scientists at MIT are working on a software-controlled "smart surface" embedded with thousands of antennas to maximize the strength of a wireless signal.

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With new each generation of Wi-Fi and cellular , wireless technology strives to improve in speed, performance, consistency, and other factors. But wireless still suffers from one major obstacle: the signal naturally degrades over distance.

One solution has been to add more antennas to the sources such as access points or cell towers as well as to the receivers such as phones and laptops. But as mobile devices become smaller, squeezing additional antennas into a tighter space becomes more of a challenge. Now researchers at MIT are working on an alternative option that could boost signal strength without having to directly modify the source or the receiving devices.

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Known as "RFocus," the system being developed at MIT's Computer Science and Artificial Intelligence Lab (CSAIL) is a software-controlled "smart surface" that uses more than 3,000 small antennas to boost the strength of the signal at the receiving end. Potentially embedded into walls at home, factories, and other locations, the system uses a two-dimensional surface to either pass through or reflect the wireless signal.

Testing so far has shown that RFocus could enhance the average signal strength by a factor of almost 10. The system itself could also be cost effective, with each antenna ringing up at only a few cents. Multiplying 3,000 by three to four cents equals $90 to $120. The technology is relatively cheap become it doesn't process the actual wireless signal but instead controls how it's reflected.

"The core goal here was to explore whether we can use elements in the environment and arrange them to direct the signal in a way that we can actually control," MIT professor Hari Balakrishnan said in a press release. "If you want to have wireless devices that transmit at the lowest possible power, but give you a good signal, this seems to be one extremely promising way to do it."

On a basic level, RFocus could act as a type of Wi-Fi range extender . But the researchers envision it as serving a more valuable purpose in network-connected homes and factories. As one example, a warehouse might need hundreds of network sensors to monitor machines and other devices. Normally, such a setup would be quite expensive and very power intensive. But a lower-power system like RFocus could provide the necessary signal strength at a cheaper cost.

The MIT CSAIL researchers aren't the first ones to come up with this type of technology. A team at Princeton University led by professor Kyle Jamieson proposed a similar system for people using computers on either side of a wall. But Balakrishnan said that the goal behind RFocus has been to design an even less expensive system that could be used in a wider variety of settings.

Right now, RFocus is still in the test phase. So there's no indication when or if it may gravitate to the real world. But as we increasingly rely on wireless communications in homes, businesses, factories, and other locations, the research holds promise for a better connected future.


Lead author Venkat Arun in front of the RFocus prototype.

Image: Jason-Dorfman, MIT CSAIL

By Lance Whitney

Lance Whitney is a freelance technology writer and trainer and a former IT professional. He's written for Time, CNET, PCMag, and several other publications. He's the author of two tech books--one on Windows and another on LinkedIn.