Infrared much better than Wi-Fi

Using open-air light waves instead of radio will solve bandwidth congestion resulting from internet-connected devices, researchers say

Infrared much better than Wi-Fi for IoT devices
Credit: Thinkstock

A few special “light antennas” dotted around a room would provide significantly more bandwidth for internet-connected devices than traditional Wi-Fi, says a Dutch scientist. Wi-Fi’s days could be numbered if the technology works as suggested.

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With this new Wi-Fi replacement system that’s been proposed, benign, infrared rays of light emitted from ceiling-mounted transmitters would beam bandwidth-intensive streams of data at smartphones and laptops within the room. And each ray of light could provide 40 gigabits per second, says Joanne Oh, a Ph.D. researcher at Eindhoven University of Technology (TU/e) in a news article on the university’s website.

Wi-Fi has traditionally been restricted in bandwidth due to the characteristics of frequencies used. The microwave spectrum at 2.4GHz and 5GHz isn’t particularly capacious compared to higher-up frequencies such as infrared. That chunk of spectrum, at 1,500 nanometers and higher in wavelength’s spectrum by a few hundred terahertz, is much roomier, the school explains.

Download rate of 42.8Gbit per second

Hence the proposed idea: Forget the traditional microwave Wi-Fi for downloads, and distribute the data via the fatter infrared pipes. Oh says she achieved 42.8Gbit per second over 2.5 meters. For comparison, fast, currently available Wi-Fi radios will deliver 1.3Gbit per second on one channel.

Oh says her system is best suited to downloading. She says one will also need Wi-Fi, or Wi-Fi-like radio, for upload functions. But there won’t be any interference between the two streams because the frequencies are so disparate.

Multiple light antennas, with no moving parts, supplied by fiber-optic internet will squirt the download data at the on-network devices—such as laptops, smartphones and video screens—through a special kind of individual aiming process.

“If you walk around as a user and your smartphone or tablet moves out of the light antenna’s line of sight, then another light antenna takes over,” the university explains.

Different wavelengths are used to point the data streams at different devices.

“The network tracks the precise location of every wireless device using its radio signal transmitted in the return direction,” the article says.

You add devices by adding wavelengths. That means each device is on its own wavelength, doesn’t share bandwidth and doesn’t interfere with another.

Other light-based systems

I’ve written about Li-Fi before. That’s a way for using a room’s LED lighting to create optical indoor networks. TU/e claims its system is better than other ideas out there because it provides more bandwidth—its connected devices won’t have to share streams because the network has directable beams with each beam dedicated to one device.

Infrared light direction using “moveable mirrors” is another open light-inspired internet delivery method being explored by others, says TU/e. Indeed I recently wrote about scientists who say infrared lasers, pointed by mechanically controlled mirrors, should replace data center wiring.

Another open-air light-based system proposed uses solar panels—the panel not only acts as a receiver, but also powers the rig. That’s conceivably an advantage over mirrors in that mirrors require power to physically move them for the pointing process.

The Eindhoven school behind light antennas claims its system won’t require power at all, though, for aiming. Gratings radiate light of differing wavelengths through different defractions and therefore angles. “Changing the light wavelengths also changes the direction of the ray of light,” it explains.

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