December 2, 2022

LED lights could also become network devices


Fraunhofer’s visible light communication (VLC) technology, shown here in an artist’s design, could transmit data to laptops and smartphones from conventional LEDs in lighting fixtures.

Fraunhofer Institute

Today you have wireless networks that use radio waves, and you have optical networks that use light traveling in tiny glass fibers. Tomorrow, if the Fraunhofer Institute’s research comes to fruition, a combination of the two could turn living room lights into network devices.

The German Applied Research Lab has developed a wireless network that uses fast-flashing LEDs to transmit data through the air. The technology can send data at speeds of up to 1 gigabit per second – and by using three colors of light, it’s possible to triple that data rate, Fraunhofer said.

The technology could be useful in crowded and interference-prone situations such as trade shows or for sending information from streetlights to passing cars, the institute said.

“My personal conviction [is that the] the first applications will be at the professional level, such as conference rooms, fair trade booths, industrial production environments and hospitals, ”said Anagnostis Paraskevopoulos, researcher in the institute’s photonic network group.

The technology could be integrated into existing room lights with conventional LEDs, Paraskevopoulos added.

There are a lot of caveats. LEDs can use significant battery power, so very short-range communications are best done with infrared lasers, Paraskevopoulos said.

Another problem is that sunlight over-saturates the light receptors of the photodiodes, hampering outdoor use. And performance decreases with distance; Fraunhofer says he gets around 100 Mbps at a distance of 20 meters.

And visible light communications require line-of-sight communications, which is much less convenient than radio communications that work anywhere in a room and often through walls. However, Paraskevopoulos said, a room could have all of its coordinated LED lights so that a person could sit anywhere inside.

Another possible problem arises with two-way communications, in which a person’s laptop or smartphone could transmit as well as receive. No one wants a laptop with a distracting bright LED on top. But in this scenario, an infrared LED could be used to produce light invisible to the human eye, Paraskevopoulos said.

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