Broadband data-over-light, sent through lighting fixtures commonly seen in commercial buildings, moves a step closer to possible mass adoption through an apparently functioning smart-office installation in Paris.
Li-Fi uses light waves for data communications, as opposed to Wi-Fi, which uses microwave radio. Li-Fi has 10,000 times Wi-Fi radio’s RF spectrum, experts say. The pilot installation by Philips is at a French real-estate company’s office.
Philips Lighting, the giant lighting-system maker, says it is now offering Li-Fi modems installed within its existing LED luminaires, such as its downlighters. A luminaire is the building-industry term for a complete lighting fixture.
The Li-Fi-enabled luminaires have 30Mb per second of data throughput for end users, according to the company in a press release. “With 30Mb per second a user can stream, simultaneously, several HD-quality videos while having video calls,” it says. Up to 15 users can be served by one fixture.
Visible light communications (VLC) could conceivably replace, or at least augment, Wi-Fi. VLC has advantages that include interference-free transmissions—good for RF-hostile environments such as hospitals, for example; and it can be secure—it won’t travel through walls. Congestion, as found in the Wi-Fi bands, isn’t an issue.
“While radio frequencies are becoming congested, the visible light spectrum is an untapped resource,” Philips says.
Handoffs are seamless, the company claims. As the user traverses the building under ceiling-mounted lighting fixtures—a plentiful resource in commercial structures—the user stays connected.
“We have a perfect handover between one luminaire to the other one,” says Eric Rondolat, CEO of Philips Lighting from a videoed press conference at the Light+Building show in Frankfurt this week. “We don’t lose the signal.”
The lighting company explains that its lighting units come fitted out with a modem that takes the cable-supplied network data, along with the LED’s current, and modulates it, creating the data-containing light-wave. A USB dongle is then placed in the users’ laptop to receive that information, and an infrared emitter link responds back to the original light fixture. The illumination itself isn’t degraded.
The company also claims that its network will work with IoT devices.
Philips isn’t the only Li-Fi operation out there. University of Edinburgh spin-off pureLiFi claims speeds of 43Mb per second from its LiFi-XC USB dongles that it launched in October 2017. It too uses lighting fixture infrastructure. That product was recently demonstrated at Mobile World Congress and performed a Skype call through a smartphone-installed Li-Fi sleeve, according to newspaper Metro who attended.
I’ve written about VLC and Li-Fi development before. Scientists are looking at ways of getting photovoltaic solar panels to not only power equipment, but to also act as data receivers: Laser transmissions could be beamed from a hilltop, say, to a remote installation with the panel performing double duty—sun collection for power and at the same time Li-Fi data node for broadband.
There has also been work taking place figuring out how to send visible light data communications in the dark. It functions through imperceptible light pulses.
Unrelated to those projects Rondolat says Philips’ commercial, compete solution Li-Fi and lighting product isn’t theory: It is “something that we are implementing at a pilot site in France for a customer,” he says.