Wi

Aug 20, 2023

Just as Wi-Fi uses radio signals to encode information, Li-Fi relies on light for incredibly fast data rates. Now a new IEEE standard for Li-Fi based off the IEEE standard for Wi-Fi (802.11) may help it expand across the globe as Wi-Fi has, with the new devices complementing instead of competing with the more established technology.

Li-Fi uses variations in the intensity of light to transmit data. The changes are so fast that they are not perceptible to people.

Light waves have frequencies more than 1,000 times greater than radio waves. This means they allow more than 1,000 more channels for communications, which can enable significantly more bandwidth for data. At the same time, Li-Fi does not experience interference from competing radio signals, as do Wi-Fi and 5G devices.

“When people began understanding that we’re not arguing for Li-Fi against Wi-Fi, but claiming a complementary use, they really began seeing the benefits of using light.”—Dominic Schulz, Fraunhofer HHI

“Li-Fi will add a massive amount of bandwidth for new use cases,” says Alistair Banham, CEO of Edinburgh-based pureLiFi, the company that chaired the IEEE working group behind the new standard.

Currently, Li-Fi devices are capable of blazing speeds of 1 Gbps. Research also suggests they can achieve 100 Gbps rates with a multiplexing strategy that simultaneously encodes data on the red, green, and blue channels within a white LED. Multiple lights can make up a single network, letting one move around a space from light to light without interrupting the connection. A clear line of sight is not always needed between the receiver and transmitter—reflections off walls and other surfaces can also carry data.

The new standard for Li-Fi, IEEE 802.11bb, is designed to provide a global framework to deploy light-based devices that are compatible with each other. It was ratified in June.

“When developing a standard, finding common ground can sometimes be very challenging. Different people have to come together, all experts in their area with different approaches to technology, and in the end, only one solution can be specified in the standard,” says Dominic Schulz, lead of Li-Fi development at Fraunhofer HHI, a Berlin-based company that supported the standard’s creation. “We also had to engage with all the big Wi-Fi companies and in the end convince them of the benefits of Li-Fi. But when people began understanding that we’re not arguing for Li-Fi against Wi-Fi, but claiming a complementary use, they really began seeing the benefits of using light.”

Critically, the standard was developed for Li-Fi to work alongside Wi-Fi. For instance, with pureLiFi’s Light Antenna ONE—the world’s first device compliant to the new standard—Li-Fi simply appears as if it was another band of Wi-Fi. The module is only 14.5 millimeters wide—smaller than a dime—and designed for integration with existing Wi-Fi chipsets into smartphones, tablets, televisions, virtual reality headsets and more. It can achieve data rates of 1 Gbps or more from a range of 20 centimeters to 3 meters.

“We are enabling interoperability of Li-Fi and Wi-Fi, positioning Li-Fi as a complementary and additive technology to the existing ecosystem,” Banham says.

For the many devices that do not have Li-Fi antennas built into them, the NEON module from Fraunhofer HHI is a dongle that can attach to laptops and other devices via USB. “It’s about the length and width of a credit card, about a half-inch thick, and has a weight of about 60 grams, so it very much feels like an external SSD hard drive,” Schulz says. “It can achieve a downlink of 1 Gbps and an uplink of about 100 Mbps.”

In terms of home, office and other indoor applications, pureLiFi has its Li-Fi Cube Gateway, a portable hotspot that can plug-and-play to a network via Ethernet, Powerline or Power over Ethernet. Compliant with the new standard, it can deliver a link of up to 250 Mbps and can sit on a table, rest on an adjustable stand or mount on a ceiling, wall or shelf.

There are outdoors applications for Li-Fi as well—it can work even in sunlight. Fraunhofer HHI has an outdoor Li-Fi point-to-point link that can supply 1 Gbps over 100 meters and 500 Mbps over 200 meters.

“That may not seem all that great a range, but in a dense urban environment, think of the time and expense it would take to lay new fiber from one building to another, versus giving 1 Gbps within minutes,” Schulz says. “You can use it for ad hoc events, or for disaster recovery after, say, an earthquake, when everything is broken. You can set up a network of links in a very flexible, easy and cost-effective way, and it works even in bad weather. It can also be used for vehicle to vehicle communication — say, between trucks in a platoon.”

One limitation Li-Fi faces is that light does not penetrate walls, so every room in a house or office would need a Li-Fi lamp. On the other hand, that can lead to improved privacy against would-be eavesdroppers. Along those lines, pureLiFi has developed its Kitefin Li-Fi system designed specifically for defense applications, with clients including the U.S. Army in Europe.

“This has been a great way to establish Li-Fi in a market that requires highly secure robust communications with rigorous attention to detail and high-quality delivery,” Banham says.

A future potential feature for Li-Fi is high-precision positioning. “That may not be the killer future for home use, but if you look, for example, at industrial or medical cases, really precise positioning with sub-centimeter accuracy may prove useful in hospitals or factory floors, whereas current positioning technologies often suffer in indoor settings,” Schulz says.

Ultimately, one may imagine the LED lights now often found in homes and offices could transmit data carried over electric wires via powerline, Schulz notes. “The new standard makes it really possible to use light for wireless access while benefiting from the very sophisticated features for Wi-Fi for mobile communications,” Schulz says. “It shows a large potential to bring together the best of two worlds in a hybrid solution.”