A guide to Li-Fi technology

What is Li-Fi?

Li-Fi products use visible light communications and similar techniques to modulate light at various wavelengths to send and receive data at short ranges. Like Wi-Fi, Li-Fi uses the 802.11 standard for wireless technology.

Li-Fi is comparable to Wi-Fi for client access that connects mainstream devices to the internet. It can also offer a utility-oriented option similar to ultra-wideband wireless in specific scenarios.

Use cases for Li-Fi

Fundamentally, Li-Fi is a client access technology. In that context, Li-Fi-capable devices connect to a nearby access point (AP). Traffic then flows across the light and onto the network wiring to a local network or internet destinations -- just as with Wi-Fi.

Li-Fi can also be a short-range, point-to-point interconnect mechanism. This possibility creates other interesting use cases. If the technology catches on, the following applications are just some of the many ways enterprises can expect to use Li-Fi:

• Simple client device access at home or work.
• Any setting where less overall radio signal presence is beneficial -- for example, medical environments, aircrafts and military facilities.
• Device interconnects in a range of systems from building controls to audiovisual systems.
• Underwater exploration.
• Virtual reality environments where Wi-Fi can't deliver required reliability or bandwidth.

Advantages and challenges of Li-Fi

One of Li-Fi's notable achievements is it can isolate itself from spectral overlap with other technologies. As a result, Li-Fi signals don't interfere with wireless devices operating on RF. This enables faster transmission speeds and hybrid systems. Expected speeds are anywhere from a few megabits per second to tens or even hundreds of gigabits per second -- on par with the latest Wi-Fi standards and 5G performance claims.

Security is another advantage, though it comes with some challenges. Li-Fi has a short range and in-room limits as light cannot penetrate walls. This is a security advantage, making signal intercept extremely difficult. However, it also limits system scalability.

If Li-Fi stays a niche market, Li-Fi products will be expensive and potentially proprietary in function. Li-Fi APs set up as rogue devices on business LANs will be almost impossible to detect. Another challenge is determining exactly how much light Li-Fi needs to function. Some products require visible light, while others function even in perceived darkness.

The Li-Fi development timeline

Scientific interest in manipulating light for communications goes back at least a century. Fiber optics already uses light to transmit information but requires wires and cabling, unlike Li-Fi.

In 2018, IEEE created the 802.11bb Light Communication Task Group to map out a viable standard for light-based communications. In 2023, IEEE ratified the 802.11bb standard as the first official Li-Fi specification, presenting a formal roadmap for Li-Fi.

In the early days of Wi-Fi, many products deviated from the standard. It remains to be seen if companies will now follow the Li-Fi standard to ensure interoperability across product lines. A group of Li-Fi companies formed LiFi Group, complete with a logo that imitates that of the Wi-Fi Alliance. Only time will tell if this arrangement gels into a formal industry advocacy group.

Early Li-Fi products exist but are quite expensive and limited in applicability. That's not a criticism of the technology -- every technology needs to start somewhere. Li-Fi has nowhere to go but forward in its development.

Lee Badman is a network architect specializing in wireless and cloud technologies for a large private university. He's also an author and frequent presenter at industry events.