Let there be light: The LiFi standard could illuminate the IoT

This story was originally published in my weekly newsletter on Friday July 21, 2023. You can sign up for my newsletter here. 

Tired of having dozens of IoT devices competing for the same wireless airwaves as your computers, phones, and televisions? There might be a solution in the form of LiFi, or light fidelity, networks. That’s thanks to the newest IEEE standard of 802.11bb, which enables data transfers over lightwaves at up to 1 Gigabit per second (Gbps). Don’t break out the disco ball just yet, however. Although there are some benefits to having a new physical network layer that doesn’t use precious Wi-Fi bandwidth, there are some limitations, too.

To understand those, you need to know what LiFi is and how it works.

Instead of radio waves like with Wi-Fi, wireless data is beamed as patterns of light using LiFi receivers and transmitters. That light can be visible to the human eye or can use a frequency that humans can’t see. For the 802.11bb standard, the light frequency wouldn’t be seen as it uses the near-infrared 800 to 1000 nm waveband. Based on the hardware and light frequency used, data could be shuffled between 10 Mbps and 9.6 Gbps. At the low end, that’s far slower than today’s Wi-Fi 6E rates, which top out at 5.4 Gbps. But at the top end, LiFi could theoretically transfer twice as fast as today’s currently available Wi-Fi hardware.

From an IoT perspective, even the slowest 802.11bb LiFi devices would be more than adequate for data transfer. Think of how small the little bits of information from a sensor are, or how little data it takes for a smart home system to, for example, send the command to lock a door. We’re talking about kilobytes of data in these situations. A slow LiFi network could easily handle such use cases. And since LiFi devices wouldn’t be using Wi-Fi, you’d have fewer devices on your Wi-Fi network. That would ease network congestion and, perhaps more importantly, simplify your wireless network to a more manageable state.

Although this demo is less about the IoT and more about internet usage and video streaming, PureLiFi shows how its products use LiFi.

There’s another IoT benefit to LiFi, although it’s likely more important to the industrial IoT: security.

Not a week goes by when we don’t hear about some Wi-Fi hack or proof of concept. Each of them illustrates some threat that could expose all of your network-connected devices and/or the data passing through them. And most of them don’t require physical access to your location or your network. Given that the intrusion happens over a wireless network, the airwaves are out there as far as your router will allow, just waiting to be attacked.

Such attacks are much more difficult to implement on a LiFi network. That’s because every LiFi network connection is a point-to-point connection between two or more devices. The field of view for these connections isn’t 360 degrees like it is for traditional Wi-Fi. Instead, a potential threat actor, or a sniffing device they set up, would generally have to be physically present between the two LiFi endpoints. That’s the only way they could access the light-based communication of the network.

So from a security standpoint, LiFi brings much to the table that Wi-Fi networks simply can’t. At least not in their present implementation. This is ideal for IoT devices in the industrial or government sectors. And I’m sure smart home owners wouldn’t mind that protection as well.

Of course, there’s a downside or two. OK, maybe three or four.

First is the hardware required to use a LiFi network. As I mentioned, the edge devices — think bulbs, locks, and sensors — need the components to send data as beams of light. So too does some type of bridge to convert the incoming IP-based data from light beams to traditional wired or wired data. LiFi isn’t going to replace Wi-Fi or ethernet networks. It needs to feed its data into standard networks, which means new or additional hardware.

The second is that LiFi generally requires direct point-to-point communication. Since LiFi uses light, it requires a line of sight to send data from one source to another. Wi-Fi has no such issue since it’s generally omnidirectional. That means you can’t have physical objects between two LiFi devices for them to communicate, which is a huge obstacle. Forget about using your phone to control LiFi devices directly; even if they had the hardware to use light-based data, you’d have to be in the right spot to do so. It’s possible that reflected light bouncing off walls and objects could work to a degree, but again, speeds would suffer.

Third is the question of range. Returning to today’s Wi-Fi 6E networks, these can send data up at full speeds for more than 50 feet. You can go further, although speeds will decline as distance increases. Since LiFi depends on light beams and the intensity of those beams becomes lower the farther they travel, data can’t be sent as far. And those lightwaves start to compete with more ambient light interference the further they travel as well. Up to now, the furthest products using light to send data only have a range of a few meters.

Lastly is a competing standard. Of course there’s a competing standard!

Back in 2019, Stacey wrote about Signify adding its own LiFi approach to some Philips Hue bulbs. Obviously, these bulbs weren’t implemented with the 802.11bb standard because that standard didn’t exist at the time.

According to The Verge, Signify’s LiFi bulbs use the International Telecommunication Union’s G.9991 standard. Hopefully that standard is incorporated into the 802.11bb spec, which is meant to be vendor-neutral. Otherwise we could have some LiFi devices not working with other LiFi devices.

I was initially skeptical of any light-based networking solutions such as LiFi. And there’s still reason for skepticism since, along with the potential benefits, there are obvious downsides and challenges. However, there are some very specific use cases where LiFi might make sense, particularly now that it has an official standard.

No, it’s probably not primarily a smart home solution in the near term. For production lines, operational technology, military, and government applications, though? The potential for LiFi is there if device makers can see it.