From WiFi to LiFi

This work was carried out with the support of UK Research and Innovation.

These days, our mobile phones are ever-present. They wake us up in the morning, play music, and send late-night emails, and are interwoven into nearly every part of daily life. But even in our hyper-connected world, there are still places where microwaves - the invisible carriers of mobile signals and data - simply can’t reach. And we all know the frustration that accompanies a bad mobile or WiFi signal. But this technological blind spot has motivated a group of scientists to wonder whether, rather than relying on microwaves, we could beam our information using something else entirely? Infrared light, for instance. Marushka Soobben reports…

Marushka - There's no network down here, no Wi-Fi, no signal, just me and this flickering overhead light. But what if the answer isn't in signal bars? It's in the invisible light all around us. Today we're exploring a technology that's not using radio waves but infrared light to send data silently and securely through the air. It's called LiFi and it might just be the future of connectivity. To understand how we got here, I came to Edinburgh to the pureLiFi headquarters and spoke to Dr Mostafa Afgani, co-founder and CTO of pureLiFi, where we find out what LiFi actually is and how it's different from the Wi-Fi we know and lose all too often.

Mostafa - The RF spectrum is quite limited and what's happening with our ever-increasing demand for data consumption is that we're running out of that limited spectrum. So this is where LiFi can help because it can offer nearly 3,000 times greater spectrum than RF and, actually, because of how it works it doesn't have the same challenges with interference either, meaning the ability to scale is significantly greater. But at the same time there is also increasing awareness of security vulnerabilities, particularly cyber security. Light doesn't go through solid objects, so it actually offers a much higher level of privacy and security compared to traditional RF. So there's also a lot of interest from the general public, governments and so on. It's primarily in government and defence use cases today where privacy and security are paramount, so it's really enabling wireless communication in industries where RF-based wireless was previously forbidden or prohibited. That's one area where this is being used as a standard mobile wireless communication technology, but there is also a completely different use case in the form of cable replacement. For example, our Bridge XE product allows telecom providers, the cellular providers, to enable gigabit internet connectivity in places where they could not do so before.

Marushka - Traditionally, light-based communication has worked by flickering or dimming LED lights in a form of binary communication. The photons from those LEDs form a sequence that can pass information to a receiver. But LED communication is limited by needing to keep it dim enough not to annoy us humans. By switching to infrared, a wavelength we can't see, that problem is alleviated. To expand on this and more, I met with the Advanced Technology Manager, Dr Mohamed Islim, the man helping make LiFi work at the speed of light.

Mohamed - You can think of digital media as being encoded in zeros and ones, in binary digits, and these can be translated in LiFi terms as lights being turned off and on. So we use infrared invisible light and these lights can be turned on and off at incredible speeds exceeding tens and hundreds of millions of times per second. You can encode binary digits like this—this is one way of translating binary digits into light communication—and another way can involve changing and affecting the light intensity of the emitters by encoding the data in the subtle changes of light intensity. These can also work at very high speeds, exceeding tens and hundreds of millions of times per second. On the other side we use a very tiny photoreceiver, which will translate these light intensity changes into electrical signals which can then be translated into binary digits. These tiny receivers can be integrated into consumer electronics devices such as mobile phones, tablets, laptops, even TVs and wearables. Think about it like fibre optic but releasing the light from the fibre into the wireless domain, and it is all around us.

Marushka - And what's pureLiFi building to make this real?

Mohamed - Our systems are currently in use in government and defence and are currently being evaluated by global consumer brands. On the other side, we have solutions for other use cases such as cable replacement. We have a Bridge XC system which is currently in trials, supporting telecommunications operations in trialling and deploying gigabit operations at a faster rate and at a lower cost.

Marushka - It all sounds very exciting, but before we wrap up I went back to Mustafa with one big question. What does the future of connectivity look like with LiFi in it?

Mostafa - Just two words really, and that's simply: better. Why? Because we can imagine connectivity that never buffers, never fails and never unintentionally leaks into your neighbour's house, for instance. So with Li-Fi we can continue to enjoy all our modern conveniences in a seamless fashion, with privacy and security that give everyone peace of mind. It will simply fit into everybody's life alongside cellular, Wi-Fi and all the other communication technologies that we're already used to. So I think with Li-Fi the future is bright and better.

Marushka - We've all been in places with no bars, no Wi-Fi and no signal, but the future of connectivity might not be above our heads in the light we see but in the light we don't. Next time I'm stuck underground I won't be searching for signal. I'll be wondering if the infrared light around me is already doing the job.