“What if every light bulb in the world could also transmit data?”

That was the question posed by Harald Haas, a professor from the University of Edinburgh, in a 2011 TED talk. It was a simple yet profound notion, especially if, like me, you can’t get a decent WiFi signal in the kitchen because your router’s in the study and you can’t stream that crucial cooking video when trying to make dinner. If I could could send and receive data at high-speed using the light bulbs right above my head, I might not have to rely on WiFi radio signals at all.

That’s the principle behind LightFidelity (LiFi), which emerged from an Edinburgh research project known as D-Light that ran from 2009 to 2011. Haas co-founded a spin-off firm called pureLiFi to commercialize the technology, and I recently met him and the firm’s chief executive Alistair Banham at the Institute of Physics (IOP) in London. They’d come to launch the IOP’s Accelerator Centre, which offers space for small start-ups in the Institute’s new headquarters. In fact, the rooms in the centre are equipped with LiFi technology developed by the firm, which won an IOP Business Innovation Award in 2017.

At the IOP event, Haas described his journey of building a technology company in the UK. PureLiFi began with a few researchers in a lab and it now has more than 130 LiFi deployments in 24 nations. Haas spoke about the advantages of LiFi and his vision for pureLiFi’s revolutionary light-communications technology transforming global communication. He showed, for example, a pureLifi transceiver just a few millimetres across that could be integrated into a mobile phone. Haas said it could securely download data at 1 Gigabit per second (Gbps) – almost 10 times faster than with WiFi. Upload speeds would be 0.4 Gbps.

Bright prospects

Researchers at the University of Oxford have shown that LiFi can work in lab demonstrations at speeds of 224 Gbps, illustrating the huge progress since Haas introduced LiFi in his 2011 TED talk. In that presentation, Haas demonstrated the benefits of LiFi with an LED light bulb housed in a desk lamp sitting on a small, filing-cabinet-sized receiver unit. He showed how the bulb could stream a high-definition movie to the receiver, with the results displayed on the screen. To gasps and applause, Haas paused the video by blocking the light with his hand, before stopping the transmission altogether by angling the lamp away from the receiver.

Now most people who haven’t heard of LiFi will probably say “faster WiFi” if you ask them what they want when it comes to better wireless communication. But innovators like Haas have a vision that others don’t share. As automobile innovator Henry Ford is once alleged to have said: “If I had asked people what they wanted, they would have said faster horses.” Non-specialists, in other words, find it easy to describe their problems, but aren’t always the best at coming up with a solution.

In his 2011 TED talk, Haas eloquently outlined the four fundamental challenges that LiFi addresses. First, it’s efficient. Second, LED lights are widely available. Third, LiFi offers high capacity (the visible spectrum is 10,000 times wider than the radio spectrum). And finally, it’s secure: light doesn’t travel through walls so you can deliver the data only where you want it.

The security aspect of LiFi is a great example of how a good entrepreneur can turn a potential bug into a feature

James McKenzie

The security aspect of LiFi is a great example of how a good entrepreneur can turn a potential bug into a feature. At first sight, the limited transmission range might seem a problem. On closer inspection, however, light’s inability to pass through walls is LiFi’s biggest benefit because it allows data to be precisely and securely delivered. Indeed, I think LiFi’s inherent security and high capacity will be what drives the market to adopt the technology. Its high efficiency, in contrast, is only a “nice-to-have”, while the wide availability of light sockets may prove only a long-term benefit given that they’ll all have to be upgraded to get data to the sockets.

LiFi will be particularly attractive for high-security applications in defence and industry. But I also think it’ll be a boon in high-density residential premises, where WiFi routers currently battle it out to deliver bandwidth in the increasingly congested WiFi spectrum for residents, who at the same time want secure transmissions. LiFi benefits too from a low “latency” – the time it takes to request data from a server and then get the information back. LiFi is therefore a great prospect for virtual-reality applications where overly high latency can give people motion sickness.

Market forces

For LiFi to become a mass-market technology, however, transmission equipment made by different manufacturers will have to talk to receivers in phones, tablets and laptops. Developing standardized technology and interoperable systems can be tortuous, but there are international attempts to do just that by 2021, with pureLiFi closely involved. Indeed, other firms are already getting in on the LiFi act.

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Signify (formerly Philips Lighting) has recently developed one of the first commercial LiFi systems. Users will need a USB-access key, plugged into a laptop, to receive the LiFi signal. Once connected, Signify’s Trulifi systems can provide wireless connectivity at up to 150 Mbps. One benefit unique to Trulifi is that it uses optical wireless transceivers built, or retrofitted, into Philips lights, meaning users won’t necessarily have to replace their existing lighting infrastructure to give LiFi a go.

As for pureLiFi, it has decided to focus on the optical front end (OFE) rather than a whole system, with its miniature 1 Gbps transceiver already being offered to system integrators, including mobile-phone manufacturers. These firms have huge sales, but with volumes falling for the first time in decades, perhaps a LiFi-enabled phone could be the next big thing for the mobile-phone industry keen to boost handset demand. Indeed, if you thought LiFi was just a replacement for WiFi, you may have missed the point entirely.