Light Fidelity: An Interview with Prof. Harald Haas

In 2011 Professor Harald Haas gave a TED lecture on a ground-breaking new concept – using LED lights to transmit wireless data. This concept he named 'Li-Fi', the immediate practical application being that an LED light bulb could be used to stream wireless data/internet to a mobile phone or computer.

Considering that currently we use 3G, and (more recently) 4G to stream wireless data to our mobile devices, alongside Wi-Fi to connect our various devices to the internet, Li-Fi presents a forward-thinking alternative (and welcome addition) to existing methods of wireless communication.

As Chair of Mobile Communications at Edinburgh University, and co-founder of spin-out company PureLiFi, it’s no surprise that both academic research and development of commercially viable Li-Fi technologies have been increasing at a rapid rate. Earlier this year, PureLiFi was awarded investment of £1.5 million to further develop its products, and the commercialisation of Li-Fi technologies.

In a city historically renowned for its innovation, it’s perhaps fitting that Li-Fi’s home is in Edinburgh. These burgeoning technological developments provide not only an exciting prospect for Scotland, but for the UK in general. The implications of Li-Fi and its related technologies are far-reaching and will no doubt be seen globally within the coming years.

I arranged to meet up with Prof. Haas to have a chat about a brighter Li-Fi-enabled future, eureka moments, data pipes, the Internet of Things, and amongst other things, the prospect of being able to test out Li-Fi on Edinburgh’s Royal Mile.

Can you explain what Li-Fi is?
Li-Fi stands for Light Fidelity, and it’s basically using off-the-shelf LED light bulbs to transmit data, wireless data, at extremely high speeds. We all know Wi-Fi, and that uses radios and antennas. Imagine the same functionality of Wi-Fi, but instead of radios we use light, the light around us. 

So what are the benefits of using light?
The benefits are plentiful. First of all, imagine how many light sources we have around us. It’s forecast that there will be half a billion LED light sources sold this year. Imagine that every LED light bulb around us is essentially a high-speed transmitter. That’s basically transforming our lives with regard to connecting ‘everything to everything’. It works underwater, it works in intrinsically safe environments – petrochemical plants, oil platforms for example. It’s secure, as light doesn’t penetrate through walls – no-one can easily intercept your connection. It’s free-spectrum and delivers very high data rates in very dense environments, and could enable the way we advertise and develop health technologies. There are plenty of advantages.

Using the example of a street lamp, could you explain how someone could stream wireless data to their phone using Li-Fi?
The scenario would be: you walk along the street, your phone would recognise there is a high-speed Li-Fi transmitter just above it. It would connect to that light source and it would stream the high-speed data rates through the street lamp. It would also transmit to that street lamp using – for example – infrared, some other optical, or even RF [Radio Frequency] channel that creates a bi-directional communication. The light itself is part of the street furniture, there are lines coming in, power coming in. There are various ways of getting data to that light source – one is using the power lines. One could also foresee that light can form very narrow beams, so that you could have Li-Fi that works as a Backhaul – we call it a Backhaul link, from a house or building to the the street light so that you have laser type beams to the streetlight – that would then broadcast in the right area. The other option is that you put an ethernet cable through the utility to the streetlight to provide data via a data cable.

So the network is already there in theory?
Yes, the advantage is that we can utilise existing infrastructure. In wireless communications, we all know radio masts – do you know what the distance is between radio masts in 4G is?

I have no idea.
It’s roughly about 300-400 metres. So with 4G, the standard that is coming at the moment – we need a radio mast every 300-400 metres. With 5G that will arrive in 2020, it will be 50 meters. Can you imagine a scenario where we have a radio mast every 50 metres?

That’s a lot of radio masts.
Yes, that is a lot. So why not use the street lights, the existing infrastructure? That’s the natural question.

Could you give us an idea of how Li-Fi could be factored into the home environment in the near future?
The way I see it is this: you would still have your 3G, 4G, maybe your 5G in the future, and your Wi-Fi. You’d have these various standards, and then you’d have your Li-Fi. The network that you are linked into would depend on who is best placed. For example these days, the 3G network may be overloaded so you’d be transferred into Wi-Fi, offloaded. If for example your home is Li-Fi enabled and you entered into your home, your mobile will see a strong signal from a light source above it and automatically detect that a better signal can be achieved from the light source – this will transfer the link to the light bulb and release the RF channels. This provides additional fat data pipes, everywhere where there is light. We need to just think where do we have light? Everywhere where there is light we can have big data pipes. Basically we’ll be surrounded by millions and billions of fat data pipes that we can use.

When will we be able to buy a Li-Fi system for the home?
We believe it’s very realistic to see this within the next couple of years.

How much would it cost?
Basically the price is a matter of volume. We don’t envisage that this is significantly more expensive than standard Wi-Fi equipment.

Are there any examples where we can see Li-Fi technology here in Scotland?
Yes, there will be examples. There will be examples here at Edinburgh University where we will be deploying it in various rooms – also as part of a project in Glasgow [at the University of Strathclyde], where the new Tech building will be equipped with a Li-Fi demonstrator. We are also working on a project with the council in Edinburgh to get an example onto the streets, hopefully the Royal Mile. We are further seeking their interest to equip a number of public spaces with Li-Fi. As this year is the United Nations' Year of Light, it would be a fantastic showcase if people arrived at Edinburgh airport to see that this is the ‘City of Li-Fi’. The airport could have places offering free Li-Fi internet.

You gave a TED lecture back in 2011 – how helpful was that in generating interest in Li-Fi?
Phenomenal. It rocketed the idea into the world. Suddenly people responded all over the world, developed their own Li-Fi systems. Things have been kickstarted tremendously.

Did you have a eureka moment where you realised that the Li-Fi concept was possible?
Yes absolutely. I think I started more or less out of curiosity in 2003 with a student project in Germany, to see if we could turn a disadvantage of an algorithm that is used in radio into an advantage when you use lights. We managed to successfully show this through our experiment, and that unlocked this capability of transmitting data at extremely high speeds – that was the eureka moment. Since then, everyone who has showed very high data rates from an LED has used this kind of algorithm.

According to Wikipedia, the Li-Fi market is projected to have a growth rate of 82% from 2013-2018, and worth over $6 billion per year by 2018. This sounds huge, could you explain this area a little?
It’s increased to $9 billion now. At the moment there are around 20 million radio base stations around the globe. Only this year it’s forecast that half a billion LED lights will be sold, so you can get an idea of the scale. If you imagine only a fraction of these lights sold are Li-Fi enabled, then one can see how it outpaces, and that is only lighting. Then imagine the Internet of Things, your cooker, kettle, microwave - all have LED lights integrated so the Li-Fi modem could potentially be stored in those devices and link them to the internet. People can gather statistical data, analytics from their devices, or even for information on when a device is about to break.

How have the existing network or service providers received Li-Fi technology?
We see a push-pull mechanism. The lighting industry is going through a radical shift at the moment – Phillips have recently sold the lighting division of their business. An LED lightbulb lasts 15-20 years, longer than a car – you can’t sell them as often. The business model is changing; it’s like the transition from analog to digital photography, where Kodak and other firms ceased to exist. We’ll see the same in the lighting industry with companies collapsing and new companies emerging. There is a ‘pull’ of Li-Fi technology into the lighting industry, because it’s needed to provide more services. On the other hand, the radio industry has invested billions into radio technology and there is a ‘push’ mechanism into the RF communications.

Could you give us any examples of obstacles you’ve had to overcome in the past few years?
From a business development perspective, the classical view or question you ask a company is ‘what is your market’? It’s a difficult question to answer for us as we’re creating new markets. When you talk to investors, you have to make it clear that it’s disruptive. The business plan is not the same as you would develop when you manufacture a new hoover for example. It’s a challenging task of overcoming the hurdle of traditional thinking.

Li-Fi is a collaborative research project between various Universities. Has this process accelerated the rate of development?
You mean the Ultra-Parallel Visible Light Communication programme, which is a UK programme funded by EPSRC [Engineering and Physical Sciences Research Council]. It pulls together people from St. Andrews, Strathclyde, Edinburgh, Cambridge and Oxford Universities. It’s a mechanism that has propelled the UK at the forefront of Li-Fi technology, and that collaborative research has meant that the UK is leading the Li-Fi space worldwide. Nowhere on the planet is there such a concerted effort; it’s important in all systems integration that you bring in all the experts on different sides. The question now for the UK is: we’ve built a base camp, how do we go to the top of Mount Everest?

15 years from now, how will we be using the internet?
I think the way humans exploit the internet will probably not change that much, it’s the content that will change; moving towards more video content that is shared. What will change radically is that machines and objects connect to the internet – this will transform many things. People say that by 2020 there’s about a 100 wireless connections per person, whereas we have only one connection now. This idea is simply not manageable with the radio frequency range, but with the visible light spectrum we can realise this.