Li-Fi was first introduced to the general public in a TED Talk in 2011, when I showed video streaming using off-the-shelf LED lights. This TED Talk has now been watched more than 1.6 million times, and Li-Fi has been featured by the BBC, New York Times, TIME Magazine, CNN International, ZDF and CNBC, and this indicates the high level of interest and potential high economic and social impact of the new, emerging Li-Fi technologies.
Li-Fi technology uses light waves instead of the current radio frequency spectrum to communicate data. Li-Fi is a bi-directional, networked, mobile, high-speed data communication technology. It complements the existing Wi-Fi, and also has the additional benefits of greater capacity, security and energy efficiency.
The visible light spectrum is huge (about 390 THz of bandwidth are available), licence-free, secure and safe. Devices such as LED lights and photo detectors are inexpensive and in common use, and Li-Fi technology can use the existing lighting systems already in place in rooms and buildings.
How Li-Fi works
With a Li-Fi chip integrated, a LED light in a room ceiling becomes a Li-Fi access point, and in the latest developments, all Li-Fi access points together can be coordinated to form an optical attocell network. This gives a high data density and enables an inter-connected networking of the access points giving multiuser access and handover when users move in a room, or indeed a building.
At the Li-Fi Centre in Edinburgh, data transmission speeds of 3.5 Gbit/s at 2 m distance, and real-time video streaming at 1.1 Gbit/s at 10 m distance have been demonstrated. The team has also demonstrated that it is possible to reach 100 Gbit/s when using different colour laser LEDs as illumination devices. While laser LEDs are not yet considered for the mass market lighting, there are niche applications such as in the most advanced car headlights where these devices are currently being used. Moreover, in 2014, researchers at the Li-Fi R&D Centre demonstrated the highest data rate received by an off-the-shelf solar cell of 15 Mbit/s. In the latest research in 2015, the use of single photon avalanche diodes (SPAD) in Li-Fi was first demonstrated and achieved highest receiver sensitivities, and this sensitivity will enable new applications to be developed for low-light situations, such as oil downhole monitoring.
These are new, small, low power Li-fi devices and offer great potential in the future.
Li-Fi is an emerging industry
Li-Fi could have a huge impact on our everyday lives, and independent market research forecasts that Li-Fi will be a $9 billion global industry by 2018. There is a desire for new lighting services and a demand for more data, and in the future lighting systems will provide functions and services in addition to simple room or building illumination.
Li-Fi Research and Development Centre
The Li-Fi Centre was established in 2013 at the University of Edinburgh, and its team of researchers and development engineers, will catalyse the new Li-Fi industry by making strong links with industry and businesses. The Li-Fi Centre produces Li-Fi platform technologies of up to a Technology Readiness Level (TRL) 7. The Li-Fi Centre offers a unique systems platform to translate leading UK photonics device and communications technologies into new emerging markets. There is great potential for completely new applications including data centres, the Internet-of-Things, security and data access, health monitoring systems, smart cities and traffic management, smart homes, indoor navigation systems in large buildings, data communication in hazardous environments such as oil rigs and petrochemical plants, underwater communications and new hybrid 5G and 6G mobile communication networks.
The first Li-Fi spin-out company, pureLiFi, is taking these networking and multiuser technologies to market through their Li-Flame product, which was launched in March 2015. Their earlier product, Li-1st, is a point-to-point communication system, and was launched in 2013.
Li-Fi is particularly suitable for environments where Wi-Fi is unsuitable or where Wi-Fi does not provide enough capacity to meet increasing demands, and new, innovative hybrid (Li-Fi/Wi-Fi) networks are now being developed, such as for:
- settings where secure data exchange is paramount such as hospitals, company headquarters, homeland security agencies.
- modern manufacturing plants where hundreds of tools and machines require constant and reliable connection to central servers. This ‘Internet-of-Things’ also has many new applications for homes and offices that will for example improve energy efficiency.
- intrinsically-safe environments such as refineries, oil platforms or petrol stations where electro-magnetic radiation of the antennas of radio frequency communication systems could spark explosions.
Harald Haas is Professor and the Chair of Mobile Communications at the University of Edinburgh. He pioneered ‘Spatial Modulation’ which is one of the principals of Li-Fi technology.
In 2012, Harald was awarded the prestigious EPSRC Established Career Fellowship, the only one in the UK that year within Information and Communications Technology.
In 2014, Harald was selected as one of ten RISE Leaders. The EPSRC RISE award, ‘Recognising Inspirational Scientists and Engineers’ honours those carrying out world-leading research, and who, with their knowledge and dedication, lead and inspire innovation.
Professor Haas is the co-founder and Chief Scientific Officer of the spin-out company, pureLiFi Limited, and holds 26 patents and 20 pending patent applications.
His new joint textbook with Svilen Dimitrov, ‘Principles of LED Light Communications’, was published by Cambridge University Press in March 2015.