By Nikola Serafimovski and Harald Haas, LiFi R&D Centre, Institute for Digital Communications
Understanding the impact of exponential growth is key to understanding the long term consequences of nascent trends. In simple terms, if something grows at 7% per year, it means that it will double in size in 10 years. To put it into context, modern demand for wireless capacity is growing at 70% compound annual growth rate. At that rate, in less than 5 years, our demand for wireless data will grow by over 14 times.
It’s impossible to avoid Wi-Fi in today’s world. It’s everywhere; your neighbors have it, it’s free in coffee shops, and it’s essential for smartphones. We all know Wi-Fi, but what is LiFi?
LiFi, like Wi-Fi, enables electronic devices like computers, laptops and smartphones to wirelessly connect to the Internet. Even though Wi-Fi was also originally intended for such devices, it is widely used today to connect all sorts of things: printers, televisions, speakers, headphones, and even running shoes! In simple terms, LiFi is equivalent to Wi-Fi, but using light waves instead of radio signals.
LiFi uses the light waves from LED light bulbs – that are rapidly replacing incandescent light bulbs for their energy saving and safety – to transmit data so it provides illumination and wireless data communications.
Anywhere that is illuminated by the LiFi-enabled LED, can also communicate via LiFi.
What is LiFi?
LiFi, a term first coined by Professor Harald Haas at his TED Global talk in 2011, is a disruptive technology that delivers high speed, bidirectional and networked wireless communications, similar to Wi-Fi, except using light. This is also the official definition according to the IEEE 802.15.7r1 committee that is developing the standard for Optical Wireless Communications.
Standard LED light bulbs are controlled by a driver that by dimming or turning the LED on and off. With LiFi enabled LED light bulbs, the driver is used to transmit encoded data by controlling the LED light. An optical sensor is used to receive the data, which is then decoded. This is conceptually similar to Morse code – but at rates of many millions and trillions of times a second. Subtle light flicker at those speeds is unnoticeable by the human eye. The transmission speeds can be up to 100 Gbps, but require special LEDs (http://www.lifi.eng.ed.ac.uk/lifi-news/2016-01-04-1329/downlink-performance-optical-attocell-networks). This is 14 times faster than the fastest Wi-Fi, referred to as WiGig. With current commercial and inexpensive, phosphorous-coated white LEDs, it is possible to achieve about 100 Mbps on a single link. However, LiFi describes a fully-fledged wireless network with multiple transceivers (just imagine how many lights are in a typical room). The network capacity of a LiFi network with commercial LEDs can be three orders of magnitude greater than Wi-Fi networks, while at the same time enjoying massively improved security. The full potential of a LiFi networks is analysed in a recent invited paper in the Journal of Lightwave Technology: http://www.lifi.eng.ed.ac.uk/lifi-news/2016-01-04-1329/downlink-performance-optical-attocell-networks. “
The receiver has optics, and is fast enough to ‘see’ the light dimming and brightening, smart enough to decode the LiFi data, and then deliver it to the attached device such as a laptop computer.
Devices can include both a transmitter and receiver for two-way communications.
Industry commentators see LiFi as the catalyst for the inevitable merger of the lighting and wireless communications industries. pureLiFi are working with partners across many industries including defense, healthcare, lighting, IT infrastructure, Tier 1 telcos, device integrators, alongside research partners such as the University of Edinburgh’s LiFi R&D Centre to deliver continued product development, commercialization and, ultimately, to grow the LiFi market in the UK and worldwide.
The company’s solutions provide a fundamentally new dimension for security and information assurance, diversification and differentiation for lighting companies, and will facilitate the continued exponential grown of the mobile communications industry.
Fundamentally, the competitive advantages of LiFi over traditional radio-based communications stem from the physics of the propagation medium. Light by its very nature is directional, does not penetrate opaque objects and is inherently safe, offering more secure and better localized wireless communications. Similar to other disruptive technologies, LiFi will be commercialized first in areas where it can leverage a competitive advantage before expanding into the mass-market as the technology matures.
Technology is accelerating, and lights in the future will become smart sensing and high speed communication devices that are not replaced because they fail, but because of the new functions and applications that the next generation enables, similar to smartphone releases today.
The first mobile phones served only one purpose: mobile telephony. Today, smartphones serve hundreds of applications. Similarly, light bulbs today serve one purpose: lighting. In the next five years, the LED lightbulb will serve countless applications and be an integral part of the emerging smart cities, homes and the Internet of Things where Light-as-a-Service (LaaS) will be a dominating theme. LiFi will be ‘pulled’ into the lighting industry by new business models.
Finally, supplying wireless capacity for a system that will demand 14x mobile data in 5 years means that the next generation of wireless communications or 5G systems is to rely on ever smaller cell sizes to provide the expected demand. Transforming a standard LED light fixture to offer connectivity similar to a 5G base station is the logical next step and provides the basis for an almost unlimited increase in wireless capacity without the need for investing in more spectrums.
Indeed, every color in the light spectrum could be used to transmit data at the same location, creating an almost limitless supply of wireless capacity.
Secure, localized, safe and incredibly fast, LiFi is here and set to increasingly shape our working and domestic lives in the future.