Sounds familiar, ya it’s the buzzword that has been surfaced after the TED talk given in 2011. Expect to hear a whole lot more about Li-Fi – a wireless technology that transmits high-speed data using visible light communication (VLC) – in the coming months.


Imagine that in the blink of an eye, your favourite movie is downloaded on an electronic device. It may sound like science fiction now but promises to be reality soon, thanks to Light Fidelity (Li-Fi)—a revolutionary new technology that transmits high-speed data using lights.

With scientists achieving speeds of 224 gigabits per second in the lab using Li-Fi earlier part of 2015 , the potential for this technology to change everything about the way we use the Internet is huge.

And now, scientists have taken Li-Fi out of the lab for the first time, trialling it in offices and industrial environments in Tallinn, Estonia, reporting that they can achieve data transmission at 1 GB per second – that’s 100 times faster than current average Wi-Fi speeds.

Li-Fi was invented by Harald Haas from the University of Edinburgh, Scotland back in 2011, when he demonstrated for the first time that by flickering the light from a single LED, he could transmit far more data than a cellular tower. Think back to that lab-based record of 224 gigabits per second – that’s 18 movies of 1.5 GB each being downloaded every single second.

Li-Fi is a Visible Light Communications (VLC) system, which means that it accommodates a photo-detector to receive light signals and a signal processing element to convert the data into ‘stream-able’ content.

lifi_wifi_istock_themacx_thumb800An LED lightbulb is a semi-conductor light source meaning that the constant current of electricity supplied to an LED lightbulb can be dipped and dimmed, up and down at extremely high speeds, without being visible to the human eye.

For example, data is fed into an LED light bulb (with signal processing technology), it then sends data (embedded in its beam) at rapid speeds to the photo-detector (photodiode).

The tiny changes in the rapid dimming of LED bulbs is then converted by the ‘receiver’ into electrical signal.

The signal is then converted back into a binary data stream that we would recognise as web, video and audio applications that run on internet enables devices.

The medium is visible light between 400 and 800 terahertz (THz). It works basically like an incredibly advanced form of Morse code – just like switching a torch on and off according to a certain pattern can relay a secret message, flicking an LED on and off at extreme speeds can be used to write and transmit things in binary code.

And while you might be worried about how all that flickering in an office environment would drive you crazy, don’t worry – we’re talking LEDs that can be switched on and off at speeds imperceptible to the naked eye.


The benefits of Li-Fi over Wi-Fi, other than potentially much faster speeds, is that because light cannot pass through walls, it makes it a whole lot more secure, this means there’s less interference between devices.

Research teams around the world are working on just that. Li-Fi experts reported for the ‘The Conversation’ last month that Haas and his team have launched PureLiFi, a company that offers a plug-and-play application for secure wireless Internet access with a capacity of 11.5 MB per second, which is comparable to first generation Wi-Fi. And French tech company Oledcomm is in the process of installing its own Li-Fi technology in local hospitals.


If applications like these and the Velmenni trial in Estonia prove successful, we could achieve the dream outlined by Haas in his 2011 TED Talk -everyone gaining access to the Internet via LED light bulbs in their home.

Potential applications

“All we need to do is fit a small microchip to every potential illumination device and this would then combine two basic functionalities: illumination and wireless data transmission,” Haas said. “In the future we will not only have 14 billion light bulbs, we may have 14 billion Li-Fis deployed worldwide for a cleaner, greener, and even brighterfuture.”

Li-Fi is still in its infancy, but some fields where it seems eminently usable are street and traffic lights. Traffic lights can communicate to the vehicles and with each other. Vehicles having LED-based headlights and tail lamps can communicate with each other and prevent accidents by exchanging information. Also, through the use of Li-Fi, traffic control can be made intelligent and real-time adaptable. Actually, each traffic and street light post can be converted into access points to convert roadsides into wireless hot spots.


Visible light being safer, they can also be used in places where radio waves can’t be used such as petrochemical and nuclear plants and hospitals. Similarly, in aircraft, where most of the control communication is performed through radio waves, there are restrictions on passenger communication using the same media, which can be easily handled through use of Li-Fi.

Li-Fi can also easily work underwater, where Wi-Fi fails completely, thereby throwing open endless opportunities for military and navigational operations. Still, the technology comes with some limitations.

As visual light can’t pass through opaque objects and needs line of sight for communication, its range will remain very restricted to start with. Also, it is likely to face interference from external light sources, such as sunlight and bulbs, and obstructions in the path of transmission, and hence may cause interruptions in communication.

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Global innovation symbol with a glowing glass light bulb shaped as the world map representing the business concept of new and future inventions in international technology and design creativity.

Also, initially, there will be high installation costs of visual light communication systems as an add-on to lighting systems. Li-Fi receiving devices will require adapters to transmit data back to the transmitter.

Once customized to the requirements of users, the technology may finally satiate consumers’ appetite for faster data. It is already being hailed as the technology that will change the way we use the Internet. It has been estimated that it will become a $113 billion industry by 2022.


-Shibendu Mukherjee


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