Li-Fi. By Paul de la Gravière & Arthur Geneix

Have you ever got frustrated at the slow speed of the Wi-Fi when more than one device is tapped into the network? Have you already tried to use wireless internet in a coffee shop or to steal it from your neighbour? Nowadays, more and more people and their many devices have access to wireless internet; clogged airwaves are going to make it increasingly difficult to latch onto a reliable signal. But many people don’t know that radio waves are just one part of the spectrum that can carry our data. What if we could use other waves to surf the internet and transmit or receive data?

Li-Fi is a technology promised since 2011; Light Fidelity offers the perspective of a replacement, at least partially, of Wi-Fi; with more flow and without the waves feared by many people because of their harmfulness.

What is Li-Fi?

Like Wi-Fi, it’s a method of transmitting data from one point to another wirelessly. Whereas Wi-Fi uses radio waves, Li-Fi uses light to communicate data.

The operation of Li-Fi is quite easy to understand. It works with the transmission of a binary message due to the lighting and the extinction of a light. Therefore, it’s not difficult at all and that’s exactly what we need to end and receive data: light off is equivalent to 0 and light on is equivalent to 1.

In fact, we can say that Li-Fi is a sort of light-based Wi-Fi. The difference between them is that Li-Fi uses light instead of radio waves to transmit information. And instead of Wi-Fi modems, Li-Fi would use transceiver-fitted LED lamps that can light a room as well as transmit and receive information. Moreover, Li-Fi use simple bulbs. That’s the reason why there can be any number of access points.

This new technology uses a part of the electromagnetic spectrum (The Visible Spectrum). Nevertheless, it’s still not greatly utilized. As you know, light is a very important part of our lives and it does not have any major negative effects. It is possible to encode data in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s. The LED intensity is modulated very quickly so that human eyes cannot notice. Therefore the output appears constant. It is the fast and cheap Wireless communication system which is an optical version of Wi-Fi.

LEDs:

Light-emitting diodes are the next big thing in the lighting world. Efficient and long-lasting, they’re already replacing filament and halogen lighting.

Working process:

Frequency changes which are very fast are not visible to the human eye. Li-Fi is a system of wireless transmission of data using light as a medium of communication. A Li-Fi router feeds the lighting system. The LED bulb turns on and off at very High speed. An integrated sensor receives data. Photodetector registers a binary ‘1’ for on else its’0’ for off. The operational procedure is very simple, if the LED is on, you transmit a digital 1, if it’s off you transmit a 0. The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data. Binary information is made up of strings of 1’s and 0’s. Any light source can transmit this ON and OFF information but LEDs are capable of the highest flickering speed. Light receivers interpret the flickering LED as 1’s and 0’s, and thus we have our Li-Fi.

Light off = 0    Light on = 1

Why is Li-Fi so much faster?

Visible light is far denser than radio waves; 10,000 times denser in fact, meaning much more data can be transferred.

Some figures:

3,4 billion internet users

19 billion global networks connections (mobile and fixed)

The global mobile data traffic will weigh 10,8 Exabytes per month.

A powerful technology:

With Li-Fi, a LED light can transmit multimedia content (video, sound, information, games, etc.) to a tablet or a smartphone.

No interference:

Increased security of communication

Wireless communication at very high speed

Multi-user communication

What’s so special about Li-Fi?

The speed! The highest speed yet recorded with a Li-Fi connection is 10 Gbit/s which is 250 times faster than the average Broadband speed. But commercial Li-Fi being produced in China is at about 150Mbps which is still 10 times higher than the average French connection speed.

Advantages:

New ultra-fast and secure communication network without cable, without radio waves, simply by the light! Also: smart lighting network, wireless, internet access, media access.

Transport:

During your travels, you have access to the Internet. Li-Fi can be used safely on planes because it does not interfere with radio equipment.

Hospitals:

Connections are possible in a place hostile to radio waves.

Traffic:

Allows vehicles (car headlights) to transmit information to secure the traffic and make it more fluid. Measuring distances between vehicles.

Security:

Sending and receiving data via the LED light. Very high speed communication within military vehicles: cars, planes, boats, submarines.

Hazardous environments:

Access your communications in a difficult or dangerous environment: tunnel, factory, petrochemical, refinery, etc.

However, this new technology has some drawbacks :

Presence of light is one of the keys for the good working of Li-Fi.

Fluorescent light and LEDs are optimal to use Li-Fi but these lights possess a low lightning.

Li-Fi & Wi-Fi…

We can say that Wi-Fi is perfect for wireless coverage within buildings; Li-Fi is great for high density wireless data coverage in restricted areas and for abating radio interference problems. To conclude Li-Fi and Wi-Fi can be considered complimentary.

Conclusion

Li-Fi is an amazing technology. It’s also in its early days. It’s hard to predict how a technology will develop over time, but it’s safe to say that a combination of Li-Fi and Wi-Fi will bring the best of both worlds to the internet.