What is LiFi?

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What is LiFi?


LiFi stands for ‘light fidelity’ and the term was first coined by Professor Harald Haas in July 2011. LIFI is an optical version of WIFI and refers to visible light communications technology (otherwise known as 'VLC'). It uses the light visible between 400 THz and 800 THz to deliver a high-speed, mobile communications network in a similar manner as WiFi, but through light emitting diodes or LEDs.

Accessing the internet is something we all do on a frequent basis. Whether at work to check emails or at home for online shopping, the connection speed that we have in our homes and businesses can have a huge impact on how quickly or easily we can do what we want. Whilst WiFi is the current standard for internet connections across the World, the next ten years will undoubtedly see LIFI's faster and cheaper technology take over.


The Advantages of LiFi


How does LiFi work?

So that’s the definition of the technology but what does that actually mean? We are all familiar with LED lightbulbs, which are coming to be used in homes and businesses as well as other functions. LED light bulbs send out a constant stream of photons that can be seen as visible light. If the output slows, the bulb dims and if it increases, the light becomes brighter. When the light reaches a certain high speed, it can be detected by a special device and converted back to electricity. This stream is invisible to our sight in the same way that radio waves used in WiFi is invisible.

how does vlc work lifi

Using LiFi involves the same principle only instead of just sending visible light, the LED bulb would also be sending data. In the most basic form, all that is needed is a lamp driver, an LED bulb or lamp with a chip added and a photo detector. Data enters the light bulb through a signal processing device, the data is embedded in the light beam and sent at rapid speeds to the photo detector, known as a photodiode. It is then converted into electrical signals by the receiver and then into a binary data stream. This means the signal could contain a web site, emails, a video or other applications.


LiFi Features and Benefits

The next question is why would homes and businesses consider switching from WiFi to LiFi? What features does it offer and benefits would it provide that would make it an improvement to the existing system?

One of the biggest issues we experience when using the internet is bandwidth problems – not enough bandwidth makes devices run slow or can even cause the connection to break up. Rural areas in particular suffer with low internet speeds and the resulting problems. But LiFi doesn’t experience this kind of issue because light is plentiful – in fact there are over 10,000 more visible light spectrums than there are RF spectrums. They are also free to use and unlicensed.

Another size issue is the amount of data that can be sent across a WiFi network. Currently, LiFi can achieve an increase of around 1000 times the amount of data that can be sent with WiFi. This is because visible light can be kept in a small illumination area as opposed to RF which spreads out everywhere. This causes interference and limits the amount of data that can be sent.

Because LiFi uses LED bulbs to function, it is easier to locate the system than it is a WiFi network. Virtually every building has illumination in its rooms and these LED lights can serve a dual purpose, creating illumination and data at the same time. It also sends this data at a far quicker speed than normal RF transmissions with very little interference with lab tests achieving a speed of 10 gigabits per second, far faster than normal WiFi.

What about the costs to the business in terms of energy usage and the components required to run the system? The LiFi system actually needs fewer components than a standard WiFi system and then there is the dual nature of the LED lights used. As a building is already being lit by the bulbs, using them to send data doesn’t require any additional electricity and therefore doesn’t impact utility bills. It is even environmentally friendly in the respect that less components need to be manufactured and less waste is created.

System security is a huge issue for businesses of all kinds and often for individuals too. The current WiFi system is notorious for the ability of people to spy on it and access the servers being used. However, LiFi signals do no travel through walls so someone outside the building would be unable to access the data.

Also, because data can go from one device to another, there is no need to use connections such as Bluetooth, which open up further points of vulnerability. Therefore, the system prevents anyone piggybacking on the data stream while eliminating interference from other systems being used in the area. Unless someone is standing in the line of sight of the data stream, they cannot access it, meaning that LiFi can offer top grade security as an automatic part of its operation.

Ever gone into a hospital and wondered why you had to turn off your smartphone? This is because it uses WiFi to connect to the internet and RF signals can interfere with equipment, a similar problem be experienced on airplanes. But because LiFi uses light it doesn’t cause any problems with complex electrical circuits and therefore be used everywhere. In fact, Professor Harald Haas who was instrumental in creating the system is currently working on a variation that will work to operate airplanes themselves.

Conclusion

Around the world, minds such as Professor Haas are looking at the ways LiFi can be used but there is little doubt that it will soon make appearances in homes and businesses around the world. Cost effective, energy efficient and very safe, it appears to make WiFi’s days numbered.


History of LiFi

While LiFi is a relatively new term that most of us may not have previously encountered, the actual idea behind the tech is much older. Back in 1880, Alexander Graham Bell created the telephone. But just four years later, he made the first wireless telephone call, using a gadget called a Photophone. It used light rather than radio and could only be used in daylight, limiting its usefulness at the time.

Research into visible light communication or VLC was started seriously back in 2003 in the UK, the US as well as in Germany, Korea and Japan. Early experiments showed that LEDs could be altered to send data in addition to providing illumination. Faster than traditional WiFi, this new idea had to potential to be cheaper than existing systems and also eliminate a much-hated element of modern communications – the radio mast.

The modern version of this technology, known now as LiFi, was the brainchild of Professor Harald Haas and his team, working in the Alexander Graham Bell Building at the University of Edinburgh. Their brief was to try and overcome the growing problem of congestion over WiFi networks that were slowing down computers around the world.


Stepping forward

It was during a speech to the TED Global 2011 where the professor first talked about the new discovery. The speech was called ‘Wireless Data from Every Light Bulb’ and has now been viewed on video format over two million times. During the talk, he demonstrated the LiFi technology by streaming a live video for the first time.

The technology at that stage looked rudimentary – a light bulb fitted with a signal processor that Professor Haas had designed especially for the project. The light shone through a hole in the lampshade onto an oblong box which had a receiver inside. This receiver converted the light signal to a high speed stream of data and then projected that data onto a screen as a short video. Place a hand over the gap in the lampshade and the video stops – because the light was transmitting the video signal.

Professor Haas grew up in Nuremberg with a father who worked as an engineer for Siemens. From an early age he was mesmerised by the new technology – LEDs – and created his first rev counter at the age of 13 that a number of his neighbours wanted to use in their cars. He went to work at Siemens creating mobile phone chips but found he needed something more challenging.

In 1995, he went to Mumbai on a scholarship, helping to develop the mobile phone network and four years later, attending Edinburgh University. He was tutored by Gordon Povey, now his business partner and created a patent for the 3G Universal Mobile Telecommunications System that was then sold to Siemens.


Developments

Following the enthusiastic reception of this new idea at the TED Global conference, Professor Haas stated a company to market it. Called PureLiFi, it is an original equipment manufacturer or OEM whose purpose is to create LiFi products to use with existing LED lightning systems.

Professor Haas also inspired others to begin working on versions of his idea. In the Nakagawa Laboratories in Tokyo, where Haas spent a semester in 2003, they are working on ‘underwater visible light communications’ a way to pick up the voice of a scuba diver using a microphone inside an LED light. This voice is then sent to another diver with another light.

In December 2010, LVX began proving light powered broadband services to six buildings in the town of St Cloud, Minnesota. While it only managed a slightly uninspiring 3 Mbps, it claimed to be showing ‘fibre optics without the fibre’.

In October 2011, a group of companies and industry groups set up the LiFi Consortium with the aim of promoting this new high speed system as well as breaking the boundary currently placed by the restrictions of WiFi.

Within two years, data rates of 1.6 Gbit/s were already being demonstrated on just a single colour LED while in September 2013, it was announced that line of sight conditions were no longer required for the successful use of LiFi. In October of the same year, the Chinese announced that they too were working on equipment to use LiFi principles.

In June 2014, using the new Fraunhoder IPMS system paired with a USB 3.0, a wireless link of 10 Gbps was created, showing the ever expanding potential of the technology.

The most recent development has been the announcement by Philips that they have developed a VLC system to help ordinary consumers in their stores. The shopper downloads an app to their smartphone that allows it to work with LEDS in the shop – by telling the app what they require, the LEDs can tell the shopper where to go to find the item and even give them a coupon with information on it regarding the product.

Professors Haas and Povey are currently focusing their attention on creating LiFi for aeroplanes, including working alongside a so-far unnamed German aircraft manufacturer. The idea is to allow continuous internet access through the avionics data-bus system but the grand plan is to create plants that needed less hard-wiring, making them lighter and greener as well as more flexible in their interior layout.

Conclusion

At the moment, LiFi looks set to become an industry worth $113 billion by 2022. Already there are developments that will allow a 1 Gbps speed in normal home conditions, easily exceeding what superfast fibre optic broadband can manage. And this looks to be just the start of a very exciting and fast change to how we access the internet.



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