What is LiFi?


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Any new technology or development always generates a lot of questions. People wonder how the development will benefit them, what problems could occur and what will happen in the future. Here we look at some of the mostly frequently asked questions about LiFi.

Is there a difference between LiFi and VLC?

LiFi is a relative of VLC or visible light communications in that both use a solid state device to emit the signals and a photosensitive receiver to collect them. However, VLC tends to be used to describe a point to point communication link using light that operates across a fixed link. It has very carefully controlled properties including being unidirectional and operating across low or medium data rates. LiFi, on the other hand, is more about a network of transceivers that can send and receive transmissions as required across a cluster of devices. It is also designed to work alongside radio wave frequencies currently used for WiFi and can work at high to ultra-high rates.

Who created LiFi?

As a concept, using light for communications was first theorised by Alexander Graham Bell, the man who invented the telephone. But more recently, Professor Harald Haas launched the concept of LiFi at a talk in 2011. He demonstrated that data could be sent via light at the TED talk he gave. Others have also taken up the idea while the professor and his team continue their work at the University of Edinburgh.

Is WiFi just for downloading data?

While VLC is known for being one directional, LiFi has already shown that it can operate in both directions. This means you can download a video to your smartphone then upload a photo to Facebook, all using the same system. This means it has the same data directionality as WiFi has.

What types of devices will be able to use LiFi?

Already, LiFi has shown it works through dedicated transceiver units but in the future, the plan is that it will work on a wide range of devices, in fact most of those that currently use either WiFi or Bluetooth systems. Eventually, all electronic devices will have the capacity to operate with LiFi. In fact, some are already saying that 5G, the next level of communications, will be a hybrid system of WiFi and LiFi, operating to achieve the best signal strength and data speeds.

Will my smartphone work when in my pocket with LiFi?

LiFi doesn’t need to be an ‘always on’ system because it operates alongside WiFi. The idea with smartphones and similar devices is that LiFi can increase the data rate when WiFi is slow or in a poor signal area. This means that the signal will be there when needed – when the device is in use – and not there when it isn’t – such as when the device is in a pocket or bag.

Does LiFi always need bright light? And what happens if the light flickers?

While LiFi does need light to operate, it doesn’t need to be bright light all of the time. It can operate at lighting levels that are low enough that the human eye cannot see them so to all intents and purposes, the lights will be out. Flickering is another issue that has been raised – all systems flicker including computer screens and TVs. But they do this at a rate so quick that the human eye cannot see them so the screen appears solid. LiFi lighting will work in the same way.

Do other lights interfere with LiFi?

For starters, many of the LiFi systems will use LED light bulbs, commonly used in homes, businesses and public places around the world. They don’t need to replace the existing system, merely adapt it. Secondly, tests have been carried out at the University of Edinburgh that show other types of lighting has virtually no effect on LiFi signals and the system can still send clean, quick signals when there are other sources of light present.

Can LiFi cause health issues?

Many people living near radio frequency masts used to send and receive WiFi signals blame them for health issues and there are people who are more sensitive to RF than others. However, because LiFi uses light to send and receive data, this problem is alleviated. All components used in the system will also comply with the various regulations to make sure they are safe to use and be around.

Is LiFi going to increase my electricity bills?

While LiFi does require electricity to operate, it is at a small level due to the efficiency of LED lightbulbs. These will light homes during darker hours and during the day, because they are so energy efficient, the different will be negligible. Also WiFi signals use electricity to operate and the systems is notoriously energy inefficient. So the switch to using LiFi could actually general a small saving over time.

Can signals travel through windows for hackers to access them?

The innate nature of LiFi means it cannot travel through glass anywhere near as well as it travels through the air. This means if someone is outside a window, trying to access LiFi signals, it is unlikely they will be able to do this. The result is that the system may be more secure by its very nature than WiFi, which can be accessed through walls, let alone through glass.

When can I switch to LiFi?

Already, commercial LiFi devices are beginning to appear in a variety of applications around the world. This year will see the steady roll out of a wide range of products that use the system and begin to familiarise everyone with it, its benefits and how it works. As these products emerge, more and more people will be able to add the benefits of LiFi to their existing systems, enjoy its higher speeds and greater reliability. It is entirely possible in the near future that this system will be the normal way to access the internet and WiFi will become the backup system for those few times that LiFi might not be at peak efficiency.