What is Li-Fi?
Light Fidelity or Li-Fi is a Visible Light Communications (VLC) system running wireless communications travelling at very high speeds. Li-Fi uses common household LED (light emitting diodes) lightbulbs to enable data transfer, boasting speeds of up to 224 gigabits per second.
The term Li-Fi was coined by University of Edinburgh Professor Harald Haas during a TED Talk in 2011. Haas envisioned light bulbs that could act as wireless routers.
How it works?
Li-Fi and Wi-Fi are quite similar as both transmit data electromagnetically. However, Wi-Fi uses radio waves while Li-Fi runs on visible light. As we now know, Li-Fi is a Visible Light Communications (VLC) system. This means that it accommodates a photo-detector to receive light signals and a signal processing element to convert the data into ‘stream-able’ content.
An 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 future internet
Li-Fi technology will in future enable faster, more reliable internet connections, even when the demand for data usage has outgrown the available supply from existing technologies such as 4G, LTE and Wi-Fi. It will not replace these technologies, but will work seamlessly alongside them.
Using light to deliver wireless internet will also allow connectivity in environments that do not currently readily support Wi-Fi, such as aircraft cabins, hospitals and hazardous environments.
Light is already used for data transmission in fibre-optic cables and for point to point links, but Li-Fi is a special and novel combination of technologies that allow it to be universally adopted for mobile ultra-high speed internet communications.
A dual use for LED lighting
The wide use of solid state lighting offers an opportunity for efficient dual use lighting and communication systems.
Innovation in LED and photon receiver technology has ensured the availability of suitable light transmitters and detectors, while advances in the modulation of communication signals for these types of components has been advanced through signal processing techniques, such as multiple-input-multiple-output (MIMO), to become as sophisticated as those used in mobile telecommunications.
Li-Fi vs Wi-Fi
While some may think that Li-Fi with its 224 gigabits per second leaves Wi-Fi in the dust, Li-Fi’s exclusive use of visible light could halt a mass uptake.
Li-Fi signals cannot pass through walls, so in order to enjoy full connectivity, capable LED bulbs will need to be placed throughout the home. Not to mention, Li-Fi requires the lightbulb is on at all times to provide connectivity, meaning that the lights will need to be on during the day.
What’s more, where there is a lack of lightbulbs, there is a lack of Li-Fi internet so Li-Fi does take a hit when it comes to public Wi-Fi networks.
In an announcement yesterday, an extension of standard Wi-Fi is coming and it’s called Wi-Fi HaLow (pronounced “HAY-Low”).
This new project claims to double the range of connectivity while using less power. Due to this, Wi-Fi HaLow is reportedly perfect for battery powered devices such as smartwatches, smartphones and lends itself to Internet of Things devices such as sensors and smart applications.
But it’s not all doom and gloom! Due to its impressive speeds, Li-Fi could make a huge impact on the internet of things too, with data transferred at much higher levels with even more devices able to connect to one another. (See also: What is the Internet of Things?)
What’s more, due to its shorter range, Li-Fi is more secure than Wi-Fi and it’s reported that embedded light beams reflected off a surface could still achieve 70 megabits per second.
The future of Li-Fi
pureLiFi already have two products on the market: Li-Flame Ceiling Unit to connect to an LED light fixture and Li-Flame Desktop Unit which connects to a device via USB, both aiming to provide light and connectivity in one device.
Plus, with faster connectivity and data transmission it’s an interesting space for businesses. The integration of internet of things devices and Li-Fi will provide a wealth of opportunities for retailers and other businesses alike. For example, shop owners could transmit data to multiple customers’ phones quickly, securely and remotely.
Li-Fi is reportedly being tested in Dubai, by UAE-based telecommunications provider, du and Zero1. Du claims to have successfully provided internet, audio and video streaming over a Li-Fi connection.
What’s more, reports suggest that Apple may build future iPhones with Li-Fi capabilities. A Twitter user found that within its iOS 9.1 code there were references to Li-Fi written as ‘LiFiCapability’ hinting that Apple may integrate Li-fi with iPhones in the future.
Is Li-Fi secure?
LiFi is more secure than WiFi because light can’t go through walls like WiFi radio signals can. That means only the people in the same room as the LiFi bulb can connect to your internet connection.
Some are also seeing LiFi as a solution in places where WiFi signals create interference with equipment. It would be great in hospitals, for example, as LiFi wouldn’t interfere with wireless medical equipment like WiFi signals can.
When Will Li-Fi Lightbulbs Be Available?
Li-Fi sounds great – but when will we be able to use it in our homes and businesses? Even though Li-Fi was only a concept in 2011, it seems as if Li-Fi will become common place sooner rather than later. Well maybe not common place, but it pureLiFi announced recently that it has partnered with a French industrial-lighting company and confirmed that it’ll be rolling out Li-Fi technology in its products by Q3 of 2016.
Is There Any Downside?
Because Li-Fi technology uses visible light as its means of communication, it won’t work through walls. This means that to have a Li-Fi network throughout your house, you will need these lightbulbs in every room (and maybe even the fridge) to have seamless connectivity.
Another major issue is that Li-Fi does not work outdoors, meaning that public Li-Fi will not be able to replace public Wi-Fi networks any time soon. While Li-Fi’s employment in direct sunlight won’t be possible, pureLiFi said that through the use of filters the technology can be used indoors even when sunlight is present.
Of course, one of the biggest drawbacks is the fact the light needs to be on all the time to deliver connectivity. While that’s not going to be an issue in industrial and retail environments, it’s will be both environmentally and practically problematic in domestic settings.