Li-Fi : Light-Based Wireless Technology 100 Times Faster Than Wi-Fi
Li-Fi, or Light Fidelity, is an interesting and exciting potential competitor to the wireless veteran, Wi-Fi. Using light bulbs and solar cells to transmit data, this "novel" alternative could take the market by storm, and who knows, make Wi-Fi history. In the following guide, we will attempt to give you an overview of what it is and how it may outcompete its predecessor.
The theory of Li-Fi is actually nothing new, we have been using visible light for "data" transfer since the dawn of time. From physical expressions to fire beacons to semaphore, we are very familiar with the use of visible light for communication. Yes, of course, these were low-tech applications but giving historical context is important to us, problem? Clearly, the development of the digital world needed a more sophisticated approach. Light Fidelity finally offers the combination of the ancient past with the very modern present and future.
Strap yourself in for a wild ride into the future of your internet connection and data transfer needs. Wi-Fi we love you but if something better comes along, watch out! Prepare yourself to be illuminated, ok cheap, sorry!
Great, so what is Li-Fi?
If Wi-Fi's accidental invention in 1992 by Australian Radioastronomer John O'Sullivan et al. hadn't happened, the modern world would be a very different place. They were attempting to detect exploding mini black holes, an experiment that ultimately failed. This "failure" has in fact revolutionized data transfer for all of us. It is, however, not perfect with security and connectivity issues. Step aside Wi-Fi there is a new kid on the block.
Li-Fi stands for Light Fidelity and is a form of Visible Light Communications (VLC). It is proposed as a system that provides wireless communications at very high data transfer speeds. This tech utilizes common LED lights to provide data transfer which may well boast speeds of 224 gigabits per second. That equates to around 18 movies of 1.5 GB each being downloaded every single second. Not too shabby.
Harald Haas, a University of Edinburgh Professor, coined the phrase during his TED talk in 2011. He envisioned wireless routers that were in the form of light bulbs. Fantastic. After four years of research, Haas set up the company pureLiFi in 2012 with the aim "to be the world leader in Visible Light Communications technology".
Since 2013, light fidelity is looking to secure 82% compound annual growth, that's, frankly, incredible. It may well be worth more than $6 billion a year by this time.
[Image Source: Jacek Abramowicz via Pixabay]
So how does it work?
As we all know, various existing wireless data transfer technologies use differing frequencies on the electromagnetic spectrum. Wi-fi is a good example which uses radio waves whereas Li-Fi, if you hadn't guessed, uses visible light instead. Given this, the technology requires a photo-detector to receive light signals and a processor to convert the data into streamable content.
Being semiconductors, LEDs allow for their electrical current to be dipped and dimmed at extremely high speeds. What's more, the human eye can't even notice the difference. Clearly, this is incredibly important when utilized for data transfer where data fed into the LED bulb through signal processing can then be embedded into the light beam at rapid speeds to the receiving photodetector (photodiode). These tiny changes in the rapid dimming of the bulb can then be converted by the receiver into a useful digital signal.
VLC uses visible light between the 400 and 800 terahertz (THz) frequencies. In effect, it acts like a highly advanced Morse Code. The transmitting light sources turn on and off, well dim actually, in a certain pattern which relays the data that can be converted into a binary signal. Because LEDs can "flicker" at higher frequencies than the human eye can detect.
This converted signal can then be 'understood' as binary data that can be streamed as web, video and audio applications that run on internet enabled devices.
Harold Haas believes that the future deployment of internet connection equipment will need to be provided by energy neutral devices. He believes that the transmission and receipt of signals should also use existing prolific technologies. His proposed solution is to provide this via LED bulbs and solar cells.
Please tell me more...
Although LED lights will need to be on for the technology to work, LEDs can be dimmed or even switched off and on at very high rates. As previously mentioned, this will be imperceptible to the naked human eye. LEDs can also be dimmed so low that the light emitted is far below that which the human eye can detect. This would still allow enough light generation to transmit data. Direct line of sight is also not absolutely necessary. Reflected light off walls and other surfaces will still achieve decent speeds of around 70 Mbit/s.
The US Federal Communications Commission has warned of a potential spectrum crisis for Wi-Fi. It is in other words close to full capacity. Light Fidelity, on the other hand, has almost no limitations on capacity at the present time. The visible light spectrum is 10,000 times larger than the entire radio frequency spectrum, which is handy.
Light fidelity is expected to be around ten times cheaper than Wi-Fi if and when fully deployed.
Wireless communication using light is nothing new. Smoke signals, for instance, have been used to communicate signals for a very long time. Not to mention mirrors, fire beacons, flags or other means of direct sight communication techniques. Napoleon covered much of Europe with optical telegraphs, otherwise known as the semaphore, to transmit information rapidly. Alexander Graham Bell also invented the photophone, a device that used a mirror to relay vibrations caused by speech over a beam of light. He considered this as his most important invention.
The unifying principles of the above examples and Li-Fi are the interruption or modulation of the light to break comprehensible messages, like morse code. Light fidelity simply brings this into the modern, digital world. It will also remove the annoying complication of human interference in data transfer. Sorry, my fellow humans, it's nothing personal.
As you can imagine some pioneer startup companies are vying for future control of this new market. At present the list of companies developing this tech are as follows (in no particular order):-
- PureLiFi, as previously mentioned they are the main company in this field. They are also developing Li-Fi luminaires with the French company Lucibel.
- VLNComm is the main startup company in U.S. These guys are being funded by the US Department of Energy and National Science Foundation.
- OLEDComm is a French company working on LiFi. They have some products for indoor positioning.
- LightPointe, who are more familiar with point-to-point gigabit Ethernet Free Space Optics and Hybrid Optical-Radio Bridges. Despite this, they are venturing into this potential market.
- i2cat, located in Barcelona, Spain, they are also throwing their lot in trying to get this to market.
- ByteLight, who were recently bought by the LED manufacturer Acuity Brands
- Nakagawa Lab, Japan
Qualcomm, GE, Panasonic, Philips, Samsung, OSRAM are but a few of the larger corporations who have also expressed interest in this technology. Which of these companies will stand the test of time? Some interesting times ahead, so watch this space.
The limits of Wi-Fi
The huge consumer demand for wireless data is putting big pressures on existing Wi-Fi technology. Wi-Fi, as we are sure you are aware, uses radio and microwave frequencies in the electromagnetic spectrum. Especially the exponential growth in mobile devices will likely result in ten billion devices demanding its use by 2019. This will require an estimated 35 quintillion (1018) bytes of information each month.
This is likely to be unsustainable with current wireless technology due to frequency congestion and interference. Current Wi-Fi transmitters and mobile phone network cell towers are unlikely to be able to cope.
There is a fundamental communications principle that there exists a maximum data transfer which scales with the frequency bandwidth available. As the radio frequency spectrum is heavily used and regulated, there simply isn't enough space available to provide the demand.
Li-Fi, therefore, provides a great option to alleviate this "pressure". This is due to the fact that light frequencies are relatively underused. Either side of this part of the spectrum is heavily congested by comparison.
At present, the visible light spectrum is huge, untapped and generally unregulated for communications.
Is Li-Fi better than Wi-Fi?
The possibility of data transfer speeds of 224 gigabits per second clearly leaves Wi-Fi in the dust. Li-Fi's exclusive use of visible light could, however, provide a potential pitfall to its future uptake.
Li-Fi cannot travel through walls, so in order to compete with Wi-Fi and provide a large area of connectivity, LED bulbs will need to be placed throughout the building. These bulbs will also need to be on 24-7 to provide the kind of connectivity offered by Wi-Fi routers. This obviously means the light bulbs will also need to be on to provide the signal.
Clearly, where there is a lack of lighting there will be a black spot for Li-Fi internet connection. Li-Fi, therefore, may not be appropriate for public networks.
Wi-Fi potentially has a new improvement coming as well, enter Wi-Fi HaLow. This project claims that it can double the range of connectivity whilst also using less power. Wi-fi HaLow should be perfect for battery powered devices such as smartwatches and smartphones. It could also prove very useful for "Internet of Things" devices such as sensors and smart apps. "Internet of Things" if realized, could have massive implications for business logistics, consumer convenience and ultimately, resource management. Here's a good overview video for your pleasure.
The potential data transfer speeds of Li-Fi is not something to be sniffed at, however. Such impressive speeds will enable rapid data transfer speeds with even more devices able to connect to on another. The short range of this technology will also potentially offer greater security when compared to Wi-Fi. It is reported that the embedded light beams reflected off objects could still provide 70 megabits per second. Nice.
See the light
Unlike Wi-Fi, optical communication will allow well-confined data transfer within the walls of a room. Although this may seem to be a disadvantage initially, it may offer key advantages for the technology. Even with windows in the room, curtains could provide a fantastic method to prevent eavesdroppers. A lighting array on the ceiling could send different signals to different users simultaneously. Transmitter power can be localized, more efficiently used and will not interfere with adjacent Li-Fi sources.
The complete lack of radio frequency interference is also another advantage. Visible light communications are intrinsically safe. It could actually lead to the end of travelers needing to switch off devices during travel. Nice.
I'll take that as a compliment
Will Li-Fi replace Wi-Fi? Potentially not.
Light fidelity will probably be better suited for situations where sensitive radio wave electronic circuitry is used. For example aircraft, medical devices and hospitals. This would greatly improve safety in these situations.
Some researchers note that existing LED light bulbs can be converted using a single microchip and one-watt LED bulbs. It's believed that up to four computers could connect to the internet.
Wi-Fi has been around for some time now and our homes, offices and industrial buildings have been fitted with the infrastructure for Wi-Fi. The complete removal and refit for light fidelity tech are likely going to be economically unfeasible for the vast majority of people.
Li-Fi for life
pureLifi already has two products on the market. Li-Flame Ceiling Unit for LED light fittings and Li-Flame Desktop Unit which can connect to a device via USB. Both of their devices aim to provide light and connectivity in one device.
The fast connectivity offered for data transmission is likely to be of great interest to businesses. Integration of "Internet of Things" devices and Li-Fi should offer a lot of opportunities for retailers and other businesses. A shop owner, for example, could transmit data to multiple customers' phones very quickly, safely and remotely.
Dubai, UAE-based telecoms providers Du and Zero1 are field testing it. Du claims that tests have been successful thus far in providing internet, audio and video streaming. It has also been tested in Tallinn, Estonia. Reports indicate that data transmission of 1GB per second was achieved. That is around 100 times faster than current average Wi-Fi speeds.
"We are doing a few pilot projects within different industries where we can utilize the VLC (visible light communication) technology," said Deepak Solanki, CEO of the Estonian tech company, Velmenni.
"Currently we have designed a smart lighting solution for an industrial environment where the data communication is done through light. We are also doing a pilot project with a private client where we are setting up a Li-Fi network to access the Internet in their office space.”
It is also rumored that Apple may consider building in Li-Fi capability in future iPhones. This was discovered by a Twitter user who found that within the iOS 9.1 update code there were references to "LiFiCapability". A clear hint that this technology may well be integrated into future Apple devices.
The future is bright
See what I did there? Oh, forget it, tough crowd. This emerging technology has the potential to provide low-cost wireless internet connection more localized and secure, as previously mentioned. Although light cannot travel through walls this may actually be beneficial from a security and privacy point of view.
The fastest speed previously achieved using Li-Fi was in October 2014, when a team of researchers from the universities of Oxford, Edinburgh, St Andrews and Strathclyde working on the Ultra-Parallel Visible Light Communications Project reached transmission speeds of 10.5Gbps via red-blue-green LEDs.
At his TED talk, Harold Haas said "We have the infrastructure there," whilst demonstrating his tech. "We can use them for communications."
"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.
"In the future, we will not only have 14 billion light bulbs, we may have 14 billion Li-Fi's deployed worldwide for a cleaner, greener and even a brighter future."
If you watched the video above you will appreciate the potential for this technology. Wi-Fi can suffer from serious interruptions for signal transfer at times. The combination of artificial light and solar cells for transmission, receipt and conversion of electromagnetic technology to transfer digital signals has an incredible potential. Really interestingly, even with the solar cell partially obscured it will still work. You don't need a huge swath of the cell exposed to transmit data, which is handy.
The proposal for using existing "off the shelf" technologies to create the interconnection between bulb and receiver will also be of great interest to businesses and private consumers alike. The selection of low energy consumption technology such as LEDs and solar cells will also be a great benefit to the future of this technology. This kind of lateral thinking is exactly the kind of solution that is likely to explode when it comes to the market proper.
Li-Fi provides the potential for:-
- Enhanced wireless infrastructures by providing additional layers of smalls cells, termed "attocells"
- This technology will also avoid radio frequency spectrum crunch given its exploitation of the visible spectrum
- As previously mentioned, there is a potential for very high data transfer speeds (perhaps 10.5 Gbps+)
- Li-fi will enable better connectivity for Internet of things devices
- Much greater security and reduced interception of signals compared to Wi-Fi
- The use of energy efficient technology for communication and illumination is of great interest
- For those worried about the health risks of Wi-Fi, Li-Fi should prevent such concerns
The potential application of this technology is actually pretty exciting. Wi-Fi bandwidths are becoming saturated, heavily regulated and they interfere with sensitive equipment. These are definite limitations for this great technology, sadly.
Li-Fi certainly has the edge for frequent fliers and we can really see Light Fidelity kicking off in airliners, hospitals etc.
Human kind's ingenious past uses for light to provide means of communication has been taken to the next level with this technology. The inevitable combination of the digital world with the principle of light manipulation to transmit information seems, for all intents and purposes, to be a natural evolution of wireless communications.
The exploitation of existing low energy technology to allow for this technology's implementation is also a massive plus. With LED lighting growing in popularity Li-Fi is an obvious potential addition for future lighting designs in buildings. The impressive data transfer speeds and self-evident security will certainly be of interest to businesses and private citizens alike.
It will be interesting to see future computer and smartphone design changes to take advantage of this technology. Perhaps we'll finally see solar panel charging capabilities with combined Li-Fi connectivity cells? Who knows. Initially, it is possible that connectivity will be provided with external accessory devices.
It is unlikely that Li-Fi will completely replace Wi-Fi given the pervasiveness of existing infrastructure all around us. But Li-Fi will certainly hold exclusive presence for data security demands or in old buildings with very thick walls to interrupt Wi-Fi signals. We can certainly see this becoming very popular in areas with older buildings in Europe and the US.
The future looks bright for this new kid on the block, watch this space.
[Edited: Featured Image Source: Frank Jones via Flickr]
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