“Li-Fi” Future of Transmitting Wireless Data

Interesting! Now the time has come, when ordinary light bulb soon will be capable of providing internet connection. It is made possible by Harald Haas, Professor of Mobile Communications at the University of Edinburgh, and inventor of Li-Fi (Light Fidelity).

Li-Fi is a bi-directional, high-speed wireless communication technology, which is very similar to Wi-Fi, but the only difference is that it uses visible light for communication. It is estimated that its bandwidth is far superior to Wi-Fi. Li-Fi is faster than some Wi-Fi implementations reaching up to the speed of 230 gigabits per second.

“It’s something we believe is big, and the reason for that is we see a variety of different applications” – Harald Haas

Li-Fi is an application of Visible light communications (VLC), which works by driving the LED on and off at a very high rate, impossible to be perceived by the human eye. Although Li-Fi technology is capable enough to sense the variations in LED light even if it is dimmed below human visibility while still emitting enough light to carry data. The light waves cannot penetrate walls, which makes a much shorter range though makes it more secure from hacking. Direct line of sight transmission is not necessary for Li-Fi to transmit a signal, light reflected from the walls can achieve 70 Mbps speed. Li-Fi is a disruptive technology, which will shift business models and create opportunities ripe for exploitation. The dominance and lifetime of LED lighting have created a need for new business models in the lighting industry. The need to offer services includes new payment; and financing models create a fantastic opportunity for Li-Fi.

Today, the need for more spectrum to serve the existing users needs for data has been increased. For an instance, the pending decision on the auction surrounding the 700 MHz slot of spectrum in the UK and the possibility of regulation of the unlicensed spectrum, where Wi-Fi and Bluetooth thrive, provide a key indication towards the urgency of the problem. Li-Fi operates in the unlicensed and safe, visible light spectrum, where the spatial reuse of bandwidth leads to dramatic increases in the overall capacity of a wireless solution.

Li-Fi different from VLC

VLC is an overall concept, which includes the unidirectional and low-speed data transfer. VLC does not provide wireless internet access, which differentiates VLC with Li-Fi and makes it unusual.
Roaming – Users can move freely between lights without disturbing the streaming like maintaining a Skype Video Call.
Multiple Access – a single light source can allow different people browse the internet at the same time.

How it Works?

In Li-Fi, an overhead lamp fitted with LED with signal processing capabilities streams data embedded in the modulated beam at ultra-high speed to a photodetector. A receiver dongle then converts the tiny changes in amplitude into the electrical signal which then translated back into the data stream and transmitted to a computer or mobile device. The same light source can be modulated to carry different data streams to multiple users connected to that source, and they can roam between lamps without disrupting the connectivity.

PureLiFi, the home of Li-Fi and co-founded by Prof. Haas, the ‘father of Li-Fi’, is recognized as the leader in the domain – the use of the visible light spectrum instead of radio frequencies to permit high-speed wireless data transmission with the internet access. PureLiFi renders ubiquitous high-speed wireless access that allows substantially greater security and data volume than Wi-Fi along with inherent properties that eradicate unwanted external network intrusion. PureLiFi demonstrated the first commercially available Li-Fi system, Li-Flame, which is the world’s first true Li-Fi system publically shown at Mobile World Congress in Barcelona in March 2015.

How Li-Fi Can Change The World

Li-Fi is particularly suitable for many modern internet “data intensive” tasks which majorly include video and audio downloads, live streaming, etc. These applications require high downlink bandwidth but require least uplink capacity. In this way, the majority of the internet traffic is offloaded from existing RF channels, thus also extending cellular and Wi-Fi capabilities.

One advantage of light waves is that they don’t travel through walls. With Li-Fi, interference pattern extends no further than the light in the room where the light source is present, no matter how big the city is and how crowded is the neighborhood.

The major limitation with Wi-Fi is that connection speed is inversely proportional to the number of users connected to the Wi-Fi. In contrast, with Li-Fi, the same light source yields full access to high-speed sharing. This in turn, generates a thousand times greater speeds.

In a museum or art gallery, each exhibition is typically illuminated by its light source. Li-Fi-enabled lighting will provide localized information within that light pool so that each visitor’s device can download information regarding the exhibit or object.

Li-Fi technology excludes the need to have radio base stations. Conventional street lamps could provide both high-speed data communication, even in daylight hours when they’re not shining.

Li-Fi technology can also serve users who are flying. Li-Fi lighting can provide high data rate connectivity for each passenger without generating electromagnetic interference with the plane’s flight deck.

The major advantage of Li-Fi is that it emits no electromagnetic interference and does not interfere with medical instruments, nor is it interfered by MRI scanners, which make it a perfect candidate for allowing connectivity even in areas where Wi-Fi isn’t accepted – hospitals.

What Li-Fi is not

Li-Fi is not “100x faster than Wi-Fi.” The latest Wi-Fi standard (IEEE 802.11ad) or Wi-Gig supports data rates of 7 Gbps. Li-Fi has never achieved 700 Gbps. The type of light source (large LED light, small LED lights, laser LEDs, etc.), directly impacts the speed that can be achieved by a Li-Fi solution. Internet speeds depend on the Internet Service Provider as much as your Wi-Fi access point. Li-Fi data rates will be limited by what is offered by the Internet Service Providers.

A Light of Hope

“What we’re envisaging now is illumination, but it (light) will be a service in the future,” says Harald Haas. Incandescent bulbs lifespan is limited to 2,000 hours while LED has as much as 50,000 hours. “People who manufacture them (LED bulbs) are aware that their lifecycles are much larger, so they need to find new ways of adding service to the light they sell. That is one of these added services that would enable Phillips and others to distinguish themselves from the competitors,” he continues.

Li-Fi still has a long way to realization, for now, Li-Fi will remain a thing of the future for most of the people.