In an era of rampant use of wireless connectivity through wireless fidelity (Wi-Fi) all over the world and India along with developing and under developed countries still struggling to reap the maximum benefits of the technology, developed countries are planning to move forward with its new version termed as light fidelity (Li-Fi). This article aims to introduce the working, progress, advantages and limitations of this (Li-Fi) technology in comparison to Wi-Fi technology. Wi-Fi is the name of a popular wireless networking technology that uses radio waves to provide wireless high-speed Internet and network connections. Wi-Fi networks have no physical wired connection between sender and receiver by using radio frequency (RF) technology - a frequency within the electromagnetic spectrum associated with radio wave propagation.

When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space.  The huge consumer demand for wireless data is putting big pressures on existing Wi-Fi technology. The exponential growth especially, 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. As radio waves used by Wi-Fi get more congested and the demand for faster and more efficient wireless communication escalates, the future is bright for Li-Fi as a reliable, affordable and more secure solution. Light Fidelity (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) light bulbs to enable data transfer, boasting speeds of up to 224 gigabits per second. Light fidelity (Li-Fi) claims to be 100 times faster than standard Wi-Fi. Li-Fi was invented by Harald Haas from the University of Edinburgh, Scotland back in 2011, when he demonstrated for the first time that by flickering the light from a single LED, he could transmit far more data than a cellular tower.

 

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 and thus, Li-Fi is a Visible Light Communications (VLC) system. The technology uses Visible Light Communication (VLC), a medium that uses visible light between 400 and 800 terahertz (THz). It works basically like an incredibly advanced form of Morse code - just like switching a torch on and off according to a certain pattern can relay a secret message, flicking an LED on and off at extreme speeds can be used to write and transmit things in binary code. 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 light bulb is a semi-conductor light source meaning that the constant current of electricity supplied to an LED light bulb 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 are then converted by the 'receiver' into electrical signal. The signal is then converted back into a binary data stream that we would recognize as web, video and audio applications that run on internet enables devices. 

 

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 light bulb is on at all times to provide connectivity, meaning that the lights will need to be on during the day. Where there is a lack of light bulbs, there is a lack of Li-Fi internet so Li-Fi does take a hit when it comes to public Wi-Fi networks. Experts say that Li-Fi will probably not completely replace Wi-Fi in the coming decades, the two technologies could be used together to achieve more efficient and secure networks. The homes, offices, and industry buildings have already been fitted with infrastructure to provide Wi-Fi, and ripping this entire out to replace it with Li-Fi technology isn’t particularly feasible, so the idea is to retrofit the devices we have right now to work with Li-Fi technology.

 

Advantages of Li-Fi

·         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.

·         The benefits of Li-Fi over Wi-Fi, other than potentially much faster speeds, is that because light cannot pass through walls, it makes it a whole lot more secure and  this also means there's less interference between devices.

·         Li-Fi project claims to double the range of connectivity while using less power.

·         Due to this, Li-Fi is reportedly perfect for battery powered devices such as smart watches; smart phones and lends itself to Internet of Things devices such as sensors and smart applications.

·         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.

·         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.

·         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.

·         'Internet of Things', is an optical communication technology that’s taking the world by storm. Light Fidelity or Li-Fi, is an exciting breakthrough in 5G visual light communication systems and the future of wireless Internet access.

·         Another advantage of Li-Fi is zero electromagnetic interference, allowing connectivity even in areas where Wi-Fi isn’t accepted - hospitals and nuclear plants among others.

·         In addition, Li-Fi offers better data defense as light waves can’t pass through walls, making it impossible to hack any internal systems in high-security buildings.

 

Progress made so far

·         Currently researchers have designed a smart lighting solution for an industrial environment where the data communication is done through light.

·         Scientists have taken Li-Fi out of the lab for the first time, trialing it in offices and industrial environments in Tallinn, Estonia, reporting that they can achieve data transmission at 1 GB per second - that's 100 times faster than current average Wi-Fi speeds.

·         The pioneer company (pureLiFi) already has 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.  

·         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.

·         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.

 

Who’s who of technology?

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:

·         PureLiFi, the main company in this field, also developing Li-Fi luminaries with the French company Lucibel.

·         VLNComm is the main startup company in U.S.  funded by the US Department of Energy and National Science Foundation.

·         OLEDComm is a French company working on LiFi and 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.

·         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

·         Basic6, Velmenni, Zero1, Axrtek, Qualcomm, GE, Panasonic, Philips, Samsung, OSRAM are but a few of the larger corporations who have also expressed interest in this technology.

Summary

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. 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. Li-Fi certainly has the edge for frequent fliers and we can really see Light Fidelity kicking off in airliners, hospitals etc. It will be interesting to see future computer and smart phone design changes to take advantage of this technology. 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.