LIFI - OUR DIGITAL FUTURE

INTRODUCTION                            

Lifi, a wireless optical networking technology which in the form of Visible Light Communications (VLC) system that makes use of light-emitting diodes (LED) for data transmission. The term was first introduced by Harald Haas on March, 2011 during TEDGlobal talk in Edinburgh. LiFi is considered to be a light-based WiFi that uses light instead of radio waves to transmit information. Information may be obtained within vicinity of visible light by means of electronic gadgets with photo-diode. Imagine  the world where you can connect to high speed internet just by flicking on your light switch. At recent times, only LED lamps can be used for the transmission of data in visible light. 

HISTORY

Professor Harald Haas, is regarded as the founding father of lifi. His team of University of Edinburgh began their research into VLC technology during early 2006. Much of their research was for the use of light as a medium for transmission of data, which paved the way for LiFi technology. Professor Hass entitled the term 'Li-Fi' to the world in 2011 during TED Talk. Li-Fi technology was demonstrated at the 2012 Consumer Electronics Show in Las Vegas, employing pair of Casio smartphones to trade the data utilizing light of varying intensities. In  2014, the Russian company Stins Coman announced the development of a Li-Fi wireless local network called BeamCaster which tarnsfers data at 1.25GB/s & a new record was established by Sisoft (a Mexican company) that was able to transfer data at speeds of up to 10 GB/s across a light spectrum emitted by LED lamps in 2014. Through the years, pure LiFi was able to produce a variety of LiFi products designed for easy integration . 

Fig: LIFI Technology

WORKING OF LIFI

Li-Fi is a Visible Light Communications (VLC) system for data transmission. A simple VLC system has two qualifying components:

1. at least one device with a photodiode able to receive light signals and
2. a light source equipped with a signal processing unit. 

Li-Fi system requires extremely high rates of light output, LED bulbs are most ideal for implementing Li-Fi because it can amplify light intensity and switch rapidly. It actually serves a dual purpose as it aims to provide overhead illumination to households as well as facilitate the transfer of data. To strike a balance between VLC light source and household illumination,  the optical output is modulated at extremely high speeds, making it detectable by the photodiode device and converted back into electrical current ,without the human eye ever noticing. Once the electronic signal is demodulated, it is converted into a continuous stream of binary data comprising of audio, video, web, and application information to be consumed by any internet-enabled device. 

LiFi technology still needs much room for growing innovation. One proposed innovation to the existing technology includes creating a bidirectional communication system similar to conventional broadband and WiFi which can be done by interchanging visible light and infrared light from a photodetector, allowing connected mobile devices to send back data to the light source for an uplink. Another proposed innovation is the multi-colored RGB LED's at retina size could be engineered to send and receive a wider range of signals than single colored phosphor-coated white LED's.        

Fig: Working of LIFI

MERITS OF LIFI

1. Speed 

Light waves are able to carry far more information than radio waves used in Wi-Fi technology since the visible light spectrum is almost 10,000 times larger than the spectrum occupied by radio waves. LiFi connection can transmit data at the rate of 224 GB per second.  

2. Proficiency

Energy utility can be minimised with use of of LED illumination which are now accessible in home, workplaces and Mall and so on for lighting reasons. Consequently transmission of information requiring negligible additional power, which makes it efficient in terms of costs as well as energy.

3. Availability 

Disponibility is not issue as light sources are available all over place. Along these lines, lights are can be utilized as model for information transmission.

4. Security

One main advantage of Li-Fi is security. Since light cannot pass through opaque structures, Li-Fi Internet is available only to the users within a room and cannot be breached by users in other rooms or buildings.

5. Cost

Not only fewer components for its service, but Lifi also requires only small additional capacity for data transmission.

DEMERITS OF LIFI

1. Limited Range

It uses visible light, and light cannot penetrate walls, the signal's range is limited by physical barriers. In open spaces, Wi-Fi’s coverage can go up to 32 meters but LiFi can only go up to 10 meters

2. Limited Compatibility

Since LiFi is a new technology, not many devices are compatible. Most devices that we use now still use hardware for Wi-Fi networking and the whole new infrastructure for Li-Fi would need to be constructed.

3. High cost of installing the VLC systems.

4. Normal light, sunlight, and ordinary electric light can influence information transmission speed.

5. Internet cannot be used without a light source that could limit the locations and situations in which Li-Fi could be used. 

APPLICATION OF LIFI

⦁ Health technologies 

 Wi-Fi has been replaced by Li-Fi in many hospitals because use of Wi-Fi in hospitals interferes with mobile devices and computers that block the monitoring equipment signals.
     

⦁ Traffic Application

 Li-Fi can be used in traffic management, which interact with LED lights of vehicles such as buses, cars which can help to deal with traffic and can regulate accidents by warning other drivers when vehicles are excessively close.

Fig: Traffic Area

⦁ Airlines

 Airline Wi-Fi wants captive audience to pay for the "service" of dial up on the plane. Passengers will soon be offered a "high-speed like" connection on some airlines. Li-Fi could easily introduce that sort of speed to each passengers reading light which would be interruption free too and from other wireless signals on the board.

⦁ Disaster management 

Li-Fi can be used as groundbreaking methods of correspondence in the middle of disaster, e.g. seismic tremor , hurricanes as subway stations and passages; common dead zones do not impede Li-Fi.

⦁ Underwater communication

 Radio waves are quickly absorbed in water, preventing underwater radio communications, but light can penetrate for large distances. Therefore, LiFi can enable communication from diver to diver, diver to mini-sub, diver to drilling rig, etc.

⦁ Schools

The wireless network is a crucial component to provide new learning experiences by connecting students and teachers to smart technology, enabling learning applications on any mobile device. Li-Fi can also provide seamless network connectivity and security throughout the whole school, from the classroom through to university dorms. Some schools have even started trialling Li-Fi technology in classrooms.

Fig: The Kyle Academy in Scotland has started trialling Li-Fi in classrooms.