LI-FI - Visible Light Communication

Don't you wish you could walk around anywhere you want an still get a great signal? I am not talking about roaming around within the vicinity of your homes, or your states. Its so irritating while travelling when we don't get a good Internet signal. You don't even get a decent cell tower signal when you are travelling by train. And you actually have to switch off your mobiles on most airplanes, forget using the internet. But we are so use to it. Some of us can't imagine a day without an internet connection. Man, that'll be a bad bad day. Good for us advancement in technology is having a great impact on wireless data transfer rates. It is also increasing the mobility factor when using a wireless transmission medium.

Imagine you are travelling in a car and you are using an internet connection via the headlights and back lights and whatever other LED lights are stuck on vehicles around you. That'll be nice. But it seems totally futuristic, right? Well, the future is here. Its actually possible now with the help of technology called Li-Fi.

Light-Fidelity (Li-Fi) is the wireless transmission of data through an optical light source by changing the intensity of the light. Researchers have made use of a micro light-emitting diode (LED) light bulb as the light source, which comes under VLC (Visible Light Communication).  This technique enables the transfer of binary data at a very high speed. Li-Fi overcomes the disadvantages of Wi-Fi, like clogging of the radio wave spectrum that Wi-Fi makes use of for data transfer. 

Prof. Harald Haas, a German physicist from the University of Edinburg, has extended upon the idea of what he calls “Illumination through Light”. According to Prof. Haas, “At the heart of this technology is a new generation of high brightness light-emitting diodes”.

Li-Fi is still in its infancy. Yet, researchers have been able to generate extremely high speed data transfer through Li-Fi. The basic concept behind transfer of data using light as a medium is that if the LED light bulb is switched on, a digital 1 gets transmitted, whereas if it is turned off it transmits a digital 0. This means that each LED light bulb can transmit a stream of binary data on being switched on and off sequentially. Hence, using more than one LED light bulb can be used to achieve parallel transmission of data.

Initially, four computers under a one-watt LED light bulb could connect to the Internet using the principle of Li-Fi , as told by Prof. Chi Nan, an information technology professor with Shanghai's Fudan University who also led a Li-Fi research team including scientists from the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences. Prof. Nan was able to create her own Li-Fi wireless system from off-the-shelf retail parts.

Researchers from U.K. have used Orthogonal Frequency Division Multiplexing (OFDM) to enable micro-LED light bulbs to endure millions of light intensity changes per second. This takes the data transmission capacity of the light bulbs to rates higher than 10Gbps. Their research led to transmission of data at 3.5Gbps across each of the three primary colors of visible light: red, blue, and green which together form white light.

          

However, the biggest disadvantage that Li-Fi poses is that it requires a light source for connectivity. Even if we do not wish to keep the lights switched on we cannot switch them off if we want to use the internet through a Li-Fi connection. Switching them off would mean disconnecting the internet. This can be overcome by using an LED bulb of lower intensity. You could use your LED watches or better, flash drives, for keeing you Li-Fi connection running. Ofcourse, the data transfer rate would be low. But with the maximum speed being 10GB(with further increase is on the way), how slow can it be? However, in case of power outage we need a back up for power supply or switch to another source of connectivity like Wi-Fi. This is also a significant reason why Li-Fi can act as an alternative to Wi-Fi but it cannot replace it completely. Still, that high surfing speed is so worth it. 

Guess those LED lights for decoration won't just be for decoration after all! On your part, you could get rid of all those useless, global warming causing bulbs and replace them with power efficient LED bulb. Which are even cheaper than normal bulbs by the way. As prof. Harald Haas says,"Li-Fi would take us towards a Cleaner, Greener and Brighter future".
What would you use as your LED light source or should I say, internet connectivity source?