Li fi, a new revolutionary technology in wireless communication. Nowadays scientists research on the fast data transfer technologies, they develop a new way for data transfer through which we can transfer data upto 250 times more than any existing technology.
Telling something!!
Li fi uses the light as the medium while Wi Fi uses the radio frequencies. Li Fi is more secure than Wi Fi because the light waves used cannot penetrate the walls. It can be used in electromagnetic sensitive areas without causing interference like in aircraft or nuclear plants.

During the TED talk in 2011, Edinburgh University’s Prof Harald Haas coined the term Li-Fi which is also known as VLC(visible light communication). A joint research between the universities of Oxford, Cambridge, Edinburgh, St Andrews and Strathclyde, carried out the research in this field under the Ultra Parallel Visible Light Communications project ,funded by Engineering and Physical Sciences Research Council. Using the single microchip existing LED light bulbs could be converted into Li Fi signals. In situations where radio frequencies cannot use due to the fear of interference this technology would be best. Using Orthogonal Frequency Divisional Multiplexing (OFDM)- a digital modulation technique , researchers enabled micro-LED light bulbs to handle millions of changes in light intensity per second, effectively behaving like an extremely fast on/off switch. This helps in sending large amount of binary data – a series of ones and zeros – to be transmitted at very high speed. The researchers used the three primary colors – red, green, blue to transmit data.

What achieved!!
Chinese achieved the speed of 3.5 Gbps through LED bulbs. While UK scientist’s one step ahead reports that they got 10 Gbps speed that is 250 times faster than the any ‘super-fast’ broadband. Fraunhofer Heinrich Hertz Institute in Germany achieved 3 GB per second speed this year.

Limitations!!
It is dependent on light, so cannot work in darkness as light not penetrates walls. Lifi receiver must be within 3 meter diameter of router and placed in the LED bulbs so that sensor read it easily.
Li-Fi system is not portable.
How differ from Wi- Fi!!
Both transfer data over electromagnetic spectrum but Li- Fi uses visible light and Wi-Fi utilizes the radio waves for wireless internet access. Speed of data transfer is high in Li-Fi .As Wi-Fi uses the radio spectrum which is limited so only limited number of router and tower can deploy. Li Fi while can be deployed in every day LED bulbs which covers the entire building through light based connection. The data connection speed can reach in Gbps.

Ravinder verma
MSCLIS
IIIT ALLAHABAD