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Mains Mapping: “Mains Paper 3: Science & Technology | Awareness in the fields of IT, Space, Computers, robotics, nano-technology, bio-technology and issues relating to intellectual property rights.”

UPSC always go after the topic of ‘breakthrough technologies’. Those technologies which can affect everyday life of Mankind.

What is LI-FI?

  1. LiFi(Light Fidelity) is a high-speed wireless communication technology that uses visible light to transmit information. It has some similarities to existing WiFi technology, as well as some huge differences.
  2. WiFi and LiFi are similar because both technologies are wireless, but also very different, because unlike WiFi, which relies on radio waves, LiFi uses visible light communication (VLC) or infrared and near-UV spectrum waves.
  3. In other words, LiFi works by using visible light, like the light that is emitted by any regular lamp or bulb!.

Working of LI-FI

  1. Li-Fi is a Visible Light Communications (VLC) system. 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. Unlike Wi-Fi, which uses radio waves, Li-Fi runs on visible light.
  2. Here, 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).
  3. The tiny changes in the rapid dimming of LED bulbs is then converted by the ‘receiver’ into electrical signal.
  4. The signal is then converted back into a binary data stream that the user would recognise as web, video and audio applications that run on internet enables devices.

What is an LED Bulb:

An LED lightbulb is a semi-conductor light source meaning that the constant current of electricity supplied to an LED lightbulb can be dipped and dimmed, up and down at extremely high speeds, without being visible to the human eye.

Advantages of LI-FI

  1. LiFi presents many unprecedented advantages for its uptake and use, as far as wireless Internet connectivity is concerned.
  2. LiFi relies on visible light to communicate, which is a good thing in more ways than one. These waves are able to carry far more information than the traditional radio waves used in WiFi technology.
  3. The visible light spectrum is almost 10,000 times larger than the spectrum occupied by radio waves.
  4. Also, LiFi is said to increase bandwidth by 100 times what we have today with WiFi.
  5. A LiFi connection can transmit data at the rate of 224 gigabytes per second.
  6. LiFi is also more suitable in electromagnetic-sensitive areas like hospitals, airplane cabins, and nuclear power plants (where electromagnetic disturbance can be disastrous).

Disadvantage of LI-FI

  1. Along with all these benefits, there are also some disadvantages of a LiFi connection.
  2. Since it uses visible light to transmit data, LiFi would be rather useless in conditions where there is no light. That means no Internet while lying in your bed at night.
  3. If you have a WiFI router installed in one room of your house, you can connect your devices sitting anywhere in the house, but this is not the case with LiFi.
  4. Since visible rays cannot pass through walls, you have to be in the immediate vicinity of the source of light to access the Internet on your device, which may not sound particularly convenient to many people.
  5. This technology is also said to be less reliable (again, due to it being dependent on visible light) and has high installation charges.

Future of LI-FI

  1. There’s no doubt that LiFi is going to transform the world of Internet connectivity, but it seems unlikely that its rise would necessarily mean the death of WiFi, since the latter is deeply embedded in the lifestyles of billions of people.
  2. A more likely scenario, though, is that we’ll eventually have a wide range of technologies available at our disposal and will be free to choose the most appropriate one.
  3. Having that flexibility certainly seems like the most desirable scenario to us.


“Li-Fi is not expected to completely replace Wi-Fi, but the two technologies could be used complementarily to create more efficient, green and future-proof access networks.” Discuss.


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