Li-Fi wireless communication technology explained

Have you ever heard of Li-Fi? No, you haven’t misread it, it’s written Li-Fi and not Wi-Fi. It’s about Light Fidelity, which as its name suggests, allows through light, to connect to internet. But let’s not go too fast and let’s take things in order.

A brief history

In 1999 was born wifi, a short-range communication network, used today by nearly 16 billion devices in the world.

In 2005, in Japan and France, the first communication experiments took place through LED lights, which will be called Li-Fi. Since 2010 and the generalization of LEDs, manufacturers and research centers have begun studies aimed at developing Li-Fi solutions.

In February 2018, at the Palais Brongniart, the first edition of the Global Lifi Congress took place, an international congress which aims to enable research and industry to create synergies in order to develop Li-Fi, access to internet via light.

Li-Fi Operation

How it works ?

The Li-Fi system consists of two main parts: the transmitting part and the receiving part, between them is the optical channel.

The digital data is first encoded in order to improve the transmission via the optical channel. They are then converted into a light signal which varies the intensity of the LED bulb according to the data to be transmitted. This light then propagates and becomes subject to deformations (weather, obstacles etc.), this is what is called the optical channel (propagation environment + light deformations). The light signal is received by a camera, a photodiode or other photoreceptor which transforms it into electric current. This electrical signal, once processed and decoded, will be used to recover the information transmitted.

The advantages of Li-Fi

The Li-Fi communication system offers several advantages resulting from the use of light and LED:

  • The frequency band used by Li-Fi is free unlike those used by Wi-Fi or 4G which are regulated and may be subject to fees.
  • The light does not interfere with radio frequencies (used by Wi-Fi and 4G) and Li-Fi is therefore compatible with these radio technologies.
  • A bright place equipped with Li-Fi can be used both for lighting and for transmitting data.
  • Finally, on the security and data protection aspect, since light cannot pass through walls (unlike radio waves), personal data and information transmitted by Li-Fi remain compartmentalized at their place of transmission. It is very complicated to be able to hack remote devices that are connected via Li-Fi, even if this has the obvious disadvantage of limiting the range of this type of transmission. Li-Fi is not considered as a competitor to Wi-Fi but is rather positioned as a complementary system, safer, more economical and also, according to some, less harmful to health than systems using radio waves.

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