LiFi: what is it and how does it work ?

Nowadays, many technicians specialized in communication are in a frantic race to offer high-speed Internet via a wireless network. With ever-changing technology, LiFi came into being. What exactly is it and how does it work ? We reveal in this article some answers.

What’does LiFi ?

Considered an alternative to WiFi, LiFi, meaning Light Fidelity, is a VLC (Visible Light Communication) system using LEDs. It thus exploits the visible part of the electromagnetic spectrum to transmit data. LiFi owes its name to its inventor, Harald Haas, a professor of mobile communication of German origin. This technology is based on coding as well as sending data thanks to the frequency or amplitude modulation of external sources of light.

It is able to transmit an unlimited amount of data via light, but in restricted areas. Indeed, its protocol layers allow wireless communications, but the range is limited to about 10 m.

Unlike WiFi, this innovative technology uses visible light, the electromagnetic spectrum that humans can perceive. The wavelength is between 280 and 650 nm, i.e. between 670 and 460 THz. In concrete terms, the transmission of data (files, photos, etc.) is obtained by lighting LED bulbs with adjustable light intensity.

It is therefore necessary to be close to light sources to connect high-tech devices to each other. The same goes for connected objects thanks to the connection by light.

How it works ?

Two main blocks make up the Li-Fi system, to know :

  • The issue block;
  • The reception block.

The data to be transmitted goes through the following steps:

  1. Encoding of digital data in the form of an electrical signal in order to optimize transmission and protect it from damage caused by the optical channel.
  2. Conversion of coded data into a light signal using an electronic circuit designed to drive multiple LEDs. The light intensity is defined according to the nature and quantity of the data to be transmitted.
  3. Propagation of emitted light in space. The set composed of the deformations undergone because of the obstacles and the environment in which the light is emitted is called "optical channel".
  4. Reception of the light signal by a photoreceptor (camera, photodiode, etc.).). It is then converted into electric current which will be processed, demodulated and decoded to ensure data transmission.

To optimize quality data transmission, specific optical devices (filter, mirror, lens, etc.).) equip the transmitting and receiving modules. You want to know more about LiFi ? Keep reading.

What are the advantages of this technology ?

The advantages presented by the Li-Fi are many :

  • The use of the frequency band covered by the spectrum of light is free.
  • The light spectrum is able to cover a frequency band around 300 THz. For comparison, WiFi uses a radio frequency spectrum ranging from 8.3 kHz to 3 THz.
  • Optical waves, the light emitted by LEDs, do not interfere with radio frequencies. As a result, LiFi is compatible with radio technologies, such as 3F, 4G, WiFi, etc.
  • The data is partitioned by the walls, because, unlike the radio waves, the light is unable to pass through these obstacles. Data security is ensured.
  • Light sources equipped with the LiFi system can be used to illuminate the room or the environment.

An improvement in maximum throughput is observed over time and technological developments. If it was 10 Mb/s in 2015, it reached 40 Mb/s in 2018. These figures are constantly increasing, thanks in particular to Oledcomm, the pioneer of LiFi in France.

What are the advantages of this technology?

LiFi: for what uses ?

THE LiFi apps are numerous given their intrinsic characteristics:

  • Optimized flow capacity;
  • Energy efficiency ;
  • The presence of obstacles such as walls that block the signal;
  • Etc.

LiFi is the preferred solution in hospitals, as medical instruments are not subject to electromagnetic interference. In addition, sensitive data relating to patient files is perfectly secure.

In offices, the number of people connected to WiFi negatively affects the quality of bandwidth. Thanks to LiFi using the light beam, data rates remain optimal.