Meaning of LiFi

LiFi networks send data via optical signals – not via radio waves as in WLAN networks. The technology is safer and faster than WLAN. Internet via light is particularly suitable for the local area.

  • LiFi stands for “light fidelity” and describes the Internet via optical light signals.
  • LiFi networks are faster and safer than wireless WiFi networks.
  • Optical data transmission is only possible at close range and within sight.

What is a LiFi network?

LiFi (English for light fidelity) describes the optical and wireless data transmission at close range – for example via light-emitting diodes, or LEDs for short. Another common name is Visible Light Communication (VLC). LiFi is a comparatively young technology. Although it was discovered by the German physicist Harald Haas in 1997, it has only been promoted in industry since the LiFi consortium was founded in 2011. LiFi-capable lamps are now available in stores. A uniform LiFi standard is expected for 2021.

Lifi technology is the optical equivalent of WLAN, which transmits data via radio waves. In the case of an optical network, there must be a line of sight between the transmitter and the receiving device. While electromagnetic waves also travel through buildings, optical signals only have a range of a few meters and cannot penetrate walls.

How does the Internet work from the LED lamp?

The optical signals are emitted via LED lights with a LiFi function. The lights flash at high frequencies in the nanosecond range – so quickly that the human eye cannot perceive the signals. Light sensors in the receiving device pick up the signals and process them further.

Commercially available LED lamps can also be used for LiFi, but they require a ballast with a chip. There are also LiFi hotspots that can provide several users with the Internet up to a distance of 30 meters. Smartphones or other end devices can be equipped with special plugs for data transmission. In the future, smartphones could be equipped with LiFi modules ex works.

Advantages and disadvantages of optical data transmission

With LiFi technology, stable speeds of more than 10 gigabits per second are possible – that’s around 100 times faster than the Internet via radio signals. Light beams can also send 10,000 times as many frequencies as a WiFi network. The effect known from radio networks that the transmission quality suffers as the number of users increases is eliminated.

The disadvantage is the short range. Optical data transmission is intended for close range and only extends a few meters. If you want to replace your WLAN with a LiFi network, you have to ensure the supply in every single room.

The short range makes the networks safe from hacker attacks at the same time. The data cannot be intercepted outside of buildings, because the data transfer is interrupted outside the optical limit. Another advantage: optical signals do not cause any interference with other signals. Unlike electromagnetic radio waves, light rays have no influence on other devices.

Where is LiFi used?

Theoretically, the Internet is possible wherever there are light sources. That makes the locations extremely diverse. In the future, entire office landscapes could be equipped with LiFi technology. The Internet then comes directly to the workstations via the LED desk lamps. The technology is particularly advantageous where electromagnetic signals interfere or are insufficient, for example on board airplanes, in hospitals or in cars.

Internet via energy-efficient light sources opens up numerous possibilities for smart cities: Museums could make visitor information accessible via light signals, street lights could send data about the location. Passenger information could also be transmitted via light sources in public transport or at bus and train stations. Optical networks are also suitable for close-range industrial production. Production chains controlled by light then run from one another undisturbed. The Lifi technology is also suitable for locations with high security requirements, for example in state institutions and authorities or in the banking industry. Optical data transmission could become an alternative to radio networks in the future, for example when radio frequencies become scarce.