Visible Light Communications
Visible Light Communications ( VLC ) is a data transmission technology . In doing so, data or information are transmitted using the transmission medium light . The frequency of the light used for transmission is in the visible range between 400 THz (750 nm; 1 THz = 1000 GHz) and 800 THz (375 nm).
technology
Fluorescent lamps or LEDs are used to generate the required light . If fluorescent lamps are used, transfer rates of up to 10 Kbit / s can be achieved. When using LEDs, up to 800 Mbit / s can currently (August 2011) be achieved. On the receiver side, a photodetector converts the light signals back into current pulses.
use
Due to the specific properties of the light used, this technology could be suitable for use as a transmission technology in “ ubiquitous computing ”, since light of the corresponding wavelength is considered completely harmless and can be used almost anywhere. In addition, the spatial propagation of the light waves can easily be limited by any optical shielding.
One advantage here is the license-free use of the relevant frequencies.
history
The first VLC devices were developed in 2003 in the Nakagawa laboratories of Keiō University in Japan.
In January 2010, a research team from Siemens and the Fraunhofer Heinrich Hertz Institute in Berlin succeeded in transmitting data at up to 500 Mbit / s over a distance of 5 meters using white LEDs. Standardization takes place in IEEE 802.15.7.
In 2015, Philips Lighting developed VLC to market maturity and developed an Indoor Positioning System (IPS) based on the technology, which in addition to directional information also includes notification and analytics. Philips uses a combination of Visible Light Communications technology, Bluetooth and the inertial sensors of smartphones. The technology is in use in various supermarkets in France and Germany.
Li-Fi consortium
In 2011, the German researcher Harald Haas coined the term Li-Fi for the latest VLC generation at a lecture at the Californian TED (Technology, Entertainment, Design) conference based on Wi-Fi . Later that year, the "Li-Fi Fi Konsortium ", including with the Fraunhofer Institute for Photonic Microsystems , which aims to promote a standard of the same name worldwide and bring it to market maturity.
See also
Web links
- VLC consortium
- Press release from the Science Information Service
- IEEE website for the standardization of VLC
Individual evidence
- ↑ Researchers manage 500 Mbit / s with a white LED . heise online
- ↑ Where are the discounts? Carrefour's LED supermarket lighting from Philips will guide you . In: Philips . ( philips.com [accessed May 3, 2017]).
- ↑ Two more indoor positioning projects sprout in European supermarkets. Retrieved May 3, 2017 .
- ↑ Favendo cooperates with Philips Lighting. (PDF) Retrieved June 3, 2017 .
- ↑ Website ( memento of the original from January 4, 2018 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
