As the terms indicate, Visible Light Communication (VLC) make use of visible light spectrum. VLC is used for data communications and uses visible light in the range of 375nm to 780nm, which is below the wavelength ranges that current day optical transmission technologies for long distance communication utilize.
In terms of frequency, the above visible light wavelength range spreads from 400THz to 800 THz. Therefore VLC is often called Wireless light communication or Optical wireless.
VLC is a subset of optical transmission technologies, which uses ordinary fluorescent lamps to transmit signals at 10 kbps. LEDs (Light Emitting Diodes) offer up to 500 Mbps over short distances. Systems such as RONJA can transmit at full Ethernet speed of 10 Mbps over distances of 1–2 kilometers. A photodiode can receive the signal or in some cases, a smartphone camera can receive the signals.
VLC if fully developed commercially can have applications in ubiquitous computing, since the light-producing devices such as indoor/outdoor lamps, TVs, traffic signs, commercial displays, and car headlights/taillights are used everywhere. Since VLC make use of visible light, it is less damaging for high-power applications because we can identify it and act to protect our eyes.
Attractive Features of VLC or LiFi
– Security (Light cannot travel through walls, a feature highly relevant to security).
– Free from interference
– VLC can assist in saving the radiofrequency spectrum.
LED and infrared are capable of transmitting data at rates high enough to support bandwidth-intensive services such as video streaming, interactive gaming, and advanced virtual reality (VR) applications. VLC is also expected to assist in unlocking the potentially multi-billion dollar indoor-positioning market by achieving positioning accuracy superior to that achieved by WiFi.
In an industrial setting that makes use of collaborative robots connected by WiFi, placing a big transmitter outside the factory walls would be enough to disrupt the production line. With LiFi technology, it is not possible as the light signals cannot penetrate the factory walls.
Visible Light Communication will have its applications in the Internet of Things (IoT).
VLC or LiFi could be a valuable complement to WiFi. VLC or LiFi and WiFi have their own unique but different strengths. Unique features of VLC can strongly complement WiFi where it faces challenges.
Crowded spectrum is creating real problems in the deployment of WiFi and VLC can alleviate some of those problems. The spectrum is limitless and we have the additional benefit of no collisions with other communications thanks to Visible Light Communication remaining within the boundaries of the walls.
Creating international standards are crucial to large-scale VLC deployment. VLC represents a meeting of many companies and two quite different industries, the connectivity industry and the lighting industry. Lighting companies like General Electric, Philips Lighting, and Osram had expressed their interest in LiFi technology and therefore it is expected that the VLC standards would be implemented by manufacturers of products such as mobile devices, PCs, VR goggles and VLC dongles.
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