Visible Light Communication

Visible Light Communication


Sushanth Nair Sushobita Nair
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Visible light communication (VLC) is a data communications medium using visible light between 400 THz and 800 THz. Visible light is not injurious to vision.
The technology uses fluorescent lamps (ordinary lamps, not special communications devices) to transmit signals at 10 kbit/s, or LEDs for up to 500 Mbit/s. Low rate data transmissions at 1 kilometer and 2 kilometers were demonstrated. It helps to achieve full Ethernet speed (10 Mbit/s) over the same distance thanks to larger optics and more powerful LED.
Specially designed electronic devices generally containing a photodiode receive signals from such light sources, although in some cases a cell phone camera or a digital camera will be sufficient. The image sensor used in these devices is in fact an array of photodiodes (pixels) and in some applications its use may be preferred over a single photodiode. Such sensor may provide a multi-channel communication thus improving the speed.

Visible Light Communication uses light emitting diodes (LEDs), for the dual role of illumination and data transmission. Using the visible light spectrum, which is free and less crowded than other frequencies, wireless services can be piggy-backed over existing lighting installations. With this leading edge technology, data including video and audio, internet traffic, etc., can be transmitted at high speeds using LED light.
VLC technology has the potential to deliver data transfer rates in excess of hundreds of megabits per second. Light radiation neither constitutes nor suffers from electromagnetic interference (EMI) making VLC a very attractive technology in places/environments where electromagnetic interference (EMI) is...

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