CEA-Leti, the French state-funded research institute, has developed a system that uses LED lighting that blinks on and off very rapidly to transmit data. Visible light communications (VLC) technology employs the high-frequency modulation capabilities of light-emitting diodes to achieve hroughputs of up to 10Mbps at a range of three meters.
The lighting is modulated so rapidly as to be undetected by the human eye.
This data rate is suitable for streaming high-definition video and Internet browsing, and can operate with lights of less than 1,000 lumens brightness and even with indirect lighting. Leti is predicting that Li-Fi technology can be taken up to and beyond 100Mbps with traditional lighting based on LED lamps without impacting the lighting characteristics.
The arrival of LED lighting, which can be modulated at very high frequencies, has created an opportunity for VLC, otherwise known as Li-Fi The European Union has established a schedule whereby halogen lamps will be phased out and replaced by LED lighting by Sept. 1, 2016.
The overcrowding of the conventional radio frequency spectrum and the desire for wireless data transmission without electrogmagnetic interference are also creating pressure to move at least some communications, such as domestic and office based to Li-Fi.
The optical system consists of an A19 lamp based on LEDs at the transmitter and an avalanche photodiode at the receiver. The digital communication component is implemented on a proprietary and reconfigurable platform that carries out a flexible multi-carrier modulation.
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