Li-Fi the new Wi-Fi?

by David Solomonoff

Visible light communication (VLC) or “Li-Fi” uses rapid pulses of light to transmit information wirelessly. Now, with a new generation of high-brightness light-emitting diodes, it may be ready to compete with conventional Wi-Fi.

VLC encodes data in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s. The LED intensity is modulated so rapidly that human eyes cannot notice, so the output appears constant.

VLC could solve some major communication problems caused by a looming spectrum crisis. Because our mobile devices are so data-hungry we will soon run out of radio-frequency bandwidth. Li-Fi could free up bandwidth, especially as much of the infrastructure is already in place. Regular incandescent bulbs could be replaced with LED ones that transmit data.

Some new experimental techniques could further increase VLC data rates, such as parallel data transmission using arrays of LEDs, where each LED transmits a different data stream, or using mixtures of red, green and blue LEDs to alter the light’s frequency, with each frequency encoding a different data channel.

Because it uses light rather than radio-frequency signals, VLC could be used safely in aircraft, integrated into medical devices and hospitals where Wi-Fi is banned, or even underwater, where Wi-Fi doesn’t work at all.….

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