Li-Fi (light fidelity) is a data transmission technology using light to wirelessly transmit data from one point to another. Wi-Fi, in contrast, transmits data through radio waves.

Li-Fi can transmit data faster than Wi-Fi. The highest speed recorded with a Li-Fi connection is 10 GB/s, 250 times faster than the average broadband speed.

Li-Fi technology uses LED bulbs to establish a data communication, switching them on and off within nanoseconds - too quickly to be noticed by the human eye.

Although Li-Fi bulbs would have to be powered to transmit data, the bulbs could be dimmed to a point where they are invisible to the eye and yet still functional. The light waves cannot penetrate walls, creating a much shorter, more secure range, with less risk of hacking.

Li-Fi has the advantage of being useful in electromagnetic sensitive areas such as aircraft cabins, hospitals and nuclear power plants without causing electromagnet interference.

Both Wi-Fi and Li-Fi transmit data over the electromagnetic spectrum, but whereas Wi-Fi uses radio waves, Li-Fi uses visible light. The visible light spectrum is 10,000 times larger than the entire radio frequency spectrum.

Li-Fi is expected to be 10 times cheaper than Wi-Fi. Its short range, poor reliability and high installation costs are the potential downsides.

Since visible light cannot pass through objects, smartphones and tablet connections are still problems for Li-Fi. It is also hard for people to receive a Li-Fi signal when they are moving.

Zhang Kexin contributed to this fact box.

(China Daily European Weekly 12/19/2014 page22)