A group of UK researchers at the University of Edinburgh are working on a new method of wireless communication, but which involves manipulating a light source instead of using radio waves. By using an LED light bulb, the transmission involves converting the digital bits from a network signal into light pulses from the bulb. By using the three primary colours (red, green & blue) to individually transmit pulses of light at 3.5Gb/s, they have been able to achieve transmission speeds of over 10Gbps.
As light does not penetrate walls, its bandwidth is not shared with neighbouring networks like radio based communication such as Wi-Fi and cannot be intercepted, assuming light does not escape the room such as through a window. Unlike Wi-Fi, the speed does not fluctuate and direct line of sight is not required either, as long as enough (reflected) light reaches the device for it to decode the pulses.
The group will be demonstrating its Li-Fi technology at the Mobile World Congress in Barcelona. At present, the prototype is too large for practical use, but they claim it can eventually be made small enough to fit inside handheld devices such as a Smartphone. Going by an earlier BBC article, Chinese scientists modified an LED light bulb was reportedly able to deliver up to 150Mbps, with connectivity between four computers from the same bulb. The technology is now being commercialised by Professor Harald Haas with a company created by Edinburgh University.
It is not clear how data is transmitted back to the source, as even in their video demonstration the receiver device did not seem to be sending light back to the source, unless it is done by Infra-red or some other means.
An obvious drawback is that each room will require at least one ‘Li-Fi’ enabled bulb to work and the light must remain switched on for connectivity. If the bulb fails, network connectivity is also lost. On the positive side, LED light bulbs are very efficient and most offices generally run their lights non-stop during business hours.
A video demonstration can be viewed on the BBC website.
