Researchers break speed record for transmitting data using light bulbs

Specially designed light bulbs have enabled scientists in the UK to set a new data transmission record for Li-Fi.

Researchers in the UK have used specialised light bulbs to transmit data at more than 10Gbps.

The micro-LED bulbs are able to transmit 3.5Gbps via each of the red, green and blue colours that makes up white light.

Various research teams worldwide are investigating ways to provide high-speed wireless internet connectivity using LED light bulbs, a method dubbed Li-Fi.

The previous speed record for transmitting data using LED light was 3Gbps, achieved earlier this year by the Fraunhofer Heinrich Hertz Institute in Germany. There were also reports that Chinese researchers had made a microchipped LED bulb that could transmit data at 150Mbps to up to four computers.

The latest research is part of the ultra-parallel visible light communications project, a joint-venture between the universities of Cambridge, Edinburgh, Oxford, St Andrews and Strathclyde, which is funded by the Engineering and Physical Sciences Research Council.

Tiny micro-LED bulbs, developed by the University of Strathclyde in Glasgow, beam light in parallel to multiply the amount of data that can be transmitted. These bulbs use a digital modulation technique called orthogonal frequency divisional multiplexing to switch light intensity millions of times per second.

Both Wi-Fi and Li-Fi transmit data over the electromagnetic spectrum, but whereas Wi-Fi utilises radio waves, Li-Fi uses visible light. Visible light can transmit a larger amount of data than radio waves as it has a far higher frequency.

Researchers are aiming to develop a system that would be able to deliver wireless internet connectivity via LED bulbs. 

They argue the advantages would be that much of the infrastructure is already in place, that each room would effectively have its own localised transmitter leading to a more consistent connection, and that light's inability to penetrate walls would make communications using Li-Fi less prone to eavesdropping.

One criticism of Li-Fi has been the need for a line-of-sight connection between the transmitter and receiver but researchers say they are addressing this limitation with a system that can transmit data using reflected light.