28 November 2017

Transmitting digital data via LEDs at the same time as using them to generate light does not make them dimmer, change their colour, or make the bulbs more energy-hungry, according to new research.

The of idea of ‘Li-Fi’ – using off-the-shelf LEDs for super high-speed data transmission – initially came from research carried out at Edinburgh University around five years ago. 

Light spectrum is 10,000 times wider than RF spectrum, and Li-Fi operates in visible light frequencies between 400THz and 800THz. As this is at the upper end of the electromagnetic range, the technology is able to deliver higher capacity throughput of up to 1Gbps. However concerns over Li-Fi’s impact on an LED’s lighting capabilities and a possible increase in power consumption have held back the technology’s more widespread adoption. 

But now, a University of Edinburgh team lead by Dr. Wasiu Popoola, say their research findings help eliminate key hurdles to using LEDs to help satisfy the increasing global thirst for wireless communications.

Focusing on LEDs producing ‘warm white’ and ‘cool white’ light, the team looked at two different data transmission techniques: on-off keying, where the LED works like Morse code, switching on and off extremely rapidly and imperceptibly to human eyes; and continuous signalling, where imperceptible changes in light intensity are used to achieve the same goal.

According to the researchers, neither technique was found to significantly reduce the bulbs’ brightness, life expectancy, or cause any significant change in its light colour. 

They say that both techniques also produced only a negligible change in the heat generated by the LEDs – a key consideration as any temperature increase would indicate the bulb using more electricity to produce light, making it less energy-efficient and less carbon-friendly.