The research funded by the Engineering and Physical Sciences Research Council (EPSRC) has shown that transmitting digital data via LEDs at the same time as using them to generate light does not make the light dimmer or change its colour, nor does it make the LED more energy-hungry.
Lead researcher Dr Wasiu Popoola at the Li-Fi R&D Centre and Institute for Digital Communications, University of Edinburgh, notes these were the two major concerns that have held back the more widespread adoption of LiFi in combination with household LEDs.
Focusing on LEDs producing ‘warm white’ and ‘cool white’ light, the Edinburgh 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.
Neither technique was found to significantly reduce the lightbulbs’ brightness or their life expectancy, or to cause any significant change in the colour of the light. 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 LED using more electricity to produce light, making it less energy-efficient and less carbon-friendly.
“Our ever more connected world will need more bandwidth than the overcrowded Radio Frequency part of the spectrum can provide. Plugging a key knowledge gap, our results are very encouraging for the future of light-based communications that could help realise the full economic and social potential of a wireless future. It’s vital that LED manufacturers know what impact the incorporation of data transmission capabilities would have on their products. Our research shows that there’s no dark side to using LED lights to supplement WiFi”, concludes Dr Popoola.
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