EDINBURGH: Data can be transmitted from any LED light source, allowing for more secure local area networks, or LANs, than ever before.
Mobile signals, wireless modems and traditional telecommunication lines could be rendered obsolete if data can be transmitted by LED (light-emitting diode) lighting on a mass scale, according to a new study published in the Journal of Lightwave Technology. This new method for transmitting data could also make networks more less susceptible to hacking.
“An expansion of wireless communications into a new and unexplored physical domain – the visible light spectrum – is very appealing,” said lead author Harald Haas of The University of Edinburgh in Scotland.
Information from anywhere
Data already travels by light – through fibre optic cables that transmit signals around the world. The system replicates the one/zero nature of computer data by switching the light on or off.
These on/off states are received at the other end at light speed and a device like a modem reassembles the data by converting the light pulses to electrical signals. Data sent through LED will behave the same as that of fibre optic cable, sending a pulse the receiver will understand as being on or off.
Currently, data transmitted by radio or telecommunication signals is putting pressure on the radio frequency spectrum as we add more devices like smartphones, and the efficiency of a mobile base station is only 5%. From a security perspective, transmitting data by radio is also easy to hijack as it goes through walls and through the air.
Data generated by an LED source, by contrast, will be much more secure. Like the light that transmits it, the data won’t go through walls. The information flow can also be far more controlled – to interrupt the stream, just turn your device away from the light source.
Abundant LED light
LED light is not only secure, it’s becoming abundant as we phase out incandescent lights and introduce more LED bulbs to homes and offices. Cabin lights on planes should be able to transmit the Internet collected from an on-board satellite receiver, and streetlights could be connected to the cars on the road, wiring up to deliver safety and traffic data, said Haas.
The technology works by modulating or changing the brightness of the LED very quickly by use of an attached microchip. The result of Haas’ study was the transmission of enough data for high bandwidth applications such as streaming video.
The crucial element of LED data is that the modulation change happens too fast and too subtly for the human eye to detect, so the transmitter is perfectly serviceable as an ordinary desk lamp or ceiling light. You can even turn the brightness down far enough so as to appear off and still be transmitting. The receiver, reading only the pulses of light from the transmitter, ignores all competing light sources – a further security measure.
“It has a number of issues,” commented John Dell, dean of the University of Western Australia’s Faculty of Engineering, Computing and Mathematics in Perth. “There are problems with shadows and you need sufficient path diversity, but it’s actually quite a good idea. The idea of using visible light isn’t new. What’s new is using the same LED for the light as for the transmitting.”