Various researchers have created ways to transmit wireless information from LED light fittings, to act as a form of enhancement to Wi-Fi based networks known as "Li-Fi." But now engineers at the University of Virginia (U.Va) have come up with a new twist on this theme – they claim to have created an algorithm that makes almost any device fitted with standard visible-light LEDs able to communicate with other equipment with similar LEDs. So, for example, the LED headlights in your car could communicate to the car in front of you through its LED taillights, or the LED display in your clock radio could tell the coffee maker to turn on via its indicator light.
Prof. Maite Brandt-Pearce and Mohammad Noshad, the latter formerly of U.Va but now a postdoctoral fellow at Harvard University, came up with a way for light from LED fixtures to transmit signals to wireless devices. Streaming data at around 300 Mbps from each light, any and all LED lights in the vicinity could be used as wireless access points without the limiting bandwidth problems of radio frequency (RF) wireless networks.
"We developed a modulation algorithm that increases the throughput of data in [visible light communications]," says Brandt-Pearce. "We can transmit more data without using any additional energy. As more light fixtures get replaced with LED lights, you can have different access points to the same network."
Unlike conventional RF Wi-Fi, the system could also be used in places where radio waves create problems or are not permitted, such as around medical equipment in hospitals, inelectromagnetically-sensitive manufacturing environments, and in passenger aircraft cabins.
"The idea in this technology is to transmit the data using the lighting systems that are already used for the illumination of indoor environments. [Visible light communications] offer a compact, dual-use, energy-saving solution and can provide a high-speed secure network connection for a large number of users," says Noshad.
"You can use it any place that has lighting," adds Professor Brandt-Pearce. "In a stadium, in a parking lot, or from vehicle to vehicle if using LED headlights and taillights." This is the point of difference of the U.Va system.
Sure, it doesn't boast the claimed speeds of a system like the SiSoft Li-Fi (though it is three times faster than a similar "Wi-Fo" set up from Oregon State), but the possibility of transmitting data from anything that has LEDs to anything with LEDs turns things on their head. The Internet of Things (IoT), for example, could be enabled much more easily and cheaply than ever thought of before.
"[Visible light communications] has the potential to significantly increase the speed of internet connection in multiuser indoor environments due to the broad bandwidth of the visible light," says Noshad. "It will offer a huge energy saving for the nation since energy is already used for lighting, and thus does not need to be expended for communications."
The researchers have already been granted several patents in relation to their work and are now working on a Li-Fi enabled desk lamp to show to investors, along with investigating ways to increase the number of concurrent users on their devices.
Source: University of Virginia
