October 29, 2013
LED Light Technology Proving Useful In Speedy Data Transmission
redOrbit Staff & Wire Reports - Your Universe Online
British researchers reported on Monday that they had achieved data transmission speeds of 10 gigabits per second (Gbps) via "Li-Fi,” an emerging technology that allows wireless Internet connectivity using light.The researchers used a micro-LED light bulb to transmit 3.5 Gbps via each of the three primary colors – red, green, blue – that comprise white light, demonstrating that data rates of more than 10 Gbps are possible. The research, part of an initiative known as the "ultra-parallel visible light communications project," involved the use of tiny micro-LED bulbs that allow streams of light to be beamed in parallel, which multiplies the amount of data that can be transmitted at any given time.
"If you think of a shower head separating water out into parallel streams, that's how we can make light behave," said project leader Professor Harald Haas, an expert in optical wireless networks at the University of Edinburgh, in an interview with BBC News.
The researchers used a digital modulation technique known as Orthogonal Frequency Divisional Multiplexing (OFDM) to enable the micro-LED lights to handle millions of alterations in light intensity per second. This allowed the system to effectively act as an ultra-fast on/off switch transmitting large amounts of binary data - ones and zeros - at very high speeds.
Professor Haas demonstrated the technology two years ago, showing how an LED bulb with signal processing technology could stream HD video. At the time, he dubbed the technology "Light Fidelity," or Li-Fi, also known as visual light communications (VLC), and founded a private company, PureVLC, based on it.
Li-Fi has tremendous potential because it is cheaper and more energy-efficient than traditional wireless radio systems, given the ubiquity of LED bulbs and the fact that it utilizes existing infrastructure. Furthermore, since visible light is part of the electromagnetic spectrum and 10,000 times bigger than the radio spectrum, the technology has potentially limitless capacity.
Haas said an additional advantage is that evenly spaced LED transmitters could provide far more localized and consistent connectivity throughout buildings compared with traditional Wi-Fi routers, whose signal weakens the farther away the user gets. Haas said he also believes that light's inability to penetrate walls makes Li-Fi potentially more secure than traditional Wi-Fi connectivity.
Previous Li-Fi research conducted this year at Germany's Fraunhofer Heinrich Hertz Institute claimed that data rates of up to 1Gbps per LED light frequency were possible in a laboratory setting. Earlier this month, researchers in China reported that they had developed a microchipped LED bulb that could generate data rates of up to 150 megabits per second (Mbps) with a single bulb, which provided Internet connectivity for four computers.