li-fi TECHNOLOGY
A new method of delivering data, which uses the visible spectrum rather than radio waves, has been tested in a working office.
Li-fi can deliver internet access 100 times faster than traditional wi-fi, offering speeds of up to 1Gbps (gigabit per second).It requires a light source, such as a standard LED bulb, an internet connection and a photo detector.
It was tested this week by Estonian start-up Velmenni, in Tallinn.
Velmenni used a li-fi-enabled light bulb to transmit data at speeds of 10Gbps. Laboratory tests have shown theoretical speeds of up to 224Gbps.
It was tested in an office, to allow workers to access the internet and in an industrial space, where it provided a smart lighting solution.
Light might be the preferred option for transmitting data over long distances via cables, but when it comes to short range wireless, radio waves rule in the form of Wi-Fi and Bluetooth. Now Mexican company Sisoft, working with researchers from the Autonomous Technological Institute of Mexico (ITAM), has developed a wireless technology that transmits data in visible light emitted from LED lamps, while lighting the room at the same time. Called Li-Fi, which is short for light fidelity, the technology is what is known as Visible Light Communication (VLC). Unlike infrared based system. VLC involves transmitting data using light visible to the human eye. In this case it is transmitted as intermittent, imperceptible flickers of light emitted by LEDs. The team started out with audio, cabling up a protoboard table to a smartphone via its 3.5 mm audio jack. The protoboard table converted the audio signal into an optical signal that is transmitted by a special emitter across the spectrum of light generated by an LED lamp. At the receiving end, a receptor located in a speaker captured the signal and converted it back into an audio signal that was played by the speaker.
For wireless internet transmission, the principle is the same but makes use of a receptor device designed to be placed above a router. The router incorporates an LED lamp to transmit data so anyone falling within the halo of light emitted by the LED will be in range. However, only those with a receptor/transmitter device will be able to send and receive the signal.
The Sisoft team says it has used the technology to transmit audio, video and internet at rates of up to 10 gigabits per second. This is an improvement over similar Li-Fi systems developed at siemens and pennsylvania state university that achieved transfer rates of 500 Mbps and 1.6 Gbps, respectively.
In addition to its impressive transfer rate, Sisoft also highlights other benefits of the technology. Since the data is transferred via light, there is no way to hack it, making it safer, (although no mention is made of how easy it would be to take a peek at the data someone else is receiving). Additionally, it could be used in areas such as hospitals where radiation equipment can block or disrupt wireless signals. And of course, it provides illumination at the same time.
source: Sisoft de Mexico,
