Transfer Data With The Help Of LEDs!

Light emitting diodes, simply called as LEDs, are already been used for lighting purpose to reduce power consumption. Now, scientists have put these little Lucifers to another use! Researchers fromFraunhofer Institute for Telecommunications, Heinrich Hertz Institute (HHI) in Berlin, Germanyhave finally demonstrated that the LEDs can also be used to transfer data. This technology is not your regular fiber optics in which cables are laid down to transfer data in form of light beams over a distance. The data transfer is wireless and this innovative technology is called as Visible Light Communication (VLC). What makes this technology promising is that there is no requirement to install a different setup in your homes to avail the benefits of VLC enabled data transfer. The LEDs used for lighting purpose multi task by acting as transmitters for data transfer. Scientists plan to demonstrate the transfer of video by light at the International Telecommunications Fair IFA (Internationale Funkausstellung IFA) in Berlin from September 2-7, 2011 in Hall 11.1, Booth 8.

Not just Lucifer!

The technology was developed by HHI in collaboration with the industrial giants: Siemens andFrance Telecom Orange Labs. The results of the research and development in VLC are amazing. People at HHI demonstrated actual data transfer with the help of overhead LEDs used for lighting to transfer data at a speed of  100 megabits per second (Mbit/s). The data was transfer was completed without any loss and the LEDs used for data transfer could light about 90 square feet of area. The LEDs were used as transmitters and the receiver’s maximum range is the radius that the LEDs could lighten up. As of now, scientists are working to increase the range of receivers. With these conditions, scientists were successful in transferring four videos simultaneously to four different receiving end gadgets (laptops in this case) in HD quality. Dr. Anagnostis Paraskevopoulos from the HHI expressed happiness over their current success and hopes for better refinements in various aspects of the technology such as range of the receivers, transfer rate, etc.

VLC is all about using the LEDs both for lighting and for transfer of data. In the project completed by the team at HHI, led by project manager Klaus-Dieter Langer, white light LEDs were used. The LEDS acted as the transmitter and their turning on and off was controlled with the help of a modulator. The data is transferred in the form of ones and zeroes when the LEDs turn on and off rapidly. The LEDs are modulated in such a way that their frequent and rapid operation is imperceptible to the human eye. The receiver used by the team at HHI was a simple photo diode. This diode acted as receiver for light transmitted by the LEDs. A separate electronic circuit in the laptop acted as decoder for the information relayed by the overhead LEDs. The information is decoded in the form of pulses and then the computer can receive the data successfully.

The VLC technology for video transfer developed is a small part of the OMEGA project of the EU. The project aims for setting international standards for ultra broadband home area network. Since its inception in 2008, the project has made the implementation of video transfer in home with the help of VLC a closer reality. The tuning in of LEDs with the existing Wireless Local Area Network connected via optical fibers is successfully done with the help of visible light communication. The data transfer does not need any cable and wiring. It can be achieved simply by sitting below the overhead LEDs that perform the dual function of lighting and data transfer with equal ease.

The biggest advantage of Visible Light Communication is the requirement of very less number of components to modify normal LEDs for data transfer. However, on the flip side, the data transfer needs a visual line of sight for communication between the transmitter (LED) and the receiver (photo diode). Scientists are working to remove this major drawback in otherwise superb technology. They know the limitations very well and do not intend to replace the most popular modes of data transfer such as regular WLAN, Power LAN or Universal Mobile Telecommunications System (UMTS). The VLC can be used efficiently in places where radio transmission cannot be executed. This mode of data transfer can also be used where laying of cables is undesirable or in some cases, almost impossible. The VLC can be used in a flexible one-way mode, such as optical WLAN to send data from mobile to laptop and VLC to send data from laptop to mobile.

VLC is going to find its applications in places where radio communication is not admired: Hospitals, Production facilities, High Sensitivity Communication panel rooms, Airplanes etc. Presently, increasing the data transfer speed is high on agenda for the scientists at HHI. They are on the right track and this is evident from their results with the help of red-blue-green-white light LEDs. Data transfer at speed of 800 Mbit/s was achieved in labs. Until then, keep your eyes open for the demonstration of video transfer by light at the International Telecommunications Fair in September.