New Delhi: Researchers in Germany have devised a method to transmit data at the rate of 100 gigabits per second (Gbps) through a wireless network over a distance of 20 metres—the equivalent of transferring 12-15 movies between two computers in one second.

The experiment was conducted in laboratory conditions at the Karlsruhe Institute of Technology, as part of the “Millilink" project that was started in March 2010 focusing on integrating wireless or radio links into broadband optical communication networks for rapid Internet access.

Professor Ingmar Kallfass, the project leader for Millilink, said in a press release that for rural areas in particular, the technology represents an inexpensive and flexible alternative to optical fibre networks.

The scientists transmitted data at 100 Gbps at a frequency of 237.5 GHz in the laboratory after applying a photonic method to generate the radio signals at the transmitter. After radio transmission, fully integrated electronic circuits were used in the receiver. Essentially, the technology used very high level spectrum in combination with lasers.

To put it in perspective, in India, the fastest wireless data technology available uses 2.3 Ghz frequency—a hundred times lower—and transfers data at around 20 megabits per second. The technology is designed to go as high as 100 megabits per second.

According to a statement issued by Karlsruhe Institute, the latest photonic and electronic technologies were combined for the experiments.

First, radio signals are generated by means of optical technology. Several bits are then combined by so-called data symbols and transmitted at the same time. Upon transmission, the radio signals are received by active integrated electronic circuits.

The transmitter generates the radio signal with the help of an ultra-broadband photon mixer made by Japanese company NTT-NEL. For this, two optical laser signals of different frequencies are superimposed on a photodiode. An electrical signal results, the frequency of which equals the frequency difference of both optical signals—here, 237.5 GHz.

The millimetre-wave electrical signal is then radiated via an antenna. Researchers and organizations around the world are racing to develop wireless network speeds in this range. In July, the European Union announced several joint projects to increase the efficiency of networks in carrying data, one of which aimed at building a network of the speed of 100 Gbps.

Today, the average speed of European broadband networks is 19.7 Mbps. The US Army’s Defense Advanced Research Projects Agency also aims to create a 100 Gbps data link that achieves a range greater than 200 km between airborne assets and greater than 100 km between an airborne asset (at 60,000 feet) and the ground. Experts were sceptical about any immediate commercial benefits from the experiment. “While something can be achieved in a lab theoretically, the question is how that gets translates from R&D (research and development) environment to a commercial environment. And that usually takes several years," said Rajan S. Mathews, director general, Cellular Operators Association of India.

“The whole functionality and application of the network can be transformed at such incredible speeds, and hence more and more experiments are being conducted in this direction," said Denzil Correa, an academic at the Indraprastha Institute of Information Technology in New Delhi.

“The whole history of telecoms has been around increasing speed. So, clearly in a lab somebody may be able to create extremely high speeds; the question is on what spectrum and what bandwidth. Because you have to be able to create an ecosystem that includes the handset, the switching environment, the call network and that entire infrastructure to make it work," Mathews said.

Mathews added, “We are a little too far (away) in terms of being able to get these speeds, but once this happens in labs, it will be just a question of time when these techniques can get into commercial networks."

Shauvik Ghosh contributed to this story.

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