A team of American and Israeli researchers from the University of Southern California, NASA's Jet Propulsion Laboratory, and Tel Aviv University have re-defined the concept of “fast” when it comes to wireless networks. These scientists have reportedly worked out a new, speedier way of transmitting wireless data, and the term 'speedier' undermines the achievement. If reports are to be believed, it is now possible to transfer a blazing 2.5 terabits of information per second wirelessly. Now, to put this figure into better perspective, ExtremeTech's Sebastian Anthony writes that this is equivalent to 320 gigabytes per second, or around seven full Blu-ray movies per second.
Super speeds (Image credit: Getty Images)
Breaking down the method used, the report explains that the researchers used twisted, vortex beams to transmit data at that speed. The advantage of using twisted signals, instead of the existing spin angular momentum (SAM) of radio waves, is that they deploy orbital angular momentum (OAM), owing to which it is possible to accommodate lot more data into a single stream. 'In current state-of-the-art transmission protocols (WiFi, LTE, COFDM), we only modulate the SAM of radio waves, not the OAM. If you picture the Earth, SAM is our planet spinning on its axis, while OAM is our movement around the Sun. Basically, the breakthrough here is that researchers have created a wireless network protocol that uses both OAM and SAM,' adds the report.
To achieve the feat, the researchers “twisted together eight ~300Gbps visible light data streams using OAM.” Reportedly, each of these eight beams has a different level of OAM twist. The beams are bundled into two groups of four and are passed through varying polarization filters. “One bundle of four is transmitted as a thin stream, like a screw thread, while the other four are transmitted around the outside, like a sheathe. The beam is then transmitted over open space (just one meter in this case), and untwisted and processed by the receiving end.“
According to Bo Thide, a Swedish physicist, OAM should allow us to twist together an “infinite number” of conventional transmission protocols without using any more spectrum. In theory, this essentially means that it will be possible to take 10 (or 100 or 1000 or…) Wi-Fi or LTE signals and twist them into one beam. “For fiber networks, where we still have a lot of spare capacity, this isn’t all that exciting — but for wireless networks, where we’ve virtually run out of useful spectrum, twisted radio waves could provide an instant, future-proof solution. For the networking nerds, Alan Willner’s OAM link has a spectral efficiency of 95.7 bits per hertz; LTE maxes out at 16.32 bits/Hz; 802.11n is 2.4 bits/Hz. Digital TV (DVB-T) is just 0.55 bits/Hz,” added the report.
The main factor, according to Willner, is holding back the maximum use of OAM is the lack of available hardware and software. Quoting Willner, the report adds, “For situations that require high capacity… over relatively short distances of less than 1km, this approach could be appealing. Of course, there are also opportunities for long-distance satellite-to-satellite communications in space, where turbulence is not an issue.”
Publish date: June 26, 2012 4:54 pm| Modified date: December 18, 2013 10:36 pm
LTE signals, NASA’s Jet Propulsion Laboratory, OAM, orbital angular momentum, SAM, Science and Technology, spin angular momentum, Tel Aviv University, University of Southern California, Wi-fi, Wi-Fi speeds