FRAMINGHAM 20 FEBRUARY 2011 - Researchers at Stanford University have shown it's possible to double the data rate of communication networks without the need for additional frequencies, something that could lead to significantly faster wireless networking.
Described by its inventors as "simple and effective," the new technique relies on three antennas, instead of the two found in the latest 801.11n wireless devices. It allows full-duplex communications on the same frequency (that is, simultaneous send and receive), something considered before now to be physically impossible.
The radio spectrum is becoming increasingly congested and boosting speeds without requiring additional frequencies is the Holy Grail of electrical engineering.
When a radio device transmits, its broadcasts are too strong for it to receive any signals. It's like two people conversing; if you're speaking, it's impossible to hear what another is saying. Both parties must take turns to speak, and generally speaking this is how radio transmissions have worked until now.
The trick behind doubling speeds is to use something akin to noise cancellation found in some headphones. Because the transmitting device knows exactly what it's sending, it can filter it out in order to hear weaker incoming transmissions. Thus, two-way communications on the same frequency can take place.
"Textbooks say you can't do it," says Philip Levis, one of the team behind the invention and assistant professor of computer science and electrical engineering at Stanford. "The new system completely reworks our assumptions about how wireless networks can be designed."
The team behind the invention showed it off at MobiCom 2010 last year, a gathering of mobile networking experts, and won a prize for the best demo. Fellow researchers told them they didn't expect it to work and, when it did, said it was so obvious that it had probably already been invented.
There's still some way to go before the technology will make it into consumer or business equipment. For example, the researchers are still working on a way for their invention to work over the kind of distances required for typical wireless networking.
Additionally, wireless networking relies on standards that are adopted by all manufacturers, which is why you can use an Dell laptop with a D-Link router, for example. These standards are controlled by the Institute of Electrical and Electronics Engineers (IEEE), and the invention would have to be cleared by the 802.11 working group before being formed into a new standard. That's likely to take many years to complete, although progress could be sped-up by the lack of need to set aside new frequencies.
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