Wireless 'breakthrough' promises to double capacity of today's networks

Stuart Corner
Friday, 09 September 2011 13:36

Business IT - Technology

Researchers at Rice University in the US have developed technology that they say could double the capacity of today's cellular networks, without the need for more spectrum or more base stations.

Their development is simple in essence but challenging in execution: they claim to have developed a means for a cellphone to transmit to and receive from a base station simultaneously on the same frequency. Today's cellular networks use different frequencies for transmit and receive because the transmit and receive signals on the same frequency would interfere with each other.

According to Ashutosh Sabharwal, professor of electrical and computer engineering at Rice, "Our solution requires minimal new hardware, both for mobile devices and for networks, which is why we've attracted the attention of just about every wireless company in the world."

He added: "The bigger change will be developing new wireless standards for full-duplex. I expect people may start seeing this when carriers upgrade to 4.5G or 5G networks in just a few years."

According to a press release from Rice "In 2010, Sabharwal and Rice colleagues Melissa Duarte and Chris Dick published the first paper showing that full-duplex was possible. That set off a worldwide race to demonstrate that the technology could actually be used in a real network. This summer, Sabharwal and Rice's Achaleshwar Sahai and Gaurav Patel set new performance records with a real-time demo of the technology that produced signal quality at least 10 times better than any previously published result."

Rice's team claims to have overcome the interference hurdle that prevents full-duplex operation by employing an extra antenna and some computing tricks. "We send two signals such that they cancel each other at the receiving antenna," Sabharwal said. "The cancelling effect is purely local, so the other node can still hear what we're sending."

He said the cancellation idea was relatively simple in theory and had been proposed some time ago. "But no one had figured a way to implement the idea at low cost and without requiring complex new radio hardware."

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