More than half a billion smart phones will likely be sold in the coming year.  And all those smart phones means the infrastructure required to manage them is going to have to grow as well. Or does it?

Engineers at Rice University in Houston say they have found a way to double wireless network capacity by adding a "multiple-input multiple-output" antenna to a smart phone. This device enables full-duplex over a single frequency. [Achaleshwar Sahai, Gaurav Patel and Ashutosh Sabharwal "Pushing the limits of Full-duplex: Design and Real-Time Implementation"]

A wireless device normally needs two frequencies for full-duplex. This lets callers speak and listen at the same time, with each signal on its own frequency.

The extra antenna allows smart phones to carry two signals over a single frequency. Each signal cancels out part of the other at the receiving antenna. The sender can't hear his own voice, but he can hear the person on the other end. Without this cancellation over a single frequency, the phone would function more like a two-way radio: you could speak or listen, but not both at the same time.

The engineers have essentially found a way to double network throughput without changing the network itself. Nice trick.

—Larry Greenemeier

[The above text is a transcript of this podcast.]