Interference Unlocks Faster Mobile Data

While demand for wireless data grows exponentially, the supply of available radio spectrum remains stubbornly fixed. A new technology could get more from that precious resource by turning a conventional piece of engineering wisdom on its head.

"Every other wireless system up to now has avoided interference," says Steve Perlman, founder of technology incubator Rearden Labs, based in San Francisco. "This embraces it."

Perlman's team is testing a new kind of wireless network that he says can fit thousands of times more data into the same amount of radio spectrum as a conventional one. The approach is known as DIDO, for distributed input distributed output, and is currently being tested around Palo Alto, California, and in rural Texas. DIDO involves intentionally combining signals from multiple transmitters, exploiting interference to create a bubble of crystal-clear reception around every user. Each signal that leaves an individual transmitter is incomprehensible until it encounters, and interferes with, other DIDO signals near a device connected to the network. This approach removes the need to share bandwidth, says Perlman, because each bubble covers a small area and can occupy all the spectrum available to the network. The size and shape of the bubbles varies depending on the number of antennas broadcasting to a device, says Perlman. Designing radio signals that will interfere with one another in just the right way takes complex mathematics and careful coordination among the different DIDO transmitters.