What’s the Frequency, Kenneth? Pick Any

A trial in England shows the power of long-range, high-speed wireless | “This could absolutely pose a challenge” to cellular carriers

Brendan Greeley

James Collier is loping in a broad circle on the Midsummer Common in Cambridge, England, holding aloft a two-foot fiberglass antenna. Cables snake from the antenna to a flat green box about the size of a vinyl record sleeve, which he’s carrying in a backpack. About 10 yards away, another antenna and another green box are connected to a laptop, receiving Collier’s signal and tracing his oval-shaped path on a map. “Of course,” he says, “this will all be much smaller.”

Collier runs Neul, the Cambridge startup that makes the green boxes, which house a new technology called “adaptive radio.” Today, anything that transmits long-range signals over the airwaves — radios, cell phones, television networks — broadcasts on a single, fixed frequency. Think of the 106.7 that appears on your radio dial. Both broadcaster and listener have to be tuned to the same wave. Each cell phone, similarly, has its own allotted frequency to communicate with nearby towers. Carriers must spend billions to license chunks of spectrum to make sure their subscribers can connect wherever they go.

A radio from Neul — or one of several startups working on similar technology — upends this whole system. An adaptive radio doesn’t always use the same fixed frequency but checks to see which frequencies around it aren’t in use, then borrows empty air for a short-term connection. As devices move around, the connection can shift, too. Collier’s loop around Cambridge is a demonstration — part of a trial led by Microsoft and other tech giants — that the idea works technologically. If it works commercially, too, it could change the dynamics of the wireless business.

An adaptive network could help companies in the U.S. such as AT&T or Verizon Wireless run their networks far more efficiently by squeezing more smartphones and other devices onto a given range of wireless spectrum. Collier says he’s in touch with some big-name companies that want to do exactly that. And since adaptive radios find unused airspace without interfering with other signals, they could make it feasible to build new, high-speed networks without spending billions to license frequencies. “This could absolutely pose a challenge” to existing mobile networks, says Rick Rotondo, the vice president of marketing at XG Technology, a Florida-based competitor to Neul. “Someone with the pockets of a Google, a Microsoft, an Apple, they could make a run of this and create their own network.”

The success of adaptive radios depends on some regulatory changes, however. The technology makes particularly good use of unlicensed spectrum, set aside by regulators for anyone to use. The problem is, there’s precious little of it, and most of what’s available works best over short ranges. In February, Congress authorized unlicensed use of the so-called white spaces that are left between television broadcast signals to prevent interference. And at a conference in Orlando, Julius Knapp, chief of the FCC’s Office of Engineering and Technology, hinted that the commission would open up more unlicensed spectrum in the future.

The Microsoft-led trial in Cambridge, which finished in April and also counted Nokia, Alcatel-Lucent, and the BBC as participants, showed that a citywide network of adaptive radios could work without affecting existing transmissions. The trial was in part an effort to persuade Ofcom, Britain’s telecom regulator, to start freeing up white spaces in the U.K.

The technology that makes adaptive radio systems work comes mostly from startups. Spectrum Bridge manages a database of radio frequencies; adaptive radios check it to know which ones to avoid. Neul, 6harmonics, and Adaptrum all make various pieces of the radios or antennae.

The startups say that by eliminating the high cost of acquiring a spectrum license, adaptive radio networks will unlock all kinds of wireless innovation. In Cambridge, Neul developed an application that notified the city council when trash cans needed emptying. Similar sensors run by New Hanover County in North Carolina monitor water quality on the Intracoastal Waterway. Such applications are possible with existing networks, but would require paying a hefty monthly fee to a telecom company such as AT&T. Collier says you could even use adaptive radios to monitor conditions in dangerous areas. “Toss hundreds of sensors out the back of a helicopter, then plant a single antenna,” he says.

The bottom line A recent trial in England proves the feasibility of adaptive radios, which could spur wireless innovation by reducing costs.


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