Imagine Wi-Fi that spans two kilometers; or a car safety system that beams news of an accident, vehicle to vehicle, from far ahead on a lightly traveled road; or a mobile phone whose calls almost never drop.
These and other new communications technologies could be helped along by a deal announced in Washington last week that permits the U.S. Federal Communications Commission (FCC) to sell off unused TV spectrum in two years. The agreement covers lower frequencies—previously set aside for analog TV broadcasts—that allow for longer-range, higher-capacity communications. But making use of the frequencies will require technology capable of flitting rapidly between different frequencies at high speed.
“This will absolutely open up new innovation,” says Dipankar Raychauduri, director of Rutgers University’s WinLab, a leading wireless research lab. “It’s really quite a breakthrough, because the U.S. would be the first country to allocate such spectrum.”
At the simplest level, the move could stave off a growing wireless overload. Mobile data usage worldwide is expected to grow 18-fold over the next five years. Wireless networks are showing signs of congestion even now. The major U.S. carriers—AT&T, Verizon, Sprint, and T-Mobile—all are groaning under the growing demands of bandwidth-hogging smart phones, tablets, and wireless data cards for laptops.
If wireless companies gain access to more spectrum, networks will be able to transmit more data with fewer glitches and delays—as well as provide faster services. FCC chairman Julius Genachowski said last week that making more spectrum available “holds tremendous promise to become another value-creating breakthrough on the order of magnitude of Wi-Fi.”
The Washington deal also sets aside $7 billion to beef up emergency response networks by building a reliable nationwide communications network dedicated to the task.
The frequencies that will become available are so-called “white spaces” in the TV spectrum. Compared to the higher frequency used by Wi-Fi routers, these frequencies can also carry information over longer distances (see this visualization of frequency allocations).
As such, the frequencies could help make it easier to remove the barrier that exists today between wireless systems in your home or office—like Wi-Fi—to those you use outside, like cellular phone services, says Raychauduri. Because the new spectrum works for both shorter and longer-range signals, “you will see new innovation fill up that space,” he says.
Some white spaces have already been made available. Recent FCC rules allow wireless carriers to selectively tap it in areas where it is underused—typically outside of major metro areas—but only if it doesn’t interfere with other broadcasts. A Microsoft technology called White Fi has been used to tap into these frequencies. It checks to see if a chosen frequency could cause interference in a particular location, and then automatically hops between different frequencies. The budget deal opening up new spectrum will provide the most benefit in urban areas, where such gaps are hard to find.
Longer term, the move could benefit efforts to develop software-defined radio systems capable of dynamically switching between different frequencies—and different wireless protocols—without dropping the signal to perform a wide variety of tasks, including bridging the gap between in-home or in-office wireless networks and mobile cellular ones.
Another beneficiary could be mesh networks. In such networks, data doesn’t follow a hub-and-spoke broadcasting model (like that of a TV station or your home modem) but instead hops from device to device, forming the so-called mesh (or ad hoc) network. This type of network is inexpensive, robust, and able to expand automatically and efficiently as the number of devices on the network increases.
While such networks are already used for several applications, including environmental or industrial sensing, the combination of more spectrum—used more intelligently—increases the options for building such networks.