For morning bus commuters, a reliable Internet connection can transform dead time in traffic into a jump on the day’s tasks. But between their high cost and low data caps, smartphone data plans are a less than ideal solution for riders hoping to get serious work done in transit.
Electrical and Computer Engineering Associate Professor Suman Banerjee (also computer sciences) thinks bus passengers can get that bandwidth via new wireless systems that tap into TV whitespace—the underused portions of broadcast space normally reserved for television and wireless microphones.
With funding from the National Science Foundation, Banerjee and Electrical and Computer Engineering Professor Parmesh Ramanathan are refining network hardware that can detect unused portions of the TV spectrum, tune to the open frequency using precise software radios, and transmit between towers and access points on the bus. The two hope to have the hardware in place on Madison Metro busses in fall 2012.
TV whitespace doesn’t have the associated spectrum costs of other wireless data communications, and a network using it can cover more geographic area with fewer towers. “TV signals propagate through walls and obstacles much better than other bands,” says Ramanathan. “The higher the frequency, the less the signals propagate.”
Of course, this creates network architecture complications that don’t exist in smaller, more traditional wireless networks. The Madison Metro project is part of a broader effort to understand the challenges, including data speeds and number of users the spectrum can support, that wireless networks operating in TV whitespace will face in the real world.
While the potential for the technology is tremendous, building a network with real hardware will be critical to understanding how city-sized wireless networks should be designed and managed. And though mainstream adoption of TV whitespace for data communications might take years, Banerjee says the Madison Metro project is an important first step. “It’s potentially a big revolution in the wireless industry because it opens up spectrum in a new way,” he says. “It can lead to very innovative solutions in the future.”