The answer is that it depends where that person lives. The number of television stations operating in an area constrains the amount of white space available, while the number of people living there determines how much white space can be dedicated to each individual.

The image shown top left, for example, shows the variation in personal bandwidth that might be available across the country in a scenario in which every 2,000 people use one white-spaces transmission tower in their area. The New York City area is noticeably darker than upstate Maine, for example, meaning that users there would experience slower speeds. "We see things like that, because where the people are, the TV broadcasters are too," says Mishra. Some places have a good balance of population and television-channel density that allows for greater per-capita bandwidth.

"These analyses could be used for a range of business or technical decisions, for example to help companies figure out what kind of services or broadband offerings are possible and start answering questions about the size of the cells needed to do that," says Mishra.

"This gives very interesting insights," says Kiran Challapali, a researcher at Philips in New York and chair of the Cognitive Networking Alliance (CogNeA), a trade group working on standards for devices to use short-range white-spaces links inside the home. "It will be useful for those thinking about getting into white-spaces broadband."

Kyutae Lim, associate director of technology at the Georgia Electronic Design Center and chairman of the only international standard yet for white-space devices, published by international standards body ECMA International in December 2009, agrees. "The commercialization aspect for long distance is less attractive than low power because you have to build towers, and spectrum availability is unclear," he explains. "It's risky to spend money to build a system, so analysis like this is needed."