White spaces refer to radio or television broadcasting frequencies that are not being used. They are usually allocated by national telecommunications organizations to avoid interference between channels, and are unlicensed and free to use.

White spaces can be used to provide wireless broadband Internet access, and can range up to 10-30km for a given frequency. A special "white spaces device" (WSD) scans local airwaves for unused frequencies and then uses them for Internet connectivity, which is referred to as "dynamic spectrum sharing." A WSD base station transmits these signals to wifi "hotspots" to provide consistent coverage over a given area. Because white spaces are a different radio standard, wifi-enabled devices such as laptops and phones cannot access white spaces directly, and the speeds are slower than commercial broadband.

Areas of the world which have switched over to digital TV have recently opened up more white space frequencies. While some broadcasting entities initially worried these devices would interfere with their signals, tests and trials all over the world in the last few years have had positive results. In July 2013, the Federal Communications Commission approved Google's online database of available U.S. white spaces.

Increasingly, there are many organizations and governments interested in exploring white space technology for Internet access globally, such as the Dynamic Spectrum Alliance. In the U.S., most libraries already use white spaces for free Internet access, which the Gigabit Libraries Network WhiteSpaces Project is looking to improve upon.

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