White spaces (radio) ||The examples and perspective in this
article deal primarily with the United States and do not
represent a worldwide view of the subject. (April 2011)|
National and international bodies assign different frequencies
for specific uses, and in most cases license the rights to
broadcast over these frequencies. This frequency allocation
process creates a bandplan, which for technical reasons assigns
white space between used radio bands or channels to avoid
interference. In this case, while the frequencies are unused,
they have been specifically assigned for a purpose, such as a
guard band. Most commonly however, these white spaces exist
naturally between used channels, since assigning nearby
transmissions to immediately adjacent channels will cause
destructive interference to both. In addition to white space
assigned for technical reasons, there is also unused radio
spectrum which has either never been used, or is becoming free
as a result of technical changes. In particular, the switchover
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