Wiktionary
n. (white space English)
Wikipedia
In telecommunications, white spaces refer to frequencies allocated to a broadcasting service but not used locally.
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 to digital television frees up large areas between about 50 MHz and 700 MHz. This is because digital transmissions can be packed into adjacent channels, while analog ones cannot. This means that the band can be "compressed" into fewer channels, while still allowing for more transmissions.
In the United States, the abandoned television frequencies are primarily in the upper UHF "700-megahertz" band, covering TV channels 52 to 69 (698 to 806 MHz). U.S. television and its white spaces will continue to exist in UHF frequencies, as well as VHF frequencies for which mobile users and white-space devices require larger antennas. In the rest of the world, the abandoned television channels are VHF, and the resulting large VHF white spaces are being reallocated for the worldwide (except the U.S.) digital radio standard DAB and DAB+, and DMB.
Usage examples of "white spaces".
He looked at maps, and wondered what lay beyond their edges: maps made in the Shire showed mostly white spaces beyond its borders.
Below the keys, where as a rule the organist works the bellows with his feet, a cylinder had been set, in which teeth were fitted, large spikes, in an order unpredictably regular or regularly unpredictable, which suggested the way notes are arranged in rising and descending patterns, unforeseen breaks, vast white spaces and a density of crotchets, on the lines of a sheet of music.
Only a few white spaces here and there, at the edges and the top left of the painting, revealed where the composition was unfinished.
This recording kept saying that the white spaces were for loading and unloading only.
He frowned deeply and peered at the narrow line of black and white spaces hanging in the air in front of him.
When you finish, you look at the white spaces that are left and you know what you have to work with.