In telecommunications, white spaces are radio frequencies allocated to a broadcasting service but not used locally. National and international bodies assign frequencies for specific uses and, in most cases, license the rights to broadcast over them. This frequency-allocation process creates bandplans that, for technical reasons, set aside white space between used radio bands or channels to avoid interference. In such cases, although the frequencies are unused, they have been specifically assigned for a purpose, such as a guard band. More commonly, these white spaces occur naturally between used channels, since assigning nearby transmissions to adjacent channels causes destructive interference. In addition to white space assigned for technical reasons, there is also unused radio spectrum that has either never been used or is becoming free due to technical changes. In particular, the switchover to digital television frees up large areas between about 50 MHz and 700 MHz, because digital transmissions can be packed into adjacent channels while analog ones cannot. This allows the band to be compressed into fewer channels while still supporting more transmissions. In the United States, the abandoned television frequencies are primarily in the upper UHF 700 MHz band, covering TV channels 52 to 69 (698 to 806 MHz). Television white spaces will continue to exist in UHF frequencies and in VHF frequencies, which require larger antennas for mobile users and white-space devices. In much of the world (except the U.S.), abandoned television channels have been in VHF, and the resulting large VHF white spaces are being reallocated for digital radio standards such as DAB, DAB+, and DMB.

Various proposals, including IEEE 802.11af, IEEE 802.22, and proposals from the White Spaces Coalition, advocate using white spaces vacated by analog TV to provide wireless broadband Internet access. A device intended to use these channels is called a white-space device (WSD). WSDs are designed to detect unused portions of the spectrum and use them for Internet signals, potentially improving broadband and Wi-Fi availability in rural areas. Early proposals included using GNSS receivers and programming each WSD with a database of local TV stations, but that approach would not address non-stationary or unlicensed users or stations licensed or modified after the database was created. Reuse of these frequencies may also impact wireless microphones, medical telemetry, and other technologies that have historically relied on them. Professional wireless microphones have used TV white space for decades, long before the emergence of consumer "white space" devices. Like Wi‑Fi, TV white space is a wireless technology that uses radio frequency bands. TV white space operates in the 470 MHz to 698 MHz range, while Wi‑Fi operates in the 2.4 GHz and 5 GHz bands. Data rates depend on the radio model, vendor, antenna, and other factors; new TV white space radios can support more than 50 Mbit/s. Wi‑Fi data rates also vary with range and line of sight, and can reach up to 1,000 Mbit/s using the IEEE 802.11ac standard. Range is a crucial difference: TV white space typically covers about 6 miles on average, though this varies with noise, line of sight, and other conditions; some vendors, such as Carlson Wireless, advertise ranges up to 24.8 miles. Both technologies typically consume between 20 and 100 watts, depending on device, antenna, and vendor, and both can meet government security standards such as FIPS 197 (the Advanced Encryption Standard). Wi‑Fi performs well in urban environments, while TV white space is well suited for rural areas. Graph 1 illustrates the differences between TV white space and Wi‑Fi. By country

Argentina
Microsoft, in partnership with the communications authority of Argentina, Ente Nacional de Comunicaciones (ENACOM), planned to deliver wireless access to schools in the province of Mendoza in August 2017. Microsoft will loan the TV White Spaces hardware to ENACOM technicians, and national satellite operator ARSAT will act as the ISP. No further trial details have been released.

Canada
In August 2011, Industry Canada, the Canadian ministry for industry, launched a consultation titled "Consultation on a Policy and Technical Framework for the Use of Non‑Broadcasting Applications in the Television Broadcasting Bands Below 698 MHz." The consultation closed on November 4, 2011. Submissions were received from a wide range of organizations in the telecom and broadcast industries.

Kenya
A pilot project by Indigo Telecom/Microsoft and the Kenyan government is reportedly delivering bandwidth speeds of up to 16 Mbit/s to three rural communities that lack electricity — Male, Gakawa, and Laikipia — using a solar‑powered network.

Namibia
In Namibia, a pilot project called Citizen Connect, a collaboration between the Microsoft 4Afrika Initiative, the MyDigitalBridge Foundation, and the Millennium Challenge Account Namibia (MCA‑N), is slated to deliver broadband Internet to twenty-seven schools and seven circuit offices of the Ministry of Education in Omusati, Oshana, and Ohangwena using TV White Space technology. Philippines: In 2014, Microsoft worked with the Philippine government to pilot a program for digitizing the management of remote fishermen.

Singapore: After the FCC, the Infocomm Media Development Authority became the second regulator in the world to regulate TV White Space, ahead of the UK and Canada. The Singapore efforts were driven mainly by the Singapore White Spaces Pilot Group (SWSPG), founded by the Institute for Infocomm Research, Microsoft, and StarHub. The Institute for Infocomm Research subsequently spun off Whizpace to commercialize TV White Space radio using intellectual property (IP) developed at the institute since 2006.

South Africa: Google, in partnership with the Independent Communications Authority of South Africa (ICASA), the CSIR Meraka Institute, the Wireless Access Providers Association (WAPA), and Carlson Wireless, delivered wireless access to ten schools through three base stations on the campus of Stellenbosch University’s Faculty of Medicine and Health Sciences in Tygerberg, Cape Town.