Radio spectrum

The portion of the electromagnetic spectrum used for radio waves and wireless signals, extending from extremely low frequencies to the boundary with infrared radiation.

Radio wave: An electromagnetic wave with a frequency in the radio portion of the spectrum. Radio waves are the signals whose frequencies define this spectrum.
Electromagnetic spectrum: The full range of electromagnetic radiation, ordered by frequency or wavelength. The radio spectrum is one region of this broader range.
Broadcasting: The one-to-many transmission of audio or video content to receivers over radio or other networks. Radio and television broadcasters use assigned spectrum to reach large audiences.
Licensed spectrum: Radio frequencies assigned to authorized users under conditions set by a regulator. Licensing contrasts with open access to designated unlicensed bands.
Spectrum scarcity: The practical limitation on usable radio frequencies caused by interference, propagation, and competing demands. Scarcity drives coordination, reuse, and disputes over frequency assignments.
Frequency: The number of cycles of a repeating event completed per unit of time. Radio spectrum allocations are specified as ranges of frequency.
Hertz: The SI unit of frequency, equal to one cycle per second. Radio frequencies are measured in hertz and its multiples.
Mobile broadband: Wireless internet access through cellular networks, typically using licensed radio frequencies. Cellular data services depend on spectrum assignments and reuse.
Unlicensed spectrum: Radio frequencies available for compliant devices without an individual operating license. Wi-Fi and Bluetooth commonly use bands governed by technical limits rather than exclusive licenses.
International Telecommunication Union: A United Nations agency that coordinates international telecommunications standards and radio-frequency matters. Its conferences coordinate frequency use across national borders.

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