US regulator frees TV spectrum
The Federal Communications Commission is releasing vacant spectrum between TV channels for unlicensed use.
The regulator says it will be the first significant block of spectrum made available for unlicensed use in more than 20 years.
TV 'white space' spectrum is considered particularly valuable because the signals propagate well, making it well suited for mobile wireless devices. The FCC says that making it available will create opportunities for new services to arise.
TV broadcasters have been concerned that 'white space' devices, which take advantage of unused spectrum on an ad hoc basis, could interfere with their programming. A number of solutions have been suggested, including insisting that white-space devices include sensors to check for broadcasts on adjacent frequencies, and using a combination of geolocation and online databases to tell each device what local spectrum is available.
The FCC's Second Memorandum Opinion and Order has resolved some of these issues. It does away with the requirement that devices working in the newly released spectrum that include geo-location and database access must also include sensing technology to detect TV signals and wireless microphones.
It also requires wireless microphone users who want to register in the TV bands databases to certify that they will use all available channels from 7 through 51 before seeking registration.
The Commission is also taking steps to ensure that incumbent services are protected from interference from the use of white spaces in various ways. It is reserving two vacant UHF channels for wireless microphones and other low-power auxiliary service devices across the country. It is also maintaining a reasonable separation distance between white-space devices and wireless microphones registered in the database.