What is Fallow Spectrum?

Finally, the FCC has come to realize that it’s a better idea to use the available radio spectrum more efficiently, thus approving the use of spectrum that has long lain fallow. On June 2, 2014, the FCC announced the TV Incentive Auction Report and Order. One of the controversial issues the FCC focused on was to provide regulatory certainty for a system of people using a section of unlicensed 600 MHz spectrum that had been allocated by the FCC with an order earlier in 2010. The technology used by this system is now empowering spectrum efficiencies in bands such as 3.5 GHz. It is now allowed for use in areas of spectrum that are licensed yet fallow.

2010’s FCC order opened up unused areas of TV broadcast spectrum for unlicensed agile radios. These were called TV white spaces devices at first. Innovators were encouraged to design and manufacture new agile spectrum sharing radios, yet they had to have very strict limitations so as to not interfere with broadcast TV stations in adjacent channels. Because the TV stations’ channels varied from town to town, however, a spectrum access system database based in the cloud was required to connect to the radios so as to ensure the channels selected by the agile radio were not ones assigned to a local TV channel. Database cloud providers such as Google, Microsoft then followed the guidance of the FCC and built the databases required to point the agile radios to the unused areas of the TV spectrum. With VoIP gaining momentum, the pressure in wireless networking will only increase.

The FCC was ordered by Congress in 2012 to auction off some of the unused 600 MHz TV spectrum they’d just assigned to the unlicensed system. In 2014, the FCC both gave and took. To wit, the FCC gave regulatory certainty to the unlicensed system by assigning many bands nationwide for unlicensed use. Before the order, large cities such as Chicago and LA had so many TV stations that there was little to no available bandwidth. After the auction, however, agile radios will have spectrum available nationwide, and will always have areas of unused TV spectrum in rural areas. Some of the 600 MHz spectrum was also re-appropriated for auction.

The FCC also broke new ground, by allowing the agile broadband radio areas of spectrum that have been auctioned to mobile licensees, but were not yet operating. Advocates of spectrum performance have said that when spectrum is licensed yet not used — in other words, spectrum in areas where no sites are operating, and there are no bars showing on a mobile device — that the unused spectrum should be available for use by others. One should not be able to simply “stake a claim” on an area of spectrum and be able to hold it indefinitely.

Arguably, such use might have interfered with other legitimate usage if the unlicensed users refused to move to another band. However, with the current database-driven ability for the FCC to deliver spectrum usage information to the agile radios there is very little possibility of interference.

Ever since the early 80s, the FCC has licensed for free or auctioned great ranges of spectrum across this nation. Much of this has been built out, yet much of it still lies fallow, especially in rural areas. Now the FCC has the tools developed by the TV white spaces system, which takes the form of a cloud database that directs agile radios, which opens up much of this poorly used fallow spectrum. This cloud-database technology has been designed to work on extremely small micro-geographies (meaning a small area) down to about 50 square meters, so as to allow for wireless microphones. Capabilities such as these may even allow the use of fallow spectrum in geographies as small as the areas in between two mobile towers where bars drop to nothing and calls are lost.

Michelle Patterson is excited with the new technologies that are threatening to change the way we stay in touch and communicate, particular in business. She works with companies that are introducing these technologies to make understanding them easy for regular people.

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