47 U.S. Code § 1454 - Guard bands and unlicensed use
(a) In general
(b) Size of guard bands
Such guard bands shall be no larger than is technically reasonable to prevent harmful interference between licensed services outside the guard bands.
(c) Unlicensed use in guard bands
The Commission may permit the use of such guard bands for unlicensed use.
Unlicensed use shall rely on a database or subsequent methodology as determined by the Commission.