600 MHz duplex gap. An 11 megahertz guard band at 652-663 MHz that separates part 27 600 MHz service uplink and downlink frequencies.

600 MHz guard band. Designated frequency band at 614-617 MHz that prevents interference between licensed services in the 600 MHz service band and channel 37.

600 MHz service band. Frequencies in the 617-652 MHz and 663-698 MHz bands that are reallocated and reassigned for 600 MHz band services under part 27 of this chapter.

Available channel. A channel which is not being used by an authorized service and is acceptable for use by the device at its geographic location under the provisions of this subpart.

Contact verification signal. An encoded signal broadcast by a fixed or Mode II device for reception by Mode I devices to which the fixed or Mode II device has provided a list of available channels for operation. Such signal is for the purpose of establishing that the Mode I device is still within the reception range of the fixed or Mode II device for purposes of validating the list of available channels used by the Mode I device and shall be encoded to ensure that the signal originates from the device that provided the list of available channels. A Mode I device may respond only to a contact verification signal from the fixed or Mode II device that provided the list of available channels on which it operates. A fixed or Mode II device shall provide the information needed by a Mode I device to decode the contact verification signal at the same time it provides the list of available channels.

Fixed device. A white space device that transmits and/or receives radiocommunication signals at a specified fixed location. A fixed device may select channels for operation from a list of available channels provided by a white space database, and initiate and operate a network by sending enabling signals to one or more fixed devices and/or personal/portable devices. Fixed devices may provide to a Mode I personal/portable device a list of available channels on which the Mode I device may operate, including channels on which the Mode I device but not the fixed device may operate.

Geo-fenced area. A defined geographic area over which the white space database has determined the set of available channels.

Geo-location capability. The capability of a white space device to determine its geographic coordinates and geo-location uncertainty. This capability is used with a white space database approved by the FCC to determine the availability of spectrum at a white space device's location.

Less congested area. Geographic areas where at least half of the TV channels within a specific TV band are unused for broadcast and other protected services and available for white space device use. Less congested areas are determined separately for each TV band—the low VHF band (channels 2-6), the high VHF band (channels 7-13) and the UHF band (channels 14-36); i.e., one, two or all three bands or any combination could qualify as less congested. White space devices may only operate at the levels permitted for less congested areas within the area and the specific TV band(s) that qualify as a less congested area. For the purpose of this definition, a channel is considered available for white space device use if it is available for fixed devices operating with 40 milliwatts EIRP at 3 meters HAAT. Less congested areas in the UHF TV band are also considered to be less congested areas in the 600 MHz service band.

Mobile white space device. A white space device that transmits and/or receives radiocommunication signals on available channels within a defined geo-fenced area. A mobile white space device uses an incorporated geo-location capability to determine its location with respect to the boundaries of the defined area. A mobile white space device may operate only in less congested areas.

Mode I personal/portable device. A personal/portable white space device that does not use an internal geo-location capability and access to a white space database to obtain a list of available channels. A Mode I device must obtain a list of available channels on which it may operate from either a fixed white space device or Mode II personal/portable white space device. A Mode I device may not initiate a network of fixed and/or personal/portable white space devices nor may it provide a list of available channels to another Mode I device for operation by such device.

Mode II personal/portable device. A personal/portable device that uses an internal geo-location capability and access to a white space database, either through a direct connection to the Internet or through an indirect connection to the Internet by way of fixed device or another Mode II device, to obtain a list of available channels. A Mode II device may select a channel itself and initiate and operate as part of a network of white space devices, transmitting to and receiving from one or more fixed devices or personal/portable devices. A Mode II personal/portable device may provide its list of available channels to a Mode I personal/portable device for operation on by the Mode I device.

Narrowband white space device. A fixed or personal/portable white space device operating in a bandwidth of no greater than 100 kilohertz.

Network initiation. The process by which a fixed or Mode II white space device sends control signals to one or more fixed white space devices or personal/portable white space devices and allows them to begin communications.

Operating channel. An available channel used by a white space device for transmission and/or reception.

Personal/portable device. A white space device that transmits and/or receives radiocommunication signals on available channels at unspecified locations that may change.

Receive site. The location where the signal of a full service television station is received for rebroadcast by a television translator or low power TV station, including a Class A TV station, or for distribution by a Multiple Video Program Distributor (MVPD) as defined in 47 U.S.C. 602(13).

Sensing only device. A personal/portable white space device that uses spectrum sensing to determine a list of available channels. Sensing only devices may transmit on any available channels in the frequency bands 512-608 MHz (TV channels 21-36).

Spectrum Act. Title VI of the Middle Class Tax Relief and Job Creation Act of 2012 (Pub. L. 112-96).

Spectrum sensing. A process whereby a white space device monitors a television channel to detect whether the channel is occupied by a radio signal or signals from authorized services.

Television bands. The broadcast television frequency bands at 54-72 MHz (TV channels 2-4), 76-88 MHz (TV channels 5-6), 174-216 MHz (TV channels 7-13) and 470-608 MHz (channels 14-36).

White space database. A database system approved by the Commission that maintains records on authorized services and provides lists of available channels to white space devices and unlicensed wireless microphone users.

[80 FR 73070, Nov. 23, 2015, as amended at 84 FR 34796, July 19, 2019; 86 FR 2290, Jan. 12, 2021]