Goto Section: 15.715 | 15.717 | Table of Contents
Revised as of November 24, 2020
Goto Year:2020 |
§ 15.717 White space devices that rely on spectrum sensing.
(a) Applications for certification. Parties may submit applications for
certification of white space devices that rely solely on spectrum
sensing to identify available channels. Devices authorized under this
section must demonstrate with an extremely high degree of confidence
that they will not cause harmful interference to incumbent radio
(1) In addition to the procedures in subpart J of part 2 of this
chapter, applicants shall comply with the following.
(i) The application must include a full explanation of how the device
will protect incumbent authorized services against interference.
(ii) Applicants must submit a pre-production device, identical to the
device expected to be marketed.
(2) The Commission will follow the procedures below for processing
applications pursuant to this section.
(i) Applications will be placed on public notice for a minimum of 30
days for comments and 15 days for reply comments. Applicants may
request that portions of their application remain confidential in
accordance with § 0.459 of this chapter. This public notice will include
proposed test procedures and methodologies.
(ii) The Commission will conduct laboratory and field tests of the
pre-production device. This testing will be conducted to evaluate proof
of performance of the device, including characterization of its sensing
capability and its interference potential. The testing will be open to
(iii) Subsequent to the completion of testing, the Commission will
issue by public notice, a test report including recommendations. The
public notice will specify a minimum of 30 days for comments and, if
any objections are received, an additional 15 days for reply comments.
(b) Power limit for devices that rely on sensing. The white space
device shall meet the requirements for personal/portable devices in
this subpart except that it will be limited to a maximum EIRP of 50 mW
per 6 megahertz of bandwidth on which the device operates and it does
not have to comply with the requirements for geo-location and database
access in § 15.711(b), (d), and (e). Compliance with the detection
threshold for spectrum sensing in § 15.717(c), although required, is not
necessarily sufficient for demonstrating reliable interference
avoidance. Once a device is certified, additional devices that are
identical in electrical characteristics and antenna systems may be
certified under the procedures of part 2, Subpart J of this chapter.
(c) Sensing requirements—(1) Detection threshold. (i) The required
detection thresholds are:
(A) ATSC digital TV signals: −114 dBm, averaged over a 6 MHz bandwidth;
(B) NTSC analog TV signals: −114 dBm, averaged over a 100 kHz
(C) Low power auxiliary, including wireless microphone, signals: −107
dBm, averaged over a 200 kHz bandwidth.
(ii) The detection thresholds are referenced to an omnidirectional
receive antenna with a gain of 0 dBi. If a receive antenna with a
minimum directional gain of less than 0 dBi is used, the detection
threshold shall be reduced by the amount in dB that the minimum
directional gain of the antenna is less than 0 dBi. Minimum directional
gain shall be defined as the antenna gain in the direction and at the
frequency that exhibits the least gain. Alternative approaches for the
sensing antenna are permitted, e.g., electronically rotatable antennas,
provided the applicant for equipment authorization can demonstrate that
its sensing antenna provides at least the same performance as an
omnidirectional antenna with 0 dBi gain.
(2) Channel availability check time. A white space device may start
operating on a TV channel if no TV, wireless microphone or other low
power auxiliary device signals above the detection threshold are
detected within a minimum time interval of 30 seconds.
(3) In-service monitoring. A white space device must perform in-service
monitoring of an operating channel at least once every 60 seconds.
There is no minimum channel availability check time for in-service
(4) Channel move time. After a TV, wireless microphone or other low
power auxiliary device signal is detected on a white space device
operating channel, all transmissions by the white space device must
cease within two seconds.
Goto Section: 15.715 | 15.717
Goto Year: 2020 |
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