§  15.407   General technical requirements.

   (a) Power limits:

   (1) For the band 5.15-5.25 GHz, the maximum conducted output power over
   the frequency band of operation shall not exceed the lesser of 50 mW or
   4 dBm + 10 log B, where B is the 26-dB emission bandwidth in MHz. In
   addition, the peak power spectral density shall not exceed 4 dBm in any
   1-MHz band. If transmitting antennas of directional gain greater than 6
   dBi are used, both the maximum conducted output power and the peak
   power spectral density shall be reduced by the amount in dB that the
   directional gain of the antenna exceeds 6 dBi.

   (2) For the 5.25-5.35 GHz and 5.47-5.725 GHz bands, the maximum
   conducted output power over the frequency bands of operation shall not
   exceed the lesser of 250 mW or 11 dBm + 10 log B, where B is the 26 dB
   emission bandwidth in megahertz. In addition, the peak power spectral
   density shall not exceed 11 dBm in any 1 megahertz band. If
   transmitting antennas of directional gain greater than 6 dBi are used,
   both the maximum conducted output power and the peak power spectral
   density shall be reduced by the amount in dB that the directional gain
   of the antenna exceeds 6 dBi.

   (3) For the band 5.725-5.825 GHz, the maximum conducted output power
   over the frequency band of operation shall not exceed the lesser of 1 W
   or 17 dBm + 10 log B, where B is the 26-dB emission bandwidth in MHz.
   In addition, the peak power spectral density shall not exceed 17 dBm in
   any 1-MHz band. If transmitting antennas of directional gain greater
   than 6 dBi are used, both the maximum conducted output power and the
   peak power spectral density shall be reduced by the amount in dB that
   the directional gain of the antenna exceeds 6 dBi. However, fixed
   point-to-point U-NII devices operating in this band may employ
   transmitting antennas with directional gain up to 23 dBi without any
   corresponding reduction in the transmitter peak output power or peak
   power spectral density. For fixed, point-to-point U-NII transmitters
   that employ a directional antenna gain greater than 23 dBi, a 1 dB
   reduction in peak transmitter power and peak power spectral density for
   each 1 dB of antenna gain in excess of 23 dBi would be required. Fixed,
   point-to-point operations exclude the use of point-to-multipoint
   systems, omnidirectional applications, and multiple collocated
   transmitters transmitting the same information. The operator of the
   U-NII device, or if the equipment is professionally installed, the
   installer, is responsible for ensuring that systems employing high gain
   directional antennas are used exclusively for fixed, point-to-point
   operations.

   Note to paragraph ( a )(3): The Commission strongly recommends that
   parties employing U-NII devices to provide critical communications
   services should determine if there are any nearby Government radar
   systems that could affect their operation.

   (4) The maximum conducted output power must be measured over any
   interval of continuous transmission using instrumentation calibrated in
   terms of an rms-equivalent voltage. The measurement results shall be
   properly adjusted for any instrument limitations, such as detector
   response times, limited resolution bandwidth capability when compared
   to the emission bandwidth, sensitivity, etc., so as to obtain a true
   peak measurement conforming to the above definitions for the emission
   in question.

   (5) The peak power spectral density is measured as a conducted emission
   by direct connection of a calibrated test instrument to the equipment
   under test. If the device cannot be connected directly, alternative
   techniques acceptable to the Commission may be used. Measurements are
   made over a bandwidth of 1 MHz or the 26 dB emission bandwidth of the
   device, whichever is less. A resolution bandwidth less than the
   measurement bandwidth can be used, provided that the measured power is
   integrated to show total power over the measurement bandwidth. If the
   resolution bandwidth is approximately equal to the measurement
   bandwidth, and much less than the emission bandwidth of the equipment
   under test, the measured results shall be corrected to account for any
   difference between the resolution bandwidth of the test instrument and
   its actual noise bandwidth.

   (6) The ratio of the peak excursion of the modulation envelope
   (measured using a peak hold function) to the maximum conducted output
   power (measured as specified above) shall not exceed 13 dB across any 1
   MHz bandwidth or the emission bandwidth whichever is less.

   (b) Undesirable emission limits: Except as shown in paragraph (b)(6) of
   this section, the peak emissions outside of the frequency bands of
   operation shall be attenuated in accordance with the following limits:

   (1) For transmitters operating in the 5.15-5.25 GHz band: all emissions
   outside of the 5.15-5.35 GHz band shall not exceed an EIRP of -27
   dBm/MHz.

   (2) For transmitters operating in the 5.25-5.35 GHz band: all emissions
   outside of the 5.15-5.35 GHz band shall not exceed an EIRP of -27
   dBm/MHz. Devices operating in the 5.25-5.35 GHz band that generate
   emissions in the 5.15-5.25 GHz band must meet all applicable technical
   requirements for operation in the 5.15-5.25 GHz band (including indoor
   use) or alternatively meet an out-of-band emission EIRP limit of -27
   dBm/MHz in the 5.15-5.25 GHz band.

   (3) For transmitters operating in the 5.47-5.725 GHz band: all
   emissions outside of the 5.47-5.725 GHz band shall not exceed an EIRP
   of -27 dBm/MHz.

   (4) For transmitters operating in the 5.725-5.825 GHz band: all
   emissions within the frequency range from the band edge to 10 MHz above
   or below the band edge shall not exceed an EIRP of -17 dBm/MHz; for
   frequencies 10 MHz or greater above or below the band edge, emissions
   shall not exceed an EIRP of -27 dBm/MHz.

   (5) The emission measurements shall be performed using a minimum
   resolution bandwidth of 1 MHz. A lower resolution bandwidth may be
   employed near the band edge, when necessary, provided the measured
   energy is integrated to show the total power over 1 MHz.

   (6) Unwanted emissions below 1 GHz must comply with the general field
   strength limits set forth in §  15.209. Further, any U-NII devices
   using an AC power line are required to comply also with the conducted
   limits set forth in §  15.207.

   (7) The provisions of §  15.205 apply to intentional radiators
   operating under this section.

   (8) When measuring the emission limits, the nominal carrier frequency
   shall be adjusted as close to the upper and lower frequency block edges
   as the design of the equipment permits.

   (c) The device shall automatically discontinue transmission in case of
   either absence of information to transmit or operational failure. These
   provisions are not intended to preclude the transmission of control or
   signalling information or the use of repetitive codes used by certain
   digital technologies to complete frame or burst intervals. Applicants
   shall include in their application for equipment authorization a
   description of how this requirement is met.

   (d) [Reserved]

   (e) Within the 5.15-5.25 GHz band, U-NII devices will be restricted to
   indoor operations to reduce any potential for harmful interference to
   co-channel MSS operations.

   (f) U-NII devices are subject to the radio frequency radiation exposure
   requirements specified in §  1.1307(b), §  2.1091 and §  2.1093 of this
   chapter, as appropriate. All equipment shall be considered to operate
   in a "general population/uncontrolled" environment. Applications for
   equipment authorization of devices operating under this section must
   contain a statement confirming compliance with these requirements for
   both fundamental emissions and unwanted emissions. Technical
   information showing the basis for this statement must be submitted to
   the Commission upon request.

   (g) Manufacturers of U-NII devices are responsible for ensuring
   frequency stability such that an emission is maintained within the band
   of operation under all conditions of normal operation as specified in
   the users manual.

   (h) Transmit Power Control (TPC) and Dynamic Frequency Selection (DFS).

   (1) Transmit power control (TPC). U-NII devices operating in the
   5.25-5.35 GHz band and the 5.47-5.725 GHz band shall employ a TPC
   mechanism. The U-NII device is required to have the capability to
   operate at least 6 dB below the mean EIRP value of 30 dBm. A TPC
   mechanism is not required for systems with an e.i.r.p. of less than 500
   mW.

   (2) Radar Detection Function of Dynamic Frequency Selection (DFS).
   U-NII devices operating in the 5.25-5.35 GHz and 5.47-5.725 GHz bands
   shall employ a DFS radar detection mechanism to detect the presence of
   radar systems and to avoid co-channel operation with radar systems. The
   minimum DFS detection threshold for devices with a maximum e.i.r.p. of
   200 mW to 1 W is -64 dBm. For devices that operate with less than 200
   mW e.i.r.p. the minimum detection threshold is -62 dBm. The detection
   threshold is the received power averaged over 1 microsecond referenced
   to a 0 dBi antenna. The DFS process shall be required to provide a
   uniform spreading of the loading over all the available channels.

   (i) Operational Modes. The DFS requirement applies to the following
   operational modes:

   (A) The requirement for channel availability check time applies in the
   master operational mode.

   (B) The requirement for channel move time applies in both the master
   and slave operational modes.

   (ii) Channel Availability Check Time. A U-NII device shall check if
   there is a radar system already operating on the channel before it can
   initiate a transmission on a channel and when it has to move to a new
   channel. The U-NII device may start using the channel if no radar
   signal with a power level greater than the interference threshold
   values listed in paragraph (h)(2) of this part, is detected within 60
   seconds.

   (iii) Channel Move Time. After a radar's presence is detected, all
   transmissions shall cease on the operating channel within 10 seconds.
   Transmissions during this period shall consist of normal traffic for a
   maximum of 200 ms after detection of the radar signal. In addition,
   intermittent management and control signals can be sent during the
   remaining time to facilitate vacating the operating channel.

   (iv) Non-occupancy Period. A channel that has been flagged as
   containing a radar system, either by a channel availability check or
   in-service monitoring, is subject to a non-occupancy period of at least
   30 minutes. The non-occupancy period starts at the time when the radar
   system is detected.

   [ 63 FR 40836 , July 31, 1998, as amended at  69 FR 2687 , Jan. 20, 2004;
    69 FR 54036 , Sept. 7, 2004]

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Subpart F--Ultra-Wideband Operation

   Source:  67 FR 34856 , May 16, 2002, unless otherwise noted.

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