Sec.  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  Sec. 15.209. Further, any U-NII devices using an AC
   power line are required to comply also with the conducted limits set forth
   in  Sec. 15.207.

   (7) The provisions of  Sec. 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  Sec. 1.1307(b),  Sec. 2.1091 and  Sec. 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]

Subpart F—Ultra-Wideband Operation

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