Goto Section: 15.405 | 15.501 | Table of Contents
Revised as of October 1, 2009
Goto Year:2008 |
§ 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
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
(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
(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.
(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
(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
(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
(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.
Goto Section: 15.405 | 15.501
Goto Year: 2008 |
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