|The Federal Communications Commission (FCC) is the authority
in the United States of America that creates and enforces the use of airwaves throughout the entire
radio frequency spectrum. This group of documents contains the entirety of the
FCC Part 15 regulations
that concern unlicensed radio frequency devices. As with all government documents, this material
is in the public domain and may be freely copied so long as the content is not changed. This copy
is provided as a convenience for RF Cafe visitors.
Click here for the
Table of Contents.
[Code of Federal Regulations]
[Title 47, Volume 1]
[Revised as of October 1, 2008]
From the U.S. Government Printing Office via GPO Access
CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION
PART 15_RADIO FREQUENCY DEVICES--Table of Contents
Subpart E_Unlicensed National Information Infrastructure Devices
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
(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
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
(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
(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.
(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
(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 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]