[Federal Register Volume 85, Number 101 (Tuesday, May 26, 2020)]
[Rules and Regulations]
[Pages 31390-31414]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-11236]
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FEDERAL COMMUNICATIONS COMMISSION
47 CFR Parts 0 and 15
[ET Docket No. 18-295 and GN Docket No. 17-183; FCC 20-51; FRS 16729]
Unlicensed Use of the 6 GHz Band
AGENCY: Federal Communications Commission.
ACTION: Final rule.
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SUMMARY: In this document, the Commission adopts rules designed to
optimize unlicensed access by authorizing two types of unlicensed
operations in the 6 GHz band while also protecting incumbent services
so that they continue to thrive in the band. The Commission is
authorizing unlicensed standard-power access points that will operate
under the control of an automated frequency coordination system in
portions of the 6 GHz band. The Commission is also opening the entire 6
GHz band for unlicensed indoor low power access points. In addition,
the Commission will permit unlicensed client devices to communicate
with both the standard-power and low-power access points. These rules
will provide opportunities for unlicensed operations to use up to 320-
megahertz channels to expand capacity and increase performance. This
forward-looking action anticipates the next generation of the
unlicensed devices and advances the U.S.'s role as an innovator and
global spectrum policy leader.
DATES: Effective July 27, 2020.
ADDRESSES: Federal Communications Commission, 445 12th Street SW,
Washington, DC 20554.
FOR FURTHER INFORMATION CONTACT: Mr. Nicholas Oros of the Office of
Engineering and Technology, Policy and Rules Division, at (202) 418-
0636, or [email protected].
SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Report
and Order, ET Docket No. 18-295 and GN Docket No. 17-183, FCC 20-51,
adopted April 23, 2020 and released April 24, 2020. The full text of
this document is available for public inspection and copying during
normal business hours in the FCC Reference Center (Room CY-A257), 445
12th Street SW, Washington, DC 20554, or by downloading the text from
the Commission's website at https://www.fcc.gov/document/fcc-opens-6-ghz-band-wi-fi-and-other-unlicensed-uses-0. Alternative formats are
available for people with disabilities (Braille, large print,
electronic files, audio format) by sending an email to [email protected]
or calling the Commission's Consumer and Governmental Affairs Bureau at
(202) 418-0530 (voice), (202) 418-0432 (TTY).
Synopsis
Unlicensed Use of the 6 GHz Band
1. The Commission adopts rules designed to optimize unlicensed
access to the 6 GHz band while also protecting incumbent services so
that they continue to thrive in the band. In doing so, the Commission
accounts for the concerns raised by parties representing the various
incumbent services that operate in the 6 GHz band, weighs the various
technical studies presented by proponents of unlicensed operations as
well as representatives of incumbent services, and addresses how the
rules the Commission adopts will enable unlicensed operations to
operate in the 6 GHz band and protect the various incumbent services
that operate in the band.
Standard-Power Operations in U-NII-5 and U-NII-7 Bands
2. The Commission adopts rules to permit standard power unlicensed
operations in the U-NII-5 (5.925-6.425 GHz) and U-NII-7 (6.525-6.875
GHz) bands to operate outdoors or indoors with similar power levels as
permitted for unlicensed portions of the 5 GHz band through use of an
automated frequency coordination (AFC) system to protect incumbent
fixed microwave operations from harmful interference. Specifically, the
Commission authorizes standard-power access points to operate in these
bands at power levels up to 36 dBm EIRP (PSD of 23 dBm/MHz EIRP), and
client devices to operate at up to 30 dBm EIRP (PSD of 17 dBm/MHz
EIRP). The rules the Commission adopts for these unlicensed device
operations will protect incumbent fixed microwave, radio astronomy, and
fixed-satellite operations, add much needed capacity to meet the
rapidly increasing demands of the wireless industry, and promote
innovation and investment in new wireless unlicensed technologies. To
protect incumbent fixed microwave operations from harmful interference,
unlicensed access to these bands is only permitted on frequencies and
locations determined by an AFC system based on the exclusion zones that
it establishes. The Commission also protects certain radio astronomy
observatories through the AFC system. Finally, in affirming the
Commission's tentative conclusion that the AFC system is not necessary
to protect incumbent fixed satellite service operations, the Commission
also adopts a restriction on unlicensed standard-power access point to
prevent them from pointing toward the space station receivers.
AFC-Based Access To Protect Fixed Microwave Services
3. Consistent with the framework proposed in the Notice, the AFC
mechanism, combined with the technical and operational rules that the
Commission adopts, will protect incumbent fixed microwave operations
from the potential of harmful interference from unlicensed standard-
power operations in the U-NII-5 and U-NII-7 bands. As noted by the
Commission, the use of an automated system to control access to
spectrum is not new. The Commission has previously used this approach
to protect television reception from unlicensed white space devices in
the TV bands and to protect satellite earth stations and government
radars from devices of the Citizens Broadband Radio Service in the
3550-3700 MHz band. A properly designed AFC system in the U-NII-5 and
U-NII-7 bands will protect incumbent operations, though they often
differ on particular design and features of that system.
4. The AFC-based system for permitting unlicensed standard power
operations in the 6 GHz bands will consist of several components which,
when taken together, will determine the specific exclusion zones that
will protect incumbent operations. These
[[Page 31391]]
components include (1) the framework, design, and operation of AFC
system; (2) the operational requirements that the Commission
establishes regarding standard-power access points (e.g., geolocation
capabilities, antenna-related restrictions); and (3) the interference
protection parameters that protect the incumbent fixed service
operations.
The AFC System Framework and Database
5. Centralized approach. The Commission requires the AFC to use a
centralized model where each standard-power access point remotely
accesses an AFC to obtain a list of available frequency ranges in which
it is permitted to operate and the maximum permissible power in each
frequency range. This is consistent with the centralized model the
Commission has employed in other contexts, will facilitate Commission
oversight of AFC operations, and reduces design complexity. Because the
Commission is concerned that allowing both architectures (centralized
and de-centralized) could create problematic or unforeseen
complications in operational management of AFC systems and devices and
thereby could delay unlicensed deployment in this band, it declines to
permit use of a dual AFC architecture as some parties have suggested.
6. Use of ULS for information on incumbent operations. the
Commission requires that the AFC system rely on the Commission's
Universal Licensing System (ULS) for fixed microwave link data when
calculating and establishing the exclusion zones to protect those
microwave links from harmful interference. The ULS is the official
licensing database for microwave links in the U-NII-5 and U-NII-7 bands
and contains extensive technical data for site-based licenses including
transmitter and receiver locations, frequencies, bandwidths,
polarizations, transmitter EIRP, antenna height, and the make and model
of the antenna and equipment used. Thus, the ULS contains the
information necessary for AFC systems to protect fixed service links.
To ensure that AFC systems have the most recent information on fixed
service links, the Commission requires AFC systems to download the
database on a daily basis.
7. The Commission recognizes the concerns of some parties that
information used by the AFC systems must be accurate and up-to-date,
and notes that there may currently be some inaccurate or incomplete
data in the ULS database. Because ULS is the official Commission
compendium of license records, licensees are obligated under the terms
of their licenses to keep their information filed with the Commission
current and complete. Thus, licensees have the responsibility, as well
as significant incentive, to maintain the continued accuracy of data in
the ULS to ensure that they are protected from harmful interference not
only from new unlicensed devices, but also from new fixed microwave
links that may access the band. To the extent licensees determine that
their actual operations differ from the Commission's licensing records,
they should modify those records to ensure they are properly protected
from harmful interference from any other spectrum users, and the
Commission directs the Wireless Telecommunications Bureau to issue a
public notice reminding such licensees of the importance of maintaining
accurate information in that system.
8. Microwave links may begin operation prior to obtaining a license
so long as certain criteria are met, such as completing successful
frequency coordination and filing an application that appears in the
ULS as pending. Because such a filing may indicate that a new station
is operational, or soon will be, the Commission requires the AFC system
to protect pending as well as granted facilities. In addition,
temporary fixed microwave links may be authorized by a blanket
authorization, in which case the licensee is not required to obtain
approval from the Commission prior to operating at specific locations
or report the technical details of their operation to the Commission.
Because the AFC system must have knowledge of the location of temporary
fixed links in order to protect them from harmful interference, the
Commission requires the operators of temporary fixed stations to
register the details of their operations (transmitter and receiver
location, antenna height, antenna azimuth, antenna make and model,
etc.) in the ULS prior to transmission if they desire to be protected
from potentially receiving harmful interference from standard-power
access points in the U-NII-5 and U-NII-7 bands. The capability to
register temporary fixed links does not currently exist in the ULS.
That functionality will be announced by Public Notice once developed.
Because temporary fixed links are not mobile and intended to operate at
a specified location for up to a year, the Commission does not believe
this registration requirement poses a significant burden on licensees.
9. Information on microwave operations in border areas near Canada
and Mexico. As required by international agreements, and consistent
with actions regarding white spaces and the CBRS, the Commission
requires the AFC to protect microwave operations in Canada and Mexico
near the United States border. The Commission recognizes that the ULS
does not contain information on microwave operations in these
countries. The Commission therefore intends to work with the
governments of Canada and Mexico to obtain information on microwave
systems in those countries and a method for providing it to AFC
operators for incorporation into their systems.
10. Information on location and antenna height of standard-power
access points. The AFC system also will make use of data concerning the
location and antenna height of standard-power access points when
calculating the availability of frequencies and channels of operations.
The Commission establishes particular operational requirements for
access points that ensure the accuracy of this data.
11. Use of specified interference protection parameters. The AFC
system will apply the specified interference protection parameters
established in this Order to protect fixed microwave operations from
harmful interference. These include use of specified propagation models
and a conservative interference protection criterion when calculating
exclusion zones, and the methodology for addressing adjacent channel
operations.
12. Determining frequency and channel availability based on
unlicensed device power levels. The Commission requires that the AFC
have the capability to determine frequency availability at the maximum
permissible power of 36 dBm for standard-power access points, as well
as at lower power levels. Because the minimum required separation
distance from a fixed service receiver, among other factors, is a
function of the access point power, lower power devices do not have to
meet as large a separation distance to provide the same level of
protection as higher power devices. This means that more spectrum may
be available for access points that operate with power levels below the
maximum, especially in congested areas where spectrum is more heavily
used by the fixed microwave services. This action is consistent with
the Commission's white space rules in which white space devices
operating at power levels less than the maximum have shorter required
separation distances from protected services, and the white space
database provides devices with a list of
[[Page 31392]]
available frequencies and the maximum permissible power on each.
13. The Commission requires that the AFC system be capable of
determining frequency availability in steps of no greater than 3 dB
below the maximum 36 dBm permissible EIRP, down to a minimum level of
21 dBm. The Commission believes 3 dB is an appropriate step size
because it is large enough to be significant (i.e. a factor of two) and
will allow the AFC to determine frequency availability at multiple
power levels so a device can select its optimum frequency and power
level combination. The Commission's requirement that an AFC only
consider power levels as low as 21 dBm is predicated on the expectation
that outdoor access points will generally operate at the higher power
levels to maximize coverage area or throughput or both. However,
because certain situations or applications may not need that much
power, there may be a need for AFCs to evaluate additional power
levels. The Commission will not preclude AFC operators from determining
frequency availability at additional power levels, e.g., below 21 dBm
or in smaller step sizes; it simply establishes minimum AFC performance
requirements. Consistent with the white space rules, the AFC will
provide a list of available frequencies and power levels to standard-
power access points but will not select the frequency or control the
power level of a device. Rather, each access point will select its
operating frequency and power level from the list provided by the AFC.
Operational Requirements for Access Points
14. The AFC system requires a device's geographic coordinates--
along with the accuracy of those coordinates--and the device's antenna
height above ground, in order to determine which frequencies are
available for use at its location.
15. Incorporated geo-location. The Commission requires all
standard-power access points to include a geo-location capability to
determine their geographic coordinates, rather than relying on a
professional installer to determine them. Additionally, an incorporated
geo-location capability provides a means for a device to automatically
re-establish its coordinates if they are lost or altered due to a power
outage or equipment reboot.
16. The Commission requires a device's geo-location capability to
determine its location uncertainty and report it to the AFC system,
which will use this information to determine the minimum required
separation distances from fixed service receivers. The Commission also
requires that it be determined, in meters, with 95% confidence level,
which is consistent with the rules for white space devices which
operate with similar geo-location requirements to those the Commission
adopts for AFC controlled standard-power access points. The
Commission's experiences with this rule confirms that it reliably
ensures protection against harmful interference, at reasonable cost.
17. The Commission recognizes that geo-location technologies such
as GPS do not work at locations where satellite signals are blocked by
obstructions such as tall buildings and trees, or deep within
buildings. To ensure that standard power access points can accurately
determine their coordinates and provide them to the AFC in these
situations, without the need for professional installation, the
Commission provides additional flexibility for manufacturers and device
operators by making provisions for standard-power access points that
operate in locations where an incorporated geo-location capability may
not work. The Commission allows standard-power access points to obtain
their geographic coordinates through an external geo-location source
when they are used at locations where an internal geo-location
capability does not function. The Commission also allows an external
geo-location source to be connected to an access point through either a
wired or a wireless connection and will allow a single geo-location
source to provide location information to multiple access points. The
Commission requires that an external geo-location source be connected
to an access point using a secure connection to ensure that only an
external geo-location source approved for use with a device provides
geographic coordinates to that device. Additionally, the Commission
allows the use of extender cables to connect a remote receive antenna
to a geo-location receiver within a fixed device. In cases where
equipment uses a remote geo-location source, the separation distance
between the access point transmit antenna and geo-location source must
be included in the location uncertainty reported to the AFC system.
This requirement will be enforced through the equipment certification
process. Based on the Commission's experience, it believes these
provisions will increase the manufacturers' flexibility to develop
devices that can be used in a wide variety of locations while ensuring
that devices accurately determine their location and report it to the
AFC to prevent harmful interference to protected services.
18. Considering the geo-location requirements, the Commission is
not requiring professional installation. It is not necessary because
manufacturers can incorporate a variety of location technologies into
their devices; many of these, such as GPS, are widely available at low
cost. Further, requiring professional installation of all standard-
power access points would be burdensome and that requiring devices to
incorporate automatic geo-location will ensure that the information
provided to the AFC system is accurate.
19. Antenna height above ground. For the AFC to accurately
calculate exclusion zones to protect fixed service receivers, it
requires the antenna height above ground of a standard-power access
point. Consistent with the rules for white space devices, the
Commission permits this information to be provided to the AFC either
automatically by the device, or manually by the installer or operator
of the device but does not require it to be determined by a
professional installer.
20. Because automated geo-location methods such as GPS may not
accurately provide height information in all cases, the Commission
allows a device installer to manually determine the antenna height
above ground and provide it to the AFC. As the Commission notes with
respect to white space devices, installers with simple measuring
equipment should be able to accurately determine antenna height above
ground. However, because improvements in technology in the future could
enable devices to automatically determine their antenna height above
ground with more precision, there is also the option for standard-power
access points to automatically do so. Industry groups are expected to
work on developing methods for automatic height determination that
could be used for standard-power access points or other applications
where the antenna height above ground must be known.
21. Frequency availability re-check interval. The Commission
requires a standard-power access point to contact an AFC system at
least once per day to obtain the latest list of available frequencies
at its location. Once per day is an appropriate re-check interval
because the ULS, from which the AFC system will obtain data, is updated
on a daily basis. The Commission disagrees with suggestions that of a
30-day re-check interval be instituted. While the likelihood is low
that a new microwave link will become operational on any given day at a
given location, when 6
[[Page 31393]]
GHz devices are widely deployed there will be situations where new
microwave links are licensed in the vicinity of co-channel standard-
power access points. To ensure that an unlicensed device quickly ceases
operation on a frequency that becomes licensed for a microwave link
near its location, standard-power access points are required to re-
check their frequency availability on a daily basis, i.e., the same as
the ULS update interval.
22. The Commission recognizes that there may be situations when an
AFC system is temporarily unavailable due to a sustained power loss, an
internet outage, or other circumstances that disrupt a device's ability
to contact an AFC system. Consistent with the Commission's actions in
other proceedings, an access point that cannot contact the AFC system
during any given day is permitted to continue operating until 11:59
p.m. of the following day at which time it must cease operations until
it re-establishes contact with the AFC system and re-verifies its list
of available frequencies. The Commission does not believe that ais one-
day grace period is not likely to result in harmful interference to
fixed service links because an access point being unable to contact the
AFC system for a day is likely to be a relatively infrequent
occurrence, and the probability that it will occur at the same time in
the same place where a new microwave link commences operation is low.
Designating AFC Operators
23. Operator approval and system certification process. Consistent
with the Commission's actions regarding white spaces and the CBRS, the
Commission directs the Chief of the Office of Engineering and
Technology (OET) to designate AFC system operators and oversee
operation of their systems.
24. OET will designate AFC operators using a multi-stage review
process similar to that it used for designating white space database
and SAS administrators. As the first step, OET will issue a public
notice inviting prospective AFC system operators to submit proposals
describing how their systems would comply with all Commission AFC
rules. The public will have an opportunity to review and comment on
these AFC system proposals. OET will conditionally approve applicants
that demonstrate that their proposed systems would comply with all AFC
requirements. Applicants that receive a conditional approval will then
be required to provide a test system that will be subject to a public
trial period to provide interested parties an opportunity to check that
it provides accurate results. This trial period will include thorough
testing, both in a controlled environment (e.g., lab testing) and
through demonstration projects (e.g., field testing).
25. The Commission encourages formation of a multi-stakeholder
group that will address issues specific to technical and operational
issues associated with the AFC system, and intends to work with
industry stakeholder groups as necessary to develop appropriate
procedures for thoroughly testing AFC systems prior to use. The
Commission will not grant final approval for an AFC system operator to
begin providing service until after the operator satisfactorily
demonstrates that standard-power access points can operate under the
control of its system without causing harmful interference to fixed
wireless services.
26. Multiple AFC Operators. As proposed in the Notice and
consistent with commenters' support and existing rules for white spaces
and CBRS multiple AFC operators may be designated. As the Commission
previously noted in regard to white spaces databases, this would
prevent a single party from obtaining monopoly control over the AFC
systems, could provide an incentive for AFC system operators to provide
additional services beyond those required by the rules, and is more
likely to result in lower costs to consumers.
27. The Commission permits AFC functions, such as a data
repository, registration, and query services, to be split among
multiple entities, as is done for white spaces and the CBRS. No parties
commented on this specific issue. This approach will allow greater
flexibility in AFC system design and potential cost savings by allowing
multiple operators to share the costs of running parts of an AFC
systems. However, to ensure that the Commission can effectively oversee
the AFC system operation, it requires that entities designated as AFC
system operators be held accountable for all aspects of system
administration, including any functions performed by third parties.
28. Term of AFC Designation. To ensure a stable operating
environment for standard-power access points and consistent with both
the white space and CBRS rules, the Commission adopts a five-year term
which, at the Commission's discretion, may be renewed. Similar to the
requirements for the white space database and SAS administrators, in
the event an AFC system operator does not wish to continue to provide
services, or if its term is not renewed, the system operator will be
required to transfer its database along with the information necessary
to access the database to another designated AFC system and will be
permitted to charge a reasonable fee for the transfer of this
information. Transferring this information assures operational
continuity for existing devices; otherwise in the event an AFC
discontinues service, devices would be denied operating frequencies and
cut-off from providing services until it established a connection to a
new database. This action allows that new connection to occur
automatically.
29. The Commission disagrees that it would be burdensome for an AFC
operator to transfer its registration data to another AFC system
operator since the data that must be transferred (e.g., location,
antenna height, device FCC ID and serial number) is relatively simple.
The Commission also adopts the proposal that an AFC system operator
must provide a minimum of 30 days' notice to the Commission when it
plans to cease operation. Because standard-power access points must be
able to access an AFC in order to operate, the Commission does not
believe that the it should designate AFC system operators that could
cease operation at any time with no notice as that could leave users
with equipment that ceases operating unexpectedly.
30. Fees. Consistent with the rules for white space database and
CBRS SAS administrators and as supported in the record, the Commission
permits AFC operators to charge fees for the provision of service.
Because the Commission is allowing multiple AFC operators to be
designated, the Commission believes that competition among them will
serve to keep fees reasonable and will allow for multiple business
models that could benefit consumers, e.g., device manufacturers or a
trade association could fund an AFC system as part of its business and
no individual transaction fees would be charged. However, as with white
space databases and the CBRS SAS, the Commission permits parties to
petition the Commission to review fees and require changes to the fees
if they are found to be excessive.
31. AFC to AFC synchronization requirements. The Commission
concludes that, under the AFC system, there is no need to require AFC
systems to synchronize their data with each other. Unlike white space
database systems that must accept and share registration information
from protected entities, e.g., cable headends and
[[Page 31394]]
licensed wireless microphone operators, that cannot be obtained from
Commission databases, AFC systems will obtain their data on protected
entities from a single source (the ULS). Therefore, there will be no
need for AFC operators to synchronize protected entity information
between different systems as NAB suggests. Additionally, because the
Commission is not requiring AFC systems to consider aggregate
interference from multiple standard-power access points when
determining frequency availability, there is no need for the AFC
systems to share information about registered standard-power access
points.
Interference Protection Analyses and Parameters
32. The Commission protects fixed microwave operations from harmful
interference by using an AFC system that establishes location and
frequency-based exclusion zones for standard-power unlicensed devices
around fixed microwave receivers operating in the U-NII-5 and U-NII-7
bands. Under this AFC system, individual unlicensed devices will not be
permitted to operate on certain frequencies within the exclusion zone.
Below, the Commission discusses technical parameters that the AFC
system will use to calculate these exclusion zones.
33. Propagation models. Evaluating potential harmful interference
from U-NII-5 and U-NII-7 unlicensed standard-power access point devices
depend on the propagation models assumed for both fixed microwave
signals and unlicensed devices. The propagation model that the
Commission adopts will, in turn, be used by the AFC system as one of
the factors when determining the exclusion zones.
34. The Commission believes an approach which combines different
propagation models is most appropriate for evaluating necessary
separation distances of 6 GHz unlicensed devices from fixed microwave
links. More specifically, because propagation models have been
developed to accommodate a variety of environments and over various
distances, the Commission finds that using a combination of models
optimized for the varying propagation conditions that will be
encountered is the best way to balance unlicensed device access and
incumbent protection in the 6 GHz band. That is, it is most appropriate
to use a set of propagation models keyed to specific separation
distances between an unlicensed device and a fixed service receiver to
determine appropriate exclusion zone size. Under this approach, the
Commission uses the free-space model for short distances, where it
accurately predicts signal path loss, the WINNER II for medium
distances, and the Irregular Terrain Model (ITM) for longer distances
to more realistically account for terrain and clutter losses.
35. Under our general approach, the Commission finds that for
separation distances of 30 meters or less, the free space pathloss
model is the appropriate model. Commenters generally assumed that 6 GHz
unlicensed devices would not be placed within 30 meters of a microwave
receiver and thus, did not suggest a propagation model for such short
distances. Because, the potential for a direct line-of-sight between an
unlicensed device and a microwave receiver is greatest at short
distances, the Commission adopts the free space pathloss model for
distances less than 30 meters. This model generates the greatest
possible path loss to account for the possibility of direct line-of-
sight from a standard-power access point to a microwave receiver. The
free space pathloss model though theoretically simple, has a limited
range of applicability because it ignores environmental clutter and
over long distances can result in extremely conservative calculations
that under predict the amount of actual path loss.
36. Incumbents generally recommend use of free space propagation
model for all separation distances regardless of environment, while
proponents of unlicensed operations advocate use of a combination of
propagation models that specifically consider the propagation
environment. Beyond 30 meters and up to one kilometer from an
unlicensed device to a microwave receiver, the Commission finds that
the most appropriate propagation model is the Wireless World Initiative
New Radio phase II (WINNER II) model for urban, suburban, and rural
environments. At these distances, the WINNER II model accounts for
obstructions by urban and suburban clutter, which the free space model
does not. The Commission makes this decision recognizing that the
WINNER II model is one of the most widely used and well-known channel
models in the world and was developed from measurements conducted by
the WINNER organization, as well as results from academic literature
and used by several commenters for analyses submitted to the record.
The Commission requires the use of site-specific information, including
buildings and terrain data, for determining the line-of-sight/non-line-
of-sight path component in the WINNER II model where this information
is available. For evaluating paths where this data is not available,
the Commission requires probabilistic combining of the line-of-sight
and non-line-of-sight path into a single path-loss. When site-specific
information regarding line-of-sight/non-line-of-sight is not available
then path losses of line-of-sight(LOS) and non-line-of-sight(NLOS)
paths can be combined into a single loss using the following formula:
Path-loss (L) = [Sigma]i P(i) * Li =
PLOS * LLOS + PNLOS *
LNLOS, where PLOS is the probability of line-of-
sight, LLOS is the line-of-sight path loss, PNLOS
is the probability of non-line-of sight, LNLOS is the non-
line-of-sight path loss, and L is the combined path loss. The WINNER II
path loss models include a formula to determine PLOS as a
function of antenna heights and distance. PNLOS is equal to
(1-PLOS). Using the WINNER II propagation model for these
separation distances will provide the best prediction of actual
pathloss between unlicensed devices and fixed service receivers as it
accounts for environmental information not considered in the free space
model.
37. The Irregular Terrain Model is a propagation model that
specifically takes into account the effects of terrain on radio
propagation but does not include clutter losses. The model accounts for
transmission loss relative to free space loss for distances between 1
km and 2,000 km. For separation distances greater than one kilometer,
commenters suggest that the Irregular Terrain Model combined with a
clutter model depending on the environment is the most appropriate
model. The Commission agrees. Consistent with Commission use of
propagation models in other proceedings, the Commission requires use of
1 arc-second digital elevation terrain data and, for locations where
such data is not available, the Commission requires use of the most
granular digital elevation terrain data available. To account for the
effects of clutter, such as from buildings and foliage, the Commission
requires that the Irregular Terrain Model be combined with a
statistical clutter model ITU-R P.2108 for urban and suburban
environments, and ITU-R P.452-16 clutter model for rural environments.
The appropriate clutter category that most closely represents the local
morphology should be selected when using ITU-R P.452-16. However, if
detailed local information is not available, the Commission believes
the ``Village Centre'' clutter category should be used as a default
because access points will generally be installed in or on buildings
(i.e., in a village) and this category most closely represents that
morphology. The Commission specifies
[[Page 31395]]
the Irregular Terrain Model because it has been widely available and
accepted since the early 1980s, has been used by the Commission for
interference prediction in other proceedings, is supported by the
record, and in its experience has served reliably as a propagation
model. The Irregular Terrain Model is the propagation model currently
used to determine spectrum availability in the spectrum access systems
(SAS) used to manage access to the 3550-3700 MHz band in the Citizens
Broadband Radio Service.
38. Interference protection criterion. The Commission requires the
prescribed AFC system to use an I/N metric rather than C/I for
determining the exclusion zones. The I/N ratio was used by most
commenters in their analyses as the interference protection metric and
is more straightforward to implement, and thus is more consistent with
one of our major goals for the AFC system--simplicity of
implementation. Use of a C/I ratio would entail additional
implementation complexities. In particular, calculating the C/I ratio
would require calculating the power arriving at the microwave receiver
from its corresponding transmitter in addition to estimating the signal
level from the access point. This would require knowledge of the
microwave link characteristics including the instantaneous transmitted
power as well as the modulation and coding scheme used, which is
information that is not available in ULS.
39. As for the specific interference protection criterion, the
Commission specifies a I/N of -6 dB I/N. By specifying that AFC
exclusion zone calculations will be based on this particular
interference protection criterion, the Commission is taking a
conservative approach to ensure that the potential for harmful
interference is minimized and important fixed microwave services in the
6 GHz band are protected. The Commission is not, however making a
determination that any signal received with an I/N greater than -6 dB
would constitute ``harmful interference.'' No commenter provides
technical justification for using a particular I/N level as the actual
level necessary to protect fixed microwave receivers against harmful
interference. In determining to apply -6 dB I/N as the interference
protection criterion, the Commission does not find the need to
establish a specific industry multi-stakeholder group to establish the
appropriate metric on this issue, as some have suggested.
40. Aggregate interference. The Commission did not propose nor find
that there is any need to consider the effect of aggregate interference
from multiple access points to point-to-point microwave links. The risk
of interference from large numbers of standard power access points
would not be due to signal aggregation from multiple unlicensed
devices, but from a single standard-power access point in or near the
main beam of a microwave link receive antenna with little or no
intervening clutter. In the event that two or more access points could
cause interference to the same microwave receiver, the signal from the
nearest would dominate over the others and make the others irrelevant
to the analysis. The Commission does not require the AFC to consider
aggregate interference when determining exclusion zones.
41. Adjacent channel protection. Although the Commission believes
that the risk of adjacent channel interference to fixed service
microwave receivers is low, the Commission takes a conservative
approach to enabling new unlicensed devices in the 6 GHz band. Thus, in
addition to the AFC calculating a co-channel exclusion zone, the
Commission also requires it to determine an adjacent channel exclusion
zone. The adjacent channel exclusion zone defines a zone under which
any standard power access point is prevented from operating adjacent to
an FS receiver within one-half channel bandwidth of the access point.
The Commission expects these adjacent channel zones will be small and
not significantly impact the amount of spectrum available to unlicensed
devices at any given location. Also, because the AFC will need to
calculate co-channel exclusion zones for all nearby fixed service
stations, the incremental burden to also calculate adjacent channel
exclusion zones should be minimal. To this end, the Commission requires
the AFC to determine an adjacent channel exclusion zone based on the
out-of-band emission mask the Commission adopts for unlicensed devices
which is designed to keep energy outside an unlicensed device's
operating channel to low levels and the same protection criterion used
to determine co-channel exclusion zones; that is the I/N ratio must be
calculated to be -6 dB or less. This requirement will protect fixed
microwave receivers from harmful interference due to unlicensed devices
out-of-band emissions.
Other AFC System Issues
42. Security Issues. The Commission requires that AFC systems and
standard-power access points employ protocols and procedures to ensure
that all communications and interactions between the AFC and standard-
power access points are accurate and secure and that unauthorized
parties cannot access or alter the database or the list of available
frequencies and power levels sent to an access point. These
requirements are similar to those adopted for the white space database
and the Citizens Broadband Radio Service spectrum access system.
43. The Commission is not mandating specific security models.
Instead, the Commission requires AFC system operators to use advanced
security standards and demonstrate that their systems contain
communication and information security features during the AFC system
certification process. These security protocols will be subject to the
Commission's review and approval. The Commission anticipates that an
industry-wide multi-stakeholder group will take the lead on this
process and develop security protocols that AFC administrators may
consider for their operation, subject to Commission review and
approval. The Commission also expects that security models will be
updated as needed to reflect state-of-the-art protection against new
security threats. The Commission will review any modifications or
updates in the security protocols AFC system operators or a multi-
stakeholder group proposes to implement.
44. AFC device registration. To further ensure the AFC ecosystem
integrity, the Commission requires standard-power access points to
register with the AFC system when requesting a list of available
operating frequencies and power levels. Although the Commission
recognizes that the AFC system would be simpler without a registration
requirement, device registration provides another layer of protection
by ensuring only authorized devices access the spectrum and by easing
the process of mitigating harmful interference if it occurs. Because
the registration information would be automatically provided by the
access point or network proxy to the AFC system, the registration
process will require little effort by the access point user.
45. To register, a standard-power access point will be required to
provide the AFC system--in addition to the technical information
described above with the device's FCC identifier (FCC ID), and its
serial number. Although the FCC ID or the access point's serial number
are not required to calculate frequency availability, the AFC will use
the information for two purposes. First, the information will be used
to authenticate the device, to ensure that no rogue devices are
operating in the
[[Page 31396]]
band. The AFC will verify the device's FCC ID by accessing the
Commission's Equipment Authorization System. The AFC can retrieve the
FCC IDs of certified standard-power access points from the Commission's
equipment authorization database using an Application Program Interface
(API) or another method and determine whether the FCC ID provided by a
device during registration is valid. Access to the equipment
authorization database and extracting FCC IDs is a process that is used
by the CBRS SAS and white space data administrators. Second, the
information will be used for interference mitigation and enforcement
purposes to identify the source if harmful interference were to occur.
In addition, the Commission requires that AFC systems have the capacity
to deny spectrum access to a particular registered standard-power
access point upon requests by the Commission, in the event of harmful
interference caused by a particular device or type of device. The
Commission also requires that AFC operators implement procedures to
respond to requests from Commission personnel for information stored or
maintained by the AFC, and that they establish and follow protocols to
comply with enforcement instructions from the Commission, including
discontinuance of access point operations in designated geographic
areas. These requirements ensure that the Commission is able to
ascertain the accuracy of information stored in the AFC, obtain
information necessary to enforce the Commission's rules, and ensure
that access points that do not comply with the rules are shut down in a
timely manner.
46. The Commission encourages formation of a multi-stakeholder
group that would include representatives of unlicensed equipment
manufacturers, equipment users and point-to-point microwave providers
to develop additional procedures to resolve interference concerns.
Regardless of the processes that stakeholders may develop for
addressing interference, consistent with statute the Commission is the
final arbiter regarding cases of harmful interference.
47. Individual standard-power access points will not be required to
interface with the AFC system if the required registration data is
communicated by a proxy device or network control device. The network
management device may be the point of interface with the AFC system for
multiple access points. In other words, the registration information
can be provided directly and individually by a single standard-power
access point or by a network proxy representing multiple devices
operating on the same network. The access point or its proxy must
register with the AFC system via any communication link, wired or
wireless, outside the U-NII-5 and U-NII-7 bands. The AFC system will
then communicate back a list of permissible frequency range(s) and the
maximum power in each range for standard-power access point operation.
In the case of a proxy, each access point must still provide its exact
location and will obtain a set of available frequencies for that
location.
48. The Commission requires the AFC system to store registered
information in a secure database until an access point ceases operation
at a location, which the Commission defines as a device not contacting
the AFC to verify frequency availability information for more than
three months. This requirement will ensure that the AFC database does
not become cluttered with entries for devices that are no longer being
used. To ensure the users' privacy, the AFC system will use the
registered data and any other access point operational information only
to protect incumbents and for potential interference mitigation.
Radio Astronomy Observatories
49. Incumbent operations in the U-NII-7 band include several radio
astronomy observatories, located in remote areas, that observe methanol
spectral lines between 6.6500-6.675.2 GHz. The Commission recognizes
the importance of these observations to the scientific community and
will adopt exclusion zones to protect them from interference over the
specified frequencies. In so doing, the Commission notes that there is
no radio astronomy allocation for these observations requiring that
they be protected from interference; the radio astronomy allocation
table footnote merely provides that ``all practicable steps shall be
taken to protect the radio astronomy service'' in this band from
harmful interference). As these observatories are located in remote
areas the Commission does not believe excluding standard-power access
points from this 25.2 megahertz of spectrum in these areas will be a
significant burden on unlicensed operations. The AFC system will
determine the size of the exclusion zones by the radio line-of-sight
distance between the radio astronomy antenna and the unlicensed access
point. The radio line-of-sight should be determined using \4/3\ earth
curvature using the following formula dkm_los = 4.12*(sqrt(Htx) +
sqrt(Hrx)), where Htx and Hrx are the heights of the unlicensed access
point and radio astronomy antenna in meters above ground level,
respectively.
Fixed-Satellite Services
50. The Commission adopts rules supporting the Commission's
tentative conclusion that the AFC system is not needed to protect
incumbent fixed-satellite operations from standard power access point
operations in the U-NII-5 and U-NII-7 bands. Considering that the
satellites receiving in these sub-bands are limited to geostationary
orbits, approximately 35,800 kilometers above the equator, the
Commission believes it unlikely that relatively low-power unlicensed
devices would cause harmful interference to the space station
receivers.
51. The Commission declines to adopt Intelsat and SES Americom's s
suggestion for an aggregate power limit from unlicensed devices to be
enforced though the use of the AFC systems. As a precautionary measure,
the Commission adopts a rule requiring outdoor standard-power access
points to limit the maximum EIRP above a 30 degree elevation angle to
21 dBm, which is similar to what the Commission requires in the U-NII-1
band to protect fixed satellite services. The Commission adopts this
restriction rather than an aggregate power limit for two reasons.
First, outdoor access points have no reason to radiate significant
power skyward, and so the Commission does not believe this requirement
will impose a burden on standard-power access point manufacturers and
users. Second, designing an AFC system to undertake aggregate power
limit monitoring would be very complex, requiring the AFC to know how
much energy is being emitted to each portion of the geostationary arc
for each unlicensed device. That in turn would require the AFC to have
knowledge of each outdoor access point's antenna pattern, orientation,
actual transmit power levels, and percent of the time it transmits as
well as similar information for unlicensed client devices operating
outdoors. Given the skyward EIRP restrictions the Commission is placing
on the AFC controlled outdoor unlicensed devices, the Commission see no
reason to require this level of complexity in the AFC systems.
Additional Issues
52. Authorizing standard-power access points to operate in the U-
NII-8 band. The Commission does not authorize standard-power access
points to operate in the lower 100-megahertz portion of the U-NII-8
band, which had been requested by some unlicensed
[[Page 31397]]
proponent. The Commission declines to do so for a number of reasons.
The U-NII-8 band is used by both fixed and mobile broadcast auxiliary
service services and the lower 25-megahertz portion of the band is
available for Low Power Auxiliary Stations operations such as licensed
wireless microphones. The geographic areas for these types of licensed
operations are specified in a variety of fashions, including point/
radius, countywide, statewide and nationwide. The AFC system would not
be able to allow standard-power access points to operate in the band
while protecting licensed operations without additional information on
their exact operating locations and times, and information on mobile
operations can change frequently. Even if licensees were to provide
additional operational information, this would increase the complexity
of the AFC system and its interactions with unlicensed devices, and
still may not adequately protect mobile operations. Accordingly, the
Commission is not authorizing standard-power access points to operate
in the lower 100 megahertz of the U-NII-8 band.
53. Adopting an ``inclusion zone'' approach. The Commission also
declines to adopt the suggested alternative to an AFC system. to permit
unlicensed devices to operate in an ``inclusion zone'' around microwave
transmitters. Under this approach, an applicant for a microwave license
would conduct coordination for both the licensed link and unlicensed
devices within the inclusion zone. In declining to adopt this approach,
the Commission notes that its proposal is nearly identical to the
concept of auxiliary stations, which the Commission considered as part
of the Wireless Backhaul proceeding. The auxiliary station proposal
contemplated placement of multiple lower power transmitters within the
signal pattern of a microwave link. These auxiliary stations would be
coordinated in advance of deployment and have secondary status. The
Commission rejects this proposal, one of the reasons being that the
proposal would create an incentive for microwave license applicants to
propose excessive power or use more diffuse antenna patterns for their
primary transmitters thereby precluding use of the spectrum by other
microwave operators.
Low-Power Indoor Operations Across the Entire 6 GHz Band
54. The Commission opens the entire 6 GHz band for unlicensed
indoor operations without the need for AFC-controlled access. By doing
so, the Commission creates new unlicensed use opportunities in these
bands--including optimizing the potential for deployment of next
generation Wi-Fi that makes use of 160 MHz channels--while protecting
the various incumbent licensed services in the band, including fixed
microwave services, various other fixed and mobile services, and fixed-
satellite services.
55. Because there will be no AFC system to prevent interference to
licensed services from occurring, the rules the Commission adopts three
restrictions designed to prevent harmful interference. Devices are: (1)
Limited to indoor operation; (2) required to use a contention-based
protocol; and (3) subject to low-power operation.
56. First, these low-power access points must operate only indoors.
The signals transmitted by these unlicensed devices will be
significantly attenuated when passing through the walls of buildings.
The median signal loss from a traditionally constructed building is 17
dB and newer, highly efficient buildings provide even higher signal
attenuation. No commenters disagreed with the ITU median signal loss
value for traditional construction. This attenuation is key to
providing the necessary signal reduction to prevent harmful
interference from occurring to incumbents.
57. Second, the Commission requires that the indoor low-power
devices, both access points and their associated client devices, employ
a contention-based protocol. A contention-based protocol allows
multiple users to share spectrum by providing a reasonable opportunity
for the different users to transmit. Because the weighted average
airtime utilization of Wi-Fi networks today is 0.4%, Wi-Fi devices
share spectrum using a contention-based protocol. For IEEE's 802.11, a
``listen-before talk'' medium access scheme based on the Carrier Sense
Multiple Access with Collision Avoidance (CSMA/CA) protocol functions
as a contention-based algorithm to provide access to all traffic.
Before initiating any packet delivery, a station listens to the
wireless medium and if the medium is idle, the station may transmit;
otherwise the station must wait until the current transmission is
complete before transmitting. To ensure efficient and cooperative
shared use of the spectrum, the Commission requires all unlicensed
indoor low power operations use technology that includes a contention-
based protocol.
58. In addition to providing equal access to the spectrum for
unlicensed devices, a contention-based protocol can also be used to
avoid co-frequency interference with other services sharing the band.
Thus, this requirement can be leveraged to facilitate spectrum sharing
with incumbent fixed and mobile services in the band. In addition,
requiring a contention-based protocol will limit the amount of time
that the low-power unlicensed device will transmit because of the need
to share the spectrum with other devices. This will limit the time
periods during which interference could potentially occur.
59. Third, the Commission limits the low-power indoor access points
to lower power levels than the standard-power access points that
operate under the control of an AFC. Consistent with the Commission's
approach for the existing U-NII bands, the Commission specifies both a
maximum power spectral density and an absolute maximum transmit power,
both in terms of EIRP. Specifically, the Commission allows a maximum
radiated power spectral density of 5 dBm per 1 megahertz and an
absolute maximum radiated channel power of 30 dBm for the maximum
permitted 320-megahertz channel (or 27 dBm for a 160-megahertz
channel). In addition, to ensure that client devices remain in close
proximity to the indoor access points, the Commission limits their PSD
and maximum transmit power to 6 dB below the power permitted for the
access points. In adopting these power levels in our rules, the
Commission authorizes indoor unlicensed devices with adequate power to
be useful to the public while also protecting the licensed services in
the 6 GHz band from harmful interference. In accordance with the record
developed in this proceeding, the Commission finds that this power
level meets these twin goals.
60. In the sections below, the Commission first discusses the
provisions adopting to keep these low-power access points indoors. The
Commission then discusses the technical parameters for indoor
unlicensed operations in this band--the power levels different parties
request, the rationale behind the power levels the Commission adopts
today, and how the technical filings in this proceeding support our
conclusion that the potential for harmful interference to incumbent
services operating in the 6 GHz band is insignificant. The Commission
then evaluates the probability of unlicensed devices causing harmful
interference to the incumbent services in the 6 GHz band--fixed
services, mobile services, FSS, and radio astronomy. The Commission
discusses the technical studies submitted to the record, most of which
employ different analysis methodologies with widely varying input
assumptions leading to divergent conclusions.
[[Page 31398]]
Certain studies are based on statistical simulations while others are
based on worst-case scenarios. In evaluating these studies, the
Commission discusses the methodologies and the underlying assumptions
regarding propagation models, building entry loss, antenna patterns,
height of unlicensed devices, activity factor and the bandwidth overlap
of incumbent and unlicensed services and the associated consequences
and conclusions.
Indoor Operations
61. The Commission first addresses measures designed to restrict
these operations to indoor use. Because building attenuation is a key
factor in minimizing the potential for harmful interference from indoor
low-power access points to licensees' receivers, the Commission adopts
reasonable and practical measures that will restrict low power access
points to indoor operations. Specifically, the Commission adopts three
equipment-related hardware requirements that are designed to keep these
low-power access points indoors. First, as suggested by Boeing, the
Commission requires that the access point devices cannot be weather
resistant. Second, the Commission requires that the low-power access
points have integrated antennas and prohibit the capability of
connecting other antennas to the devices, which will prevent
substituting higher gain directional antennas and make the devices less
capable or suitable for outdoor use. Third, the Commission prohibits
these low-power access points from operating on battery power.
Furthermore, the Commission requires that the access points be marketed
as ``for indoor use only'' and include a label attached to the
equipment stating that ``FCC regulations restrict to indoor use only.''
The Commission also requires that this statement be placed in the
device's user manual. This statement along with existing Commission
requirements for Part 15 equipment will inform consumers of the
appropriate use.
62. The Commission finds that these requirements will make outdoor
operations impractical and unsuitable, and disagree with those
commenters that suggest either that no requirements are needed or that
any requirements would be ineffective. The Commission declines to adopt
a suggestion to use GPS to determine whether a device is indoors.
Furthermore, the Commission is hesitant to require all devices to incur
the cost of incorporating a GPS capability given that the effectiveness
of this idea has not been demonstrated.
Power Spectral Density Limit
63. In determining the appropriate power spectral density for low
power indoor unlicensed devices in this band, the Commission has
carefully reviewed the studies submitted into the record by all
parties. Various analysis methodologies are used which fall into two
main categories: (i) Monte Carlo simulations, which take into account
probabilistic factors such as building entry loss, activity factor, and
co-channel probability, and (ii) static link budgets with limited
considerations of probabilistic dependencies. The studies submitted to
the record result in widely varying conclusions. While the studies
performed by the incumbents tend to assume worst case conditions and
ignore the very low probabilities associated with such worst-case
scenarios, the proponents of unlicensed usage tend to assume very low
probabilities for the activity factor and high building entry losses.
Other assumptions that vary between the models are building entry loss
and propagation loss, with incumbents generally assuming line of sight
free space propagation and unlicensed device proponents applying
industry standard models that either inherently include clutter loss or
treat such loss as an additive factor determined by a separate
statistical clutter model appropriate for the environment.
64. The Commission adopts a 5 dBm/MHz PSD. Based on our experience
with unlicensed operations and interference analyses as well as our
engineering judgment, the Commission finds that 5 dBm/MHz PSD will both
adequately protect all incumbents in the band from harmful interference
as well as offer enough power to unlicensed devices, commensurate with
the levels in the other U-NII bands, to sustain meaningful applications
especially when using wider bandwidths. At this power limit and with
the other constraints imposed on these operations, the risk of harmful
interference to incumbent operations is insignificant.
65. With respect to unlicensed client devices, the Commission
adopts the proposal and does not permit client devices to operate with
the same power spectral density as access points. The Commission finds
that client devices does not need the same power level due to the
asymmetrical nature of traffic. An additional margin of 6 dB will
provide protection to incumbents as client devices operate in the
vicinity of access points. Accordingly, the Commission concludes that
the appropriate maximum power spectral density for low power indoor
client devices in this band is 6 dB below the limit for access points
(or -1 dBm/MHz based on the adopted PSD limit).
Protecting Incumbent Operations
66. Fixed Microwave Service. The Commission finds that fixed
microwave receivers will be protected from harmful interference from
unlicensed indoor low power devices operating at the power levels the
Commission is authorizing. The Commission reaches this conclusion based
on the examination of two representative technical studies submitted to
the record. First, a Monte Carlo simulation submitted by CableLabs
provides a strong basis for reaching this conclusion. This study
assumes realistic operating conditions for both licensed incumbent
services and unlicensed operations. Second, a link budget analysis for
six particular cases submitted by AT&T illustrates that interference is
not likely to occur with the proposed power levels when realistic
assumptions are made regarding propagation losses and taking into
account the probabilistic nature of unlicensed transmissions. Because
these six cases represent microwave receiver/unlicensed device
geometries that are challenging from an interference perspective, the
results give us confidence that interference is unlikely to occur. The
Commission explains in more detail the numerous other technical filings
submitted and why they are not significant to the conclusion.
67. Among several technical studies submitted by advocates of
indoor low-power operations showing that the likelihood of interference
to fixed microwave receivers is extremely low, the Commission finds the
CableLabs study the most significant. These studies generally perform
Monte Carlo computer simulations that model a random deployment of low-
power unlicensed devices and calculate statistics on the likelihood of
interference occurring to microwave receivers. Advocates of indoor low-
power operations claim that fixed microwave links will not experience
harmful interference from the unlicensed devices.
68. In general, any technical study pertaining to spectrum sharing
should take into consideration the specific behavior of services
involved and the complexity of the propagation environment where the
services operate. Studies that focus on static link budgets, for
example, neglect the effects of the sporadic nature of most unlicensed
transmissions (activity factor) and the probability of co-channel
operation of
[[Page 31399]]
the unlicensed device and the licensed service (e.g., an 80-megahertz
unlicensed channel covers less than 7% of the 6 GHz band). These
factors reduce the probability of interference to the licensed service.
69. CableLabs submitted a technical study that models the
interference potential of low-power indoor unlicensed devices to
microwave receivers. This Monte Carlo simulation explores the potential
for interference to fixed links in the New York City area. The
simulation uses the WINNER II urban propagation model, the propagation
model the Commission adopts in this Report and Order for intermediate
distances for AFC systems (By intermediate distances the Commission is
referring to distances between 30 meters and 1 kilometer.). The
CableLabs study selects a building entry loss between 10 dB and 30 dB,
which is consistent with ITU recommendation P.2109. Furthermore, the
simulation uses a distribution of airtime utilization based on data
taken from 500,000 Wi-Fi access points to model how often each access
point in the simulation transmits. The simulations showed that the I/N
ratio is far below the conservative -6 dB I/N threshold. This is the
same -6 dB threshold that the Fixed Wireless Communications Coalition,
which represents the interest of the fixed microwave licensees, uses as
a threshold for protecting against harmful interference to fixed
microwave links.
70. The Commission finds the CableLabs' study persuasive because it
uses actual airtime utilization data for hundreds of thousands of Wi-Fi
access points along with a statistical model for building entry loss.
Rather than using a single average or median value to represent
building entry loss the CableLabs' study uses attenuation values drawn
from a probability distribution for each access point in the
simulation. In this way the simulation more accurately models the
variability of the building loss than using a single number for
building loss such as the median or average.
71. Wi-Fi is the predominant use of the U-NII bands, and is
ubiquitous in both residences and businesses. The Commission expects
that the majority of indoor unlicensed operations in the 6 GHz band
will be for Wi-Fi as well. Additionally, while the adopted rules do not
limit the activity factor, the Commission requires devices to use a
contention-based protocol which will prevent devices from transmitting
at extremely high duty cycles. For these reasons, the Commission finds
that the CableLabs study is the best evidence in the record of the
impact that unlicensed low-power indoor devices will have on incumbent
operations--and it demonstrates that such operations will not cause
harmful interference.
72. AT&T offered six scenarios where an unlicensed device operates
in close proximity to a fixed microwave receiver or where an unlicensed
device operates relatively far from the microwave receiver but the
terrain causes the unlicensed device to be in or close to the main
receiver beam.
73. AT&T's technical study attempts to overcome the limitation of
simple deterministic interference calculations by introducing a
probability distribution around building entry loss. AT&T claims that
their examples properly apply building entry loss by treating it as a
probabilistic quantity using the distribution from ITU-recommendation
P.2109 and that prior analyses have oversimplified building entry loss
into a single value. The Commisison concludes that this step does not
fully remedy the limitation of a static link budget analysis
limitations. Some of the most significant elements of the AT&T link
budgets are also probabilistic quantities. AT&T's link budget makes the
following assumptions: (a) An EIRP of 30 dBm in an 80 MHz channel (11
dBm/MHz); (b) the maximum unlicensed device EIRP is in the direction of
the microwave antenna; (c) free-space propagation for the interfering
signal; (d) zero clutter loss; (e) that an unlicensed device at the
specified location is capable of 6 GHz band operation and is operating
co-frequency with the microwave receiver; and (f) the unlicensed device
has a 100% duty cycle. Clearly, all of these parameters except for the
EIRP have an associated probability distributions that are missing from
AT&T's link budgets. For example, AT&T's use of a free-space
propagation model ignores clutter that often surrounds the transmitter
and receiver sites (and that may significantly reduce the risk of
harmful interference). Recognizing that each of these factors can take
on a range of values and that it is unlikely that each will be worst
case at the same time and location, the Commission finds that AT&T
overstates the potential for harmful interference.
74. The Commission presents a detailed comparison in Table 1 for
one of AT&T's examples (Example 2) The Commission does this because it
gives a more useful indication of unlicensed device signal levels than
only treating one factor in the calculation as a probabilistic quantity
as AT&T has done in their examples. By treating only the building entry
loss as a probabilistic quantity while not considering all the other
statistical quantities, AT&T's examples exaggerate the likelihood of
interference occurring.
Table 1--AT&T Example 2
----------------------------------------------------------------------------------------------------------------
AT&T Apple, Broadcom et al. FCC
----------------------------------------------------------------------------------------------------------------
EIRP/BW.............................. 30 dBm/80 MHz.......... 30 dBm/160 MHz......... 24 dBm/80 MHz.
PSD.................................. 11 dBm/MHz............. 8 dBm/MHz.............. 5 dBm/MHz.
Antenna Gain......................... 37.9 dB................ 37.9 dB................ 37.9 dB.
Antenna Discrimination............... -1.5 dB................ -2.538 dB.............. -1.5 dB.
RLAN/FS Antenna Mismatch............. 0 dB................... -5 dB.................. -5 dB.
Clutter.............................. 0 dB................... -25.00 dB.............. -18.4 dB (using ITU-R
P.452 clutter model).
Path Loss............................ -118.96 dB (free space) -118.92 dB (free space) -120.12 dB (ITM P2P
model).
Bandwidth Mismatch................... -3 dB (assuming 80 MHz -7.27 dB (assuming 160 -4.26 (assuming 80 MHz
channels). MHz channels). channels).
Noise Figure......................... -3.0 dB................ -3.0 dB................ -3.0 dB.
Polarization Loss.................... -3.0 dB................ -3.0 dB................ -3.0 dB.
Feeder Loss.......................... 0 dB................... 0 dB................... 0 dB.
Building Entry Loss (50%)............ -17.00 dB.............. -17.00 dB.............. -20.62 dB (70/30 mix).
Interference (I)..................... -78.76 dBm............. -113.83 dBm............ -114 dBm.
Noise Floor (N)...................... -99 dBm................ -99 dBm................ -99 dBm.
I/N.................................. 20.44 dB............... -14.83 dB.............. -15.0 dB.
----------------------------------------------------------------------------------------------------------------
[[Page 31400]]
75. The parameters in the above table were adjusted as follows:
(i) EIRP/BW: The analysis assumes a nominal channel bandwidth of 80
MHz, which results in a 5 dBm/MHz PSD limit.
(ii) RLAN/FS Antenna mismatch: The Commission agrees with Apple,
Broadcom et al. that there will be an antenna pattern mismatch between
the unlicensed devices and the microwave antenna and that 5 dB is a
reasonable assumed loss.
(iii) Clutter: The Commission uses a standard clutter model (ITU-R
P.452) to derive an 18.4 dB clutter loss.
(iv) Path loss: The Commission believes that the ITM P2P path loss
model is most appropriate for this scenario.
(v) Bandwidth mismatch: The mismatch is based on an 80-megahertz
bandwidth unlicensed channel. However, The Commission assumes that the
mismatch factor should be -4.26 dB based on the ratio of the passband
of AT&T's receiver and the bandwidth of the unlicensed channel.
(vi) Building Entry Loss: The Commisison finds that a 70%
traditional construction/30% energy efficient construction mix of
building types for determining building entry loss is appropriate.
76. Table 2 presents all of AT&T's six examples but substitutes
more realistic technical parameters.
Table 2--FCC Analysis of the AT&T Examples
--------------------------------------------------------------------------------------------------------------------------------------------------------
Example 1A Example 1B Example 2 Example 3 Example 4 Example 5
--------------------------------------------------------------------------------------------------------------------------------------------------------
EIRP Power Spectral Density (dBm/ 5................. 5................. 5................. 5................. 5................. 5.
MHz).
Bandwidth (MHz)................. 80................ 80................ 80................ 80................ 80................ 80.
EIRP (dBm)...................... 24................ 24................ 24................ 24................ 24................ 24.
RLAN Antenna Discrimination (dB) -5................ -5................ -5................ -5................ -5................ -5.
BW Mismatch..................... -4.26............. -4.26............. -4.26............. -4.26............. -4.26............. -4.26.
(80 MHz Chan.) (dB).............
Polarization Loss (dB).......... -3................ -3................ -3................ -3................ -3................ -3.
Propagation Model............... Winner II Urban Winner II Urban ITM P2P........... ITM P2P........... Winner II Suburban Winner II Suburban
LOS. LOS. LOS. LOS.
Propagation Loss (dB)........... -103.6............ -99.5............. -120.12........... -122.7............ -96.1............. -83.6.
Clutter Loss(dB)................ 0................. 0................. -18.4............. -18.4............. 0................. 0.
MW Antenna Gain (dB)............ 43.2.............. 43.2.............. 37.9.............. 38.8.............. 41.3.............. 38.8.
MW Antenna Discrimination (dB).. -36............... -38............... -1.5.............. -0.9.............. -38............... -40.
Feeder Loss (dB)................ -2................ -2................ 0................. 0................. -2................ 0.
Building Entry Loss (70T/30E) -21.4............. -21.9............. -20.6............. -20.6............. -23.1............. -24.0.
50th Percentile (dB).
Noise (dBm)..................... -99.0............. -99.0............. -99.0............. -99.0............. -99.0............. -99.0.
Noise Figure (dB)............... 3................. 3................. 3................. 3................. 3................. 3.
I/N (dB)........................ -12.06............ -10.46............ -15............... -16.1............. -10.1............. -1.06.
--------------------------------------------------------------------------------------------------------------------------------------------------------
77. Table 2 shows that when more realistic technical parameters
than assumed by AT&T are used, the I/N ratio in all but one case now
falls below the conservative -6 dB interference protection benchmark--
indicating that there is an insignificant risk of harmful interference
in five of these cases, when considering a static link budget analysis.
Significantly, because these examples represent cases where the
unlicensed devices are close to the microwave receivers or have terrain
features that place the unlicensed device squarely in the main beam,
they are representative of the worst cases that are likely to occur.
Accordingly, they do not serve to rebut the persuasive showing by
CableLabs based on a reliable probabilistic assessment derived from
measurements associated with hundreds of thousands of actual Wi-Fi APs.
78. In only one case does a static link budget analysis suggest a
nontrivial possibility of harmful interference (Case 5), and the
Commission does not believe this one case poses a significant potential
for actual harmful interference. That is in part because a -6 dB I/N
interference protection criterion is a conservative approach to
ensuring that the potential for harmful interference is minimized and
in part because many statistical factors unaccounted for in this link
budget analysis further make the potential for harmful interference
much less likely. Combining the low probability of co-channel operation
and low activity factor, the Commission concludes that based on a 5
dBm/MHz EIRP, the low power indoor operation will have an insignificant
chance of causing harmful interference to the microwave links for any
of these six examples (or fixed microwave links more generally). If the
EIRP where increased to 8 dBm/MHz, the I/N ratios for examples 1B, 4,
and 5 in Table 5 would recalculate to -7.46 dB, -7.1 dB, and 1.94 dB
respectively, which would create a higher risk of harmful interference
(although still very low). As the Commission cannot conduct an analysis
for every fixed station and each of their associated link paths, it
chooses to adopt a conservative 5 dBm/MHz EIRP at this time to enable
low-power indoor operations throughout the 6 GHz band with
insignificant risk of harmful interference.
79. CITA, Southern Company, the Critical Infrastructure Industry,
and Apple, Broadcom et al. also submitted technical studies exploring
the potential for harmful interference to fixed microwave receivers.
The Commission examined these technical studies. These technical
studies did not change the Commission's conclusion that unlicensed low-
power indoor operations would present an insignificant risk of harmful
interference.
80. Additional Considerations. The Commission is convinced, that as
the Monte Carlo simulations involving extensive use of unlicensed
devices in the band and examination of the link budget studies show,
fixed microwave links will have an insignificant chance of experiencing
harmful interference from indoor low-power unlicensed operations.
Further, the non-continuous nature of the transmissions of the most
widely used unlicensed systems today, like Wi-Fi makes the occurrence
of harmful interference even less likely. And the Commission's rule
requiring
[[Page 31401]]
that low-power indoor access points employ a contention-based protocol
ensures that none of these unlicensed devices will employ continuous
transmissions. The data that CableLabs submitted collected from 500,000
Wi-Fi access points shows that 95% of access points have an activity
factor of less than 2% and only 1% of access points are active more
than 7% of the time. This illustrates that most of the time a
particular access point will not be transmitting.
81. The sporadic and bursty nature of Wi-Fi transmissions is
significant for two reasons. First, it illustrates why discussions of
aggregate interference from Wi-Fi devices cannot simply add the power
received from the individual access points to calculate the received
interference. Instead, to more accurately estimate aggregate
interference a Monte Carlo simulation which accounts for the
intermittent nature of the transmissions should be undertaken.
82. Second, potential degradation of a microwave link will only
occur if a deep atmospheric multipath fade occurs at the same time the
microwave receiver receives an excessively high powered transmission
from an unlicensed device, such that natural losses due to separation
distance, clutter, and terrain do not sufficiently diminish the power
received from the unlicensed device.
83. The Commission disagrees with the Fixed Wireless Communications
Coalition to the extent that it implies that our obligation regarding
harmful interference from unlicensed devices goes beyond what is
enumerated in our rules. While as general matter harmful interference
is defined as ``[a]ny emission, radiation or induction that endangers
the functioning of a radio navigation service or of other safety
services or seriously degrades, obstructs or repeatedly interrupts a
radiocommunications service operating in accordance with this
chapter,'' the Part 15 rules apply this criteria on a case by case
basis for different bands after careful consideration of the incumbent
services in each band that ensures such harmful interference is
unlikely to occur. The technical and operational limits the Commission
adopts in this proceeding ensures that unlicensed devices will not have
a significant potential for causing harmful interference to the users
authorized to operate in the 6 GHz band.
84. The Commission, however, is not required to refrain from
authorizing services or unlicensed operations whenever there is any
possibility of harmful interference. Indeed, such a prohibition would
rule out virtually all services and unlicensed operations, given that
there is virtually no type of RF-emitting device that does not have the
potential for causing such interference if used incorrectly. NCTA notes
that the Commission may promulgate rules for unlicensed operations in
bands occupied by other users so long as unlicensed devices do not
``transmit[ ] enough energy to have a significant potential for causing
harmful interference.'' In rulemakings, the Commission may authorize
operations in a manner that reduces the possibility of harmful
interference to the minimum that the public interest requires, and it
will then authorize the service or unlicensed use to the extent that
such authorization is otherwise in the public interest. The Commission
determines that the restrictions and requirements that it is
establishing for indoor use of low power access points eliminates any
significant risk of causing harmful interference.
85. AT&T, CTIA, and others express concern that harmful
interference nonetheless may occur, and the rules do not go far enough
to ensuring that the interfering devices can be identified and the
operation cease. Both AT&T and CTIA advocate use of an AFC system to
address these concerns. While in certain bands the Commission has
required database use, for other bands the Part 15 rules have no such
requirement. Of particular relevance here, there is no spectrum
management system in the 2400-2483.5 MHz band, where unlicensed devices
share spectrum with the incumbent broadcast auxiliary service licensees
and operate at higher powers than the indoor low-power access points
authorized here. Nor are there such requirements in the 5 GHz band,
which includes sensitive incumbent operations and where the unlicensed
operations are similar to the kinds of low-power operations anticipated
in the 6 GHz band. Wi-Fi devices have been deployed in these bands in
abundance for well over 20 years, and the Commission expects that the
deployment of 6 GHz devices will resemble the deployment of devices in
these other bands, where instances of harmful interference have been
effectively identified and addressed.
86. The Commission disagrees with CTIA's contention that our rules
will be ineffective in keeping the low-power indoor devices from being
used outdoors. The Commission's Part 15 rules prohibited outdoor
operation in the U-NII-1 band from 1997 until 2014 and currently
prohibit outdoor operation for unlicensed devices in the 92-95 GHz band
and many ultra-wideband devices. As outdoor operation of these indoor
devices has not been a problem, the Commission's rules restricting
devices to indoors cannot be categorized as ineffective. None of these
existing and previous rules contain all of the restrictions the
Commission adopts here to discourage outdoor use. As in the rules for
those operations, the Commission concludes that the technical and
operational rules will be sufficient to protect incumbent operations.
87. In the unlikely event that harmful interference does occur, the
Commission's Part 15 rules in section 15.5 (b)-(c) require that such
operations cease, and the Commission's Enforcement Bureau has the
ability to investigate reports of such interference and take
appropriate enforcement action as necessary. Also, once interference to
a protected service crosses the relevant threshold specified in section
15.3(m) for harmful interference, it is immediately actionable for
enforcement purposes. Any user causing interference may be required to
cease operating the U-NII device, even if the device in use was
properly certified and configured and will not be permitted to resume
operation until the condition causing the harmful interference has been
corrected.
88. Here, as always, the Commission focuses on identifying and
protecting against actual-use cases; were the Commission to act on
every unrealistic or contrived situation that purports to show the
potential for harmful interference, the Commission's rules would allow
for few or no opportunities for sharing between unlicensed devices and
licensed services; sharing that has allowed Wi-Fi to prosper along with
continued licensed spectrum use. The Commission emphasizes, however,
that under our long-established rules, Part 15 devices are not
permitted to cause harmful interference. This fundamental principle
stands regardless of the particular band- and application-specific
rules adopted.
Mobile Services
89. The 6 GHz band Mobile service allocation is limited to the U-
NII-6 (6.425-6.525 GHz) and U-NII-8 (6.875-7.125 GHz) bands. In these
bands, the mobile service incumbents operate electronic news gathering
and other Part 74 broadcast auxiliary services, as well as Part 78
Cable Television Relay Service, and Part 101 Local Television
Transmission Service. Incumbents operate portable camera relays to
``jumbotron'' screens for major sporting events at stadiums and arenas,
and at musical concerts at large venues, indoors and outdoors; use the
spectrum bands for video relay to production
[[Page 31402]]
trucks at news events; and for video signal multi-hop mobile relay from
newsworthy events to either a satellite news truck, a fixed receive
site or a temporary relay site. Low Power Auxiliary Stations, also
licensed in the U-NII-8 band, operate on an itinerant basis and
transmit over distances of approximately 100 meters for uses such as
wireless microphones, cue and control communications, and TV camera
synchronization signals. Additional terrestrial uses of the band
include short range video relay for video production at automobile and
sailboat racing event, political conventions and golf tournaments.
Because of the nature of their use--breaking news, event coverage,
etc.--the use of particular portions of this band by these auxiliary
services is unpredictable.
90. NAB opposes allowing indoor unlicensed operations in the bands
where there are broadcast auxiliary service operations (U-NII-6 and U-
NII-8), unless a ``robust, reliable mechanism is developed to
coordinate'' the unlicensed operations with the licensed uses. To
support of its position, NAB submitted a study which evaluates the
impact of indoor and outdoor unlicensed operations in the U-NII-6 and
U-NII-8 bands in three different use scenarios: (i) An electronic news
gathering truck transmitting to a central receive site; (ii) portable
cameras transmitting to an outdoor electronic news gathering truck
receive site; and (iii) portable cameras transmitting to an indoor
receive site.
91. Though the NAB study provides some valuable information about
the potential risk of harmful interference to electronic news gathering
receive sites, the Commission disagrees with certain of its
assumptions. The Commission disagrees with NAB's use of free-space path
loss for all paths based on a predicted percentage of area that is
line-of-sight when in fact unlicensed devices will be randomly located
and could very well be in areas of buildings without line-of-sight to
the electronic news gathering receiver. Under more realistic
conditions, the Commission notes that NAB's use of a -10 dB I/N
benchmark is rarely exceeded in the electronic news gathering truck
receiver case. The Commission notes that the use of a conservative but
more reasonable -6 dB would show much less likelihood of any potential
for harmful interference. And taking into account the power-level and
contention-based protocol limitations would show even less likelihood
of harmful interference.
92. NAB's study includes co-channel operation probability in its
statistical study but bases this probability on unlicensed devices
being restricted to the U-NII-6 and U-NII-8 bands. NAB's assumption
increases the probability of co-channel operations and thus, over
predicts the potential for harmful interference to electronic news
gathering operations.
93. Finally, NAB requests that the Commission authorize low power
indoor operations in the U-NII-6 band altogether or alternatively to
reserve 80 megahertz in the upper U-NII-8 band for ENG use only. As
discussed below, low-power indoor operations will have little potential
of causing harmful interference to ENG operations and decline to take
this action. Moreover, eliminating the spectrum available for 6 GHz
unlicensed devices could have the unintended effect of actually
increasing the potential interference to other users as more unlicensed
devices would have access to fewer channels.
94. Outdoor electronic news gathering central receive sites. For
the reasons outlined above, the Commission believes NAB's study
overstates the potential of exceeding its chosen I/N criterion of -10
dB and therefore also overstates the likelihood of exceeding the
conservative and sufficiently protective I/N value of -6 dB. Apple,
Broadcom et al. submitted a statistical study of the same scenarios but
based on a combination of WINNER II and Irregular Terrain Model with
the P.2108 propagation models. The Apple, Broadcom et al. study
considers two activity factors and a 70/30 mix of building entry loss
based on ITU Recommendation P.2109. The Apple, Broadcom et al. results
indicate that aggregate signal level from indoor unlicensed devices
will exceed a level 6 dB below the electronic news gathering central
site receiver noise floor only 0.1% of the time. Thus, concluding that
there is a negligible risk of harmful interference. The Commission
finds that the Apple, Broadcom et al. study uses more appropriate
propagation models and therefore more accurately represents the risk of
harmful interference from indoor unlicensed devices to electronic news
gathering central receive sites and find that risk to be insignificant.
95. Interference to electronic news gathering truck receivers.
Results of NAB's own study show that at the lower activity factor of
0.44% indoor unlicensed devices are unlikely to cause the I/N to exceed
-10 dB. At the 10% activity factor, the electronic news gathering truck
receiver results showed that between 0.2 and 49.8% of the time the
aggregate I/N exceeds the -10 dB I/N threshold. CableLabs' empirical
activity factor data show a weighted distribution of 0.4%. The
Commission concludes that it is highly unrealistic to assume that every
unlicensed device in an area surrounding an electronic news gathering
truck will be transmitting at the high 10% activity factor.
96. The NAB study also concludes that the level of unwanted signal
seen by the electronic news gathering truck receiver is dependent on
the relationship between the height of the unlicensed device, the
height of the electronic news gathering antenna and the height of the
surrounding environment. The same relationship between local
environment and antenna heights will exist for the desired link between
the electronic news gathering transmitter and truck mounted receiver,
except the electronic news gathering link can be planned and the
electronic news gathering truck can be positioned to achieve the best
possible signal between transmitter and receiver. Given the sensitivity
of potential interference to geometry coupled with NAB's unrealistic
assumption that every unlicensed device in an area surrounding an
electronic news gathering truck will be transmitting at the high
activity factor, the Commission concludes that the potential for
harmful interference (using a more appropriate -6 dB threshold) is
again insignificant for the scenario indicated.
97. CableLabs and Apple, Broadcom et al. both submitted studies
indicating that potential for harmful interference from indoor
unlicensed devices to outdoor electronic news gathering truck receivers
will be unlikely. The Commission agrees with CableLabs' and Apple,
Broadcom et al.'s findings, that the risk of harmful interference to
outdoor electronic news gathering receivers from indoor unlicensed
devices is negligible. The Commission notes that the same conditions
that cause signal variations in the electronic news gathering signal
will also act upon a signal from an unlicensed device. CableLabs states
that a 10 dB signal-to-interference-plus-noise provides an accurate
basis for determining the impact of unlicensed indoor devices on
broadcast auxiliary service signals. Apple, Broadcom et al. asserts
``[n]ews truck operators will be able to improve their link budgets by
slightly adjusting the positions of their trucks or shooting
locations.'' The Commission also notes that both Apple, Broadcom et al.
and CableLabs' studies assume a maximum of 30 dBm EIRP with at least an
8 dBm/MHz PSD, and that it is permitting indoor unlicensed devices to
transmit with only a maximum 5 dBm/MHz PSD. This 3 dB variance further
reduces the probability of harmful interference to
[[Page 31403]]
electronic news gathering trucks from unlicensed devices.
98. Interference to indoor electronic news gathering receivers. The
final scenario studied by NAB is communication between indoor
electronic news gathering transmitters, such as microphones and camera-
back transmitters, and indoor electronic news gathering receivers. The
Commission is not permitting client devices to be used as hotspots and
requires 6 GHz unlicensed devices to use a contention-based protocol.
The Commission concludes that such a protocol will allow unlicensed
devices to sense the energy from nearby indoor licensed operations and
avoid using that channel. Apple, Broadcom et al. points out that the
802.11 specification dictates that devices sense the energy in the
channel and not transmit if they detect energy at a level greater than
-62 dBm. To confirm that energy sensing could be used to mitigate
interference to indoor electronic news gathering receivers, Apple,
Broadcom et al. simulated the receive power level from electronic news
gathering transmitters at 20 unlicensed access points operating within
the US House of Representatives chamber. The results of this simulation
demonstrate that, even at the lowest electronic news gathering transmit
power level, all unlicensed access points would detect the electronic
news gathering signal at greater than -62 dBm and therefore not
transmit co-channel. While it is not requiring a specific technology
protocol or contention method, the Commission concludes that the
results of the Apple, Broadcom et al. study shows the likely potential
of contention-based protocols to protect indoor mobile links, including
electronic news gathering and Low Power Auxiliary Stations. Thus, the
Commission concludes that the risk of harmful interference to indoor
electronic news gathering receivers from indoor unlicensed devices is
insignificant.
Fixed-Satellite Services
99. The entire 6 GHz band is also home to a FSS allocation (Earth-
to-space), while U-NII-8 has a few space-to-Earth MSS feeder downlinks.
The Commission agrees with Sirius XM, Intelsat, and SES that there will
be negligible interference to satellite receivers from low-power indoor
unlicensed devices. The low power levels of these devices as well as
building attenuation will prevent harmful interference. With regard to
earth station receivers, the Commission disagrees with Globalstar's
analysis. As Apple, Broadcom et al. point out Globalstar's analysis
represents an impossible worst-case scenario because it assumes that
the earth station antenna is pointing at its minimum usable elevation
angle in each of the interfering indoor access points resulting in the
assumption that earth station antennas will simultaneously receive
unlicensed device transmissions from all directions with the same
antenna gain. Globalstar also assumes all unlicensed devices are
operating at the same location where the incidence angle at the
building wall is always zero, yielding the least building entry loss.
Globalstar, uses a conservative 10% activity factor with all unlicensed
activity concentrated at a small number of sites resulting in an
unrealistic assumption that unlicensed transmission will always be
subject to 7 dBi of earth station gain. However, it is unlikely that
all indoor unlicensed devices will be operating at the same location
and orientation with respect to the path between the device and the
earth station receiver. Instead, the elevation angle at the building
fa[ccedil]ade should be considered to be variable, resulting in
incidence angles greater than zero, which would increase the building
entry loss value and minimize the probability of interference.
Globalstar assumes line-of-sight and free-space propagation for all
paths. The Commission disagrees that line of sight and free-space
propagation loss is appropriate in all cases between a randomly placed
unlicensed device and Globalstar's earth station.
100. Finally, Globalstar's analysis assumes all unlicensed devices
are operating at the proposed maximum permissible power with the peak
antenna gain directed toward its earth stations. The Commission is
allowing unlicensed indoor devices to operate at a maximum 5 dBm/MHz
PSD which represents at least a 3 dB/MHz reduction over the power
levels assumed in the Globalstar analysis. Additionally, when
considering random placement of unlicensed devices and variations in
the unlicensed device antenna pattern, it is unlikely that the
unlicensed device EIRP in the direction of the earth station will
always be at maximum power, thus the risk of harmful interference is
further reduced. For the reasons outlined here, the Commission finds
that Globalstar's link budget analysis fails to fully consider all the
probability factors that must align in order for interference to occur.
The Commission therefore finds that the risk of harmful interference
occurring to Globalstar's earth stations to be low.
Radio Astronomy
101. The National Academy of Sciences Committee on Radio
Frequencies requests that the Commission use the AFC system to protect
four radio astronomy observatories located in remote areas. The
Commission is not adopting any AFC-based requirements for unlicensed
low-power indoor operations generally, and declines to adopt such a
requirement here. The four radio observatories that receive in the 6
GHz band are in remote locations and it is unlikely that indoor low-
power unlicensed devices will be operating nearby. Furthermore, these
observatories can restrict installation of such devices at their
facilities. The Commission believes that indoor unlicensed devices do
not pose any risk of harmful interference to radio astronomy
operations.
Multi-Stakeholder Group
102. The Commission notes that many of the companies and
organizations with interest in the 6 GHz band may not have previously
participated in multi-stakeholder groups on matters related to specific
Commission proceedings. Therefore, while the Commission takes no
position on whether an existing organization could or should serve as
host of the 6 GHz multi-stakeholder group, the Commission believes that
any such multi-stakeholder group should be newly formed (not an
offshoot of an existing group) and focus solely on issues relevant to
the 6 GHz band. To ensure that all viewpoints are considered, the
Commission encourages stakeholders comprising all sectors of the 6 GHz
ecosystem to participate, including: wireless service providers with
interest in providing service through standard-power and indoor low
power devices, RLAN and network equipment manufacturers, potential AFC
operators, fixed service vendors and operators, existing 6 GHz band
incumbent licensees, ultrawideband equipment manufacturers, academic
experts, testing organizations, and other 6 GHz band stakeholders. The
Commission does not, however, take a position on the exact makeup or
organizational structure of any such stakeholder group.
103. The Commission encourages the multi-stakeholder group to
address any issues it deems appropriate regarding interference
detection and mitigation in the event that an incumbent licensee
believes it may be experiencing harmful interference from standard-
power or indoor low-power operations. These issues would include
procedures and
[[Page 31404]]
processes that could be followed if an incumbent licensee has, or
potentially has, an interference complaint. For example, network
operators of standard-power or indoor low-power operations could decide
to make points of contact publicly available or to create a website to
facilitate addressing concerns or for reporting complaints. The
Commission also believes that the group should set a goal of creating a
process through which the industry can effectively address and resolve
interference claims without necessitating involvement of the
Commission's Enforcement Bureau.
104. While the Commission is not requiring general device testing
as a gating criterion for devices before they begin operating in the 6
GHz band, the Commission recognizes that it will take some time before
devices can be designed, manufactured and made available to consumers.
During this interim period, members of the multi-stakeholder group
could work cooperatively to develop and test devices to aid in the goal
of developing processes for introducing and operating devices across
the 6 GHz band. As the Commission does not require the multi-
stakeholder group to conduct testing, the Commission also declines to
set any timelines if any testing is conducted. Because the Commission
does not expect widespread availability of 6 GHz unlicensed devices
immediately, the Commission encourages the multi-stakeholder group, if
conducting any testing related to developing procedures and processes
regarding interference detection and mitigation, to set a goal of
implementing any agreed-upon device-related features before unlicensed
6 GHz devices reach consumers.
105. The Commission also encourages the multi-stakeholder group to
address any other issues that may be specific to standard-power
operations or indoor low-power operations. In particular, the
Commission encourages the group to address, as proposed in the Notice,
AFC system development for standard power access points. Related tasks
are expected to include any standards that are necessary for AFC
operators, such as how to implement the required propagation models or
whether common communications protocols are needed between standard
power unlicensed devices and the AFC(s). Additionally, the Commission
expects that the multi-stakeholder group will develop AFC system
testing and certification procedures and processes for ensuring that
AFC systems contain complete and up-to-date incumbent data.
106. Finally, the Commission expects that the multi-stakeholder
group will develop best practices and standards concerning standard-
power operations (and use of the AFC system) and for indoor low-power
operations--practices that the Commission expects will benefit all
users of the 6 GHz band, both incumbents that desire additional
protection and new unlicensed users that want to use the spectrum more
intensely. The Commission expects that these best practices will
include such concerns as device and communication link security. These
activities should be viewed as a starting point; participants of the
multi-stakeholder group should tackle any issues they deem appropriate.
107. The Commission's Office of Engineering and Technology (OET)
will act as a liaison for the Commission with any such multi-
stakeholder group so formed. In particular, the Commission expects the
Office to observe the functioning of any such group and the technical
concerns that it is considering to ensure that the group's activities
are useful and pertinent. OET will provide guidance to any such group
on the topics on which it would be most helpful for the Commission to
receive input and a sense of the time frames in which such input would
be helpful.
Equipment Issues
108. LAntenna Requirements. The Commission requires that all low
power devices incorporate permanently attached integrated antennas.
Requiring an integrated antenna makes it significantly more difficult
for a party to replace a device's antenna with a higher gain antenna,
which could increase a device's EIRP above the limit and therefore
increase the potential for a device to cause harmful interference.
109. The Commission does not, however, require a permanently
attached antenna for standard-power access points. The Commission finds
that a requirement to use a permanently attached antenna on standard
power access points could be overly restrictive. These types of devices
are typically used outdoors by parties such as schools, businesses and
WISPs and are configured in a manner where the antenna is mounted on a
mast or building and connected through a cable to a separately located
transmitter. Such a requirement could be difficult to implement for
these configurations. In addition, permitting such devices a choice of
appropriate antennas will provide options for meeting the antenna
pointing restrictions which limit outdoor devices to antenna elevation
angles less than 30 degrees for devices transmitting more than 21 dBm
EIRP to protect satellite operations in the band. Further, the
Commission notes that devices in other U-NII bands do not have a
requirement for permanently attached antennas, so adding a requirement
for equipment in the 6 GHz bands could make it more difficult for
manufacturers to develop devices that are capable of operating across
multiple bands. Consistent with the existing Part 15 rules, applicants
for standard-power access point equipment authorizations will be
required to list all types of antennas that will be used with a device
and demonstrate that the equipment complies with the EIRP limits with
all types of antennas with which it is authorized.
110. Maximum Channel Bandwidth. Because the Commission is setting a
power spectral density limit of 5 dBm/MHz for low power indoor devices
to limit their potential for causing interference to incumbent
services, the Commission permits these devices to operate with a
maximum channel bandwidth to 320 megahertz to permit a maximum power of
up to 30 dBm. For consistency the Commission also specifies a maximum
bandwidth of 320 megahertz for AFC controlled standard-power access
points.
111. The Commission finds that this bandwidth requirement is
appropriate for several reasons. It will permit manufacturers to
develop equipment under current standards with bandwidths of up to 160
megahertz as a number of parties suggest. In addition, the Commission's
understanding is that industry standards under consideration such as
IEEE 802.11be will specify channel bandwidths of up to 320 megahertz.
Thus, a 320 megahertz bandwidth limit will permit future equipment
development under anticipated standards without a need for additional
rule changes. However, the Commission is placing a 320-megahertz upper
limit on bandwidth so as not to supplant the rules for wideband and
ultrawideband operations in the 6 GHz band. These rules permit
operation with bandwidths greater than 500 megahertz, but with a lower
-41 dBm/MHz power spectral density. The Commission notes that
unlicensed proponents have not requested channels bandwidths greater
than 320 megahertz and that the Commission did not provide notice of
any proposed changes to the wideband or ultrawideband rules.
112. Standard power transmitted power levels in rural areas. The
Commission does not at this time permit higher power limits in rural
areas, nor make any specific provisions for higher power point-to-point
or point-to-multipoint operations in the U-NII-5 and U-NII-7 bands as
suggested by some commenters. While the Commission recognizes that
establishing
[[Page 31405]]
a single power limit of 36 dBm for standard-power access points differs
from the rules for the U-NII-1 and U-NII-3 bands that permit higher
power for fixed point-to-point devices, and from the white space rules
that permit higher power for fixed devices in ``less congested'' (e.g.,
rural) areas, the Commission is not adopting higher power limits for
several reasons. The Commission first notes that the rules adopted does
not place an upper limit on antenna gain; the transmit limits are based
solely on EIRP, and manufacturers can use any combination of
transmitter power and antenna gain to reach that limit. The Commission
interprets parties' requests for higher antenna gain limits as requests
for higher EIRP limits. While allowing higher power could encourage the
provision of additional services in rural and other areas, it also
increases the range at which harmful interference to incumbent users in
the bands could potentially occur. Therefore, the Commission is taking
a conservative approach at this time and not permitting power levels
greater than 36 dBm for standard-power access points. In addition,
permitting higher power in only certain areas would make the AFC
implementation more complex because criteria for where to allow higher
power operation would have to be defined and incorporated into the AFC.
Also, taking into account the directivity of standard-power access
point transmit antennas as some parties suggest would make AFC
calculations more complex.
113. Client Device Transmit Power Levels. The Commission is
adopting rules that limit client devices to power levels 6 dB below the
power limits for access points. The Commission concludes that this 6 dB
reduction is necessary because when the client device is operating
under the control of the access point, the client device may have a
slightly different propagation path and interference potential to a
victim receiver.
114. The Commission generally declines to increase client device
power levels to the same power levels as access points, as suggested by
some commenters. The Commission recognizes commenters concerns
regarding the power differential between access points and client
devices. However, because a client device may be portable (e.g., a cell
phone) and operate at different locations around its serving access
point, the propagation path of its emissions could vary. This could, in
turn, slightly change the potential for interference from any
particular client device to incumbent operations within the area. Thus,
the Commission declines to adopt power limits for client devices
commensurate with access points. However, the Commission makes two
limited exceptions to this requirement.
115. First, to the extent that an access point and a client device
are both permanently fixed and operate under the control of an AFC
system that provides a list of available frequencies to each device,
each may operate at up to the maximum 36 dBm level. In such cases, the
Commission does treat the client device as another access point with
respect to operational rules, provided it complies with all of the
requirements for access points, including using an AFC to obtain a list
of available channels, having a geolocation capability and complying
with the limit on upward antenna radiation from outdoor devices (no
greater than 21 dBm at more than 30 degrees above the horizon). To
distinguish these devices from actual access points for equipment
certification purposes (as they differ in not having a direct
connection to the internet), the Commission defines them as fixed
client devices.
116. The Commission also adopts an exception to accommodate devices
such as Wi-Fi extenders and mesh networking equipment intended to work
in conjunction with an indoor access point and share the same
propagation path and thus the same power requirements. The Commission
also permits other devices under certain conditions to operate at the
full 5 dBm/MHz power spectral density. The Commission permits such
devices to operate at the same power levels as an access point provided
that they comply with all the requirements set out for low power indoor
access points (i.e., the device cannot be weather resistant, must have
an integrated antenna and cannot have capability of connecting other
antennas, cannot be capable of operating on battery power, and must
include a label regarding proper usage) and the end unit obtains its
own equipment certification. Under these requirements modules do not
qualify for higher power. Further, such devices may only be used within
a single structure and not to connect separate buildings or structures.
The Commission believes such relief is a reasonable accommodation to
keep most popular consumer devices less complex and more affordable
without increasing the potential of harmful interference to incumbent
licensees as these devices will be installed and used in a manner
analogous to an access point.
117. The Commission does not find it necessary to restrict the
power radiated upward from client devices as required for standard-
power access points. The Commission believes it is unlikely that
relatively low-power unlicensed devices will cause harmful interference
to receivers on geostationary satellites approximately 36,000 km above
the equator. The Commission is limiting upward power from standard-
power access points merely as a precautionary measure as they are more
likely to operate outdoors and with higher power. The Commission notes
that client devices can operate with EIRP as high as 30 dBm, but finds
that they are less likely to cause interference to satellite receivers
than similarly powered outdoor access points due to the nature of their
operation. The Commission first notes that client devices are limited
to a power level 6 dB lower than access points, but the Commission
expects them to generally operate at much lower power levels to
maximize battery life and comply with RF exposure limits. In addition,
client devices communicate with access points in an asymmetric nature,
in that relatively little data is transmitted in the uplink direction
(i.e., from the client device) as compared to the downlink direction
where any single access point may be serving many client devices.
Moreover, client devices typically operate with omnidirectional
antennas at low antenna heights and in a mobile or portable mode (i.e.,
not installed in permanent outdoor locations). Thus, the Commission
expects that upwardly directed client device emissions will often be at
low power levels and shielded to some extent by buildings, foliage, or
other obstructions.
118. Emission Mask and Out-of-Band Emission Limits. The Commission
concludes that the emission mask suggested by RKF Engineering, with
certain modifications, protects incumbent microwave links and other
services operating in the adjacent channel to unlicensed devices within
the U-NII-5 through U-NII-8 bands. Accordingly, the Commission requires
emissions from standard power access points and low power indoor
devices within the U-NII-5 through U-NII-8 bands to comply with the
transmit emission mask proposed in the Notice. Specifically, the
Commission is requiring 20 dB suppression of power spectral density at
one megahertz outside of an unlicensed device's channel edge, 28 dB
suppression of power spectral density at one channel bandwidth from an
unlicensed device's channel center, and 40 dB suppression of power
spectral density at one and one-half times the channel bandwidth
[[Page 31406]]
away from an unlicensed device's channel center. At frequencies between
one megahertz outside an unlicensed device's channel edge and one
channel bandwidth from the center of the channel, the limits must be
linearly interpolated between 20 dB and 28 dB suppression, and at
frequencies between one and one and one-half time an unlicensed
device's channel bandwidth from the center of the channel, the limits
must be linearly interpolated between 28 dB and 40 dB suppression.
Emissions removed from the channel center by more than one and one-half
times the channel bandwidth, but within the U-NII-5 and U-NII-8 bands,
must be suppressed by at least 40 dB.
119. The Commission adopts a -27 dBm/MHz limit for emissions from
all 6 GHz unlicensed devices at frequencies below the bottom of the U-
NII-5 band (5.925 GHz) and above the upper edge of the U-NII-8 band
(7.125 GHz), but will not require it between the sub-bands, i.e.,
between the U-NII-5 and U-NII-6, the U-NII-6 and U-NII-7, and the U-
NII-7 and U-NII-8 bands. The Commission believes that a limit of -27
dBm/MHz is necessary to protect services outside the U-NII-5 and U-NII-
8 bands, including the Intelligent Transportation Service below the U-
NII-5 band and federal government operations above the U-NII-8 band.
The Commission is not requiring devices to meet this emission limit
between the sub-bands as suggested by Sony because it is seeking to
maximize spectrum use and it would stifle innovation by precluding the
use of wide bandwidth channels (up to 320 megahertz) that straddle sub-
bands. Standards bodies have generally developed channeling plans for
unlicensed devices based on technical characteristics, including
devices' out-of-band emissions. Manufacturers will have the freedom to
determine how they will meet this limit either by reducing power
levels, through filtering or through other means, such as not enabling
channels closest to the U-NII-5 and U-NII-8 band edges.
120. Finally, the Commission addresses the measurement procedures
for 6 GHz unlicensed devices. To protect Intelligent Transportation
Services in the band below 6 GHz, 5GAA states that the -27 dBm/MHz
standard the Commission is adopting, when based on a root-mean-square
(RMS) measurement, is sufficient to protect those services from indoor
device OOBE. RLAN proponents agree that the OOBE should be verified
using an RMS detector or other appropriate techniques for measuring
average power. The Commission agrees and will provide guidance to the
test labs and telecommunications certification bodies which conduct
equipment approval measurements and oversight that 6 GHz unlicensed
device measurements may be conducted based on using an RMS detector.
Because RMS measurements represent the continuous power being generated
from a device as opposed to peak power which may only be reached
occasionally and for short periods of time, the Commission believes an
RMS measurement is more appropriate. The Commission notes that this is
a departure from the Commission's measurement guidance for similar
devices in the 5 GHz band where the Commission specifies a peak
measurement. However, that procedure was instituted to mitigate a known
interference issue with federal radars in the 5 GHz band. No such
situation exists in the 6 GHz band. The Commission will update its
Knowledge Database guidance consistent with this decision.
121. Client Device Restrictions. The Commission adopts a
requirement that client devices operate either under the control of a
standard-power access point or a low-power access point. The purpose of
this requirement is to prevent client devices from transmitting
outdoors at locations where they may cause interference to a microwave
receiver or other incumbent. When client devices are under the control
of a standard-power access point, they will be in close proximity to
the access point and may transmit only on frequencies that the AFC
system has determined will not cause interference to fixed microwave
links. When a client device is under the control of a low-power indoor
access point, it should also be indoors and in close proximity to the
access point, and therefore avoid presenting an interference risk to
licensed services. However, the Commission also adopts an exception to
this general requirement to allow a client device to transmit brief
messages (``probe requests'') to an access point when attempting to
join its network as discussed below.
122. The Commission recognizes the utility of permitting probe
requests to enable client devices to join an access point's network.
However, these probe requests have the potential to cause harmful
interference to licensed operations. The Commission therefore only
permits a client device to send a probe request to an access point
after it has detected a transmission from the access point. The client
device will be required to send the probe request on the same frequency
as the access point's transmission. This is consistent with the white
space rules that permit a fixed white space device establishing a
network to make brief transmissions on a frequency that it detects is
in use by another fixed device prior to receiving a list of available
channels from a database. Under this exception, because the client
device will have to detect an access point transmission, the client
device will only transmit when it is close enough to an access point to
be under its control and on a frequency on which the access point has
permission to transmit. This will prevent harmful interference from
occurring.
123. The Commission prohibits the use of client devices as mobile
hotspots that could authorize the operation of other client devices.
The rules the Commission adopts for AFC controlled operation of
unlicensed access points are designed to prevent harmful interference
to licensed stations by only allowing operation at locations where an
access point and client devices directly communicating with it would
not cause interference to licensed stations. Permitting a client device
operating under the control of an access point to authorize the
operation of additional client devices could potentially increase the
distance between these additional client devices and the access point
and increase the potential for harmful interference to fixed service
receivers or electronic news gathering operations. For standard-power
devices in the U-NII-5 and U-NII-7 bands hotspot operation could allow
the additional client devices to transmit in locations where the AFC
otherwise would prevent operation to protect incumbent service
operations. With regard to low-power indoor access points, our rules
are designed to prevent the low-power access points from being used
outdoors which should also keep the client devices indoors. In
addition, as APCO states, allowing such portable access points could
make identifying and resolving interference difficult.
Making Portions of the 6 GHz Band Available for New Licensed Services
124. The Commission declines the requests to repurpose substantial
portions of the 6 GHz band for new licensed services in place of new
unlicensed operations and existing incumbents. Most importantly, the
Commission believes that providing new opportunities for unlicensed
operations across the entire 6 GHz band can help address the critical
need for providing additional spectrum resources for unlicensed
operations. Making the entire band available for these unlicensed
operations enables use of wide swaths of spectrum, including several
160-megahertz channels as well
[[Page 31407]]
as 320-megahertz channels, which promotes more efficient and productive
use of the spectrum, and would also help create a larger ecosystem in
the 5 GHz and 6 GHz bands for U-NII devices. Repurposing large portions
of the 6 GHz band for new licensed services would diminish the benefits
of such use to the American public. Accordingly, the Commission agrees
with the unlicensed proponents to reject these requests. Similarly,
repurposing substantial portions of the band, as CTIA and Ericsson
request substantially affects existing licensed services in the band.
This is contrary to the Commission's goal in this proceeding to ensure
that existing incumbents can continue to thrive in the 6 GHz band.
Representatives of the incumbent fixed microwave services also raise
concerns about the reasonableness and practicality of relocation, and
question whether other appropriate spectrum can be found. The fixed
satellite service commenters also strongly reject the contention of
CTIA and Ericsson that satellite services would not need to be
relocated because new licensed services would not cause harmful
interference to the satellite services. Further, there is no certain or
clear path for achieving what CTIA and Ericsson propose, and it would
take years. For all of these reasons, the Commission will not take the
approach suggested by CTIA and Ericsson to repurpose this band. By the
actions the Commission takes today to open the entire 6 GHz band for
new unlicensed operations, the American public will begin to see the
benefits in the near term.
125. The Commission also declines to reconsider the approach it is
taking to authorize unlicensed low-power operations in the U-NII-6
band. Ericsson asked to make the U-NII-6 band available for licensed
indoor use rather than permitting unlicensed indoor use as proposed in
the Notice. The Commission has made the entire 6 GHz band available for
indoor low-power operations under rules that will protect incumbent
operations across the band while also enabling use of wide channels
that promote efficient use of the entire band. These unlicensed devices
can provide the IoT applications envisioned by Ericsson in the entire 6
GHz band while protecting incumbent operators from harmful
interference.
Mobile Operations and Use in Moving Vehicles
126. General prohibition on mobile operations. The Commission does
not at this time permit standard-power and low-power indoor access
points in the 6 GHz band to operate while in motion, with one exception
in the U-NII-5 band with respect to large passenger aircraft operating
over 10,000 feet. The Commission declines to permit operation in
vehicles because of the potential for increasing interference to
incumbent services. As a result, the use of unlicensed access points
shall not be permitted in moving vehicles such as cars, trains, ships,
or small aircraft. Also, the Commission is prohibiting unlicensed
devices in the 6 GHz band to be installed on unmanned aircraft systems.
127. As commenters note, the white space rules do provide a method
that could enable personal/portable devices to operate while in motion
by obtaining channel availability information for multiple locations
and using this information to define a geographic area of operation.
However, no personal/portable white space devices have yet been
certified and such devices are limited to a lower power level than
other white space devices. The Commission is concerned that allowing
standard-power access points to operate while in motion would add
complexity to the AFC system as it would need to continuously update
available frequency lists for such devices, and that this could add
substantial congestion to links connecting devices to the AFC,
potentially degrading the quality of service for the expected
predominant fixed access point use. Given the lack of a record as to
the power levels and operational requirements that would be needed to
permit mobile operation, the Commission will not permit mobile
standard-power access point operation at this time.
128. Similarly, the Commission rejects the Wi-Fi Alliance's
position that it should consider the signal attenuation provided by the
vehicle or the user's body to establish appropriate power levels to
enable mobile and transportable operations. Unlicensed devices will
have no way to determine whether they are within a car, train, or plane
and therefore would not be able to adjust their output power
accordingly.
129. While the Commission is prohibiting the use of 6 GHz access
points while in motion, the Commission is not prohibiting transportable
devices, which the rules define as devices that ``are not intended to
be used in motion, but rather at stationary locations.'' However
transportable access points will have to otherwise comply with the
rules the Commission adopting. That is, they will either operate under
the control of an AFC system or they will have to operate only indoors.
Indoor transportable access points will have to comply with all of the
restrictions the Commission is adopting to prevent outdoor use.
130. The Commission is prohibiting use of access points in cars,
trains, and small aircraft because of the complications of using an AFC
to control frequency access while in motion and because of the
uncertain attenuation properties of these vehicles. Use of 6 GHz
devices on ships raises the same issues as use in cars, trains, and
aircraft regarding use of the AFC systems to protect licensees and lack
of building attenuation when access points are used indoors. To address
these issues and protect the earth exploration satellite service
operations over oceans, the Commission also prohibits standard-power
and low-power indoor access points aboard ships and on oil platforms.
131. The Commission prohibits unlicensed devices in the 6 GHz
band--whether standard-power or low-power devices--from operating on
unmanned aircraft systems. Unmanned aircraft systems pose similar
issues as other vehicles with the added complication of operating at
significant height, and the Commission has no technical bases in the
record to enable an evaluation of the potential harmful interference
concerns posed by these systems. For the reasons it is not permitting
standard-power and low-power indoor devices generally in vehicles, the
Commission is not permitting them in unmanned aircraft systems.
132. Exception for large aircraft operating above 10,000 feet.
Boeing requests that that the Commission permit unlicensed operations
aboard large aircraft when flying above 10,000 feet. The Commission
agrees with Boeing that the fuselage of large passenger aircraft will
provide significant attenuation of signals from unlicensed in-flight
entertainment systems. The measured average signal attenuation from the
fuselage of a large aircraft at 5 gigahertz is 17 dB, which is
comparable to a building of traditional construction. The Commission
does not expect the aircraft fuselage signal attenuation at 6 GHz to
differ significantly from 5 GHz given the closeness in frequency. In
addition, large passenger aircraft normally fly at high altitudes which
will provide additional signal attenuation preventing signals from
reaching terrestrial fixed and mobile receivers. The only potential
area of concern would be if an aircraft flew through the main beam of a
microwave link during take-off or landing. To address this concern, the
Commission limits the use of low-power
[[Page 31408]]
access points for in-flight entertainment systems in aircraft to above
10,000 feet. Because the only data on the signal attenuation from
aircraft fuselage submitted on the record is for large passenger
aircraft, the Commission shall also limit use to this type of aircraft.
Finally, to prevent harmful interference to radio astronomy and earth
exploration satellite service, the Commission limits airborne use of
low-power access points to the U-NII-5 band where such passive
scientific operations do not occur.
Microwave Links in the Gulf of Mexico
133. The Commission does not find RigNet's technical study
regarding aggregate interference from indoor unlicensed devices
convincing for several reasons. RigNet's study presents a link budget
analysis of aggregate interference to each of ten microwave receivers
located on land. In each of the link budget calculations the study
assumes that a number of access points ranging from 2 to 100 are
present. For each receiver all the access points are assumed to be at
the same distance from the microwave receiver, but this distance varies
from 250 m to 5 km for the different receivers. The reason for assuming
these distances and number of access points is not explained. The study
assumes that the access points would transmit power at a power spectral
density of 23 dBm/MHz and that there would be 11 dB of building loss.
Because the Commission is only permitting access points to transmit at
5 dBm/MHz and, as discussed above, an appropriate assumption for
building loss is 20.5 dB, the calculated signal from each access point
should be 26.5 dB lower than what the study assumes. While the study
does not discuss the propagation model used, from the pathloss shown in
the link budgets it appears that free space was used for all cases. In
addition, the study assumes that every access point was directly in the
main beam of the microwave receiver, which is unrealistic considering
the height of the microwave receivers compared to the likely height of
the indoor access points. Thus, the Commission believes the calculated
interference levels should be at least 50 dB lower than what RigNet's
study finds. This is consistent with the Commission's conclusion that
microwave receivers will not experience harmful interference from
indoor access points. With respect to AFC-controlled devices, RigNet's
microwave links will be protected by the AFC as would any other
microwave link licensed in the 6 GHz band. RigNet's microwave network
appears to be no different from any other microwave links, which our
new unlicensed rules are designed to protect from harmful interference.
Accordingly, the Commission's rules do not exclude the Gulf of Mexico
from unlicensed operations.
Ultra-Wideband and Wideband
134. The Commission declines to adopt specific provisions to
provide special protections for ultra-wideband and wideband devices. As
ultra-wideband and wideband devices operate under Part 15 unlicensed
rules, taking such action would effectively provide those devices with
a level of interference protection to which they are not entitled.
Ultra-wideband and wideband devices are permitted to operate at a
variety of power levels, all of which are below -41.3 dBm/MHz. These
devices also operate over large bandwidths that are typically allocated
to a variety of services.
135. The Commission notes that ultra-wideband and wideband devices,
as with all unlicensed devices operating under our Part 15 rules, are
subject to the condition that they may receive interference--including
interference from other unlicensed devices. Unlicensed Part 15 devices
have no vested right in the continued use of any particular block of
spectrum. Moreover, ultra-wideband and wideband devices operate across
a varied spectrum landscape with different types of licensed services
(in this case, microwave links and satellite uplinks) that are governed
by differing service and technical rules. Thus, by their nature,
wideband and wideband devices must be designed to tolerate varying
levels of interference with no assurance of an interference-free
operating environment.
136. All of the provisions that the ultra-wideband and wideband
advocates request would in effect reserve spectrum in a manner that the
Commission has not previously contemplated or proposed for such
devices. The Commission declines to let the spectrum provisions
applicable to ultra-wideband and wideband devices preclude the
provision of other services that the Commission has widely permitted
under the unlicensed framework applicable to the U-NII bands. The
Commission's experience with the 2.4 GHz and existing U-NII bands has
shown that the adoption of technology neutral rules has resulted in an
explosion of innovation and the widespread adoption of unlicensed
technologies by consumers and businesses. The Commission expects a
similar experience to occur in the 6 GHz band. If the Commission were
to adopt the suggested limitations on power levels, available spectrum,
and duty cycle it would limit the range and data rates of the new
unlicensed devices in a way that limits their utility. The Commission
finds that it would not be in the public interest to restrict the use
of the 6 GHz band unlicensed devices in this way. However, the
Commission notes that the contention-based protocol requirement it is
adopting for low power indoor devices will limit the unlicensed device
duty cycle and that it could also detect the presence of ultra-wideband
and wideband devices. The Commission encourages ultra-wideband and
wideband interests to work with standards bodies to explore protocols
that may enhance those devices coexistence with new 6 GHz unlicensed
devices.
137. Additionally, the record provides compelling evidence of
circumstances where unlicensed devices operating under both the
existing and new rules will be able to peacefully co-exist. A study
submitted by Broadcom indicates that wideband devices may be able to
operate outdoors in areas immediately adjacent to locations where
unlicensed devices operating indoors under the new rules are deployed
and that, where devices are in close proximity, users will likely be
able to promote co-existence by adjusting the positioning of UWB and
RLAN devices. Thus, for ultra-wideband and wideband devices employed in
industrial applications and other indoor locations, the facility owner
will be able to exercise control over the use and placement of new
unlicensed devices, and if necessary, can choose which devices to
deploy to avoid unwanted interference. In addition, according to data
submitted by CableLabs, the weighted average of the activity factor for
Wi-Fi is 0.4% which is below the 0.5% activity factor suggested by the
ultra-wideband and wideband proponents to enable co-existence. Thus,
the Commission has reason to believe that in many cases ultra-wideband
and wideband devices will be able to operate in the presence of new
devices that will operate under the new 6 GHz unlicensed rules.
Synchronized Unlicensed Operation
138. Qualcomm requests that the Commission adopt a rule which it
claims will permit access points that use synchronized contention
windows to operate without disadvantaging other technologies. The
specific rule that Qualcomm requests would establish a synchronized
mode for unlicensed devices with contention windows every 6
milliseconds.
[[Page 31409]]
139. The Commission has historically adopted rules that are
technologically neutral and remains committed to this policy. This is
reflected by our U-NII rules which do not require the use of a
particular contention method for unlicensed devices to share access to
spectrum. The Commission's embrace of technology neutrality has
encouraged the development of a vast variety of unlicensed devices
operating under our Part 15 rules. In fact, Qualcomm has endorsed our
policy stating that this ``approach to both licensed and unlicensed
spectrum bands has supported perpetual innovation by the entire
wireless industry'' and that ``[t]here is no question that the FCC
should continue its successful tech neutral policy to existing and
future spectrum bands.'' While there may be ways to increase spectrum
efficiency by synchronization as Qualcomm advocates, this would
necessarily require restricting the flexibility that Part 15 has
permitted to U-NII devices. The Commission does not believe that this
would be an acceptable tradeoff and rejects Qualcomm's request.
140. The Commission also does not find convincing Qualcomm's
contention that granting its request would be in keeping with our
technology neutral policy. The Commission agrees with HP Enterprise
that ``far from being technologically neutral, the stated purpose of
[Qualcomm's] proposal is to advantage one specific type of unlicensed
technology over all others.'' The Commission also expects that
technologies other than IEEE 801.11be (EHT) or 5G NR-U will be used by
unlicensed devices in this band and do not see any reason to place
limitations on their operation.
Digital Identifying Information
141. The Commission declines to adopt a requirement that 6 GHz
unlicensed devices transmit digital identifying information. To impose
such a requirement requires the Commission to mandate a modulation
format for the transmitted information, which necessarily imposes
restrictions on the development of unlicensed technology in the band.
Given that the record has provided no details on how this requirement
will help resolve interference, the Commission does not believe that
imposing this requirement can be justified. The Commission also agrees
with those commenters who express concern that this requirement could
intrude upon the privacy of device users by facilitating tracking of
devices.
Benefits and Costs
142. Making available 1200 megahertz of spectrum in the 6 GHz band
for new types of unlicensed use will yield important economic benefits
and will allow more extensive use of technologies such as Wi-Fi and
Bluetooth by American consumers. Consumers are using more and more
data, on average, and this is expected to continue to grow
significantly. As demand for data increases, making more spectrum
available for two types of unlicensed use--standard-power and low-power
indoor--will provide economic benefits by relieving potential
congestion, allowing more users to access these new bands, and
potentially making new use cases possible. As noted above, the ability
of unlicensed devices to use significant portions of this band may also
complement new licensed 5G services by allowing providers to offer a
full range of services to consumers and will help to secure U.S.
leadership in the next generation of wireless services. One report
cited by several commenters estimates that in 2018, the economic
benefits associated with Wi-Fi in the United States was valued at
almost $500 billion. A further report estimated that these new rules
will produce over $150 billion in economic value. In some ways,
unlicensed usage on the new spectrum will be more restricted than for
current Wi-Fi usage due to the AFC and lower power limits. However, in
the United States, Wi-Fi currently operates in different bands over
nearly 700 megahertz of spectrum, none of which enables channels as
large as 160 megahertz. Making an additional 1200 megahertz of 6 GHz
spectrum available for unlicensed use, including enabling the use of
160-megahertz channels that will lead to expanded throughput, capacity,
and performance will have a significant economic benefit.
143. The Commission notes, however, that the new rules for
unlicensed spectrum use could impose some economic costs if harmful
interference to incumbent services occurs. As explained above, the
technical and operational rules are designed to minimize the potential
interference to incumbent licensed uses. While under the rules there
can be interference with ultra-wideband and wideband applications,
these costs will be lower than the total U.S. economic value for ultra-
wideband and wideband products, which in turn, are lower than the total
economic value of new unlicensed use. The CableLabs study gives reason
to believe that interference with ultra-wideband and wideband will only
be intermittent, so that coexistence with new users will be possible.
Further, when ultra-wideband and wideband use is specific to an indoor
facility, it will be feasible for facility owners to prevent
interference by regulating use of unlicensed activity within the
facility. Thus, in most cases, the full value of ultra-wideband or
wideband will be preserved, with only management costs incurred by
facility owners. While the Commission is unable to precisely estimate
the value of U.S. ultra-wideband and wideband, one market research firm
cited the global value of the ultra-wideband industry will be $85.4
million in 2022. In addition, the Commission notes that revenues from a
non-exhaustive list of U.S. firms producing ultra-wideband products,
among others, imply that even if costs are incurred, they will be
significantly less than the potential hundreds of billions of dollars
of economic value created. Overall, while the Commission identifies
some economic costs, the Commission believes that they are limited and
do not outweigh the substantial economic benefits of making such a
large amount of spectrum available for unlicensed use.
Procedural Matters
144. Final Regulatory Flexibility Analysis.--As required by the
Regulatory Flexibility Act of 1980 (RFA), as amended, the Commission
has prepared a Final Regulatory Flexibility Analysis (FRFA) regarding
the possible significant economic impact on small entities of the
policies and rules adopted in this First Report and Order, which is
found in Appendix B of the link provided in the beginning of this
SUPPLEMENTARY INFORMATION section. The Commission's Consumer and
Governmental Affairs Bureau, Reference Information Center, will send a
copy of the Report and Order, including the FRFA, to the Chief Counsel
for Advocacy of the Small Business Administration.
145. Paperwork Reduction Act Analysis.--This document does not
contain new or modified information collection requirements subject to
the Paperwork Reduction Act of 1995 (PRA), Public Law 104-13. In
addition, therefore, it does not contain any new or modified
information collection burden for small business concerns with fewer
than 25 employees, pursuant to the Small Business Paperwork Relief Act
of 2002, Public Law 107-198, see 44 U.S.C. 3506(c)(4).
146. Congressional Review Act.--The Commission has determined, and
the Administrator of the Office of Information and Regulatory Affairs,
[[Page 31410]]
Office of Management and Budget, concurs that this rule is major under
the Congressional Review Act, 5 U.S.C. 804(2). The Commission will send
a copy of this Report & Order to Congress and the Government
Accountability Office pursuant to 5 U.S.C. 801(a)(1)(A).
Ordering Clauses
147. Accordingly, it is ordered, pursuant to Sections 4(i), 201,
302, and 303 of the Communications Act of 1934, as amended, 47 U.S.C.
154(i), 201, 302a, 303, and Section 1.411 of the Commission's Rules, 47
CFR 1.411; that this Report and Order and Further Notice of Proposed
Rulemaking, is hereby adopted.
148. It is further ordered that the amendments of the Commission's
rules as set forth in Appendix A are adopted, effective sixty days from
the date of publication in the Federal Register.
149. It is further ordered that the Commission's Consumer and
Governmental Affairs Bureau, Reference Information Center, shall send a
copy of this Report and Order and Further Notice of Proposed
Rulemaking, including the Initial and Final Regulatory Flexibility
Analyses, to the Chief Counsel for Advocacy of the Small Business
Administration.
150. It is further ordered that the Commission's Consumer and
Governmental Affairs Bureau, Reference Information Center, shall send a
copy of this Report and Order and Further Notice of Proposed
Rulemaking, including the Initial and Final Regulatory Flexibility
Analysis, to Congress and the Government Accountability Office pursuant
to the Congressional Review Act, see 5 U.S.C. 801(a)(1)(A).
List of Subjects
47 CFR Part 0
Reporting and recordkeeping requirements, Telecommunications.
47 CFR Part 15
Communications equipment, Radio.
Federal Communications Commission.
Cecilia Sigmund,
Federal Register Liaison Officer.
Final Rules
For the reasons discussed in the preamble, the Federal
Communications Commission amends 47 parts 0 and 15 as follows:
PART 0--COMMISSION ORGANIZATION
0
1. The authority citation for Part 0 continues to read as follows:
Authority: Secs. 5, 48 Stat. 1068, as amended; 47 U.S.C. 155.
0
2. Section 0.241 is amended by adding paragraph (k) to read as follows:
Sec. 0.241 Authority delegated.
* * * * *
(k) The Chief of the Office of Engineering and Technology is
delegated authority to administer the Automated Frequency Coordination
(AFC) system and AFC system operator functions set forth in subpart E
of part 15 of this chapter. The Chief is delegated authority to develop
specific methods that will be used to designate AFC system operators;
to designate AFC system operators; to develop procedures that these AFC
system operators will use to ensure compliance with the requirements
for AFC system operations; to make determinations regarding the
continued acceptability of individual AFC system operators; and to
perform other functions as needed for the administration of the AFC
systems.
PART 15--RADIO FREQUENCY DEVICES
0
3. The authority citation for Part 15 continues to read as follows:
Authority: 47 U.S.C. 154, 302a, 303, 304, 307, 336, 544a, and
549.
0
4. Section 15.401 is revised to read as follows:
Sec. 15.401 Scope.
This subpart sets out the regulations for unlicensed National
Information Infrastructure (U-NII) devices operating in the 5.15-5.35
GHz, 5.47-5.725 GHz, 5.725-5.85 GHz, and 5.925-7.125 GHz bands.
0
5. Section 15.403 is revised to read as follows:
Sec. 15.403 Definitions.
Access Point (AP). A U-NII transceiver that operates either as a
bridge in a peer-to-peer connection or as a connector between the wired
and wireless segments of the network or as a relay between wireless
network segments.
Automated Frequency Coordination (AFC) System. A system that
automatically determines and provides lists of which frequencies are
available for use by standard power access points operating in the
5.925-6.425 GHz and 6.525-6.875 GHz bands.
Available Channel. A radio channel on which a Channel Availability
Check has not identified the presence of a radar.
Average Symbol Envelope Power. The average symbol envelope power is
the average, taken over all symbols in the signaling alphabet, of the
envelope power for each symbol.
Channel Availability Check. A check during which the U-NII device
listens on a particular radio channel to identify whether there is a
radar operating on that radio channel.
Channel Move Time. The time needed by a U-NII device to cease all
transmissions on the current channel upon detection of a radar signal
above the DFS detection threshold.
Client Device. A U-NII device whose transmissions are generally
under the control of an access point and is not capable of initiating a
network
Contention-based protocol. A protocol that allows multiple users to
share the same spectrum by defining the events that must occur when two
or more transmitters attempt to simultaneously access the same channel
and establishing rules by which a transmitter provides reasonable
opportunities for other transmitters to operate. Such a protocol may
consist of procedures for initiating new transmissions, procedures for
determining the state of the channel (available or unavailable), and
procedures for managing retransmissions in the event of a busy channel.
Digital modulation. The process by which the characteristics of a
carrier wave are varied among a set of predetermined discrete values in
accordance with a digital modulating function as specified in document
ANSI C63.17-1998.
Dynamic Frequency Selection (DFS) is a mechanism that dynamically
detects signals from other systems and avoids co-channel operation with
these systems, notably radar systems.
DFS Detection Threshold. The required detection level defined by
detecting a received signal strength (RSS) that is greater than a
threshold specified, within the U-NII device channel bandwidth.
Emission bandwidth. For purposes of this subpart the emission
bandwidth is determined by measuring the width of the signal between
two points, one below the carrier center frequency and one above the
carrier center frequency, that are 26 dB down relative to the maximum
level of the modulated carrier.
Fixed client device. For the purpose of this subpart, a client
device intended as customer premise equipment that is permanently
attached to a structure, operates only on channels provided by an AFC,
has a geolocation capability, and complies with antenna pointing angle
requirements.
[[Page 31411]]
Indoor Access Point. For the purpose of this subpart, an access
point that operates in the 5.925-7.125 GHz band, is supplied power from
a wired connection, has an integrated antenna, is not battery powered,
and does not have a weatherized enclosure.
In-Service Monitoring. A mechanism to check a channel in use by the
U-NII device for the presence of a radar.
Non-Occupancy Period. The required period in which, once a channel
has been recognized as containing a radar signal by a U-NII device, the
channel will not be selected as an available channel.
Operating Channel. Once a U-NII device starts to operate on an
Available Channel then that channel becomes the Operating Channel.
Maximum Power Spectral Density. The maximum power spectral density
is the maximum power spectral density, within the specified measurement
bandwidth, within the U-NII device operating band.
Maximum Conducted Output Power. The total transmit power delivered
to all antennas and antenna elements averaged across all symbols in the
signaling alphabet when the transmitter is operating at its maximum
power control level. Power must be summed across all antennas and
antenna elements. The average must not include any time intervals
during which the transmitter is off or is transmitting at a reduced
power level. If multiple modes of operation are possible (e.g.,
alternative modulation methods), the maximum conducted output power is
the highest total transmit power occurring in any mode.
Power Spectral Density. The power spectral density is the total
energy output per unit bandwidth from a pulse or sequence of pulses for
which the transmit power is at its maximum level, divided by the total
duration of the pulses. This total time does not include the time
between pulses during which the transmit power is off or below its
maximum level.
Pulse. A pulse is a continuous transmission of a sequence of
modulation symbols, during which the average symbol envelope power is
constant.
RLAN. Radio Local Area Network.
Standard Power Access Point. An access point that operates in the
5.925-6.425 GHz and 6.525-6.875 GHz bands pursuant to direction from an
Automated Frequency Coordination System.
Subordinate Device. For the purpose of this subpart, a device that
operates in the 5.925-7.125 GHz band under the control of an Indoor
Access Point, is supplied power from a wired connection, has an
integrated antenna, is not battery powered, does not have a weatherized
enclosure, and does not have a direct connection to the internet.
Subordinate devices must not be used to connect devices between
separate buildings or structures. Subordinate devices must be
authorized under certification procedures in part 2 of this chapter.
Modules may not be certified as subordinate devices.
Transmit Power Control (TPC). A feature that enables a U-NII device
to dynamically switch between several transmission power levels in the
data transmission process.
U-NII devices. Intentional radiators operating in the frequency
bands 5.15-5.35 GHz, 5.470-5.85 GHz, 5.925-7125 GHz that use wideband
digital modulation techniques and provide a wide array of high data
rate mobile and fixed communications for individuals, businesses, and
institutions.
0
6. Section 15.407 is amended by:
0
A. Redesignating paragraphs (a)(4) and (5) as (a)(11) and (12);
0
B. Adding paragraphs (a)(4) through (10);
0
C. Revising newly redesignated paragraph (a)(12);
0
D. Redesignating paragraphs (b)(5) through (8) as (b)(7) through (10);
0
E. Adding paragraphs (b)(5) and (6), (d) and (k) through (n).
The additions and revisions read as follows.
Sec. 15.407 General technical requirements.
(a) * * *
(4) For a standard power access point and fixed client device
operating in the 5.925-6.425 GHz and 6.525-6.875 GHz bands, the maximum
power spectral density must not exceed 23 dBm e.i.r.p in any 1-
megahertz band. In addition, the maximum e.i.r.p. over the frequency
band of operation must not exceed 36 dBm. For outdoor devices, the
maximum e.i.r.p. at any elevation angle above 30 degrees as measured
from the horizon must not exceed 125 mW (21 dBm).
(5) For an indoor access point operating in the 5.925-7.125 GHz
band, the maximum power spectral density must not exceed 5 dBm e.i.r.p.
in any 1-megahertz band. In addition, the maximum e.i.r.p. over the
frequency band of operation must not exceed 30 dBm.
(6) For a subordinate device operating under the control of an
indoor access point in the 5.925-7.125 GHz band, the maximum power
spectral density must not exceed 5 dBm e.i.r.p in any 1-megahertz band,
and the maximum e.i.r.p. over the frequency band of operation must not
exceed 30 dBm.
(7) For client devices, except for fixed client devices as defined
in this subpart, operating under the control of a standard power access
point in 5.925-6.425 GHz and 6.525-6.875 GHz bands, the maximum power
spectral density must not exceed 17 dBm e.i.r.p. in any 1-megahertz
band, and the maximum e.i.r.p. over the frequency band of operation
must not exceed 30 dBm and the device must limit its power to no more
than 6 dB below its associated standard power access point's authorized
transmit power.
(8) For client devices operating under the control of an indoor
access point in the 5.925-7.125 GHz bands, the maximum power spectral
density must not exceed -1 dBm e.i.r.p. in any 1-megahertz band, and
the maximum e.i.r.p. over the frequency band of operation must not
exceed 24 dBm.
(9) Access points operating under the provisions of paragraphs
(a)(5) and (a)(6) of this section must employ a permanently attached
integrated antenna.
(10) The maximum transmitter channel bandwidth for U-NII devices in
the 5.925-7.125 GHz band is 320 megahertz
* * * * *
(12) Power spectral density measurement. The maximum power spectral
density is measured as either a conducted emission by direct connection
of a calibrated test instrument to the equipment under test or a
radiated measurement. Measurements in the 5.725-5.85 GHz band are made
over a reference bandwidth of 500 kHz or the 26 dB emission bandwidth
of the device, whichever is less. Measurements in all other bands are
made over a bandwidth of 1 MHz or the 26 dB emission bandwidth of the
device, whichever is less. A narrower resolution bandwidth can be used,
provided that the measured power is integrated over the full reference
bandwidth.
(b) * * *
(5) For transmitters operating within the 5.925-7.125 GHz band: Any
emissions outside of the 5.925-7.125 GHz band must not exceed an
e.i.r.p. of -27 dBm/MHz.
(6) For transmitters operating within the 5.925-7.125 GHz bands:
Power spectral density must be suppressed by 20 dB at 1 MHz outside of
channel edge, by 28 dB at one channel bandwidth from the channel
center, and by 40 dB at one- and one-half times the channel bandwidth
away from channel center. At frequencies between one megahertz
[[Page 31412]]
outside an unlicensed device's channel edge and one channel bandwidth
from the center of the channel, the limits must be linearly
interpolated between 20 dB and 28 dB suppression, and at frequencies
between one and one- and one-half times an unlicensed device's channel
bandwidth, the limits must be linearly interpolated between 28 dB and
40 dB suppression. Emissions removed from the channel center by more
than one- and one-half times the channel bandwidth must be suppressed
by at least 40 dB.
* * * * *
(d) Operational restrictions for 6 GHz U-NII devices. (1) Operation
of standard access points, fixed client devices and indoor access
points in the 5.925-7.125 GHz band is prohibited on oil platforms,
cars, trains, boats, and aircraft, except that indoor access points are
permitted to operate in the 5.925-6.425 GHz bands in large aircraft
while flying above 10,000 feet.
(2) Operation of transmitters in the 5.925-7.125 GHz band is
prohibited for control of or communications with unmanned aircraft
systems.
(3) Transmitters operating under the provisions of paragraphs
(a)(5), (a)(6), and (a)(8) of this section are limited to indoor
locations.
(4) In the 5.925-7.125 GHz band, indoor access points and
subordinate devices must bear the following statement in a conspicuous
location on the device and in the user's manual: FCC regulations
restrict operation of this device to indoor use only. The operation of
this device is prohibited on oil platforms, cars, trains, boats, and
aircraft, except that operation of this device is permitted in large
aircraft while flying above 10,000 feet.
(5) In the 5.925-7.125 GHz band, client devices, except fixed
client devices, must operate under the control of a standard power
access point, indoor access point or subordinate devices; Subordinate
devices must operate under the control of an indoor access point. In
all cases, an exception exists for transmitting brief messages to an
access point when attempting to join its network after detecting a
signal that confirms that an access point is operating on a particular
channel. Access points and subordinate devices may connect to other
access points or subordinate devices. Client devices are prohibited
from connecting directly to another client device.
(6) Indoor access points, subordinate devices and client devices
operating in the 5.925-7.125 GHz band must employ a contention-based
protocol.
(7) Fixed client devices may only connect to a standard power
access point.
* * * * *
(k) Automated frequency coordination (AFC) system. (1) Standard
power access points and fixed client devices operating under paragraph
(a)(4) of this section must access an AFC system to determine the
available frequencies and the maximum permissible power in each
frequency range at their geographic coordinates prior to transmitting.
Standard power access points and fixed client devices may transmit only
on frequencies and at power levels that an AFC system indicates as
available.
(2) An AFC system must be capable of determining the available
frequencies in steps of no greater than 3 dB below the maximum
permissible e.i.r.p of 36 dBm, and down to at least a minimum level of
21 dBm.
(3) An AFC system must obtain information on protected services
within the 5.925-6.425 GHz and 6.525-6.875 GHz bands from Commission
databases and use that information to determine frequency availability
for standard power access points and fixed client devices based on
protection criteria specified in paragraph (l)(2) of this section.
(4) An AFC system must use the information supplied by standard
power access points and fixed client devices during registration, as
set forth in this section, to determine available frequencies and the
maximum permissible power in each frequency range for a standard power
access point at any given location. All such determinations and
assignments must be made in a non-discriminatory manner, consistent
with this part.
(5) An AFC system must store registered information in a secure
database until a standard power access point or fixed client device
ceases operation at a location. For the purpose of this paragraph, a
standard power access point or fixed client device is considered to
have ceased operation when that device has not contacted the AFC system
for more than three months to verify frequency availability
information.
(6) An AFC system must verify the validity of the FCC identifier
(FCC ID) of any standard power access point and fixed client device
seeking access to its services prior to authorizing the access point to
begin operation. A list of standard power access points with valid FCC
IDs and the FCC IDs of those devices must be obtained from the
Commission's Equipment Authorization System.
(7) The general purposes of AFC system include:
(i) Enacting all policies and procedures developed by the AFC
system operators pursuant to this section.
(ii) Registering, authenticating, and authorizing standard power
access point and fixed client device operations, individually or
through a network element device representing multiple standard power
access points from the same operating network.
(iii) Providing standard power access points and fixed client
devices with the permissible frequencies and the maximum permissible
power in each frequency range at their locations using propagation
models and interference protection criteria defined in paragraph (l) of
this section.
(iv) Obtaining updated protected sites information from Commission
databases.
(8) Standard power access points and fixed client devices:
(i) Must register with and be authorized by an AFC system prior to
the standard power access point and fixed client device's initial
service transmission, or after a standard power access point or fixed
client device changes location, and must obtain a list of available
frequencies and the maximum permissible power in each frequency range
at the standard power access point and fixed client device's location.
(ii) Must register with the AFC system by providing the following
parameters: Geographic coordinates (latitude and longitude referenced
to North American Datum 1983 (NAD 83)), antenna height above ground
level, FCC identification number, and unique manufacturer's serial
number. If any of these parameters change, the standard power access
point or fixed client device must provide updated parameters to the AFC
system. All information provided by the standard power access point and
the fixed client device to the AFC system must be true, complete,
correct, and made in good faith.
(iii) Must provide the registration information to the AFC system
either directly and individually or by a network element representing
multiple standard power access points or fixed client devices from the
same operating network. The standard power access point, fixed client
device or its network element must register with the AFC system via any
communication link, wired or wireless, outside 5.925-6.425 GHz and
6.525-6.875 GHz bands.
(iv) Must contact an AFC system at least once per day to obtain the
latest list of available frequencies and the
[[Page 31413]]
maximum permissible power the standard power access point or fixed
client device may operate with on each frequency at the standard power
access point and fixed client device's location. If the standard power
access point or fixed client device fails to successfully contact the
AFC system during any given day, the standard power access point or
fixed client device may continue to operate until 11:59 p.m. of the
following day at which time it must cease operations until it re-
establishes contact with the AFC system and re-verifies its list of
available frequencies and associated power levels.
(v) Must incorporate adequate security measures to prevent it from
accessing AFC systems not approved by the FCC and to ensure that
unauthorized parties cannot modify the device to operate in a manner
inconsistent with the rules and protection criteria set forth in this
section and to ensure that communications between standard power access
points, fixed client devices and AFC systems are secure to prevent
corruption or unauthorized interception of data. Additionally, the AFC
system must incorporate security measures to protect against
unauthorized data input or alteration of stored data, including
establishing communications authentication procedures between client
devices and standard power access points.
(9) Standard power access point and fixed client device geo-
location capability:
(i) A standard power access point and a fixed client device must
include either an internal geo-location capability or an integrated
capability to securely connect to an external geolocation devices or
service, to automatically determine the standard power access point's
geographic coordinates and location uncertainty (in meters), with a
confidence level of 95%. The standard power access point and fixed
client device must report such coordinates and location uncertainty to
an AFC system at the time of activation from a power-off condition.
(ii) An external geo-location source may be connected to a standard
power access point or fixed client device through either a wired or a
wireless connection. A single geo-location source may provide location
information to multiple standard power access points or fixed client
devices.
(iii) An external geo-location source must be connected to a
standard power access point or fixed client device using a secure
connection that ensures that only an external geo-location source
approved for use with a standard power access point or fixed client
device provides geographic coordinates to that standard power access
point or fixed client device. Alternatively, an extender cable may be
used to connect a remote receive antenna to a geo-location receiver
within a standard power access point or fixed client device.
(iv) The applicant for certification of a standard power access
point or fixed client device must demonstrate the accuracy of the geo-
location method used and the location uncertainty. For standard power
access points and fixed client devices that may not use an internal
geo-location capability, this uncertainty must account for the accuracy
of the geo-location source and the separation distance between such
source and the standard power access point or fixed client device.
(10) An AFC system operator will be designated for a five-year term
which can be renewed by the Commission based on the operator's
performance during the term. If an AFC system ceases operation, it must
provide at least 30-days' notice to the Commission and transfer any
registration data to another AFC system operator.
(11) The Commission will designate one or more AFC system operators
to provide service in the 5.925-6.425 GHz and 6.525-6.875 GHz bands.
(12) The Commission may permit the functions of an AFC system, such
as a data repository, registration, and query services, to be divided
among multiple entities; however, entities designated as AFC system
operators will be held accountable for the overall functioning and
system administration of the AFC system.
(13) The AFC system must ensure that all communications and
interactions between the AFC system and standard power access points
and fixed client devices are accurate and secure and that unauthorized
parties cannot access or alter the database, or the list of available
frequencies and associated powers sent to a standard power access
point.
(14) An AFC system must implement the terms of international
agreements with Mexico and Canada.
(15) Each AFC system operator designated by the Commission must:
(i) Maintain a regularly updated AFC system database that contains
the information described in this section, including incumbent's
information and standard power access points and fixed client devices
registration parameters.
(ii) Establish and follow protocols and procedures to ensure
compliance with the rules set forth in this part.
(iii) Establish and follow protocols and procedures sufficient to
ensure that all communications and interactions between the AFC system
and standard power access points and fixed client devices are accurate
and secure and that unauthorized parties cannot access or alter the AFC
system, or the information transmitted from the AFC system to standard
power access points or fixed client devices.
(iv) Provide service for a five-year term. This term may be renewed
at the Commission's discretion.
(v) Respond in a timely manner to verify, correct, or remove, as
appropriate, data in the event that the Commission or a party presents
to the AFC system Operator a claim of inaccuracies in the AFC system.
This requirement applies only to information that the Commission
requires to be stored in the AFC system.
(vi) Establish and follow protocols to comply with enforcement
instructions from the Commission, including discontinuance of standard
power access point operations in designated geographic areas.
(16) An AFC system operator may charge fees for providing service
in registration and channel availability functions. The Commission may,
upon request, review the fees and can require changes to those fees if
the Commission finds them unreasonable.
(l) Incumbent Protection by AFC system: Fixed Microwave Services. A
standard power access point or fixed client device must not cause
harmful interference to fixed microwave services authorized to operate
in the 5.925-6.425 GHz and 6.525-6.875 GHz bands. Based on the criteria
set forth below, an AFC system must establish location and frequency-
based exclusion zones (both co-channel and adjacent channel) around
fixed microwave receivers operating in the 5.925-6.425 GHz and 6.525-
6.875 GHz bands. Individual standard power access points and fixed
client devices must not operate co-channel to fixed microwave system
frequencies within co-channel exclusion zones, or on adjacent channel
frequencies within adjacent channel exclusion zones.
(1) Propagation Models: Propagation models to determine the
appropriate separation distance between a standard power access point
or a fixed client device and an incumbent fixed microwave service
receiver. For a separation distance:
(i) Up to 30 meters, the AFC system must use the free space path-
loss model.
(ii) More than 30 meters and up to and including one kilometer, the
AFC system must use the Wireless World Initiative New Radio phase II
(WINNER II) model. The AFC system must use site-specific information,
including buildings and terrain data, for
[[Page 31414]]
determining the line-of-sight/non-line-of-sight path component in the
WINNER II model, where such data is available. For evaluating paths
where such data is not available, the AFC system must use a
probabilistic model combining the line-of-sight path and non-line-of-
sight path into a single path-loss as follows:
Path-loss (L) = [Sigma]i P(i) * Li =
PLOS * LLOS + PNLOS *
LNLOS,
where PLOS is the probability of line-of-sight,
LLOS is the line-of-sight path loss, PNLOS is the
probability of non-line-of sight, LNLOS is the non-line-of-
sight path loss, and L is the combined path loss. The WINNER II path
loss models include a formula to determine PLOS as a
function of antenna heights and distance. PNLOS is equal to
(1-PLOS). In all cases, the AFC system will use the correct
WINNER II parameters to match the morphology of the path between a
standard power access point and a fixed microwave receiver (i.e.,
Urban, Suburban, or Rural).
(iii) More than one kilometer, the AFC system must use Irregular
Terrain Model (ITM) combined with the appropriate clutter model. To
account for the effects of clutter, such as buildings and foliage, that
the AFC system must combine the ITM with the ITU-R P.2108-0 (06/2017)
clutter model for urban and suburban environments and the ITU-R P.452-
16 (07/2015) clutter model for rural environments. The AFC system
should use the most appropriate clutter category for the local
morphology when using ITU-R P.452-16. However, if detailed local
information is not available, the ``Village Centre'' clutter category
should be used. The AFC system must use 1 arc-second digital elevation
terrain data and, for locations where such data is not available, the
most granular available digital elevation terrain data.
(2) Interference Protection Criteria:
(i) The AFC system must use -6 dB I/N as the interference
protection criteria in determining the size of the co-channel exclusion
zone where I (interference) is the co-channel signal from the standard
power access point or fixed client device at the fixed microwave
service receiver, and N (noise) is background noise level at the fixed
microwave service receiver.
(ii) The AFC system must use -6 dB I/N as the interference
protection criteria in determining the size of the adjacent channel
exclusion zone, where I (interference) is the signal from the standard
power access point or fixed client device's out of channel emissions at
the fixed microwave service receiver and N (noise) is background noise
level at the fixed microwave service receiver. The adjacent channel
exclusion zone must be calculated based on the emissions requirements
of paragraph (b)(6) of this section.
(m) Incumbent Protection by AFC system: Radio Astronomy Services.
The AFC system must enforce an exclusion zones to the following radio
observatories that observe between 6650-6675.2 MHz: Arecibo
Observatory, the Green Bank Observatory, the Very Large Array (VLA),
the 10 Stations of the Very Long Baseline Array (VLBA), the Owens
Valley Radio Observatory, and the Allen Telescope Array. The exclusion
zone sizes are based on the radio line-of-sight and determined using
\4/3\ earth curvature and the following formula:
dkm_los = 4.12 * (sqrt(Htx) + sqrt(Hrx)),
where Htx is the height of the unlicensed standard power access point
or fixed client device and Hrx is the height of the radio astronomy
antenna in meters above ground level. Coordinate locations of the radio
observatories are listed in section 2.106, notes US 131 and US 385 of
this part.
(n) Incumbent Protection by AFC system: Fixed-Satellite Services.
Standard power access points and fixed client devices located outdoors
must limit their maximum e.i.r.p. at any elevation angle above 30
degrees as measured from the horizon to 21 dBm (125 mW) to protect
fixed satellite services.
[FR Doc. 2020-11236 Filed 5-22-20; 8:45 am]
BILLING CODE 6712-01-P