Proposed Rule2023-28620
Unlicensed Use of the 6 GHz Band; and Expanding Flexible Use in Mid-Band Spectrum Between 3.7 and 24 GHz
Primary source
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Published
February 26, 2024
Issuing agencies
Federal Communications Commission
Abstract
In this document, the Federal Communications Commission (Commission) explores additional steps it could take and rules it could modify to provide more utility for very low power (VLP) unlicensed devices. Specifically, the Commission seeks comment on permitting higher power VLP devices under a two-tiered system where those higher powered devices would be permitted to operate only in locations where the potential for causing harmful interference to incumbent operations remains insignificant. The Commission's decision provides a balance between accommodating these new and novel devices to deliver innovative applications to the American public now and taking a judicious approach toward modifying the rules to provide even more robust use at most locations. The Commission also seeks comment on VLP device requirements and limits for operation in the U- NII-6 (6.425-6.525 GHz) and U-NII-8 (6.875-7.125 GHz) bands.
Full Text
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<title>Federal Register, Volume 89 Issue 38 (Monday, February 26, 2024)</title>
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[Federal Register Volume 89, Number 38 (Monday, February 26, 2024)]
[Proposed Rules]
[Pages 14015-14036]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-28620]
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FEDERAL COMMUNICATIONS COMMISSION
47 CFR Part 15
[ET Docket No. 18-295 and GN Docket No. 17-183; FCC 23-86; FR ID
192755]
Unlicensed Use of the 6 GHz Band; and Expanding Flexible Use in
Mid-Band Spectrum Between 3.7 and 24 GHz
AGENCY: Federal Communications Commission.
ACTION: Proposed rule.
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SUMMARY: In this document, the Federal Communications Commission
(Commission) explores additional steps it could take and rules it could
modify to provide more utility for very low power (VLP) unlicensed
devices. Specifically, the Commission seeks
[[Page 14016]]
comment on permitting higher power VLP devices under a two-tiered
system where those higher powered devices would be permitted to operate
only in locations where the potential for causing harmful interference
to incumbent operations remains insignificant. The Commission's
decision provides a balance between accommodating these new and novel
devices to deliver innovative applications to the American public now
and taking a judicious approach toward modifying the rules to provide
even more robust use at most locations. The Commission also seeks
comment on VLP device requirements and limits for operation in the U-
NII-6 (6.425-6.525 GHz) and U-NII-8 (6.875-7.125 GHz) bands.
DATES: Comments are due on or before March 27, 2024 and reply comments
are due on or before April 26, 2024.
ADDRESSES: You may submit comments, identified by ET Docket No. 13-115
and RM-11341, by any of the following methods:
Federal Communications Commission's Website: <a href="https://www.fcc.gov/ecfs/">https://www.fcc.gov/ecfs/</a>. Follow the instructions for submitting comments.
<bullet> Mail: Filings can be sent by hand or messenger delivery,
by commercial overnight courier, or by first-class or overnight U.S.
Postal Service mail (although the Commission continues to experience
delays in receiving U.S. Postal Service mail). All filings must be
addressed to the Commission's Secretary, Office of the Secretary,
Federal Communications Commission.
<bullet> People with Disabilities: Contact the Commission to
request reasonable accommodations (accessible format documents, sign
language interpreters, CART, etc.) by email: <a href="/cdn-cgi/l/email-protection#dc9a9f9fe9ece89cbabfbff2bbb3aa"><span class="__cf_email__" data-cfemail="2c6a6f6f191c186c4a4f4f024b435a">[email protected]</span></a> or phone:
202-418-0530 or TTY: 202-418-0432.
For detailed instructions for submitting comments and additional
information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Nicholas Oros of the Office of
Engineering and Technology, at <a href="/cdn-cgi/l/email-protection#bdf3d4ded5d2d1dcce93f2cfd2cefddbdede93dad2cb"><span class="__cf_email__" data-cfemail="cd83a4aea5a2a1acbee382bfa2be8dabaeaee3aaa2bb">[email protected]</span></a> or 202-418-0636.
SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Second
Further Notice of Proposed Rulemaking, ET Docket No. 18-295 and GN
Docket No. 17-183; FCC 23-86, adopted on October 19, 2023 and released
on November 1, 2023. The full text of this document is available for
public inspection and can be downloaded at: <a href="https://docs.fcc.gov/public/attachments/FCC-23-86A1.pdf">https://docs.fcc.gov/public/attachments/FCC-23-86A1.pdf</a>. Alternative formats are available
for people with disabilities (Braille, large print, electronic files,
audio format) by sending an email to <a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="55333636606561153336367b323a23">[email protected]</a> or calling the
Commission's Consumer and Governmental Affairs Bureau at (202) 418-0530
(voice), (202) 418-0432 (TTY).
Comment Period and Filing Procedures. Pursuant to sections 1.415
and 1.419 of the Commission's rules, 47 CFR 1.415, 1.419, interested
parties may file comments and reply comments on or before the dates
indicated on the first page of this document. For comments regarding
the Second Further Notice, comments must be filed in ET Docket No. 13-
115. Comments may be filed using the Commission's Electronic Comment
Filing System (ECFS). See Electronic Filing of Documents in Rulemaking
Proceedings, 63 FR 24121 (1998).
<bullet> All filings must be addressed to the Commission's
Secretary, Office of the Secretary, Federal Communications Commission.
<bullet> Electronic Filers: Comments may be filed electronically
using the internet by accessing the ECFS: <a href="https://www.fcc.gov/ecfs/">https://www.fcc.gov/ecfs/</a>.
[ssquf] Paper Filers: Parties who choose to file by paper must file
an original and one copy of each filing. If more than one docket or
rulemaking number appears in the caption of this proceeding, filers
must submit two additional copies for each additional docket or
rulemaking number.
[cir] Commercial overnight mail (other than U.S. Postal Service
Express Mail and Priority Mail) must be sent to 9050 Junction Drive,
Annapolis Junction, MD 20701.
[cir] U.S. Postal Service first-class, Express, and Priority mail
must be addressed to 45 L Street NE, Washington, DC 20554.
Ex Parte Presentations. These proceedings shall be treated as
``permit-but-disclose'' proceedings in accordance with the Commission's
ex parte rules. Persons making ex parte presentations must file a copy
of any written presentation or a memorandum summarizing any oral
presentation within two business days after the presentation (unless a
different deadline applicable to the Sunshine period applies). Persons
making oral ex parte presentations are reminded that memoranda
summarizing the presentation must (1) list all persons attending or
otherwise participating in the meeting at which the ex parte
presentation was made, and (2) summarize all data presented and
arguments made during the presentation. If the presentation consisted
in whole or in part of the presentation of data or arguments already
reflected in the presenter's written comments, memoranda or other
filings in the proceeding, the presenter may provide citations to such
data or arguments in his or her prior comments, memoranda, or other
filings (specifying the relevant page and/or paragraph numbers where
such data or arguments can be found) in lieu of summarizing them in the
memorandum. Documents shown or given to Commission staff during ex
parte meetings are deemed to be written ex parte presentations and must
be filed consistent with rule 1.1206(b). In proceedings governed by
rule 1.49(f) or for which the Commission has made available a method of
electronic filing, written ex parte presentations and memoranda
summarizing oral ex parte presentations, and all attachments thereto,
must be filed through the electronic comment filing system available
for that proceeding, and must be filed in their native format (e.g.,
.doc, .xml, .ppt, searchable .pdf). Participants in this proceeding
should familiarize themselves with the Commission's ex parte rules.
Paperwork Reduction Act. This document may contain proposed
modified information collection requirements. The Commission, as part
of its continuing effort to reduce paperwork burdens, invites the
general public and the Office of Management and Budget to comment on
the information collection requirements contained in this document, as
required by the Paperwork Reduction Act of 1995, Public Law 104-13. In
addition, pursuant to the Small Business Paperwork Relief Act of 2002,
Public Law 107-198, see 44 U.S.C. 3506(c)(4)), the Commission seeks
specific comment on how it might further reduce the information
collection burden for small business concerns with fewer than 25
employees.
Procedural Matters
Initial Regulatory Flexibility Analysis. The Commission has also
prepared an Initial Regulatory Flexibility Analysis (IRFA) concerning
the potential impact of the rule and policy changes contained in the
Second Further Notice of Proposed Rulemaking. The IRFA is set forth in
Appendix D of the FCC document, <a href="https://docs.fcc.gov/public/attachments/FCC-23-86A1.pdf">https://docs.fcc.gov/public/attachments/FCC-23-86A1.pdf</a>. Written public comments are requested on
the IRFA. Comments must be filed by the deadlines for comments on the
Second Further Notice of Proposed Rulemaking
[[Page 14017]]
indicated on the first page of this document and must have a separate
and distinct heading designating them as responses to the IRFA.
Accessing Materials
Providing Accountability Through Transparency Act: The Providing
Accountability Through Transparency Act requires each agency, in
providing notice of a rulemaking, to post online a brief plain-language
summary of the proposed rule. Accordingly, the Commission will publish
the required summary of the Second Further Notice of Proposed
Rulemaking at <a href="https://www.fcc.gov/proposed-rulemakings">https://www.fcc.gov/proposed-rulemakings</a>.
Synopsis
1. As discussed in greater detail below, the Commission seeks
comment on how it can refine the very low power (VLP) device rules to
provide VLP devices greater use of the 6 GHz band while continuing to
protect licensed incumbents. The Commission's intent is to seek comment
on specific rules aimed at providing additional power and flexibility
for VLP devices. With the limited exception of seeking comments on some
aspects of the VLP out-of-band emission limits, the Commission is not
seeking comment on any of the rules adopted in the Second Report and
Order (89 FR 874, January 8, 2024). Below, the Commission proposes to
allow VLP devices to operate in the U-NII-5 (5.925-6.425 GHz) through
U-NII-8 (6.875-7.125 GHz) bands (i.e., a total of 1200 MHz of spectrum)
at a PSD level greater than -5 dBm/MHz--up to 1 dBm/MHz EIRP PSD and 14
dBm EIRP--provided they operate under the control of a geofencing
system that prevents devices from operating in close proximity to co-
channel licensed incumbent services in these bands. VLP access points
would obtain information from a geofencing system on locations where
operation is prohibited on specific frequencies, and VLP client devices
would operate only under the control of VLP access points. These
geofenced VLP devices would be a new class of higher-power VLP devices
in addition to those the Commission is permitting in the Second Report
and Order. The Commission also seeks comment on whether it should relax
the restrictions on mobile use of VLP devices (e.g., on aircraft and
oil platforms). In addition, the Commission seeks comment on whether it
could allow VLP devices that operate without a geofencing system in the
U-NII-6 (6.425-6.525 GHz) and U-NII-8 (6.875-7.125 GHz) bands in
addition to the U-NII-5 and U-NII-7 bands where the Second Report and
Order permits them to operate. As the Commission stated in the Policy
Statement (FCC 23-27), ``[r]elevant information about services'
transmitter and receiver standards, guidelines, and operating
characteristics is needed to promote effective spectrum management and
efficient co-existence.'' Thus, going forward, the Commission
encourages representatives from the unlicensed device community and
those representing the incumbent services to work collaboratively and
provide relevant information on their systems to the Commission to
allow us to continue to refine its rules for the 6 GHz band and to
ensure that equipment designed for and used in the 6 GHz band can fully
function within the spectral environment.
A. Power Limits for Geofenced VLP Devices in the U-NII-5 Through U-NII-
8 Bands
2. As discussed in the Second Report and Order, the Commission is
permitting VLP devices to operate at power levels up to -5 dBm/MHz EIRP
PSD and up to 14 dBm EIRP. Apple, Broadcom, et al. request that the
Commission permits a higher maximum level of 1 dBm/MHz EIRP PSD with
the same maximum total power of 14 dBm EIRP, which they contend would
enable important new VLP devices while protecting incumbent operations.
This PSD level would permit VLP devices to operate at the maximum 14
dBm EIRP levels for any channel bandwidth greater than 20 megahertz,
whereas under the rules the Commission is adopting in the Second Report
and Order that maximum EIRP level can only be achieved for 80 megahertz
and wider channel bandwidths. Based on the record and the Commission's
analysis of that record, it declined to adopt rules permitting VLP
devices to operate at this requested level of 1 dBm/MHz EIRP PSD in the
Second Report and Order. However, the Commission believes that it can
leverage the automated frequency coordination (AFC) systems used for 6
GHz band standard-power devices for use within a framework that
combines higher power operation with geofencing to keep these higher
powered VLP devices in locations where there have an insignificant
potential to cause harmful interference to other users in the band. The
Commission notes that these proposals are not intended to curtail the
VLP use the Commission is adopting in the Second Report and Order. The
Commission is fully satisfied that VLP devices operating at -5 dBm/MHz
EIRP PSD in the U-NII-5 (5.925-6.425 GHz) and U-NII-7 (6.525-6.875 GHz)
bands will protect incumbent operations and the Commission does not
seek comment on these existing rules. Rather, these proposals are
designed to explore the possibility for providing more flexibility for
higher power use at the expense of additional complexity to implement
and use a geofencing capability so that additional use cases and
applications can be brought to the American public.
1. In-Band Power Limits
3. The Commission believes that it could allow geofenced VLP
devices to operate at the higher PSD level suggested by Apple,
Broadcom, et al. if the Commission requires certain frequency and
geographic area restrictions, specifically, that VLP devices with
higher PSD be prohibited from operating co-channel and in close
proximity to licensed incumbent services receive sites. Accordingly,
the Commission proposes to allow VLP devices to operate in the U-NII-5
through U-NII-8 bands at a level greater than -5 dBm EIRP PSD and 14
dBm EIRP, specifically up to 1 dBm EIRP PSD and 14 dBm EIRP, provided
they operate under the control of a geofencing system to minimize the
likelihood of harmful interference to licensed incumbent services.
Under this system, geofenced VLP devices would be required to
incorporate a capability to ensure that they avoid transmitting on
certain channels within certain geographic areas, i.e., this is
analogous to erecting a fence to prevent VLP devices from operating on
certain channels within certain geographic areas, hence the descriptive
term ``geofencing system.'' While a geofencing system is not identical
to an AFC system that several parties requested be required for VLP
device operation, it will provide similar protection to licensed
incumbent operations.
4. The Commission seeks comment on these proposals. Should the
Commission allow VLP devices to operate with up to 1 dBm EIRP PSD and
14 dBm EIRP, provided they are prevented from operating in areas where
there is an elevated risk of harmful interference? What are the
advantages and disadvantages of allowing a higher PSD limit? What
additional VLP applications could be enabled by this proposed increase?
Could the Commission allow a power limit higher than 14 dBm EIRP, e.g.,
up to 21 dBm EIRP, as suggested by some commenters? What are the
advantages and disadvantages of a higher power limit? Would higher
power limits result in higher data usage and if so by how much? Would a
higher power limit create new use cases for VLP? Would
[[Page 14018]]
even higher PSD and EIRP limits increase the risk of harmful
interference to licensed incumbent services, and would the proposed
geofencing system described below be sufficient to reduce this risk?
What are the costs and benefits of requiring higher power VLP devices
to operate under a geofencing system? How would the additional benefits
of geofenced U-NII-6 and U-NII-8 operations compare to the benefits the
Commission estimates for non-geofenced U-NII-5 and U-NII-7 operations
in the Second Report and Order? Would the power level increase that the
Commission proposes provide a sufficient incentive for equipment
manufacturers to develop geofencing systems?
2. Transmit Power Control
5. Consistent with the rules the Commission adopts for VLP devices
in the Second Report and Order, it proposes to require geofenced VLP
devices operating within the U-NII-5 through U-NII-8 bands to employ a
transmit power control mechanism that has the capability to operate at
least 6 dB below the maximum EIRP the Commission permits for the bands
(e.g., 14 dBm or 21 dBm). Because geofenced VLP devices do not yet
exist and the Commission does not know what specific transmit power
control algorithm these devices may employ, the Commission does not
propose any specific requirements in its rules as to how the transmit
power control algorithm of the VLP devices will function. The
Commission does not expect that adopting this transmit power control
requirement will present an undue burden on geofenced VLP device
manufacturers since these are expected to be battery-powered devices
that are likely to employ transmit power control to conserve battery
power. In the Second Report and Order, the Commission requires VLP
devices to employ a transmit power control mechanism with the
capability to operate at least 6 dB below the permitted power level.
Because many VLP devices will be capable of both geofenced and non-
geofenced operation, these devices will by necessity incorporate the
ability to implement at least a 6 dB power reduction. Nevertheless, the
Commission seeks comment on whether a different transmit power control
requirement may be appropriate for geofenced VLP devices. Is there a
need to specify any additional transmit power control requirements for
geofenced VLP devices that the Commission proposes could operate at a
higher power than VLP devices? For example, should the Commission adopt
a different requirement along the lines of the European requirement in
the 5250-5350 MHz and 5470-5725 MHz bands? That requirement specifies
that transmit power control shall provide, on average, a mitigation
factor of at least 3 dB on the maximum permitted output power of the
systems; or, if transmit power control is not in use, then the maximum
permitted mean EIRP and the corresponding mean EIRP density limit shall
be reduced by 3 dB. What information should manufacturers be required
to include in their application for certification to show compliance
with a transmit power control requirement, e.g., an attestation of
compliance, a detailed operational description, actual equipment test
data? What are the advantages and disadvantages of requiring a transmit
power control mechanism in terms of spectrum efficiency, costs, and
complexity? Commenters who favor the European requirement should
provide specific information regarding how such an requirement could be
implemented, verified during the equipment certification process, and
enforced. What ramifications, if any, would arise if there were
differing transmit power control requirements for VLP devices and
geofenced VLP devices?
3. Emission Mask
6. The Commission proposes to require emissions from geofenced VLP
devices within the U-NII-5 through U-NII-8 bands to comply with the
transmission emission mask adopted for standard power and LPI devices
in the 6 GHz Order (FCC 20-51, 33 FCC Rcd 10496) and for VLP devices in
the Second Report and Order. That is, the power spectral density would
have to be suppressed by 20 dB at one megahertz outside of an
unlicensed device's channel edge, suppressed by 28 dB at one channel
bandwidth from an unlicensed device's channel center, and suppressed by
40 dB at one and one-half times the channel bandwidth 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 would be linearly
interpolated between the 20 dB and 28 dB suppression levels. At
frequencies between one and one and one-half times an unlicensed
device's channel bandwidth from the center of the channel, the limits
would be linearly interpolated between the 28 dB and 40 dB suppression
levels. 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, would have to be suppressed by at least 40 dB. Because
geofenced VLP devices would operate in the same bands and on the same
channels as VLP devices, LPI, and standard power 6 GHz devices and need
to protect the same incumbent operations, the Commission believes that
using the same emission mask for geofenced VLP devices as the
Commission adopted for VLP devices, LPI, and standard power devices is
appropriate. Using the same mask would ensure that licensed incumbent
operations are fully protected from unlicensed adjacent channel
operations. Moreover, by specifying the same emission requirements, the
Commission anticipates that these requirements would act to reduce
costs by permitting all devices throughout the VLP ecosystem to use the
same filters and benefit from economies of scale for their acquisition.
4. Emission Limits Outside the U-NII-5 and U-NII-8 Bands
7. The Commission proposes emissions limits at the edge of the U-
NII-5 and U-NII-8 bands for geofenced VLP devices that are identical to
the emissions limits that the Commission adopted in the 6 GHz Order and
the Second Report and Order. Specifically, the Commission proposes a -
27 dBm/MHz EIRP limit for 6 GHz VLP devices 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 proposes to 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; those emissions would be
subject to the emission mask and OOBE limits proposed above. These
limits are intended to protect cellular vehicle-to-everything (C-V2X)
operations below the 6 GHz band and federal operations above the 6 GHz
band. The Commission previously determined that the -27 dBm/MHz limit
will sufficiently protect C-V2X operations from harmful interference
from U-NII devices operating in other bands. Because geofenced VLP
devices could be mobile and potentially used near C-V2X operations, to
help protect these services below the U-NII-5 band from harmful
interference, the Commission proposes to require that geofenced VLP
devices prioritize spectrum above 6105 MHz, as the Commission required
in the Second Report and Order for VLP devices.
8. The Commission seeks comment on the proposed emission mask and
the proposed emission limits outside the U-NII-5 and U-NII-8 bands. Are
these
[[Page 14019]]
limits appropriate for geofenced VLP devices? Would they adequately
protect licensed incumbent services, both within and outside of the U-
NII bands? Would different emission limits be more appropriate? If so,
what limits should the Commission requires and why? Is a requirement
for geofenced VLP devices to prioritize spectrum use above 6105 MHz
necessary? What are the costs and benefits of the proposed emission
mask and limits? Would requiring the same emission limits for geofenced
devices that the Commission requires for non-geofenced VLP devices
reduce the cost of compliance with the emission mask?
B. Geofencing System for Geofenced VLP Devices in the U-NII-5 Through
U-NII-8 Bands
9. The Commission proposes to allow VLP devices to operate at a PSD
greater than -5 dBm/MHz EIRP PSD, up to a maximum of 1 dBm/MHz EIRP
PSD, when they operate under the control of a geofencing system to
minimize the likelihood of causing harmful interference to licensed
incumbent services. The proposed geofencing system would ensure that
geofenced VLP devices with greater than -5 dBm/MHz EIRP do not operate
on the same channels as licensed incumbents inside of defined exclusion
zones designed to minimize the potential for geofenced VLP devices to
cause harmful interference. The Commission proposes requirements for
geofencing systems and the criteria that would be used to calculate the
exclusion zones as well as technical requirements for geofenced VLP
devices. The Commission also proposes procedures for testing and
approving geofencing systems to ensure that they would operate as
intended and correctly restrict co-channel operation with licensed
incumbents in the 6 GHz band at certain locations.
1. Requirement To Use Geofencing
10. Background. Standard power access points and fixed client
devices must register with and be authorized by an AFC system prior to
their initial service transmission by providing their geographic
coordinates, antenna height above ground level, FCC identification
number, and manufacturer's serial number. They may transmit only on
frequencies and at power levels as indicated by an AFC system. After
registration, they must contact an AFC system at least once per day to
obtain the latest list of available frequencies and the maximum
permissible power the device may use on each frequency at their
location. As discussed in the Second Report and Order, the Commission
is permitting VLP device operation at levels up to -5 dBm/MHz PSD EIRP
and 14 dBm EIRP maximum without the use of an AFC or other database
system because the Commission determined that the risk of harmful
interference to licensed incumbent services is insignificant at that
power level.
11. Discussion. For VLP device operation at PSD levels higher than
-5 dBm/MHz EIRP where the risk of harmful interference to incumbent
services is elevated, the Commission proposes to require VLP access
points to use a geofencing system to protect fixed microwave service,
BAS, CARS, radio astronomy, and FSS receive sites in the 6 GHz band.
The Commission believes that this would be an effective approach to
protecting licensed incumbent services since it could be implemented
using the same methodology that the Commission previously developed for
standard power access points and fixed client devices to protect these
services. A geofencing approach, as opposed to requiring VLP devices to
access an AFC system, could help preserve VLP device battery life by
not requiring each device to re-check a database every time it moves,
as is the case for standard power access points. Similarly, a
geofencing approach could help protect user privacy since devices would
not be required to report their location to a centralized system. A
geofencing system would enable VLP devices to operate at PSD levels
greater than -5 dBm/MHz EIRP to enable a variety of uses while
protecting licensed incumbent services in the 6 GHz band. The
Commission previously required certain types of devices to operate
pursuant to a geofencing system. It adopted similar requirements to
ensure protection to fixed service receivers in the 5925-6425 MHz
portion of this band when it granted Higher Ground a blanket earth
station license to operate SatPaqs on a non-interference basis through
an automated frequency coordination system basis to enable cellphones
to communicate with FSS space stations. Additionally, the Commission
permits unlicensed white space devices to operate in certain bands
subject to their use of a geofencing system to protect licensed
incumbent services.
12. The Commission proposes to protect licensed services in the 6
GHz band by prohibiting geofenced VLP access points with power levels
greater than -5 dBm/MHz EIRP PSD from operating on certain channels
within defined exclusion zones around the sites where licensed
incumbent services operate. The geofencing system would prevent a VLP
access point from operating on the frequencies within these exclusion
zones where there may be a higher risk of causing harmful interference.
The Commission proposes that the exclusion zones be determined based on
the operational frequency being used by the incumbent service licensee
as well as the power of the geofenced VLP access point. A geofenced VLP
access point located within an exclusion zone would be prohibited from
operating only on the specific frequencies excluded within that zone
and would be permitted to operate on any other frequencies that are
available at its location at the maximum power level permitted.
Depending on the number of incumbent licensees in an area and the size
of the exclusion zones, a geofenced VLP access point could fall within
multiple overlapping exclusion zones at a particular location. In such
cases, the device would have to avoid all excluded frequencies for all
the overlapping zones in which it is located. To provide manufacturers
flexibility in developing geofencing systems, the Commission proposes
that geofencing systems may also determine areas where particular
frequencies are available throughout the entire area based on the same
protection criteria used to calculate exclusion zones. Each approach
may have advantages in terms of spectrum availability or device
complexity, so permitting either approach would provide manufacturers
with the ability to determine the most suitable implementation for a
specific use case. The proposed methodology for calculating exclusion
zones is described below.
13. The Commission seeks comment on these proposals. Is a
geofencing system necessary to minimize the likelihood of harmful
interference from VLP devices with a PSD greater than -5 dBm/MHz EIRP
to licensed incumbent services in the 6 GHz band? Is the proposed
method of using exclusion zones around licensed incumbent receive sites
an appropriate way to protect these sites? Would the proposed
alternative method allowing geofencing operators to calculate zones in
which a channel is available over an entire zone provide the same
protection to incumbent services as determining exclusion zones in
which one or more channels are unavailable? Should the Commission
permit use of either method, or is one method preferable to the other,
and if so, why? How would the benefits of higher power VLP operations
in the 6 GHz band vary with differences in exclusion zone design?
14. The Commission also seeks comment on whether an approach other
than geofencing, such as requiring the
[[Page 14020]]
use of an AFC system for higher power VLP devices, would be more
appropriate. What are the advantages and disadvantages of requiring a
geofencing approach for protecting licensed services as opposed to
other approaches? What are the benefits and costs of the various
approaches for the public, unlicensed device manufacturers, and
incumbent users of the 6 GHz band? Are there any other factors that the
Commission should consider in determining whether to require use of a
geofencing system for VLP devices with a PSD greater than -5 dBm EIRP?
Commenters advocating for the proposed approach or any alternatives
should provide details explaining why their desired approach is most
beneficial for enabling these higher powered geofenced VLP devices.
2. Geofencing Architecture
15. Definition of geofenced VLP devices. The Commission proposes to
define a geofenced VLP access point as an access point that operates in
the 5.925-7.125 GHz band, has an integrated antenna, and uses a
geofencing system to determine channel availability at its location.
The Commission proposes that these devices could simultaneously operate
as clients to other access points or telecommunications systems (e.g.,
low-power indoor access points, standard power access points, other U-
NII band access points, commercial telecommunication carriers'
networks, etc.) and very low power access points. The Commission
believes that this definition adequately describes the types of VLP
devices that could operate under a geofencing system, and the proposed
requirement for an integrated antenna, which is consistent with the
current rules for indoor access points and subordinate devices, will
help ensure that geofenced VLP devices cannot be easily modified to
increase their EIRP.
16. The Commission proposes to require that geofenced VLP access
points obtain or calculate the exclusion zones--where some operational
restrictions are required--that will protect licensed services, have
the capability to determine their location, and intelligently choose
their operating channel to avoid operating on a prohibited frequency
within an exclusion zone. The Commission further proposes to require
that client devices operating under the control of a geofenced VLP
access point operate only on channels as determined by its connected
geofenced VLP access point. Under these proposals, client devices would
not be required to directly obtain or calculate exclusion zone
information as they would only be operating on channels already cleared
through the geofenced VLP access point. The same client devices may
also be capable of operating under the control of LPI access points and
standard power access points, in which case the client devices must
adjust their power levels depending on which type of access point they
are connected to. That is, when connected to an LPI access point or
standard power access point, the client device would have to follow the
client device rules for those operations, which require those client
devices to reduce their power at least 6 dB below the access point
power level. Because geofenced VLP access points and client devices
would operate at lower power levels than standard power and LPI
devices, thus reducing the distance at which harmful interference may
possibly occur, the Commission does not propose to require client
devices to reduce their power below that of the access point and
propose to limit both geofenced VLP access points and client devices
operating under the control of a geofenced VLP access point to the same
power levels.
17. The Commission seeks comment on these proposals. Is the
proposed geofenced VLP two-tier model based on access points and client
devices in which a geofenced VLP access point is required to obtain
geofencing information, but the client device is not, appropriate? Is
the proposed definition of VLP access point appropriate, or are
different or additional definitions that better describe the types of
permissible geofenced VLP devices necessary? Should all geofenced VLP
devices be required to incorporate an integrated antenna? Should client
devices be permitted to operate at a different power level than
geofenced access points? Is there any need for a 6 dB power reduction
for a client to a geofenced VLP device?
18. System architecture. The Commission proposes to allow
geofencing systems for VLP devices operating at greater than -5 dBm/MHz
flexibility in their design by permitting the use of either a
distributed architecture or a centralized model. One possible
architecture would have a centralized geofencing system calculate
exclusion zones based on information obtained from Commission
databases, e.g., the Universal Licensing System (ULS) and Cable
Operations and Licensing System (COALS) databases, as well the
Commission's rules. A VLP access point would contact this centralized
geofencing system to download the exclusion zones and then manage its
use of spectrum based on these areas. Another possible architecture
would be for a VLP access point to regularly send its location to a
centralized geofencing system, which would then inform the access point
as to the channels it may use. Yet another possible architecture would
be for the geofencing system to be integrated within a VLP access
point. A VLP access point would download information about the licensed
services to be protected from an external source. It would contain the
data and software necessary to independently determine exclusion zones
and manage its use of spectrum. The Commission is not proposing
specific details for the geofencing system architecture for VLP devices
because the Commission wants to provide manufacturers with the
flexibility to design appropriate geofencing systems for different
equipment use cases, many of which may not be known at this time.
19. The Commission seeks comment on these proposals. How much
flexibility should the Commission provide in geofencing system
architecture? Should the Commission provide flexibility for different
geofencing system implementations or should a single approach be
specified? What are the benefits and drawbacks of each approach? How
would costs for users of a geofencing system vary between different
approaches? Is there a need to specify the overall framework of
geofencing systems in more detail, e.g., whether they are centralized
or decentralized? Does the Commission need to provide more specific
requirements for a geofencing system architecture and if so, what
requirements should be specified? Does the Commission need to provide
further details on the process that the Commission will use to approve
geofencing systems, and if so, what additional details are necessary?
3. Protection of Incumbent Services
20. The Commission proposes requirements for geofenced VLP devices
operating at greater than -5 dBm/MHz EIRP to protect licensed incumbent
services in the 6 GHz band, specifically, fixed microwave services, BAS
and CARS receive sites, as well as radio astronomy and FSS receive
sites. Consistent with the requirements for standard power access
points and fixed client devices, the Commission proposes that
geofencing systems use data from Commission databases to protect fixed
microwave services. The Commission proposes that BAS and CARS receive
sites be protected using data provided by licensees, as described
[[Page 14021]]
below. The Commission further proposes that geofenced VLP devices
protect certain radio astronomy sites and FSS receive sites as provided
in the Commission's rules. Geofenced VLP operations, like all other
unlicensed 6 GHz band operations, would have to comply with
international agreements with Canada and Mexico.
21. Fixed microwave services protection. The Commission proposes to
require geofencing systems to follow the same criteria for protecting
fixed and temporary fixed microwave receive sites used for standard
power access points and fixed client devices. Specifically, the
Commission proposes that geofenced VLP device exclusion zones be
calculated based on the -6 dB I/N interference protection criterion
used in the 6 GHz Order, where N (noise) represents the background
noise level at the fixed microwave receiver, and I (interference)
represents the co-channel signal from the VLP device at the fixed
microwave service receiver. The Commission noted in the 6 GHz Order
that use of this metric is a conservative approach that will ensure
that the potential for harmful interference to the fixed microwave
services is minimized and that the important fixed microwave services
in the 6 GHz band are protected.
22. The Commission also proposes to allow an assumption of 4 dB for
body loss in the exclusion zone calculations because of its finding,
discussed in the Second Report and Order, that due to the nature of VLP
devices and how they will be used, an additional 4 dB attenuation for
body loss is appropriate when analyzing the potential effect of their
emissions. The Commission does not propose to consider aggregate
interference from geofenced VLP devices since they will operate at a
significantly lower power level than standard power access points and
fixed client devices for which the Commission previously determined
that an aggregate interference limit is not necessary.
23. The Commission seeks comment on these proposals. Are the
proposed interference metric and body loss assumption appropriate?
Would other values be more appropriate? Are there other parameters in
addition to body loss that should be accounted for when determining
exclusion zones (e.g., transmit power control)? Commenters who advocate
for additional parameters should specify the parameters, appropriate
values, and a detailed justification for why that parameter and value
are appropriate. The Commission seeks estimates of the benefits and
costs of different parameter proposals. The Commission also seeks
comment on whether there is a need for an aggregate interference limit.
If so, what is the appropriate limit and why? How could the Commission
enforce an aggregate interference limit using a geofencing system?
Would a centralized system be required and if so, who would build and
run such a system?
24. The Commission proposes to require geofencing systems to use
the same propagation models that are used for standard power access
points and fixed client devices to determine the VLP device exclusion
zones. Specifically, the Commission proposes to require geofencing
systems to use the free space path-loss model at separation distances
of up to 30 meters, the Wireless World Initiative New Radio phase II
(WINNER II) model at separation distances greater than 30 meters and up
to and including 1 kilometer, and the Irregular Terrain Model (ITM)
combined with the appropriate clutter model at separation distances
greater than 1 kilometer. Where such data are available, the Commission
proposes that the exclusion zone calculation use 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.
For evaluating paths where such data are not available, the Commission
proposes that the calculation use a probabilistic model combining the
line-of-sight path and non-line-of-sight path into a single path-loss
as set forth in the requirements for AFC systems. The Commission
believes that these propagation models are appropriate for determining
exclusion zones for geofenced VLP access points for the same reasons
that they are appropriate for determining channel availability for
standard power devices described in the 6 GHz Order. The Commission
proposes that these propagation models be implemented to determine the
exclusion zones consistent with the way that they are being used to
determine standard power device exclusion zones and consistent with the
consensus methodology WinnForum published for AFC systems, which
permits certain allowances for feeder loss and antenna mismatch. Each
of these models could be used at the antenna height above ground (1.5
meters) that the Commission assumed for VLP operation in the Second
Report and Order.
25. The Commission seeks comment on these proposals. Are the
proposed propagation models appropriate for calculating geofenced VLP
device exclusion zones? Could the Commission allow the use of different
propagation models for calculating geofenced VLP device exclusion zones
or simplify the methodology in some way? For example, could the
Commission require use of a single propagation model, such as ITM, for
all distances? If so, what is the appropriate propagation model? If the
Commission specifies a different propagation model for determining
exclusion zones, should the Commission make its use mandatory or should
it be an optional alternative to the proposed propagation models?
Parties should address how a different propagation model would ensure
that incumbent services in the 6 GHz band are adequately protected. The
Commission also seeks comment on the benefits and costs of requiring or
allowing the use of different propagation models. Could this approach
reduce the size of the exclusion zones where geofenced VLP devices are
prohibited from operating on certain frequencies?
26. The Commission also seeks comment on whether there are land-use
databases that could account, for example, for actual buildings and
other structures, especially in cities and suburbs, that could allow a
more accurate determination of where VLP devices can operate without
causing harmful interference? If so, what databases are available for
this purpose? If this information is not available, would it be
possible for parties to develop it, either nationwide or for specific
areas? Could the Commission allow modifications to any parameters used
in the specified propagation models, and if so, which ones? If the
Commission allows modifications to the method of determining spectrum
availability for VLP devices, what criteria would the Commission have
to specify in the rules? Would the Commission needs to develop a
process for modifying the locations where VLP devices can and cannot
operate? Should a geofencing system operator be required to obtain
prior permission from the Commission to use a modified methodology, or
could the Commission adopt rules that do not require operators to
obtain prior permission?
27. Electronic news gathering central receive site protection. The
Commission proposes to require that geofencing systems protect BAS and
CARS operations in the U-NII-6 and U-NII-8 bands, including low power
auxiliary devices. Both the U-NII-6 and U-NII-8 bands are used by
mobile broadcast auxiliary services, including outdoor electronic news
gathering (ENG) trucks and low power short range devices, such as
portable cameras and microphones. Low Power Auxiliary
[[Page 14022]]
Stations, which are licensed in portions of 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. ENG trucks
transmit video programming, generally using telescoping directional
antennas that are oriented toward a central receive site from remote
sites, such as the location of news or sporting events, to a central
receive site. According to the ITU, ENG collection sites are generally
operated by TV networks in major city areas where the typical central
collection site is located within the city center, on the roof of a
high building (e.g., 150 m above the surrounding terrain) and that many
TV networks also have alternative dedicated ENG collection sites
mounted on their broadcast transmission towers. The ITU also states
that these receive sites include both steerable antennas and fixed
arrays that may have up to 360[deg] of azimuthal coverage. The central
receive sites, align with the locations of the ENG trucks. Hence, the
communication link between the ENG truck and central receive site
shares many of the characteristics of a fixed microwave link--i.e.,
they use directional antennas to send signals between two fixed
locations that are located mostly above the local clutter--and can be
protected by the geofencing system by creating exclusion zones to
protect the receiver at the central receive site. Due to the steerable
nature of the central receive antennas, would exclusion zones
surrounding central receive sites need to be circular to ensure
protection in all directions, or could they be only part of a circle,
i.e., less than 360 degrees, if they only receive from specific
directions and the directional pattern and range of orientations of the
receive antenna are known?
28. Because links from ENG trucks to BAS and CARS receive sites are
essentially temporary fixed point-to-point links, the Commission
proposes the use of the same -6 dB I/N interference protection
criterion and propagation models along with an additional 4 dB body
loss consistent with the Commission's proposal for calculating
geofenced VLP device exclusion zones for fixed microwave links. Since
BAS and CARS operations are typically licensed for the entire band(s)
in which they operate (i.e., U-NII-6, U-NII-8, or both), should
geofenced VLP devices avoid operation across the entire band that a
BAS/CARS site receives within the area where the interference
protection criterion is calculated to be greater than -6 dB I/N unless
more information about actual operations are known? Should the
exclusion zones be circular when the directivity of the BAS/CARS
receive antenna is not known?
29. A full record of BAS and CARS central receive sites would be
needed in the Commission's licensing databases to calculate the
geofencing exclusion zones. The Wireless Telecommunications Bureau, the
Media Bureau, and the Office of Engineering and Technology could
collect information from BAS and CARS licensees regarding locations and
associated information for existing central receive sites to ensure
that the Commission's databases are complete and up-to-date. The
Commission would not permit geofenced VLP unlicensed devices to operate
in the U-NII-6 and U-NII-8 bands until after the Commission's databases
are updated.
30. The Commission seeks comment on these proposals. Although the
Commission is proposing to protect BAS/CARS using the -6 dB I/N ratio
and 4 dB body loss assumption, the Commission seeks comment on whether
a different metric or assumption is more appropriate? Are the
propagation models the Commission proposes above to protect fixed
microwave links also appropriate for BAS/CARS? Commenters should
provide detailed technical justification and analysis. The Commission
seeks comment on whether there are ways that it could reduce the size
of the exclusion zones to protect BAS and CARS receive sites, limit the
number of frequencies excluded within those zones, or limit receive
site protection to only the specific times when they are in use. For
example, should the Commission requires BAS and CARS users to notify a
geofencing system of their ENG operations, and for the geofencing
systems to incorporate a push notification feature or similar
functionality to provide information (e.g., actual operating locations
and frequency usage, on a near real-time basis) to VLP devices so that
the exclusion zones in the U-NII-6 and U-NII-8 bands can be tailored to
actual usage rather than all possible usage areas? What specific
requirements would the Commission need to specify for a push
notification system? Would it be better for the Commission to simply
require the geofencing system to provide updated exclusion zone
information to devices within a defined time interval from the time it
receives updated usage information, similar to the approach in the
Citizens Broadband Radio Service, which requires devices to respond to
instructions within a specific time limit, and allow device
manufacturers to determine the most appropriate way to comply with this
requirement?
31. The Commission seeks comment on the benefits of obtaining more
detailed information from BAS/CARS licensees and limiting protection to
only the associated exclusion zones and times that these services
actually operate. The Commission also seeks comment on how much
spectrum ENG operations typically use. The Policy Statement (FCC 23-27)
emphasized data-driven regulatory approaches to promote co-existence.
In this regard, the Commission specifically noted that ``[r]elevant
information about services' transmitter and receiver standards,
guidelines, and operating characteristics is needed to promote
effective spectrum management and efficient coexistence.'' The
Commission therefore proposes that BAS/CARS licensees be required to
register their receive site information in Commission databases so that
geofencing systems can use site-specific data to create appropriate
exclusion zones for these sites. The Commission seeks comment on what
information should be collected. Should it be limited to information
currently collected by Commission databases, such as location, antenna
height, antenna model, and azimuth, or are there other information
fields that the Commission should collect? Is the current information
in ULS and COALS appropriate for estimating the number of affected
incumbents and their equipment? Could the Commission use past activity
on ULS and COALs systems to extrapolate the future number of necessary
updates? The Commission seeks comment on this proposal and whether the
Commission should conduct an information collection for these sites.
Assuming that the Commission does initiate an information collection,
what is an appropriate time frame over which to require licensees to
provide their information?
32. The Commission also seeks comment on whether multiple ENG
operations at a location use the same or different receive sites. What
is the number of ENG operations that typically occur at a news event,
sporting event, or other event where such operations may be used? And
what is the maximum that might be used at larger national events such
as political conventions or large scale sporting events? How much time
do ENG operations typically need to transmit for these events? Is
continuous operation required before, during, and after an event or
only within discrete timeframes? Are there ways to predict
[[Page 14023]]
when operation may be heaviest? Looking across these dimensions of
time, location, and spectrum occupancy, how much additional spectrum,
operating area, and time could this approach make available for VLP
devices, as compared to assuming that ENG might always be operating
within a circular or part of a circular area around an ENG receive
site? How would this differ from a system where ENG operations simply
preregistered their entire service areas and operating channels, but
with no time limit to account for use at unscheduled breaking news
events? If the specific location, antenna pattern, and look angle of an
ENG receive antenna are known, is it necessary for the exclusion zone
to be circular, or could the Commission considers non-circular
exclusion zones, such as keyhole shaped zones or arcs, to protect ENG
receive sites? If the Commission were to implement a registration
requirement, should the ENG use be updated during in-use times or for
non-real-time registration, or should the ENG use be updated on a
regular basis? What is a reasonable time period for such updates? Can
ENG operations be automated to inform a geofencing system when it is
operating and on which channels and to which receive site it is
broadcasting, or would registration have to be a manual process? What
up-front and ongoing costs would be involved with setting up and using
such a system and who would incur them?
33. Although the Commission proposes to allow either a distributed
or centralized architecture model for VLP device geofencing systems, if
the Commission were to adopt a push notification or similar approach to
protect BAS/CARS based on actual usage, it appears that there would be
a need for one or more centralized systems to register BAS/CARS usage
and provide the information to geofencing systems. The Commission seeks
comment on whether this would be necessary. If so, who would develop
and operate these systems? How should any information be shared amongst
geofencing systems? For example, in the white space rules, white space
device operators are required to share registration information with
all other database administrators. Would such a requirement be
necessary here? If so, how would data sharing work to ensure that all
geofencing systems, both centralized and decentralized, have up-to-date
information to protect ENG operations at scheduled and unscheduled
events? What information should licensees be required to file and what
procedure would they use to get their information to the system? Should
licensees be required to file or update information within a specific
timeframe? What would be the burden on licensees for filing this
information? Could the filing process be automated? The Commission
seeks comment on any other options for transmitting channel utilization
information to geofencing operators. Are there any other factors that
should be considered in this process? Finally, the Commission seeks
comment on whether there should be any channels (e.g, one or two
channels) set aside as a safe harbor for ENG operations in these bands
where ENG could operate without risk of harmful interference from VLP
devices at times when the operator could not register its parameters?
If so, how much spectrum would need to be set aside for such operation?
Would spectrum be needed in both U-NII-6 and U-NII-8? Are there
particular places in the band that would be most useful; e.g., the top
of the band, bottom of the band, middle of the band, or on the same
spectrum permitted for satellite downlink operations? Would such safe
harbor be needed nationwide or only in certain areas (e.g., around
large cities)? Commenters advocating such an approach should provide
detailed information regarding ENG requirements and fully support their
position with technical information.
34. The Commission seeks comment, especially quantitative, on the
benefits and costs of requiring a push notification system. Should any
particular protocol or security measures be required? To what extent
would a push notification system permit service continuity for
geofenced VLP devices, as compared to how often such users would need
to modify their channel usage to avoid exclusion zones when those areas
are tailored to the specific situation rather than assuming that ENG
might always be operating within a circular or part of a circular area
around an ENG receive site? How would data rates be affected? What
would be the potential costs associated with establishing, maintaining,
and operating the push notification system? In particular, the
Commission seeks comment on the costs for BAS and CARS licensees to
report their location information to enable push notifications.
35. Low-power short range mobile device protection. The Commission
proposes that low power short range BAS and CARS devices, such as
portable cameras and microphones, and Low Power Auxiliary stations be
protected from harmful interference by a combination of a required
contention-based protocol and low probability of a VLP device operating
on the same channel in a nearby location. This proposal is consistent
with the 6 GHz Order in which the Commission required that all 6 GHz
unlicensed LPI access points, subordinate devices, and client devices
employ a contention-based protocol. Further, the 6 GHz Order showed
that the probability of channel overlap between 6 GHz unlicensed
devices and incumbent station operations is low due to unlicensed
devices having a full 1200 megahertz over which to operate.
36. The Commission believes that a similar approach for geofenced
VLP devices will adequately reduce the risk that mobile service
incumbents in the U-NII-6 and U-NII-8 bands will be subjected to
harmful interference and keep that risk to an insignificant level. The
Commission's reasoning is consistent with the 6 GHz Order, i.e., the
sensing function associated with the contention-based protocol, along
with the low probability for co-channel operation, is sufficient to
ensure that geofenced VLP devices detect nearby mobile BAS operations
and avoid transmitting co-channel to protect those operations from
harmful interference. While the Commission is not proposing a specific
technology protocol or contention method, the Commission proposes to
require geofenced VLP devices to use a contention-based protocol as the
Commission requires for LPI devices. The Commission believes that this
proposal has additional benefits as it provides multiple geofenced VLP
devices as well as LPI devices equal access to the spectrum, while
protecting mobile incumbents' services. The Commission also believes
that the use of a contention-based protocol will limit the duty cycle
of geofenced VLP devices as they will need to share the spectrum with
other devices. Additionally, geofenced VLP devices would transmit at
lower power levels than LPI devices, further reducing the risk of
harmful interference to mobile services. Given all these reasons, the
Commission believes that requiring use of a contention-based protocol
by geofenced VLP devices would protect mobile service incumbents.
37. The Commission seeks comment on this proposal. Would requiring
geofenced VLP devices to incorporate a contention-based protocol
adequately protect mobile service incumbents? If not, what other
protection measures could be used by geofenced VLP devices to protect
mobile services? For example, could a registration system with a push
notification provide near real-time information to geofenced VLP
devices to
[[Page 14024]]
avoid transmitting near mobile BAS operations? Is there a need to
provide greater specificity in the requirements for a contention-based
protocol used by geofenced VLP devices? If so, what particular
requirements should be specified and why? What are the costs and
benefits of requiring the use of a contention-based protocol?
38. Radio astronomy and fixed satellite protection. The Commission
proposes to require that geofencing systems implement the same
exclusion zone rules for protecting radio astronomy sites in the 6650-
6675.2 MHz band as standard power access points and fixed client
devices, which are based on the distance to the radio horizon. The
locations of the protected radio astronomy sites and the protection
criteria for these sites are specified in the rules for standard power
access points and fixed client devices. Additionally, the entire 6 GHz
band is home to an FSS allocation (Earth-to-space), while the U-NII-8
band has a few space-to-Earth MSS feeder downlink earth stations
operated by Globalstar. The only requirement the Commission adopted to
protect the Fixed Satellite Service in the 6 GHz Order was restricting
standard power access point EIRP to 21 dBm above a 30 degree elevation
angle. Because the Commission proposes to limit geofenced VLP devices
to 14 dBm EIRP and seeks comment on a maximum EIRP of no greater than
21 dBm, the Commission proposes no additional restrictions to protect
FSS Earth-to-space operations. The Commission seeks comment on these
proposals.
39. Globalstar operates receiving earth stations for non-
geostationary Mobile-Satellite Service feeder links at five locations.
The Commission proposes to require that geofenced VLP access points
protect Globalstar's earth stations using the same exclusion zone
calculation methodology used to protect radio astronomy sites. The
Commission proposes to require the geofencing system to implement these
exclusion zones over 6875-7055 MHz at each of Globalstar's five feeder
link earth station locations. As these exclusion zones are designed to
protect extremely sensitive radio astronomy facilities, the Commission
believes that they will provide more than adequate protection for
Globalstar's earth stations.
40. The Commission seeks comment on this proposal. If different
criteria are appropriate, what are the key parameters that must be
considered to protect these earth stations? Are parameters such as
minimum elevation angle from the earth station to the satellite, gain
of earth station antenna, and earth station receiver characteristics
readily available? Are Commission databases, such as the International
Communications Filing System (ICFS), able to collect the necessary
parameters for calculating exclusion zones? If not, and given the
limited number of these Earth stations in the U-NII-8 band, could
exclusion zones around these Earth stations be determined based on
generalized parameters? What should those parameter values be? Would
earth station receivers require a different level of protection than
the -6 dB I/N ratio used to protect other incumbents in the band? If
so, what is the protection criterion? What would be the cost of
implementing and maintaining necessary protections for space-to-Earth
stations from geofenced VLP devices? The Commission also seeks
information on the economic harm from interference that these
protections would prevent. Commenters should provide technical analysis
to support their positions.
41. Adjacent channel protection. The Commission proposes that
exclusion zones for geofenced VLP access points account for only co-
channel operations and not consider adjacent channel operations. The
Commission believes that this proposal is appropriate due to the
significantly lower power the Commission proposes for geofenced VLP
devices as compared to standard power and fixed client devices. The
out-of-band emission rules for 6 GHz unlicensed devices require such
emissions to be suppressed by 20 dB at 1 megahertz 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. When compared to standard power devices that may
operate at EIRP levels up to 23 dBm/MHz and must meet the same OOBE
mask, VLP adjacent channel emissions begin at least 22 dBm below those
standard power device OOBE levels. Thus, VLP OOBE levels must begin at
-19 dBm/MHz at 1 megahertz outside the channel edge and reduce from
that level with spectral distance. Moreover, the Commission notes that
adding 20 dB or more additional emission reduction represents at least
a tenfold reduction (assuming free space propagation) in distance along
any radial for determining adjacent channel protection as compared to
standard power device adjacent channel geofenced distances. In the 6
GHz Order, the Commission concluded that the risk of adjacent channel
interference to microwave receivers was low and stated that it expects
these adjacent channel zones will be small and not significantly impact
the amount of spectrum available to unlicensed devices at any given
location, but included adjacent channel protection in the adopted rules
for standard power devices as part of a conservative approach to
protecting the incumbent receivers. Given the additional 22 dB in
adjacent channel protection provided by geofenced VLP devices as
compared to standard power devices, and the further reduction in
protection areas size, the Commission concludes that the risk of
adjacent channel interference is so low as to not require geofencing
systems to account for them. The Commission seeks comment on this
proposal.
42. Geofencing update interval. The Commission proposes to require
a geofencing system to obtain the most recent public access file data
from Commission databases (e.g., ULS and COALS) for registered fixed
microwave links and BAS/CARS central receive sites at least once per
day and to recalculate the exclusion zones, as necessary, to account
for any new or updated information. The Commission believes that once
per day would be an appropriate re-check interval because the ULS and
COALS, which contain the data that will be used to determine the
exclusion zones to protect fixed microwave services and BAS/CARS
central receive sites, are generally updated on a daily basis, and a
daily re-check requirement would also ensure that newly registered
microwave receive sites and BAS/CARS central receive sites are promptly
protected. The Commission seeks comment on this proposal. Is a daily
update necessary, or recognizing that not many new stations get
licensed on a daily basis and that there is often a lag between
licensing and operation, could a longer interval be specified? If so,
what update interval should be required? Conversely, as discussed
above, could the Commission or should it establish a process to update
BAS/CARS information in a much shorter timeframe to enable more
efficient use of spectrum in areas near BAS and CARS receive sites? How
would the benefits and costs change with differing interval lengths?
4. Other Geofencing Requirements
43. The Commission proposes additional requirements for geofencing
systems and operators that are similar to certain requirements for 6
GHz AFC systems. Specifically, the Commission proposes that each
geofencing system and operator thereof for centralized systems and the
equipment certification responsible party for systems internal to the
very low power device must: (1) ensure that a regularly updated
[[Page 14025]]
geofencing system database that contains the information required for
geofencing systems by paragraphs (o) through (r) of proposed Sec.
15.407, including incumbent's information and very low power access
points authorization parameters, is maintained; (2) respond in a timely
manner to verify, correct, or remove, as appropriate, data in the event
that the Commission or a party presents a claim of inaccuracies in the
geofencing system; (3) establish and follow protocols to comply with
enforcement instructions from the Commission, including discontinuance
of very low power access point operations on specified frequencies in
designated geographic areas and predetermined exclusion zones; and (4)
comply with instructions from the Commission to adjust exclusion zones
to more accurately reflect the potential for harmful interference.
44. The Commission further proposes that for centralized geofencing
systems, geofencing system operators must provide continuous service to
all VLP devices for which it has been designated to provide service,
and that if a geofencing system ceases operation, the operator must
provide at least 30-days' notice to the Commission and a description of
any arrangements made for those devices to continue to receive
exclusion zone update information. In addition, the Commission proposes
that a geofencing system operator may charge fees for providing service
and that the Commission may, upon request, review the fees and can
require changes to those fees if the Commission finds them to be
unreasonable. The Commission also proposes that at the time that a VLP
device receives equipment certification, the device must either have
its geofencing system approved or specify an already approved
geofencing system that it is using. The Commission further proposes
that it may specify criteria for such approval, which could require
test results to be submitted.
45. The Commission seeks comment on these proposals. Are all the
proposed requirements appropriate and necessary? Should the Commission
modify any of these proposed requirements or establish additional
requirements for geofencing systems and operators? If so, what
requirements are necessary? The Commission seeks quantitative analysis
of the likely fee structure that would result under its proposal
allowing fees. What would be the initial cost of developing a
geofencing system and the ongoing cost of providing daily information
to it? The Commission also seeks comment on how any fees would relate
to usage or other costs of operating the geofencing system.
46. Finally, in light of the proposals to base higher power VLP
operation on using a geofencing system, the Commission seeks comment on
whether there are alternative methods to achieve the same result. Are
there other technical or operational approaches that would similarly
permit more flexible VLP operation while protecting incumbent
operations? Commenters advocating for alternative approaches should
provide specific detail regarding any alternative approach along with
descriptions and analysis of how such an approach would protect
incumbent operations.
C. Client-to-Client Device Communications
47. In the 6 GHz Order, the Commission prohibited unlicensed client
devices from operating as ``mobile hotspots'' because ``[p]ermitting 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.'' To
avoid this situation, the Commission's rules prohibit 6 GHz unlicensed
client devices from directly communicating with one another. The
Commission proposes two limited exceptions to this rule for VLP devices
that operate above the -5 dBm/MHz EIRP PSD level. First, the Commission
proposes to permit higher powered VLP devices that are all operating
under the control of the same LPI access point to directly communicate
with each other. The Commission further proposes that these
communications be limited to the LPI client device power spectral
density level (i.e., 6 dB below the LPI access point power level) and
the VLP device 14 dBm EIRP limit. Because both VLP devices under this
approach would also meet the LPI requirements, the Commission would
have assurance that their operations are indoors and thus that their
emissions are subject to the same building entry loss as LPI devices.
With their lower power limit, these client devices will have even lower
potential to cause harmful interference to incumbent operations than
the insignificant level the Commission already determined exists for
LPI devices. This proposed exception could provide increased
flexibility to a limited class of devices, such as laptop computers,
that generally do not incorporate GPS or other geolocation technologies
while protecting incumbent operations beyond levels that similar
devices (i.e., LPI devices) already provide.
48. Second, the Commission proposes to permit direct client-to-
client communications between VLP client devices when they are both
under the control of the same VLP access point and the geofencing
system determines that they are operating outside of any geofencing
restrictions; i.e., there are channels available for VLP use that are
not subject to geofencing requirements in the location where these
devices are being used. The rules the Commission proposes for geofenced
VLP devices would permit up to 1 dBm/MHz EIRP PSD and up to 14 dBm EIRP
when operating on channels that are not within an exclusion zone. Thus,
because each client device in this scenario would be permitted to
operate at the maximum power permitted for VLP devices, there would be
no increase in the potential for causing harmful interference to
incumbent operations if the client devices being used are also able to
communicate directly with each other. However, all VLP access points
would still be subject to the applicable geofencing requirements
including location and geofencing recheck intervals and switching
channels or ceasing communications should they enter an exclusion zone
and are currently using a channel that is prohibited within that area.
In that case, client devices operating under the control of a VLP
access point that switches channels would also be required to switch
channels as directed by the VLP access point. This proposed limited
exception, as with the first, could provide additional flexibility to
implement novel VLP use cases without increasing the risk of harmful
interference to incumbent operations.
49. The Commission seeks comment on these proposals. Are these
proposed limited exceptions to the prohibition on client-to-client
device communications appropriate? Would any other exceptions with
respect to VLP devices be appropriate? Does the Commission need to
specify any additional requirements or limitations on client-to-client
device communications? How much and what kinds of additional usage
would these proposals create in client-to-client operations? Would
these proposals impose any additional costs to users of the associated
spectrum?
D. Very Low Power Device Requirements
50. In the 6 GHz Order, the Commission established that an AFC
system require a device's geographic coordinates--along with the
accuracy of
[[Page 14026]]
those coordinates--and the device's antenna height above ground to
determine which channels are available for use at the device's
location. Standard power access points (APs) are required to contact an
AFC system at least once per day, consistent with the frequency of the
update to the ULS public access file, to obtain the latest lists of
available channels at their locations. The daily update ensures that
stationary unlicensed devices do not operate on a channel in proximity
of a newly licensed fixed service receiver. Although VLP devices may be
mobile or stationary, mobile VLP devices may move to different
locations, potentially resulting in a changing available channel list.
In lieu of an AFC system, the Commission proposes to require that
geofenced VLP devices access a simpler geofencing system to prevent
them from operating where there may be an elevated risk of causing
harmful interference to licensed incumbent services in the 6 GHz band.
Under this proposed geofencing system, geofenced VLP devices would have
to incorporate provisions to ensure that they avoid transmitting on
certain channels within certain geographic areas.
51. A mobile geofenced VLP device operating at a power level
greater than -5 dBm/MHz EIRP PSD would have to consider exclusion
zone(s) not only at its present location, but also at all areas that
may be traversed by a mobile VLP device between the present time and a
future location update. Naturally, the area traversed by the mobile VLP
device is a function of the VLP device's speed and direction. For
example, a mobile VLP device located in a vehicle traveling 35 miles
per hour could cover approximately one kilometer within one minute.
However, there are other mobile use cases in which a pedestrian using a
VLP device will cover well under a hundred meters in the same one-
minute time period. Accordingly, rather than proposing a set time
period within which a mobile VLP device must update its location to
check if it is in an area with different geofencing requirements than
the previous area in which it checked, the Commission proposes a
flexible approach with varying recheck times based on speed to better
meet device usage requirements. Thus, the recheck interval can be
tailored to require fewer rechecks when moving at slow speeds and thus
ease processing requirements and save battery power.
52. Incorporated geo-location. Consistent with the requirements for
standard power access points, the Commission proposes to require that
geofenced VLP access points generally include a geo-location capability
to determine their geographic coordinates. The Commission proposes to
require a geofenced VLP device's geo-location capability to determine
its location uncertainty in meters, with a 95% confidence level, and
that the applicant for certification of a VLP access point demonstrate
the accuracy of the geo-location method used and the location
uncertainty. The Commission further proposes to require that a
geofenced VLP access point, using its geographic coordinates, take this
location uncertainty into account when it determines whether the VLP
access point is within an exclusion zone. The Commission seeks comment
on this proposal. The Commission also seeks quantitative information on
the benefits and costs of this proposal to VLP device users,
manufacturers and the wider public.
53. Location Update. The Commission proposes to require that
geofenced VLP access points have the capability to timely adjust their
operating frequencies when moving into, out of, or between exclusion
zones. The Commission proposes flexible requirements to enable device
designers to optimize efficiency while still meeting the requirement to
avoid operating on channels where -6 dB I/N interference protection
criterion is not met. Specifically, the Commission proposes that the
time interval for a geofenced device to re-check its location and
adjust its frequency usage must decrease proportionally based on an
increase in the mobile device's speed. Under this proposal, a geofenced
VLP access point that is in a powered state must regularly re-check its
location and speed and identify its position with respect to any
exclusion zones that may exist within the vicinity of its current
location. The Commission further proposes that this geolocation update
be done frequently enough that, based on the geofenced VLP access
point's position and speed, the device will not transmit on a channel
that is unavailable within an exclusion zone. The Commission believes
that this proposal provides flexibility to device designers to adjust
how often the VLP access point must obtain geolocation information
based on how fast the VLP access point is moving and how far it is from
an exclusion zone where it would have to change its operating channel.
As an additional safeguard, the Commission proposes to require the VLP
access point to determine its location and speed at least once a
minute. This one-minute update proposal is designed to provide
additional assurance that the VLP access point avoids transmitting on
frequencies that are not permitted by the geofencing system. The
Commission further proposes to require applicants for geofenced VLP
access point certification to submit an attestation describing their
algorithm for updating the device's location with an explanation
describing how these requirements are met.
54. The Commission seeks comment on these proposals. Do they
provide sufficient flexibility for mobile geofenced VLP devices? Is it
necessary for us to specify more detailed requirements on how often a
geofenced device must re-check its speed and its position with respect
to exclusion zones? If so, what additional requirements should be
specified and why? Is a requirement for devices to re-check their
location and speed at least once per minute necessary? Is the proposed
information that applicants for certification of geofenced VLP access
points must submit appropriate, or should any additional information be
required? If so, what information? The Commission seeks quantitative
information on the benefits and costs to VLP device users,
manufacturers and the wider public of its proposal and any proposed
alternatives.
55. Antenna Height. The Commission proposes to require geofencing
systems to use an assumed antenna height above ground level of 1.5
meters for geofenced VLP access points similar to the approach used in
the Second Report and Order for interference modeling of VLP devices.
The Commission seeks comment on this proposal. Is an assumed 1.5 meter
antenna height appropriate, or should the Commission specifies a
different value? If so, what height should the Commission require for
the exclusion zone calculations? The Commission also seeks quantitative
information on the benefits and costs to VLP device users,
manufacturers and the wider public of the Commission's proposed
antennas height. Commenters proposing alternative values should
quantify the benefits and costs of alternatives.
56. Fixed Infrastructure. Consistent with the Commission's actions
in the Second Report and Order, the Commission proposes to prohibit
geofenced VLP devices from operating as part of a fixed outdoor
infrastructure as an additional measure to reduce the likelihood of
interference to licensed incumbent services. The Commission seeks
comment on this proposal. Is a prohibition on fixed outdoor
infrastructure necessary when a geofencing system is used? The
Commission seeks quantitative information on the benefits and costs to
VLP device users, manufacturers and
[[Page 14027]]
the wider public of the Commission's proposal versus allowing
operations as part of fixed outdoor infrastructure.
57. Updates to exclusion zones. The 6 GHz Order established a
requirement that standard power access points must recheck the
frequency availability with an AFC system once per day. Similarly, the
Commission proposes to require geofencing systems to update the
exclusion zones at least once per day using the data from Commission
databases on the licensed microwave links and BAS/CARS central receive
sites. The Commission also proposes to require geofenced VLP access
points to obtain or calculate the updated exclusion zones from the
geofencing system at least once per day. This proposal is designed to
ensure that newly registered microwave receive sites and BAS/CARS
central receive sites are promptly protected. Consistent with the rules
for standard power access points and fixed client devices, the
Commission also proposes that if a VLP device is unable to obtain the
latest ULS or COALS data on a given day, it may continue operating
until 11:59 p.m. of the following day at which time it must cease
operation until it is able to obtain the latest geofencing data. The
Commission seeks comment on these proposals. The Commission also seeks
quantitative information on the benefits and costs to VLP device users,
manufacturers and the wider public of the Commission's proposal and
alternative update schedules and requirements.
58. Security Issues. Consistent with the Commission's requirements
for standard power devices and AFC systems in the 6 GHz Order, the
Commission proposes to require that geofenced VLP access points
incorporate adequate security measures to: (1) prevent them from
accessing geofencing systems and geofencing methods not approved by the
Commission, (2) ensure that unauthorized parties cannot modify devices
to operate in a manner inconsistent with the rules and licensed
incumbent protection criteria, and (3) ensure that communications
between VLP access points and geofencing systems are secure to prevent
corruption or unauthorized interception of data. The Commission also
proposes to require that geofencing systems, whether centralized or
internal to a VLP device, must ensure that all communications and
interactions between the geofencing system and VLP access points and/or
all communications between the geofencing system and Commission
databases are accurate and secure and that unauthorized parties cannot
access or alter the database, the exclusion zones, or the list of
excluded or available frequencies. The Commission further proposes to
require that a geofencing system incorporate security measures to
protect against unauthorized data input or alteration of stored data,
including establishing communications authentication procedures between
client devices and VLP access points. These proposed requirements are
intended to prevent a VLP device from using geofencing methods not
approved by the Commission and to ensure that unauthorized parties
cannot modify a device to operate in a manner inconsistent with the
rules. The Commission seeks comment on these proposals. What would be
the cost of implementing the Commission's security proposals versus
alternatives? The Commission seeks quantitative information on the
costs of geofenced VLP device security requirements.
59. Device testing and approval. As indicated above, the Commission
proposes to require that VLP devices operating with greater than -5
dBm/MHz PSD EIRP incorporate a geofencing capability that prevents them
from operating where there may be an elevated risk of causing harmful
interference to licensed incumbents in the 6 GHz band. Under this
proposal, geofenced systems in the 6 GHz band would determine exclusion
zones within which specific channels are prohibited from use by
geofenced VLP access points when a -6 dB I/N interference protection
criterion is not met (e.g., areas around fixed microwave and BAS/CARS
central receive sites), and each geofenced VLP access point would have
to be able to connect to a geofencing system or have an integrated
geofencing system capability.
60. Applicants seeking VLP device certifications would have to show
in their applications how their device will comply with any geofencing
requirements adopted in this proceeding. For example, applicants for
geofenced VLP access point certification would have to demonstrate that
the device operates only pursuant to a geofencing system and that the
geofencing system prevents operation in areas where the -6 dB I/N
metric is not met when calculated in accordance with the proposed
methodology. They would also have to demonstrate that their devices
could not operate on any channel that the geofencing system determines
is prohibited at its location at a power level greater than -5 dBm/MHz
EIRP PSD. Applicants would also be required to demonstrate that their
VLP access points comply with the proposed requirements to periodically
check their location and comply with the database recheck intervals
proposed above as well as adjust their operating channel if they move
into an exclusion zone where that channel is not available. They would
further have to demonstrate how geofenced VLP access points obtain
exclusion zone data either from a geofencing system or through
calculations based on data downloaded from Commission databases.
61. The Commission seeks comment on testing and certification
issues for geofenced VLP access points and client devices. Are there
any specific testing or certification issues that the Commission will
need to address, either in a subsequent item in this proceeding or
subsequent to adopting rules, e.g., through the KDB process? If so,
what issues would need to be addressed? Would industry groups such as
the Wi-Fi Alliance or WinnForum be likely to develop procedures for
testing geofencing systems? The Commission seeks quantitative
information on the benefits and costs to VLP device users,
manufacturers and the wider public of geofenced VLP testing and
certification requirements.
E. Spectrum Availability for Very Low Power Devices
62. The Commission seeks comment on any changes that it could make
that would allow for increased spectrum availability for geofenced VLP
devices without increasing the likelihood of harmful interference to
incumbent services, i.e., more efficient spectrum use. Consistent with
the Commission's recent Policy Statement, the Commission seeks
additional data that can be used to assess geofenced VLP device
operation and the potential impact on incumbent services. Are there any
particular characteristics of geofenced VLP devices, e.g., size,
operating location, specific applications, operating bandwidth,
modulation types, data rates, duty cycle/activity factor, or mobility
or lack thereof, that could be considered in enabling increased
spectrum availability for these devices? Is there currently any
operational or other data that would be helpful in this regard? How
much additional spectrum could be made available for geofenced VLP
devices? Would there be any significant increase in the areas where
they could operate as compared to the rules proposed above? The
Commission recognizes that actual operational data that may help us
reach a decision on these issues may not yet be available. In this
regard, the Commission encourages parties with additional data to
approach
[[Page 14028]]
the Commission in the future when such data becomes available. The
Commission also seeks information from incumbents regarding their
systems, particularly with respect to the amount of fade margin
incorporated into system design, statistics on when fades occur, their
severity, and how long they last, and how systems are designed to cope
with fading events using techniques such as adaptive modulation or
adjusting their data streams to focus on more time-sensitive critical
data over less critical data.
F. Restrictions on Very Low Power Device Mobile Operations
63. The Commission also seeks comment on whether to relax the
restrictions on VLP device mobile operations (e.g., on aircraft, boats
on the ocean, oil platforms, and terrestrial vehicles). In the 6 GHz
Order, the Commission prohibited standard power and LPI access points
from operating on board aircraft, with the exception of LPI use in the
U-NII-5 band on large passenger aircraft while flying above 10,000
feet. In the Second Report and Order, the Commission is largely
adopting the same operational restriction for VLP devices, except the
Commission is permitting them to operate on boats. Similar to the rules
for standard power and LPI access points, the Commission is prohibiting
VLP devices from operating on oil platforms. The restrictions on oil
platforms is being put in place to protect incumbent EESS remote
sensing operations, which, in this band are used inter alia for
monitoring ocean temperature.
64. As noted, these decisions were made largely to provide
consistency with the Commission's prior decision regarding standard
power and LPI devices. However, given the inherent differences between
those devices and VLP devices, the Commission seeks comment on whether
these restrictions on mobile operations on aircraft and oil platforms
can be relaxed for non-geofenced VLP devices, geofenced VLP devices, or
both. First, emissions from both types of VLP devices will be lower
than standard power and LPI devices; geofenced VLP access points and
associated client devices are permitted to operate with no more than 1
dBm/MHz EIRP PSD and 14 dBm EIRP while standard power and LPI devices
may operate at 23 dBm/MHz EIRP PSD and 36 dBm EIRP and 5 dBm/MHz EIRP
PSD and 30 dBm EIRP, respectively. VLP devices operate at an even lower
-5 dBm/MHz EIRP PSD. Second, both types of VLP devices are mobile,
generally operate close to the ground and in proximity to the body or
other objects, are likely to be battery powered, and either operate
pursuant to a geo-location system or at or below -5dBm/MHz EIRP PSD.
65. Considering expected use cases and the minimal potential for
VLP and geofenced VLP devices to cause harmful interference, the
Commission proposes to permit mobile operation on commercial and
general aviation aircraft more generally, but not on UAS. The
Commission can speculate that several prominent use cases will occur on
aircraft. The Commission seeks comment on permitting more general use
of VLP and geofenced VLP devices onboard commercial and general
aviation aircraft. For example, because FAA guidance specifies that
aircraft operators, when operating aircraft that have been certified to
meet portable electronic device tolerance standards, may permit certain
portable electronic devices to operate in all phases of flight (i.e.,
from gate-to-gate), body-worn VLP and geofenced VLP devices could be
used to monitor a person's health metrics or to stream a movie (e.g.,
from a smartphone to smart glasses). In such cases, operation is not
likely to be near a fixed microwave, BAS, or CARS receive site and is
likely to be low power, given the short transmission distance and the
fact that emissions will be shielded by the aircraft fuselage and will
be subject to clutter loses from nearby seats and passengers. In
addition, the Commission notes that the worst case for harmful
interference potential is likely to be on take-off or landing when the
aircraft is lower to the ground and thus, potentially closer to an
incumbent receiver. However, good engineering practice should prevent
microwave links in locations where aircraft are likely to fly as their
mere presence could cause link degradation. And even if an aircraft
were to fly in an area where it may be seen by a microwave receive
antenna main beam, the aircraft will be moving at significant speed and
the time a VLP or geofenced VLP device's emission could be within an
incumbent's receiver main beam will be fleeting and handled by forward
error correction or other techniques. In addition, when operated on the
ground, geofenced VLP access points and associated clients would
operate under the control of a geofencing system, while non-geofenced
VLP devices would operate at even lower power. As an initial matter,
considering operation on aircraft, should the Commission considers
permitting all VLP devices to operate across all phases of flight or
just VLP devices that are not geofenced? Or should geofenced VLP
devices be limited to only operating when above 10,000 feet or not
permitted to operate on aircraft at all? The Commission is already
permitting non-geofenced VLP devices to operate on large aircraft above
10,000 feet and ask if there is a different metric that could be used
for the specific case of aircraft. For example, noting the very fast
take-off and landing speeds, could the Commission implement a rule
stating that if a geofenced VLP access point is moving at an average
speed over 100 mph, it would no longer need to check the geofencing
system? Moving at or above this speed would imply operation on a very
fast moving vehicle, such as an aircraft. If the Commission allows a
minimum average speed metric for this purpose, should it apply only to
devices operated on aircraft, or could it apply to other modes of
transportation such as rail? Is there a different speed or metric that
would work better in providing a demarcation between when the
geofencing system must be used and when it is not necessary when
considering use on aircraft? What other considerations need to be taken
into account? For example, could there be issues that affect radio
astronomy sites? If so, should certain channels be prohibited from use
until an aircraft exceeds 10,000 feet? We seek comment on the
Commission's proposal to permit any or all VLP devices to operate gate-
to-gate while on aircraft.
66. The Commission continues to believe that any VLP operation when
such devices are mounted on a UAS could pose more than an insignificant
harmful interference risk, given the potential of UAS to fly almost
anywhere and to have clear line of sight to an incumbent's receiver. In
addition, because the geofencing system determines exclusion zones
based on an assumed 1.5 meter antenna height, any exclusion zone
associated with a UAS would be much larger than for general VLP device
usage. Nevertheless, the Commission seeks comment on whether there are
operational limitations or guidelines the Commission could adopt that
could permit VLP devices to operate when mounted on a UAS. Are there
applications that are specifically well-suited for use on a UAS? Are
there methods using the geofencing system or otherwise that could be
implemented to ensure that incumbent receivers are protected from
harmful interference? If so, how complex and feasible would these
methods be to implement? Would the costs associated with additional
complexity outweigh any benefits that might be gained from permitting
such operation?
[[Page 14029]]
67. In the Second Report and Order, the Commission maintained its
prohibition on all types of 6 GHz device usage on oil platforms to
protect EESS operations but did not prohibit the use of VLP devices on
boats. The Commission now seeks comment on whether the prohibition on
all types of 6 GHz device usage on oil platforms can be scaled back or
lifted. For example, given the differences between VLP devices (both
geofenced and non-geofenced) and standard power and LPI devices, does
the use of VLP devices on oil platforms pose the same risk of harmful
interference to EESS operations? Could standard power, LPI or either
type of VLP devices be used on oil platforms without causing a risk to
EESS ocean temperature monitoring operations? The Commission can
foresee applications where a 6 GHz device could provide utility through
augmented reality to a worker on an oil platform to provide relevant
information, such as for safety, maintenance tasks, or general
operating instructions. Is any restriction of VLP device use on boats
appropriate to protect EESS operations? If such a restriction were
adopted, could it be limited to boats located in the ocean, given that
EESS is used for sensing over the ocean? How could the prohibition on
use of VLP devices on oil platforms or a prohibition on use on boats,
if adopted, be implemented for non-geofenced VLP devices?
68. Finally, the Commission seeks comment on whether there is
additional flexibility that can be provided for terrestrial in-vehicle
use (e.g., cars, buses, and trucks). For example, are there devices
that are designed to be used solely in vehicles, such as an in-car
hotspot, that can only be used in a vehicle where due to the nature of
use--within a vehicle cabin, generally in motion at high speeds--
different requirements regarding power or exclusion zones could apply?
If so, are there requirements that could provide assurance that a VLP
device (geofenced or non-geofenced) is, in fact, in a vehicle, such as
having a connection to Carplay or Android Auto?
69. The Commission invites commenters to address these issues and
provide detailed information regarding whether the Commission can
provide more flexibility to VLP devices, both geofenced and non-
geofenced, for expanded use in aircraft, on boats, in vehicles, and in
more places while still ensuring that incumbent operators' facilities
are protected from harmful interference. The Commission seeks
quantitative estimates of benefits or costs of its proposals for
relaxing the VLP prohibition in these locations and potential
alternatives. How much and what kinds of additional VLP operations
might occur? How much and what kind of costs would be incurred to
accommodate these increased operations?
G. Expanding Very Low Power Operations to U-NII-6 and U-NII-8
70. In the Second Report and Order, the Commission adopted rules to
permit VLP devices to operate in the U-NII-5 and U-NII-7 bands at power
levels up to -5 dBm/MHz EIRP PSD and 14 dBm EIRP. The Commission
determined that the risk of harmful interference to incumbent services
in those bands, e.g., fixed microwave links and radio astronomy, was
insignificant for VLP devices operating at that power level. In this
Second Notice of Proposed Rulemaking, the Commission proposes to permit
VLP devices to also operate in the U-NII-6 and U-NII-8 bands without
geofencing. Given that fixed microwave links in the U-NII-8 band have
the same characteristics as those in U-NII-5 and U-NII-7, the
Commission concludes that any risk of harmful interference from VLP
devices to these microwave links is insignificant. The Commission seeks
comment on whether allowing VLP devices on U-NII-6 and U-NII-8 band
devices will yield comparable benefits to those that stem from allowing
VLP devices in the U-NII-5 and U-NII-7 bands in the Second Report and
Order. The Commission tentatively concludes that at a minimum the
benefits would be in proportion to the amount of spectrum in U-NII-6
and U-NII-8 bands relative to the amount of spectrum in the U-NII-5 and
U-NII-7 bands. The Commission anticipates that these benefit estimates
are conservative, as making available the full 1200 MHz in the 6 GHz
band could lead to larger channel sizes that could increase speed and
decrease latency. The Commission seeks comment on this and alternate
methods of estimating these benefits.
1. Protection of Mobile Services
71. As discussed above, both the U-NII-6 and U-NII-8 bands are used
by mobile BAS and CARS, including outdoor electronic news gathering
(ENG) trucks and low power short range devices, such as portable
cameras and microphones. Low Power Auxiliary Stations, which are
licensed in portions of 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. There are also BAS and CARS fixed microwave
links in these bands, which are used for such purposes as video links
between studios and transmitters and to relay video signals between
cities.
72. Outdoor electronic news gathering central receive sites. As
described above, the communications link between ENG trucks and a
central receive site shares many of the characteristics of a fixed
microwave link--i.e., they use directional antennas to send signals
between two fixed locations that are mostly above the local clutter.
The Commission proposes to permit VLP devices to also operate in the U-
NII-6 and U-NII-8 bands and seek comment on whether VLP devices could
operate at up to -5 dBm/MHz EIRP PSD and 14 dBm EIRP while keeping the
risk of harmful interference to ENG central receive sites to an
insignificant level. Would the same type of analysis discussed in the
Second Report and Order showing an insignificant risk of harmful
interference to fixed microwave receive sites be appropriate with
respect to ENG receive sites? Are there inherent differences between
BAS/CARS operations as compared to fixed point-to-point operations that
must be considered when analyzing the harmful interference risk? For
example, are there differences in antenna types, e.g., beamwidth and
gain, or in typical antenna heights or the locations of receive
antennas? Commenters noting differences should provide detailed
descriptions and information regarding how any difference could affect
the potential for VLP devices to cause harmful interference? Are there
specific VLP device characteristics that need to be considered in
analyzing their interference potential to ENG operations and if so,
what are they? The Commission seeks to provide uniform rules for
operations across the full 6 GHz band, but recognizing that there could
be differences in how VLP emissions may interact with different
incumbent systems, the Commission also seeks comment on what effect a
lower power limit for VLP devices might have regarding protecting ENG
operations in the U-NII-6 and U-NII-8 bands. Commenters advocating for
a lower power level should provide detailed analysis regarding their
preferred power level and the incremental effect such a power level
would have on the ability for VLP devices to access spectrum as well as
to what extent ENG operations would have additional protection from
harmful interference. Are there any other requirements that the
Commission
[[Page 14030]]
could adopt for VLP devices to protect ENG operations?
73. Apple, Broadcom, and Meta submitted a Monte Carlo simulation
addressing the potential for VLP devices operating at -5 dBm/MHz to
exceed -6 dB I/N for two specific ENG receive sites. For the ENG
receivers, the simulation used the same two ENG receive sites and
technical parameters that were used in a Monte Carlo simulation
previously submitted by NAB that examined the potential for 6 GHz band
unlicensed access points to interfere with ENG receivers. As the ENG
receive antennas are directional but generally are able to provide
360[deg] azimuthal coverage, it is not practical to simulate every
azimuth. Thus, Apple, Broadcom, and Meta limited their simulation to
the same three antenna orientations that NAB simulated for the two ENG
receive sites. For the VLP devices, the simulation used similar
assumptions for body loss, transmit power control, and propagation
models as the Apple, Broadcom et al. and Apple simulations discussed in
the Second Report and Order that assessed the potential for VLP devices
to exceed -6 dB I/N for microwave links in San Franscisco and Houston.
The Apple, Broadcom, and Meta Monte Carlo analysis found no instances
where the VLP devices caused the signal received at the ENG receive
sites to exceed -6 dB I/N. The Commission notes that NAB previously
expressed skepticism about the accuracy of a similar Monte Carlo
simulation provided by Apple, Broadcom, et al. that likewise found that
the -6 dB I/N threshold was never exceeded for one of these ENG receive
sites. The Commission seeks comment on the Apple, Broadcom, and Meta
simulation. The Commission seeks comment on its conclusions that -6 dB
I/N will not be exceeded or will only be exceeded in so few instances
at ENG central receive sites that the Commission can conclude that the
risk of harmful interference from VLP devices operating at -5 dB/MHz
EIRP PSD is insignificant. Given that this simulation used two ENG
receive sites that were chosen by NAB, can the Commission assume that
they are representative of BAS and CARS receive sites in general? Are
there particular scenarios that need further study?
74. Outdoor electronic news gathering ENG trucks. ENG trucks are
generally situated near news or sporting events and receive signals
from hand-held cameras or other portable news gathering devices. Based
on a study previously submitted by NAB, the ENG truck receive antenna
may be omni-directional or sectoral with adjustable height and
location. Additionally, the ENG truck signals may use various
bandwidths between 3 to 20 megahertz. For its study, NAB evaluated
harmful interference based on free space path loss and on whether an
unlicensed device would cause the I/N to exceed -10 dB.
75. Broadcom submitted a simulation showing a low probability
(<0.001%) that a VLP device operating at -5 dBm/MHz will cause the
signal-to-interference-plus-noise ratio (SINR) at the ENG truck
receiver to fall below 1 dB. Broadcom's 1 dB SINR threshold is based on
a previously submitted Broadcom study showing that a 10 megahertz ENG
channel with a 7/8 coding rate can maintain a signal with a bit-error-
rate (BER) less than 1e-8 in the presence of an RLAN signal operating
with a 2% duty cycle. Charter, Comcast, Cox and CableLabs also
previously submitted studies of the ENG truck signal SINR requirements
in the presence of RLANs operating at various duty cycles. While these
studies examined the impact of LPI transmissions, which operate at a
higher power than is proposed for VLP, their findings with respect to
SINR are also applicable to assessing VLP impact to BAS operations.
CableLabs finds that a 10 dB SINR ``provides an accurate view of system
requirements for high-quality BAS video delivery''.
76. The Commission proposes to permit non-geofenced VLP devices
operate in the U-NII-6 and U-NII-8 bands and seeks comment on whether
those devices could operate at up to -5 dBm/MHz EIRP PSD and 14 dBm
EIRP while minimizing the risk of harmful interference to ENG truck
receive sites. What is the appropriate metric for evaluating the
harmful interference risk to a ENG truck receiver, which is fixed
during operation but otherwise transportable, from a mobile or
transient VLP transmission? Regarding potentially using SINR, because
actual signal levels are not known prior to any transmission, what
value or range of values should be used for the ENG signal level for
any analysis? Commenters should provide insight and data regarding how
any assumed signal level is consistent with the signal levels used for
ENG operations. Previously submitted studies show that the required
SINR will vary according to channel bandwidth and coding rate. What are
the typical bandwidths and coding rates used by ENG truck receivers? If
the Commission were to rely on evaluating SINR, what SINR threshold
should be assumed to be necessary at the ENG truck receive site to
maintain a high quality signal? Broadcom's study predicted an impact
when the VLP device was within 5 meters of the receiver. Under normal
operating conditions, how close could a random user's VLP device
actually come to an ENG truck receiver? Is assuming at least a 5 meter
separation distance realistic? Or is that distance too short or too
long? Will the itinerant nature of VLP devices help reduce the
likelihood of a VLP device causing harmful interference? Are there any
particular connections the Commission should make between its reliance
on an I/N metric when evaluating ENG trucks connecting to a central
receive site and potentially evaluating the harmful interference risk
from portable devices to an ENG truck based on SINR? In evaluating
analysis methodology and protection metrics, commenters should detail
how such an approach supports permitting non-geofenced VLP operations
at power levels up to -5 dBm/MHz EIRP PSD or indicates that a different
power level may be appropriate.
77. Low-power short range mobile devices. The Commission proposes
that low power short range BAS and CARS devices, such as portable
cameras and microphones, and Low Power Auxiliary stations be protected
from harmful interference by a combination of a required contention-
based protocol and the low probability of a VLP device operating on the
same channel in a nearby location. This proposal is consistent with the
6 GHz Order in which the Commission required that all 6 GHz unlicensed
LPI access points, subordinate devices, and client devices employ a
contention-based protocol as well as the Commission's proposal above
with respect to geofenced VLP devices. Further, the 6 GHz Order showed
that the probability of channel overlap between 6 GHz unlicensed
devices and incumbent station operations is low due to unlicensed
devices having a full 1200 megahertz over which to operate.
78. The Commission believes that a similar approach for VLP devices
will adequately reduce the risk that mobile service incumbents in the
U-NII-6 and U-NII-8 bands would be subjected to harmful interference
and keep that risk to an insignificant level. The Commission's
reasoning is consistent with the 6 GHz Order, i.e., the sensing
function associated with the contention-based protocol, along with the
low probability for co-channel operation, is sufficient to ensure that
VLP devices detect nearby mobile BAS operations and avoid transmitting
co-channel to protect those operations from harmful interference. While
the Commission is
[[Page 14031]]
not proposing a specific technology protocol or contention method, the
Commission proposes to require VLP devices to use a contention-based
protocol as the Commission requires for LPI devices. The Commission
believes that this proposal has additional benefits as it provides
multiple VLP devices as well as LPI devices equal access to the
spectrum, while protecting mobile incumbents' services. The Commission
also believes that the use of a contention-based protocol will limit
the duty cycle of VLP devices as they will need to share the spectrum
with other devices. Additionally, VLP devices would transmit at lower
power levels than LPI devices, further reducing the risk of harmful
interference to mobile services. Given all these reasons, the
Commission believes that requiring use of a contention-based protocol
by VLP devices would protect mobile service incumbents.
79. The Commission seeks comment on this proposal. Would requiring
VLP devices to incorporate a contention-based protocol adequately
protect mobile service incumbents in the U-NII-6 and U-NII-8 bands? If
not, are there any other protection measures that could be used by VLP
devices to protect mobile services? Is there a need to provide greater
specificity in the requirements for a contention-based protocol used by
VLP devices? If so, what particular requirements should be specified
and why? What are the costs and benefits of requiring the use of a
contention-based protocol?
2. Fixed Satellite Services
80. The U-NII-7 and U-NII-8 bands contain Fixed Satellite Service
(FSS) space-to-Earth allocations and are restricted to feeder links for
Mobile-Satellite Service non-geostationary satellite systems. No such
earth stations are currently licensed in the U-NII-7 band. The U-NII-8
space-to-Earth allocation is limited to use by Globalstar's non-
geostationary Mobile-Satellite Service feeder links and earth stations
receiving at locations within 300 m of coordinates in Brewster, WA,
Clifton, TX, and Finca Pascual, PR. Globalstar also operates earth
station receive sites at Naalehu, HI, Wasilla, AK, and Sebring, FL.
These last two locations are authorized to operate on a co-primary
basis for FSS feeder downlinks, except for the 7.025-7.055 GHz band,
where they are authorized only on an unprotected basis. In the 6 GHz
Order, the Commission determined that the probability of harmful
interference to FSS space-to-Earth stations from LPI device operations
in U-NII-8 is low, primarily due to the restriction that LPI devices
operate indoors and at EIRP power levels no greater than 30 dBm.
81. The Commission seeks comment on whether any restrictions on VLP
device operation is necessary to protect space-to-Earth stations.
Because VLP devices would operate at significantly lower PSD levels
than geofenced VLP access points and associated client devices, how
does this impact the analysis of the potential for harmful interference
occurring? As VLP devices operate without the supervision of a
geofencing system, how could such restrictions, if needed, be
implemented? Would there be differences in the cost of protection for
VLP devices compared to geofenced VLP access point and associated
client devices? The Commission also seeks comment on how the earth
station antenna sites themselves provide interference protection by
creating a physical barrier (e.g., fencing) or using geographic
features to keep members of the public that could be using a VLP device
beyond some minimum distance from those earth stations. Commenters
should provide technical analysis to support their positions.
H. Emission Limits Below the U-NII-5 Band
82. The 5.895-5.925 GHz band immediately below the U-NII-5 band is
used by the Intelligent Transportation Service (ITS) which the
Commission is requiring to transition to C-V2X-based technology. In the
Second Report and Order, the Commission adopted the same -27 dBm/MHz
out-of-band emission (OOBE) limit for VLP devices for emissions below
the U-NII-5 band and above the U-NII-8 band as it had already required
for standard power and low-power indoor 6 GHz devices. NTIA filed a
technical exhibit into the record that includes a Department of
Transportation study (DoT Exhibit) addressing C-V2X protection
requirements in the 5.895-5.925 GHz band from 6 GHz VLP devices' and
mobile access points' out-of-band emissions. Deployers plan to transmit
basic safety messages for crash-avoidance applications that require
low-latency, free-from-harmful-interference in the 5.895-5.925 band.
According to the DoT Exhibit, testing shows that VLP devices operating
within a motor vehicle and that comply with the 27 dBm/MHz OOBE limit
will decrease the operational range of C-V2X receivers in the same
vehicle by more than 50%. While these tests are based on U-NII-4
(5.850-5.895 GHz) devices in the band immediately below the 5.895-5.925
GHz ITS band, the DoT Exhibit contends that the results can be
translated to assess the impact of VLP devices in the U-NII-5 band. The
DoT Exhibit claims that implementing both parts of a two-part
compromise submitted by several VLP proponents is necessary to protect
C-V2X receivers. This compromise proposal would require VLP devices to
prioritize their operations to frequencies above 6.105 GHz and limit
VLP OOBE below 5.925 GHz to -37 dBm/MHz. The Alliance for Automotive
Innovation, 5GAA, and ITS America similarly point to the compromise
proposal and advocate that the Commission modifies the VLP OOBE limits.
While the rules the Commission adopted for VLP devices implement the
former requirement, the Commission adopted the same -27 dBm/MHz OOBE
limit.
83. The Commission seeks additional information on the potential
impact that VLP devices operating in motor vehicles could have on C-V2X
performance when a VLP device is operating within the same motor
vehicle as the C-V2X receiver. In seeking comment on this issue, the
Commission notes that the DoT Exhibit is narrowly limited to VLP
operation as an access point or as a client connected to a 6 GHz
enabled mobile access point within motor vehicles and does not address
any other 6 GHz device or VLP device operation outside of motor
vehicles. In particular, the Commission seeks technical information,
including studies, analyses, and measurements detailing the interaction
between VLP devices operating under the Commission's rules and C-V2X
receivers in the 5.895-5.925 GHz band when these devices are in close
proximity such as in the same motor vehicle. What affect, if any, do
VLP devices' OOBE have on C-V2X devices' ability to communicate at
distances and with timing necessary to ensure a vehicle has sufficient
reaction time to keep passengers safe in various situations? In
undertaking studies to submit to the record, commenters should assess
realistic scenarios for VLP device deployment, whether VLP devices are
installed inside the vehicle or carried by a passenger from outside of
the vehicle, as well as realistic scenarios for C-V2X devices as they
pertain to device location within the vehicle, power level, OOBE level,
antenna directivity, and activity factor. For example, are VLP devices
expected to be mounted on dashboards, in headrests, etc. and are C-V2X
antennas expected to be mounted inside or outside the vehicle, on the
roof, in the grille, etc.? How do the various relative placements
between VLP and C-V2X
[[Page 14032]]
devices affect performance? The Commission seeks comment on whether any
adjustments are needed to its VLP device rules to adequately protect C-
V2X operation in vehicles. Commenters advocating for adjustments should
address whether they believe prioritization and a more stringent
emission limit, such as -37 dBm/MHz below 5.925 GHz for VLP devices, is
necessary as the DoT Exhibit advocates. Or whether either acting on its
own provides the protection level being claimed as needed. Similarly,
commenters advocating for prioritizing spectrum should address whether
a single limit is needed, such as above 6.105 GHz, or whether a
variable limit based on channel bandwidth can be implemented to provide
more flexibility for VLP devices. For example, would one bandwidth
buffer suffice such that 20-megahertz channels would not transmit on
the lowest 20 megahertz of the band, 40-megahertz channels would not
transmit on the lowest 40 megahertz of the band, etc.? Are there other
alternative measures that VLP devices could use to safeguard C-V2X
operations? Although, the Commission seeks comment on the narrow issue
of in-vehicle VLP device use, the Commission asks how any change to the
OOBE limit might affect the entire VLP device market. Commenters should
address whether permanently installed in-vehicle VLP devices should be
treated differently than other VLP devices, such as those used as
mobile access points or ``hotspots,'' or would all VLP devices need to
comply with a more stringent OOBE limit should the record indicate some
adjustments to the Commission's rules are necessary for in-vehicle VLP
operation? Finally, the Commission seeks comment on whether or how any
changes to its rules would affect device harmonization regarding the
global VLP device market. The Alliance for Automotive Innovation, 5GAA,
and ITS America state that dozens of countries have adopted a -37 dBm/
MHz OOBE level to protect ITS services. They claim that the European
Union (EU) as well as many non-EU member countries in the CEPT region,
adopted a more stringent OOBE level of -45 dBm/MHz below 5935 MHz,
which may be adjusted to -37 dBm/MHz in 2025 following additional
protection studies. The Commission notes, however, that the EU OOBE
limit is designed to protect urban rail intelligent transport systems,
including communication based train control systems, not C-V2X
operations. Thus, the Commission seeks comment on the applicability of
the EU adopted rule to C-V2X operations. Do equipment manufacturers
seeking to supply a global market plan to do so with a single device
that meets the most stringent OOBE level or would they provide variants
for different regions based on local rules? What are the costs and
benefits of various approaches?
I. LPI Client-to-Client Communications
84. In this section, the Commission seeks comment on whether the
Commission should permit direct communications between clients to LPI
devices. The Commission also seeks comment on the requirements that it
would have to specify to enable client-to-client communications without
causing harmful interference to licensed incumbent operations in the 6
GHz band.
85. Background. Standard-power access points can operate in the U-
NII-5 and U-NII-7 bands and require use of an AFC system for providing
access to spectrum in the band. LPI access points can operate across
the entire 6 GHz band but at lower power levels than standard power
devices. Client devices operate under the control of either a standard-
power or LPI access point and communicate using power levels that
depend on the type of access point to which they are connected. To
ensure that client devices not associated with standard power access
points transmit indoors, the Commission required that these devices
operate under the control of an indoor access point and prohibited 6
GHz U-NII client devices from directly communicating with one another.
The Commission prohibited unlicensed client devices from acting as
``mobile hotspots'' because ``[p]ermitting 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.'' To avoid this
situation, the Commission's rules prohibit 6 GHz U-NII client devices
from directly communicating with one another. The Commission did not,
however, consider whether a more limited approach to indoor client-to-
client communications should be permissible, such as when a client is
not acting as a mobile hotspot.
86. In response to suggestions by Apple, Broadcom et al. that
client devices could be permitted to directly communicate with each
under certain conditions, OET released a public notice on January 11,
2021 seeking information regarding client-to-client device
communications in the 6 GHz band. The conditions that Apple, Broadcom
et al. suggest for permitting client-to-client communications include
requiring client devices to decode an enabling signal transmitted by an
LPI device within the last four seconds, and requiring that an enabling
signal be received at a signal strength of at least -99 dBm/MHz. These
parties assert that these requirements would ensure each individual
client participating in client-to-client communications is safely
inside the area where a client device is authorized to communicate with
an access point.
87. Fourteen parties filed comments and 12 parties filed reply
comments in response to the OET public notice. Advocates of unlicensed
operation support permitting client-to-client communications by LPI
devices, arguing that they will enable new applications that benefit
the public, such as AR/VR and digital education and training. Incumbent
operators in the 6 GHz band (e.g., fixed microwave and broadcast) and
in adjacent bands express concern about permitting client-to-client
operations; specifically the potential for harmful interference and a
lack of interference testing with devices operating under the current
rules.
88. Discussion. The Commission invites comment on whether and under
what circumstances LPI client devices could be permitted to directly
communicate with each other in a limited manner while protecting
incumbent licensed services. The Commission recognizes that OET
previously sought comment on these issues. However, more than two years
have passed since the Commission received responses to OET's public
notice. During that time, many LPI devices have been certified and put
into operation. In addition, the approval process for AFC systems for
standard power devices has advanced, and as discussed in the Second
Report and Order, several parties have provided detailed analyses on
the potential for interference from 6 GHz devices to incumbent services
such as fixed microwave and broadcast services. Given that there is now
more information available or that could become available in the near
future concerning the interference potential of 6 GHz devices, the
Commission believes it is now appropriate to refresh and further build
the record on whether the Commission could permit LPI client-to-client
operations.
89. Specifically, the Commission seeks comment on whether the
Commission should permit 6 GHz client
[[Page 14033]]
devices to directly communicate when they are under the control of or
have received an enabling signal from a LPI access point. Commenters
should explain how to define an enabling signal (e.g., power level,
modulation type, how often it should be broadcast if it is discrete
from the regular data stream, etc.), what characteristics it should
have, how it would be similar or different from signals, such as
beacons, that access points already use to connect with client devices,
and the degree to which an enabling signal would tether a client device
not under the direct control of an access point to that access point.
Commenters should also provide information on the types of applications
that direct client-to-client communications would enable that cannot be
accomplished by communications through an access point. In addition,
commenters advocating for rule changes should address whether direct
client-to-client communications should be under the current power
limits or restricted to lower power limits to reduce the potential for
harmful interference to incumbent operations.
90. The requirement that 6 GHz client devices operate under the
control of either a standard-power or low-power indoor access point is
intended to prevent client devices from causing harmful interference by
limiting their operation either to outdoors in areas where an AFC
system has determined that interference is unlikely to occur, or in the
case of LPI devices to indoor locations where other factors such as
building entry loss prevent harmful interference. It may be possible
for a client device to receive an enabling signal from an access point
even when the enabling signal is too weak to enable the client device
to conduct communications with the access point. In such situations,
the weak received signal level makes it more likely that the client
device could be outdoors. By requiring that the enabling signal have a
specific signal strength, this problem could be potentially avoided. If
the Commission were to adopt rules permitting client-to-client
communications, should it require the enabling signal from the low-
power indoor access point to be received by the client device with a
particular signal level, such as -99 dBm/MHz as suggested by Apple,
Broadcom et al.? If not, what signal level would be appropriate? How
can a specific signal level be correlated with the requirement that the
client device be under the control of an access point? Should the
enabling signal level be of sufficient strength to effectively require
that the signal levels between the access point and client device be
sufficiently strong to permit bi-directional communications between the
client devices and the access point, thereby ensuring that both client
devices are close to the access point? How frequently should a client
device be required to receive an enabling signal to continue
transmitting to another client device?
The Commission also seeks comment on whether client devices should
be limited to receiving an enabling signal from the same access point
or whether client-to-client communications could be permitted so long
as each client device receives an enabling signal from any authorized
access point. Apple, Broadcom et al.'s suggestion would potentially
permit two client devices to communicate even if they receive enabling
signals from two different access points. For example, client devices
in two different buildings receiving enabling signals from different
low-power indoor access points could attempt to communicate with each
other. Would permitting this situation to occur increase the potential
for the client devices to cause harmful interference to licensed
services? Should other configurations be permitted? For example, could
a client device controlled by a standard power access point be
permitted to communicate with a client device controlled by a low-power
indoor access point? In such a case, should the client device power
level be restricted to the standard power client device power level?
Could client-to-client communications be permitted between devices when
both clients are controlled by a standard power access point? If so,
are any changes needed to the AFC systems? Must an enabling signal be
received on the same channel for each device under any of the scenarios
contemplated? Under any envisioned client-to-client communication
scenario, commenters should provide detailed descriptions of how such
communications can be enabled including how such communications fit
under the current rules that limit client devices to operating only
under the control of a standard power access point or a low-power
indoor access point or whether, and which, rules would need to be
modified. Commenters should provide detailed analysis of how any
client-to-client communication configurations they prefer would protect
incumbent operations from harmful interference. Finally, commenters
should provide any other information relevant to evaluating whether
direct client-to-client communications should be permitted, including
any alternative methods or necessary rule changes not directly
discussed above.
E. Ordering Clauses
1. Accordingly, it is ordered, pursuant to sections 2, 4(i), 302,
and 303 of the Communications Act of 1934, as amended, 47 U.S.C. 152,
154(i), 302a, and 303, this Second Further Notice of Proposed
Rulemaking is hereby adopted.
2. It is further ordered that the Office of the Secretary,
Reference Information Center, shall send a copy of the Second Further
Notice of Propose Rulemaking including the Initial Regulatory
Flexibility Analysis, to the Chief Counsel for Advocacy of the Small
Business Administration.
List of Subjects in 47 CFR Part 15
Communications equipment, Radio, and Reporting and recordkeeping
requirements.
Federal Communications Commission.
Marlene Dortch,
Secretary.
Proposed Rules
For the reasons discussed in the document, the Federal
Communications Commission proposes to amend 47 CFR part 15 as follows:
PART 15--RADIO FREQUENCY DEVICES
0
1. 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
2. Section 15.403 is amended by adding the definitions of ``Geofenced
very low power access point'' and ``Geofencing'' in alphabetical order,
to read as follows:
Sec. 15.403 Definitions.
* * * * *
Geofenced Very Low Power Access Point. For the purpose of this
subpart, an access point that operates in the 5.925-7.125 GHz band, has
an integrated antenna, and uses a geofencing system to determine
channel availability at its location.
Geofencing. For the purposes of this subpart, a method of
establishing exclusion zones within which very low power devices are
not permitted to operate on frequencies specified by the geofencing
system.
* * * * *
0
3. Amend Sec. 15.407 by:
0
A. Redesignating paragraphs (a)(7) and (8) as paragraphs (a)(8)(i) and
(ii);
[[Page 14034]]
0
B. Adding new paragraphs (a)(7) and (a)(8)(iii);
0
C. Redesignating paragraphs (a)(9) through (a)(12) as paragraphs
(a)(10) through (a)(13);
0
D. Revising newly redesignated paragraph (a)(10);
0
E. Revising paragraphs (d)(3) and (d)(5);
0
F. Removing and reserving paragraph (d)(7);
0
G. Adding paragraphs (d)(8) through (10); and
0
H. Adding paragraphs (o) through (r).
The revisions and additions read as follows:
Sec. 15.407 General technical requirements.
(a) * * *
(7) For a geofenced very low power access point operating in the
5.925-7.125 GHz band, the maximum power spectral density must not
exceed 1 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 14 dBm.
(8) * * *
(iii) For client devices operating under the control of a geofenced
very low power 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 14 dBm.
* * * * *
(10) Access points operating under the provisions of paragraphs
(a)(5), (6), and (7) of this section must employ a permanently attached
integrated antenna.
* * * * *
(d) * * *
(3) Transmitters operating under the provisions of paragraphs
(a)(5), (6), and (8)(ii) of this section are limited to indoor
locations.
* * * * *
(5)(i) In the 5.925-7.125 GHz band, client devices must operate
under the control of a standard power access point, low-power indoor
access point, subordinate device, or geofenced very low power access
point; Subordinate devices must operate under the control of a low-
power indoor access point.
(ii) Fixed client devices may only connect to a standard power
access point.
(iii) In all cases, an exception exists such that a client device
may transmit 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.
(iv) Client-to-client communications: Client devices are prohibited
from connecting directly to another client device, except that client
devices under the control of the same indoor access point or geofenced
very low power access point may communicate directly with each other.
(v) Client devices under the control of indoor access point, that
directly connect to another client, transmit power must not exceed -1
dBm e.i.r.p. in any 1-meghertz band, and the maximum e.i.r.p. over the
frequency band of operation must not exceed 14 dBm.
* * * * *
(7) [Reserved]
(8) Geofenced very low power and very low power devices may not
employ a fixed outdoor infrastructure. Such devices may not be mounted
on outdoor structures, such as buildings or poles.
(9) Geofenced very low power and very low power devices must
prioritize operations on frequencies above 6.105 GHz prior to operating
on frequencies between 5.925 GHz and 6.105 GHz.
(10) Transmit power control (TPC). Geofenced very low power devices
operating in the 5.925-7.125 GHz bands shall employ a TPC mechanism. A
very low power device is required to have the capability to operate at
least 6 dB below the maximum EIRP PSD value of -5 dBm/MHz.
* * * * *
(o) Geofencing system. (1) A geofencing system must obtain
information on protected services within the 5.925-7.125 GHz band from
Commission databases and use that information to determine frequency-
specific exclusion zones where very low power access points and
associated client devices may not operate on specified frequencies
based on the propagation models and protection criteria specified in
paragraph (p) of this section. The geofencing system must access the
Commission's licensing databases and update the frequency-specific
exclusion zones at least once per day to ensure that they are based on
the most recent information in the Commission's databases.
(2) Geofencing systems may be implemented using a centralized
database or may be integrated into geofenced very low power access
point devices.
(3) A geofenced very low power access point operating under
paragraph (a)(7) of this section must access a geofencing system to
obtain frequency-specific exclusion zones for the area in which it is
operating or intends to operate (e.g., within a specific point radius
or within specific geopolitical boundaries) prior to transmitting. If
the geofenced very low power access point moves outside this area, it
must obtain additional frequency-specific exclusion zones for the area
and adjust its operating frequency, if necessary, prior to operating in
this new area. The geofenced very low power access point must obtain
updated frequency-specific exclusion zones from the geofencing system
at least once per day. If the geofenced very low power access point
fails to obtain the updated frequency specific exclusion zones on any
given day, the geofenced very low power access point may continue to
operate until 11:59 p.m. of the following day at which time it must
cease operations until it can obtain updated frequency-specific
exclusion zones.
(4) A geofenced very low power access point must determine its
location and avoid transmitting on frequencies that are not available
in accordance with the frequency specific exclusion zones. The
geofenced very low power access point may not permit a client device
operating under its control to transmit on frequencies that are not
available in accordance with the frequency specific exclusion zones.
The geofenced very low power access point must determine its location
frequently enough that, based on its position and speed, it will not
transmit on an unavailable frequency. The geofenced very low power
access point must determine its location and speed at least once a
minute.
(5) A geofenced very low power access point must incorporate
adequate security measures to prevent it from accessing geofencing
systems and geofencing methods 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 geofenced very
low power access points and geofencing systems are secure to prevent
corruption or unauthorized interception of data.
(6) A geofenced very low power access point must include an
internal geo-location capability to automatically determine the
geofenced very low power access point's geographic coordinates and
location uncertainty (in meters), with a confidence level of 95%.
(i) The geofenced very low power access point must use such
coordinates and location uncertainty when comparing the devices
specific location to the exclusion zone boundaries.
(ii) The applicant for certification of a geofenced very low power
access point
[[Page 14035]]
must demonstrate the accuracy of the geo-location method used and the
location uncertainty.
(7)(i) For centralized geofencing systems, geofencing system
operators must provide continuous service to all very low power devices
for which it has been designated to provide service. If a geofencing
system ceases operation, the operator must provide at least 30-days'
notice to the Commission and a description of any arrangements made for
those devices to continue to receive exclusion zone update information.
(ii) For geofencing systems internal to the geofenced very low
power device, the equipment certification responsible party must ensure
that the device continues to be capable of receiving Commission
database updates as required by this section.
(iii) As required by paragraph (o)(3) of this section, devices that
do not receive timely geofencing update information or timely
Commission database updates necessary to calculate up-to-date exclusion
zones must cease operating.
(8) The geofencing system whether centralized or internal to the
geofenced very low power device must ensure that all communications and
interactions between the geofencing system and the geofenced very low
power access point and/or all communications between the geofencing
system and Commission databases are accurate and secure and that
unauthorized parties cannot access or alter the database, the exclusion
zones, or the list of excluded or available frequencies. Additionally,
the geofencing 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 geofenced very low power access points.
(9) A geofencing system must implement the terms of international
agreements with Mexico and Canada.
(10) At the time that the geofenced very low power device receives
equipment certification, the device must either have its geofencing
system approved or specify an already approved geofencing system that
it is using. The Commission may specify criteria for such approval,
which could require test results to be submitted.
(11) Each geofencing system and operator thereof for centralized
systems and the equipment certification responsible party for systems
internal to the geofenced very low power device must:
(i) Ensure that a regularly updated geofencing system database that
contains the information described in this section, including
incumbent's information and geofenced very low power access points
authorization parameters, is maintained.
(ii) Respond in a timely manner to verify, correct, or remove, as
appropriate, data in the event that the Commission or a party presents
a claim of inaccuracies in the geofencing system.
(iii) Establish and follow protocols to comply with enforcement
instructions from the Commission, including discontinuance of geofenced
very low power access point operations on specified frequencies in
designated geographic areas and predetermined exclusion zones.
(iv) Comply with instructions from the Commission to adjust
exclusion zones to more accurately reflect the potential for harmful
interference.
(12) A geofencing system operator may charge fees for providing
service. The Commission may, upon request, review the fees and can
require changes to those fees if the Commission finds them to be
unreasonable.
(p) Incumbent protection by geofencing system. A very low power
access point or very low power client device must not cause harmful
interference to fixed microwave services and Broadcast Auxiliary
Service and Cable Television Relay Service receive sites authorized to
operate in the 5.925-7.125 GHz bands. Based on the criteria set forth
below, a geofencing system must establish location and frequency-based
exclusion zones around fixed microwave receivers, fixed Broadcast
Auxiliary Service receive sites, and fixed Cable Television Relay
Service receive sites operating in the 5.925-7.125 GHz bands.
Individual very low power access points and their associated client
devices must not operate co-channel to the frequencies licensed for
fixed microwave systems, fixed Broadcast Auxiliary Service receive
sites, and fixed Cable Television Relay Service sites within an
exclusion zone.
(1) Geofencing systems must use the following propagation models to
determine exclusion zones for very low power access points. For a
separation distance between geofenced very low power devices and fixed
microwave receive sites, fixed Broadcast Auxiliary Service receive
sites, or fixed Cable Television Relay Service receive sites.
(i) Up to 30 meters, the geofencing system must use the free space
path-loss model.
(ii) More than 30 meters and up to and including one kilometer, the
geofencing system must use the Wireless World Initiative New Radio
phase II (WINNER II) model. The geofencing system must use 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 such data are available. For evaluating paths
where such data are not available, the geofencing 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:
Equation 3 to paragraph (p)(2)(ii)
Path-loss (L) = [Sigma]<INF>i</INF> P(i) * L<INF>i</INF> =
P<INF>LOS</INF> * L<INF>LOS</INF> + P<INF>NLOS</INF> *
L<INF>NLOS</INF>;
Where:
P<INF>LOS</INF> is the probability of line-of-sight;
L<INF>LOS</INF> is the line-of-sight path loss;
P<INF>NLOS</INF> is the probability of non-line-of sight;
L<INF>NLOS</INF> is the non-line-of-sight path loss; and
L is the combined path loss.
(iii) The WINNER II path loss models include a formula to determine
P<INF>LOS</INF> as a function of antenna heights and distance.
P<INF>NLOS</INF> is equal to (1-P<INF>LOS</INF>).
(iv) In all cases, the geofencing system will use the correct
WINNER II parameters to match the morphology of the path between a very
low power access point and a fixed microwave receiver, fixed Broadcast
Auxiliary Service receiver, or fixed Cable Television Relay Service
receiver (i.e., Urban, Suburban, or Rural).
(v) More than one kilometer, the geofencing 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, the geofencing 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 geofencing 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 geofencing system must use 1 arc-
second digital elevation terrain data and, for locations where such
data are not available, the most granular available digital elevation
terrain data.
(vi) Geofencing systems may include up to 4 dB additional loss to
account for losses due to scattering and absorption from a nearby body
or object.
(vii) Geofencing systems may calculate exclusion zones based on a
1.5 meter very low power access point antenna height above ground
level, regardless of the actual antenna height above ground level.
(2) The geofencing system must use -6 dB I/N as the interference
protection criteria when calculating the exclusion zones where I
(interference) is the co-
[[Page 14036]]
channel signal from the very low power access point at the fixed
microwave service receiver, fixed Broadcast Auxiliary Service receiver,
or fixed Cable Television Relay Service receiver and N (noise) is
background noise level at the fixed microwave service receiver, fixed
Broadcast Auxiliary Service receiver, or fixed Cable Television Relay
Service receiver.
(q) Incumbent Protection by Geofencing System: Radio Astronomy
Services. (1) The geofencing system must enforce 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.
(2) The exclusion zone sizes are based on the radio line-of-sight
and determined using 4/3 earth curvature and the following formula:
Equation 4 to paragraph (q)(2)
dkm_los = 4.12*(sqrt(Htx) + sqrt(Hrx))
Where:
Htx is the height of the very low power access point and is set at
1.5 meters above ground level; and
Hrx is the height of the radio astronomy antenna in meters above
ground level.
(3) Coordinate locations of the radio observatories are listed in
Sec. 2.106(c)(131), (c)(385) of this part.
(r) Incumbent Protection by Geofencing System: FSS (space-to-Earth)
Earth Stations. (1) The geofencing system must enforce exclusion zones
to protect FSS earth stations that receive in the 6875-7055 MHz band at
Clifton, TX, Cabo Rojo, PR, Wasilla, AK, Sebring, FL, and Naalehu, HI.
(2) The exclusion zone sizes are based on the radio line-of-sight
and determined using 4/3 earth curvature and the following formula:
Equation 5 to Paragraph (r)(2)
dkm_los = 4.12*(sqrt(Htx) + sqrt(Hrx))
Where:
Htx is the height of the very low power access point and is set at
1.5 meters above ground level; and
Hrx is the height of the FSS antenna in meters above ground level.
Coordinate locations of the FSS sites are listed in the following
table:
Table 1 to Paragraph (r)(2)
------------------------------------------------------------------------
Location Coordinates
------------------------------------------------------------------------
Clifton, Texas....................... 31[deg]47'59.22'' N,
97[deg]36'46.71'' W
Clifton, Texas....................... 31[deg]48'2.149'' N,
97[deg]36'44.37'' W
Clifton, Texas....................... 31[deg]47'57.4'' N,
97[deg]36'47.9'' W
Clifton, Texas....................... 31[deg]48'0.1'' N,
97[deg]36'48.9'' W
Clifton, Texas....................... 31[deg]48'3'' N, 97[deg]36'49.2''
W
Clifton, Texas....................... 31[deg]47'57.5'' N,
97[deg]36'44.7'' W
Clifton, Texas....................... 31[deg]48'0.2'' N,
97[deg]36'44.3'' W
Sebring, Florida..................... 27[deg]27'34.3'' N,
81[deg]21'26.6'' W
Sebring, Florida..................... 27[deg]27'35.6'' N,
81[deg]21'26.8'' W
Sebring, Florida..................... 27[deg]27'35.6'' N,
81[deg]21'28.4'' W
Sebring, Florida..................... 27[deg]27'34.3'' N,
81[deg]21'28.3'' W
Wasilla, Alaska...................... 61[deg]35'24.9'' N,
149[deg]29'9.6'' W
Wasilla, Alaska...................... 61[deg]35'24.1'' N,
149[deg]29'6'' W
Wasilla, Alaska...................... 61[deg]35'24.6'' N,
149[deg]29'2.4'' W
Cabo Rojo, Puerto Rico............... 17[deg]58'48'' N, 67[deg]8'15'' W
Cabo Rojo, Puerto Rico............... 17[deg]58'50'' N, 67[deg]8'13'' W
Cabo Rojo, Puerto Rico............... 17[deg]58'49'' N, 67[deg]8'14'' W
Cabo Rojo, Puerto Rico............... 17[deg]58'48'' N, 67[deg]8'12'' W
Naalehu, Hawaii...................... 19[deg]0'51.99'' N,
155[deg]39'47'' W
Naalehu, Hawaii...................... 19[deg]0'52.99'' N,
155[deg]39'48.99'' W
Naalehu, Hawaii...................... 19[deg]0'51'' N,
155[deg]39'48.9'' W
------------------------------------------------------------------------
[FR Doc. 2023-28620 Filed 2-23-24; 8:45 am]
BILLING CODE 6712-01-P
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</html>Indexed from Federal Register on February 26, 2024.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.