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Proposed Rule2021-16637

FCC Seeks To Enable State-of-the-Art Radar Sensors in 60 GHz Band

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Published

August 19, 2021

Issuing agencies

Federal Communications Commission

Abstract

In this document, the Commission proposes to revise the Commission's rules to provide expanded operational flexibility to unlicensed field disturbance sensor (FDS) devices (e.g., radars) that operate in the 57-64 GHz band (60 GHz band). The Commission's proposal recognizes the increasing practicality of using mobile radar devices in the 60 GHz band to perform innovative and life-saving functions, including gesture control, detection of unattended children in vehicles, and monitoring of vulnerable medical patients, and it is designed to stimulate the development of new products and services in a wide variety of areas to include, for example, personal safety, autonomous vehicles, home automation, environmental control, and healthcare monitoring, while also ensuring coexistence among unlicensed FDS devices and current and future unlicensed communications devices in the 60 GHz band.

Full Text

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<title>Federal Register, Volume 86 Issue 158 (Thursday, August 19, 2021)</title>
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[Federal Register Volume 86, Number 158 (Thursday, August 19, 2021)]
[Proposed Rules]
[Pages 46661-46672]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2021-16637]

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FEDERAL COMMUNICATIONS COMMISSION

47 CFR Part 15

[ET Docket No. 21-264; FCC 21-83; FR ID 41217]

FCC Seeks To Enable State-of-the-Art Radar Sensors in 60 GHz Band

AGENCY: Federal Communications Commission.

ACTION: Proposed rule.

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SUMMARY: In this document, the Commission proposes to revise the
Commission's rules to provide expanded operational flexibility to
unlicensed field disturbance sensor (FDS) devices (e.g., radars) that
operate in the 57-64 GHz band (60 GHz band). The Commission's proposal
recognizes the increasing practicality of using mobile radar devices in
the 60 GHz band to perform innovative and life-saving functions,
including gesture control, detection of unattended children in
vehicles, and monitoring of vulnerable medical patients, and it is
designed to stimulate the development of new products and services in a
wide variety of areas to include, for example, personal safety,
autonomous vehicles, home automation, environmental control, and
healthcare monitoring, while also ensuring coexistence among unlicensed
FDS devices and current and future unlicensed communications devices in
the 60 GHz band.

DATES: Comments are due on or before September 20, 2021; reply comments
are due on or before October 18, 2021.

ADDRESSES: You may submit comments, identified by ET Docket No. 21-264,
by any of the following methods:
<bullet> Electronic Filers: Comments may be filed electronically
using the internet by accessing the ECFS: <a href="http://apps.fcc.gov/ecfs/">http://apps.fcc.gov/ecfs/</a>.
<bullet> Paper Filers: Parties who choose to file by paper must
file an original and one copy of each filing.
<bullet> Filings can be sent by commercial overnight courier, or by
first-class or overnight U.S. Postal Service mail. All filings must be
addressed to the Commission's Secretary, Office of the Secretary,
Federal Communications Commission.
<bullet> 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.
<bullet> U.S. Postal Service first-class, Express, and Priority
mail must be addressed to 45 L Street NE, Washington, DC 20554
<bullet> Effective March 19, 2020, and until further notice, the
Commission no longer accepts any hand or messenger delivered filings.
This is a temporary measure taken to help protect the health and safety
of individuals, and to mitigate the transmission of COVID-19. See FCC
Announces Closure of FCC Headquarters Open Window and Change in Hand-
Delivery Policy, Public Notice, DA 20-304 (March 19, 2020). <a href="https://www.fcc.gov/document/fcc-closes-headquarters-open-window-and-changes-hand-delivery-policy">https://www.fcc.gov/document/fcc-closes-headquarters-open-window-and-changes-hand-delivery-policy</a>.
People with Disabilities: To request materials in accessible
formats for people with disabilities (braille, large print, electronic
files, audio format), send an email to <a href="/cdn-cgi/l/email-protection#a4c2c7c7919490e4c2c7c78ac3cbd2">[email&#160;protected]</a> or call the
Consumer & Governmental Affairs Bureau at 202-418-0530 (voice), 202-
418-0432 (TTY).

FOR FURTHER INFORMATION CONTACT: Anh Wride, Office of Engineering and
Technology, 202-418-0577, <a href="/cdn-cgi/l/email-protection#ff9e9197d1888d969b9abf999c9cd1989089">[email&#160;protected]</a>, or Thomas Struble at 202-
418-2470 or <a href="/cdn-cgi/l/email-protection#7e2a1611131f0d502d0a0c0b1c121b3e181d1d50191108">[email&#160;protected]</a>

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Notice
of Proposed Rulemaking (NPRM), in ET Docket No. 21-264, FCC 21-83,
adopted on July 13, 2021 and released on July 14, 2021. The full text
of this document is available for public inspection and can be
downloaded at: <a href="https://www.fcc.gov/document/fcc-seeks-enable-state-art-radar-sensors-60-ghz-band-0">https://www.fcc.gov/document/fcc-seeks-enable-state-art-radar-sensors-60-ghz-band-0</a> or by using the search function for ET
Docket No. 20-382 on the Commission's ECFS web page at w<a href="http://ww.fcc.gov/ecfs">ww.fcc.gov/ecfs</a>.

Synopsis

Discussion. The Part 15 rules permit low-power intentional
radiators (popularly known as ``unlicensed devices'') to operate
without an individual license where such use is not anticipated to
cause harmful interference to authorized users of the radio spectrum.
Unlicensed devices in the 60 GHz band generally include indoor/outdoor
communication devices such as WiGig wireless local area networking
(WLAN) devices, outdoor fixed point-to-point communication links, and
field disturbance sensors (FDS)--which includes radar operations.
Unlicensed device users must account for the operations of authorized
Federal and non-Federal users in the band, who operate under a variety
of co-primary allocations. These allocations, which vary by band
segment, consist of the Mobile, Fixed, Inter-Satellite, Earth-
Exploration Satellite Service (EESS), Space Research, Mobile-Satellite,
Radiolocation, Radionavigation, and Radionavigation-Satellite services.
Section 15.255 of the rules stipulates operational policies and
technical parameters for the 60 GHz band. The rule limits FDS
operations to fixed operation or when used as short-range devices for
interactive motion sensing (SRIMS). Furthermore, a fixed FDS with an
occupied bandwidth fully contained within the 61.0-61.5 GHz band may
operate with average output power levels up to 40 dBm and peak output
power levels up to 43 dBm, while all other FDS devices (including those
being used for SRIMS) are limited to a maximum transmitter conducted
output power not to exceed -10 dBm and a maximum EIRP level not to
exceed 10 dBm.
When it first adopted Sec. 15.255 in 1995, the Commission stated
that its intent was to foster the potential of the 60 GHz band ``for
allowing the development of short-range wireless radio systems with
communications capabilities approaching those . . . achievable only
with coaxial and optical fiber cable.'' When it finalized the rule by
adopting a spectrum etiquette three years later, it also included a
provision that permitted fixed FDS operation in the band.
In 2016, the Commission further expanded unlicensed device use in
the

[[Page 46662]]

band to permit limited mobile radar operations and to extend the use of
fixed field disturbance sensors to the 64-71 GHz band. At that time,
the Commission recognized that wireless innovation included the
development of gesture-recognition technology using short-range radars
that would allow users to interact with devices without needing to
touch them. It thus decided to permit SRIMS radars while also noting
that the record before it was insufficient to allow for the unfettered
operation of mobile radars in the band. Specifically, the Commission's
decision permitted the ``narrow application of mobile radars for short-
range interactive motion sensing'' at reduced power levels to ensure
that they would successfully co-exist with co-channel communications
devices already permitted to operate in the band. While the Commission
did not adopt a specific definition for SRIMS, in permitting narrow use
of short-range mobile radars it discussed the work of Google LLC
(Google) in developing its ``Soli'' sensor technology, which envisioned
that smartphones and other personal devices would be able to sense hand
gestures when a user is located at a very short distance from the
device to perform functions such as controlling web pages or answering
phone calls. Furthermore, while the Commission specifically rejected
comments calling on it to completely eliminate restrictions on FDS use,
it also stated that it might consider allowing higher power levels in
the future after it had acquired more experience with the devices it
was permitting at that time.
Since the 2016 decision, there has been continued interest in
developing mobile radar applications that use the 60 GHz band. To date,
the Commission's Office of Engineering and Technology (OET) has granted
focused waivers of the rules to support discrete applications. First,
Google requested a waiver of the emission limits to allow Soli radar
devices to operate at a higher output power level than what had been
authorized in the rulemaking, arguing that it had determined that
higher power levels were necessary for the radar sensor to provide
sufficient resolution to engage in effective interactions. In its 2018
order granting that waiver, which was limited to use of the specific
Soli sensor described in Google's request, OET found that allowing
Google Soli sensors to operate at the requested power levels would not
materially change the operating environment in the 57-64 GHz band from
the perspective of the other users in the band. Specifically, it
determined that the higher-power Google Soli device would be able to
cooperatively share this spectrum with all users. The waiver permitted
Google to deploy its Soli sensor technology at 10 dBm peak transmitter
conducted output power, 13 dBm peak EIRP level, and 13 dBm/MHz power
spectral density, with a maximum 10% duty cycle in any 33 milliseconds
(ms) interval. This represented a lesser peak power limit than Google
had originally sought, as it had revised its request following
discussions with other parties who had interests in using the band for
unlicensed operations, such as Facebook, in an effort to facilitate
coexistence between unlicensed users in the band.
Recently, OET granted waivers to several parties to permit the
operation of vehicle cabin-mounted radars as well as health-care
related and other applications in the 57-64 GHz range at the same power
levels as those granted to Google in 2018. These narrowly tailored
waivers support an especially compelling public interest--using radar
technology to monitor for children left in dangerous, hot cars and to
trigger alerts that could save lives. While radars operating under
these waivers must be installed within the vehicle cabin and have the
primary function of preventing children from inadvertently being left
unattended in rear car seats, they are also expected to provide
additional passenger safety and theft prevention benefits. In addition,
OET granted a waiver to Leica Geosystems AG in July 2020 that allows a
limited number of radars to operate in the 60-64 GHz band on
specialized unmanned aircraft for the specific purpose of avoiding
collisions with structures, supporting wires, or other fixed objects
during the visual inspection of structures.
Applications such as the use of in-cabin automotive radars
represent one of the many uses that parties have identified as being
well suited for development in the 57-71 GHz band if the Sec. 15.255
rules were amended to permit expanded mobile radar use. The Commission
has received additional waiver requests asking for permission, for
example, to install a radar on the exterior of a vehicle to enable
closure of a door by the detection of foot movement or hand gestures;
to operate 60 GHz radars in robotic lawn mowers, or in personal safety
wall-mount devices to detect changes in a person's gait or a fall, and
in 3D imaging equipment in healthcare environments. In general, these
requests have been consistent with the same technical parameters as the
waiver granted to Google and are represented to occupy the same
``spectrum footprint'' as the Soli device. The increased interest in
use of the band and accompanying breadth of potential applications that
parties have identified is a relatively recent development,
attributable at least in part, the Commission believes, to the
availability of mass-produced chipsets that are capable of operating in
the band, as well as the prospect of marketing and operating these
mobile radar devices on a broad international scale.
To that end, the Commission notes that operation at higher power
than specified in the Commission's rules has been allowed in Europe
under general rules for short-range devices. A European
Telecommunications Standards Institute (ETSI) standard, which has been
in effect since 2014, permits short-range devices to operate in a
portion of the 57-71 GHz band at power levels that exceed those for
FDS--including those operating as SRIMS--under Sec. 15.255 of the
Commission's rules. Specifically, ETSI Standard EN 305 550 permits
operation of short-range devices in the 57-64 GHz band at up to 20 dBm
mean EIRP, while Sec. 15.255(c)(3) presently specifies that the peak
EIRP level for FDS devices shall not exceed 10 dBm. ETSI EN 305 550
also permits a maximum transmitter output power of 10 dBm, which is 20
dB greater than the level that Sec. 15.255(c)(3) permits in this band.
There are some additional differences between the US and European
approaches. For example, the ETSI power limits are based on average
measurements, whereas the Commission's limits are based on peak power
measurements. In addition, ETSI EN 305 550 also requires short-range
devices in the 57-64 GHz band to comply with a power spectral density
(PSD) limit of 13 dBm/MHz, which the Commission's rules do not include.
Finally, unlike the U.S, ETSI does not have a separate provision that
allows for higher EIRP levels of up to 40 dBm for FDS in the 61.0-61.5
GHz band, nor does it provide for operation in the 64-71 GHz band.
The protocols for wireless systems operating in the 60 GHz band
within the U.S. have been established by the Institute of Electrical
and Electronics Engineers (IEEE) 802.11 Standards Committee. These
protocols are often referred to as ``WiGig,'' named for the former
Wireless Gigabit Alliance which advocated for their development. The
current IEEE 802.11ad standard allows for channel sizes of up to 2.16
gigahertz in the 60 GHz band, which support a data rate of up to 8
gigabits per second and permits a total of six channels in the 57-71
GHz band available in the United States. Furthermore, there are

[[Page 46663]]

IEEE 802.11 working groups with ongoing activities to define the
channel access protocols to enable the same 60 GHz system transmitting
communication signals to transmit radar signals.
The ongoing interest in expanding the scope of permissible
unlicensed operations in the 60 GHz band has prompted interested
parties to form a 60 GHz Coexistence Study Group that has been looking
into ways to accommodate both unlicensed communications device and FDS
operations in the band. This group, which has attracted the active
participation of many key members of the industry and meets on a
regular basis, operates independently of the Commission. Members of
this group, however, have submitted comments and ex parte filings in
conjunction with many of the recent waiver proceedings. In general,
these submissions have documented the parties' interest in 60 GHz
unlicensed operations and have encouraged us to initiate a rulemaking
proceeding to review Sec. 15.255 of the Commission's rules with a goal
of putting into place a new framework to promote further innovation in
the 60 GHz band by both unlicensed communications and FDS operations.
Finally, the 2020 panel of the FCC's Technological Advisory Council
(TAC) took notice of the 60 GHz Coexistence Study Group when its Future
of Unlicensed Operations working group examined ways to improve
regulations for the 60 GHz band. As part of the TAC's January 14, 2021
meeting, the working group recommended that the Commission initiate a
rulemaking proceeding to examine the 60 GHz rules in Sec. 15.255 to
address issues raised by the numerous waiver requests that had been
filed.
Discussion. The Commission believes that there are significant
benefits in initiating this rulemaking proceeding, and the Commission
agrees with the TAC and other parties that have urged us to
comprehensively evaluate unlicensed operations under Sec. 15.255 of
the Commission's rules. The Commission realizes that past individual
waivers have served as an important ``relief valve'' that allow for
unique types of operations that have important public interest benefits
and that do not result in harmful interference to incumbent licensed
users or jeopardize coexistence with other unlicensed users but do not
comply with the Commission's rules. However, they are an inappropriate
mechanism for providing the type of broad-based relief that the
Commission considers here. Together, the overwhelming interest in FDS
operations in the 60 GHz band, the breadth of deployments that parties
have identified, and the opportunities for innovation that will be made
possible by the availability of relatively inexpensive application-
agnostic FDS-capable chipsets make the Commission's initiation of a
rulemaking proceeding both timely and appropriate. In recognition that
unencumbered unlicensed operation has proven to be an especially
powerful engine for innovation and economic growth, the Commission's
proposals are designed to expand the opportunities for unlicensed FDS
operations in the band to the greatest extent possible. At the same
time, the Commission's proposals are also designed to provide assurance
that the unlicensed communications devices that have been permitted to
use the band since it was first made available for unlicensed
operations will be able to coexist with these new unlicensed
operations. And, in all cases, the Commission's proposals remain true
to the bedrock principle that unlicensed devices, regardless of type,
must not cause harmful interference to authorized users of the band.
In this NPRM, the Commission proposes targeted changes to Sec.
15.255 of the Commission's rules to expand unlicensed FDS device
operations in the 60 GHz band. First, the Commission proposes that all
FDS devices that limit their operating frequencies to the 57-64 GHz
portion of the band would be permitted to transmit at a maximum of 20
dBm average EIRP, 13 dBm/MHz average EIRP power spectral density, and
10 dBm transmitter conducted output power, along with a maximum 10%
duty cycle restriction within any 33 ms interval. FDS devices will be
able to continue to operate across the entire 57-71 GHz band at the 10
dBm EIRP and -10 dBm conducted output power limits specified in the
Commission's existing rules. By streamlining the Commission's rules in
this manner, the Commission would no longer need the special provisions
for short-range interactive motion-sensing mobile radars (i.e. SRIMS)
that are contained in the Commission's existing rules. Second, the
Commission also proposes to retain and potentially to expand on the
provision of Sec. 15.255(c)(2) allowing fixed FDS devices that contain
their operating bandwidth to the 61.0-61.5 GHz band to transmit at 40
dBm average EIRP and 43 dBm peak EIRP. Finally, the Commission seeks
comment on methods to enhance coexistence (e.g., listen-before-talk or
other spectrum sensing/contention avoidance capabilities) that could be
used to allow the same power level for FDS devices as is currently
permitted for 60 GHz communication devices (up to 40 dBm EIRP) across
the entire 57-71 GHz band. The Commission is not proposing any rule
revisions for existing unlicensed communication devices such as WiGig
WLAN or fixed point-to-point wireless links that currently operate in
the 57-71 GHz band. However, the Commission seek comment on whether
there are particular provisions that the Commission is proposing for
FDS operation, such as an antenna gain limit instead of a conducted
power limit and requiring use of a spectrum sensing mechanism, that
should be more broadly applied to all Part 15 devices operating in the
57-71 GHz band.
The Commission notes that the TAC's Future of Unlicensed Operations
working group suggested the Commission seek comment on whether the
rules should allow greater radiated power for radar applications, if
the parameters of the Google Soli waiver should be incorporated into
the rules, and whether there are changes to the conditions and
technical requirements set forth in the recent waivers that would
improve sharing with communications applications. It further suggested
that the Commission ask whether the use of a contention-based protocol
should be required, and whether 60 GHz band unlicensed radar
applications should be allowed to use the same power levels as
communications applications in the band if they incorporate listen-
before-talk procedures. The Commission invites commenters to address
these specific questions.
As an initial matter, given that the Commission refers to both FDS
and radars extensively throughout this document, the Commission
addresses the relationship between the two terms. Field disturbance
sensors broadly include radar operations. Although Sec. 15.3(l) of the
Commission's rules provides a definition for ``field disturbance
sensor,'' it does not provide a definition for ``radar,'' and instead
parties must look to the radar definition contained in Sec. 2.1 of the
Commission's rules. The Commission seeks comment on whether the rules
related to ``field disturbance sensors'' in Sec. 15.255 are
sufficiently broad and flexible to accommodate the class(es) of devices
that parties anticipate will be developed to operate in the 57-71 GHz
band. The Commission also seeks comment on whether the Commission
should modify the definitions contained in Part 15 of the Commission's
rules to provide greater clarity about the relationship between FDS and
radars and, if so, how? Commenters that support modifying the

[[Page 46664]]

existing Part 15 definitions should also address whether such
modifications would require adjustments elsewhere in the rules.
As noted above, a number of parties have been granted waiver of
certain provisions of Sec. 15.255 to permit operation of innovative
radar devices in the 60 GHz band. To the extent the Commission modifies
its rules in this proceeding to expand unlicensed FDS device operations
in the 60 GHz band, the Commission expects that all future 60 GHz FDS
operations would be conducted subject to the Commission's modified
rules. Accordingly, the Commission proposes that if the Commission
adopts such modifications to the Commission's rules in this proceeding,
the previously granted 60 GHz FDS waivers would be terminated and FDS
device manufacturers would be expected to conform their operations to
the Commission's rules as revised. The Commission seeks comment on this
proposal.
The Commission first proposes to modify Sec. 15.255 of the
Commission's rules to afford greater opportunities for fixed and mobile
FDS devices operating in the 57-64 GHz portion of the 60 GHz band. The
extensive analysis that has accompanied the multiple waiver requests
that have been submitted to the Commission, the widespread consumer use
of Google's Soli-equipped devices without reported cases of harmful
interference and the ongoing efforts of the industry and standards
groups to identify model coexistence practices for unlicensed users
gives us confidence that there is now sufficient information for us to
build a record to expand unlicensed mobile radar use beyond the toehold
the Commission first provided in 2016 and the narrow waivers that have
been issued to date. The Commission's baseline proposals draw from the
technical and operating conditions incorporated into the waivers
granted to Google for its Soli device and to automobile manufacturers
and suppliers for in-cabin radars to detect children left in cars, with
additional modifications to account for harmonization with
international provisions governing operation in the band.
As discussed below, the Commission proposes to: Focus device
operation to the 57-64 GHz portion of the 60 GHz band; allow operations
at higher power levels than were permitted in the waivers but
consistent with the well-established ETSI standards; and require a duty
cycle that is consistent with what was established in the Google
waiver, with the possibility of mandating a minimum off-time between
cycles.
Based on the Commission's review of the multiple waiver requests
that pertain to FDS use of the 60 GHz band, parties designing and
manufacturing radars to operate in the 60 GHz band have proposed to
restrict their spectrum usage to frequencies below 64 GHz (constituting
the 60-64 GHz or 57-64 GHz band segments, depending on the filing),
although Sec. 15.255 permits operation across the 57-71 GHz band for
fixed FDS and SRIMS devices such as the Google Soli. The Commission
surmises that the requests seek to limit operation to the lower portion
of the 57-71 GHz band to align operations and devices with
international standards such as the European ETSI Harmonized Standard
EN 305 550 that restrict short-range devices, e.g., radars, to the 57-
64 GHz band. The Commission seeks comment on this assumption.
The Commission notes that a proposal has been submitted to IEEE
802.11 to define a channel access protocol to enable the same 60 GHz
systems to transmit signals that can be used both for communications
and radar purposes to be decoded by a similar system at the receiving
end. Equipment designs for 60 GHz transmitters are thus considering
radar transmissions alongside communication transmissions in the same
transmitter or chip. While the IEEE efforts in this area may be
considering the entire 57-71 GHz band, the Commission proposes to limit
operation of FDS devices operating under the Commission's proposed
higher power limits (20 dBm EIRP) to the 57-64 GHz band. As discussed
above, limiting the Commission's proposal in this way provides for
devices that are consistent with the international standards, which
only specify FDS operation in the 57-64 GHz band. The Commission seeks
comment on this proposal. Would limiting operation of higher power FDS
devices to the 57-64 GHz band benefit 60 GHz WLAN systems operating in
close proximity to FDS devices by leaving the 64-71 GHz band clear of
higher power FDS operations? The Commission seeks comment on whether,
alternatively, the Commission should allow the proposed FDS operation
across all of the 57-71 GHz band or some other segment of the band. If
the Commission were to allow the proposed FDS operation across the
entire 57-71 GHz frequency range under the proposed requirements
discussed below--which include a duty cycle limit--should the
Commission remove the current provision that permits operation in this
band at 10 dBm EIRP with no duty cycle limit? Should the Commission
modify the Commission's rules in any other respect? The Commission also
seeks comment on the benefits or costs of these proposed changes with
respect to 60 GHz authorized users. Parties that oppose these proposed
rules should cite specific harms that they believe would result from
changing the rules.
EIRP Limits. The current rules permit FDS devices to operate at a
maximum 10 dBm EIRP. All of the waiver requests the Commission received
requested a maximum of 13 dBm EIRP to provide greater accuracy and
finer resolution imaging. Subsequent waiver requests to Google's waiver
described the intended target detection to be either in the sub-
millimeter range such as the breathing patterns of a child in a car
seat, or as in the case of Leica Geosystems AG, thin cables as small as
2.5 mm in diameter; thus, requesters argue that 60 GHz FDS devices need
higher power than specified in the rules, because the existing power
levels do not allow the devices to provide the necessary accuracy in
detection of small-size targets due to poor signal-to-noise ratio.
The Commission proposes to allow FDS devices to operate at no more
than 20 dBm average EIRP. This proposed EIRP limit is higher than the
level requested in the multiple waivers that the Commission received;
however, it is consistent with ETSI EN 305 550. The Commission believes
this EIRP level will promote additional growth for new FDS applications
beyond those anticipated to be deployed under the Commission's issued
and pending waiver requests. The Commission also believes that
harmonization with other regions will likely increase efficiency for
American manufacturers by reducing design and manufacturing costs. The
Commission further believes that this EIRP limit will not cause harmful
interference to authorized services in the band. These radars will
operate at a comparatively much lower EIRP level than what is already
permitted for communication devices (indoors and outdoors) in the same
frequency band. Communication devices such as 60 GHz WLAN devices can
operate at up to 40 dBm EIRP, as compared to the 20 dBm EIRP limit that
the Commission is proposing for radars. The Commission notes that a
WLAN device may already have to operate in the presence of signals from
neighboring WLAN devices and other Part 15 devices operating at similar
power levels; thus the proposed lower EIRP limit for FDS devices should
have little or no effect on the operational environment that WLAN
devices can expect under the Commission's rules. The Commission also
observes that 60 GHz WLAN

[[Page 46665]]

devices have operated at this EIRP limit (i.e., 40 dBm average/43 dBm
peak) for several years without causing harmful interference to other
authorized services, such as the Passive EESS operating at 57-59.3 GHz.
In addition, the IEEE 802.11 standards group's activity to define
channel access protocols to allow transmission of radar signals
alongside communication signals may allow coexistence of both signals
in the 60 GHz band. The Commission seeks comment on the proposed EIRP
level for FDS devices and on the Commission's tentative interference
assessment. The Commission also seeks comment on the state of standards
development -- specifically, with respect to coexistence issues between
radar signals and communications signals. Should the Commission specify
any coexistence measures or requirements, such as listen-before-talk in
its rules? Does the fact that many radars are mobile mean that they
will not be used in close proximity to communication devices for
extended periods of time, thus limiting any potential for causing
interference to short durations? Further, the Commission seeks comment
on the benefits or costs of the proposed change to the EIRP limit with
respect to 60 GHz authorized users. How would this change, if adopted,
benefit stakeholders, consumers and others? Parties that oppose these
proposed rules should: Cite specific harms that they believe will
result from changing the rules in the manner proposed, estimate the
costs of such potential harms, and specify under what parameters they
believe radar systems can coexist with communications systems in the
band.
Because 60 GHz FDS devices will need to coexist with 60 GHz
communications devices, the Commission also seeks comment on the state
of development in the 60 GHz communications device ecosystem. What is
the current state of deployment of 60 GHz communications systems? What
use cases are supported by 60 GHz communications systems today, and
what use cases are contemplated for these systems in the future? Do 60
GHz communications systems generally take advantage of the higher EIRP
limits permitted under the Commission's rules? Facebook, Intel, and
Qualcomm assert that the 60 GHz band will be used by unlicensed devices
for latency-sensitive augmented reality/virtual reality/extended
reality (AR/VR/XR) applications. Is this likely to be a widely-deployed
use case in the 60 GHz band? Do AR/VR/XR applications present distinct
interference scenarios or raise other considerations compared to other
60 GHz WLAN applications? Do 60 GHz unlicensed communications systems
operate throughout the entirety of the 60 GHz band? Could these systems
operate effectively in a subsection of the overall band, for example,
the 64-71 GHz band segment?
Transmitter Conducted Output Power Limit. The rules currently
permit FDS devices to operate at a maximum -10 dBm transmitter
conducted output power, whereas 60 GHz WLAN devices are allowed up to
27 dBm. The Commission proposes to allow FDS devices to operate at a
maximum 10 dBm conducted output power, consistent with the waivers the
Commission has already granted in the band. The Commission notes that
the ETSI standard specifies the conducted output power as a mean
(average) limit, rather than a peak limit as the Commission's rules do.
The Commission seeks input on whether the Commission should consider
average transmitter conducted output power limit and what impact this
would have on the different types of FDS devices (e.g., FMCW, pulse,
etc.). On the other hand, the Commission notes that for 60 GHz
transmitters, including communications and radar devices, that are
implemented at the chip level, access to the transmitter output port
may not be available, rendering a demonstration of compliance to this
requirement burdensome. The Commission seeks input on whether this
requirement is necessary in view of the technological evolution of such
system-on-chip devices. A 10 dBm transmitter conducted output power
limit along with a 20 dBm EIRP limit implies a limit on transmit
antenna gain. The Commission inquires as to whether the transmitter
conducted output power limit instead should be replaced by an antenna
gain limit. If so, what limit would be appropriate? Should an antenna
gain limit be applied to all 60 GHz transmitters, including 60 GHz
communication devices, since these devices also have transmitters
implemented at the chip level, and thus would encounter the same
measurement difficulties? The Commission also seeks comment on whether
a transmitter conducted output limit is necessary for 60 GHz
transmitters, including communications and radar devices. The
Commission seeks input on this issue in order to develop a
comprehensive record. The Commission also seeks comment on the benefits
or costs of the proposed change to the transmitter conducted output
power with respect to 60 GHz authorized users. Proponents of such a
change should provide specific details regarding measurement
difficulties than might be encountered for system-on-a-chip devices as
well as details on what maximum antenna gain they believe should be
specified and whether there are circumstances under which that gain can
be exceeded (e.g., with a corresponding EIRP reduction).
Power Spectral Density Limit. The existing rules do not restrict
the power spectral density for 60 GHz devices. The Commission proposes
to require a 13 dBm/MHz EIRP power spectral density on FDS devices, to
be consistent with the ETSI limit. This is the same restriction the
Commission placed on Google and other parties operating FDS devices
pursuant to Commission issued waivers. The Commission seeks comment on
the proposed power spectral density limit. Is there a need for a power
spectral density limit, and if so, what is the appropriate limit and
for which types of devices should it apply? For example, would a power
spectral density limit be necessary for FDS devices using frequency-
modulated continuous wave (FMCW), or pulse/impulse transmissions?
Although the Commission is mindful of harmonizing the technical rules
that the Commission adopts with the existing ETSI standards, the
Commission seeks input and technical analyses on the utility of this
proposed requirement. FMCW sensors generally modulate their
transmission over a frequency band in order to obtain the necessary
target resolution. At any given time, FMCW sensor emissions are limited
to a small portion of the spectrum. As such, implementing a PSD limit
appears to be an appropriate measure for spectrum sharing for these
types of sensors. The Commission seeks comment on whether a PSD limit
alone is a sufficient power limit to facilitate sharing between field
disturbance sensors and communication devices. Are there other FDS
modulation techniques that would benefit from a power spectral density
limit? The Commission also seeks comment on the benefits or costs of
the proposed power spectral density limit for FDS devices with respect
to 60 GHz authorized users. If the Commission does not adopt a power
spectral density limit, what are the ramifications if devices are
permitted to operate with all of their energy concentrated in a narrow
bandwidth? Parties that oppose these proposed rules should cite
specific harms that they believe would result by imposing a power
spectral density requirement.
The Commission notes that the EIRP, transmitter conducted output
power, and power density limits proposed here

[[Page 46666]]

are consistent with those stipulated by the ETSI standard EN 305 550.
This standard has been in existence since 2014, thus these limits have
been tested and deployed in other geographic regions with similar
spectrum allocations. In fact, ETSI released an updated draft of this
standard in 2017 and did not recommend changes to the limits. Thus, it
appears that these proposed power levels have been successful in
providing an environment that supports robust sharing of the 60 GHz
spectrum among various users as the Commission is proposing to allow
here. The Commission seeks comment on this view. The Commission also
seeks input on the development status of the draft 2017 ETSI EN 305 550
Standard with respect to the technical parameters the Commission is
proposing herein. The Commission understands that ETSI is undertaking a
major revision of EN 305 550 to address receiver performance
parameters, which the 2014 Harmonized version did not address. The
Commission seek comment on the status of this revision and what changes
to the specification are anticipated. In light of this ongoing
revision, are changes to the Commission's proposed rules warranted? To
develop a comprehensive record, the Commission seeks input on current
or planned standards, both domestic and international, regarding
operation of FDS devices in the 57-71 GHz band, or any subset frequency
band thereof. In addition, because radar resolution is generally
dependent on bandwidth, the Commission seeks comment on whether the
proposed rules will provide the sufficient resolution over the ranges
needed for the applications envisioned for radars in the 60 GHz band.
Peak vs. Average Power Limits. The Commission notes that, except
for fixed FDS devices that contain their operating bandwidth within the
61.0-61.5 GHz band, the existing rules for FDS devices do not specify
an average power limit, but instead only a peak or maximum power limit,
unlike the power limits for 60 GHz communications devices, where the
Commission specifies both an average EIRP and a peak EIRP of 3 dB above
the average limit. The Commission observes that 60 GHz FDS and radar
devices will mostly use constant-amplitude continuous-wave (CW),
frequency-modulated continuous wave (FMCW), or pulse/impulse
transmissions. If the limits are applied only during active
transmission (i.e., only over the chirp or pulse duration), then the
peak and the average signals will be equivalent. The Commission further
notes that by specifying the limits only in terms of average power,
potential measurement instrument desensitization phenomena can be
avoided. The Commission proposes to define the power limits for FDS/
radar devices in terms of average power and seek comment on the
benefits of such a measurement. Are there consequences to specifying
average power measurements rather than peak with respect to the
potential to cause harmful interference to authorized users, or for
unlicensed radar systems to coexist with unlicensed communications
systems? Those who believe that such a change might result in harmful
interference should estimate the costs of such interference. Would this
change impact passive EESS users in the 57-59.3 GHz band? Are there are
other possible FDS/radar modulation techniques that would make
requiring a peak power limit necessary?
The existing rules do not place a duty cycle restriction on 60 GHz
devices. Similarly, the ETSI EN 305 550 standard does not stipulate a
duty cycle limit for 60 GHz short-range devices; however, the standard
does specify requirements for 60 GHz receivers to ensure that they can
adequately handle interferer signals. The Commission imposed a 10% duty
cycle limit in the Google Waiver Order and subsequent waivers for 60
GHz FDS devices operating under higher emission limits than permitted
in the rules. This 10% duty cycle is based on a maximum 3.3 ms
transmission time in every 33 ms interval and was derived from Google's
2018 final agreement with stakeholders from the WLAN communications
industry whose technology operates in the 60 GHz spectrum. The
Commission proposes to require the same duty cycle restriction as that
imposed in the multiple waivers.
However, the Commission notes that in some of the waiver requests,
parties asked for a longer transmission time frame. The Commission
further notes certain parties recommend modifying the duty cycle
restriction adopted in the waivers to read that ``any radar off-time
period between two successive radar pulses that is less than 2 ms shall
be considered `on time' for purposes of computing the duty cycle.''
These parties express concern that the duty cycle requirement in the
waivers will not promote coexistence with communications applications,
including AR/VR/XR communication devices which require very high data
throughput and very low latency. They point out that the 10% duty cycle
requirement could lead to certain radars transmitting very short bursts
(in micro-second durations) followed by similarly short silent periods
(also in the micro-second durations) during the entire total 33 ms
interval. This would result in interspersed, non-contiguous micro-
second short silent intervals during which 60 GHz AR/VR communication
devices may have difficulty accessing the spectrum due to the briefness
of the radars' quiet intervals; yet, when added together, the total
amount of transmission time and silent intervals would comply with the
``10% on, 90% off'' definition of a 10% duty cycle.
On the other hand, other parties indicate that ``regulatory
guarantees of such latency targets would substantially degrade
performance of FMCW radars, which generally need to transmit frequent
chirps (to prevent velocity aliasing) and span a sufficient burst time
to enable good velocity resolution.'' These parties argue that a duty
cycle rule restricting radars to ``guarantee that at least 99% of WiGig
packets experience on-air latency of no more than a few milliseconds''
would be unnecessary due to ``radars' low transmission power, low
potential to generate interference, and antenna directionality, as well
as propagation loss in the 60 GHz band.'' A regulatory latency target
will have a similar impact on pulse radars as well, as the radar's
observable maximum velocity and velocity resolution both depend on the
pulse repetition frequency. As such, should duty cycle be defined
differently for radar systems with different modulation techniques
(FMCW, pulse, etc.) operating on different time scales? On the other
hand, in view of these apparent limitations with respect to maximum
velocity and velocity resolution, is duty cycle a suitable parameter
for regulation? Can limiting peak and average power within a defined
band be a better approach than specifying a duty cycle? If regulating
the duty cycle is necessary, then how should it be defined? The
Commission seeks comment and technical input on appropriate parameters
for regulation including definition/characterization of the duty cycle
with respect to radar devices. The Commission seeks input on this issue
to maximize the efficiency of both communications and radar operations
without unduly degrading the operating environment for unlicensed users
of the band or causing harmful interference to authorized users in the
band. The Commission also seeks comment on whether radar signals could
mimic the spectrum access protocols of communications devices to appear
like any other communication signal thereby making a duty cycle
restriction unnecessary. The

[[Page 46667]]

Commission seeks comment on whether the recent activities in the IEEE
standards group examining channel access protocols that would enable
the same 60 GHz system transmitting communication signals to transmit
radar signals address this issue. Commenters should provide technical
detail, studies and analyses supporting their position on how a duty
cycle requirement for FDS devices should be specified.
The Commission notes that the 60 GHz Co-existence Study Group's
activities have been geared toward developing ``a consensus approach''
to a framework for a potential Commission rulemaking, with discussions
concerning duty cycles; transmission on- and off-times; operating
bandwidth and channelization (e.g., radar implementations with 2-
gigahertz, 4-gigahertz, 7-gigahertz-bandwidth); contention-based
protocols; transmit power; and antenna gain.'' Although representatives
from the 60CSG recently informed us that the group has yet to achieve
consensus on a recommended regulatory approach to accomplish
coexistence among the diverse operations in the 60 GHz band, they also
described several potential ``frameworks'' for further unlicensed
development in this frequency range. These include establishing a
single rule for radar operations in the 57-64 GHz portion of the 60 GHz
band, establishing a rule based on average power and/or average PSD
limits that draws from the ETSI EN 305 550 standard, taking a
channelization approach to radars in the 60 GHz band, and amending the
rules to reflect different categories of technologies that operate in
the 60 GHz band, such as allowing for different operating parameters
when operating in a vehicle, indoors, or outdoors, or between
implementations that are fixed, mobile, or portable. The Commission
seeks comment on the 60 GHz CSG filing. What are the technical trade-
offs and cost/benefits for each framework? What parts of these four
frameworks can the Commission incorporate into the Commission's final
rules to optimize the benefits and minimize the costs to all authorized
60 GHz users, and help us achieve the Commission's objective of
fostering a greater variety of unlicensed uses in the 60 GHz band? The
Commission also seeks input on the work results of any other
coexistence standards activities (international and domestic) and/or
cooperative works between communications and FDS study groups that may
have taken place, and how such work may inform the Commission's
proposals to expand unlicensed use of the band.
Because the Commission is proposing to permit fixed and mobile
radars to operate in the 60 GHz band, the Commission believes it is no
longer necessary to qualify an application as SRIMS to operate as a
mobile radar under Sec. 15.255. The Commission therefore proposes to
remove this designation from the rules and replace it with the general
designation of FDS devices for both fixed and mobile radars. As
indicated, when adopting the rule for SRIMS, the Commission stated that
it intended it to be a narrow application of mobile radar use, while
continuing to prohibit general mobile radar use in Sec. 15.255. As
such, the Commission did not adopt a definition for SRIMS. Over the
last few years, there has been much confusion on which 60 GHz mobile
and fixed radar applications should qualify under the SRIMS
designation. The Commission also requested input in response to the
multiple 60 GHz waiver requests but was not able to make a bright-line
determination for certain applications. The Commission seeks comment on
the proposal to remove the SRIMS exception from Sec. 15.255 and
replace it with general rules covering all FDS devices. The Commission
also seeks comment on the benefits or costs of this proposal with
respect to 60 GHz authorized users. Parties that oppose removing the
SRIMS designation from the rules should cite specific harms that they
believe would result from making this change to the rules.
The Commission next addresses Sec. 15.255(c)(2) of its rules,
which permits a fixed FDS device to operate at up to 40 dBm average
EIRP and at up to 43 dBm peak EIRP in the 61.0-61.5 GHz band segment.
Under this rule, a fixed FDS device's occupied bandwidth must be fully
contained within the 500-megahertz bandwidth of the 61.0-61.5 GHz band;
and it must attenuate its signals outside the 61.0-61.5 GHz band, but
still within the 57-71 GHz band, to less than 10 dBm average EIRP and
13 dBm peak EIRP. The Commission believes that this rule is valuable
insofar that it permits the operation of fixed FDS devices at power
levels as high as communication devices, albeit restricted to a more
narrow operating bandwidth, without being restricted to a specific duty
cycle limit. As such, the Commission proposes to retain Sec.
15.255(c)(2) but also seeks comment on whether the Commission should
expand this provision to apply to both fixed and mobile FDS
applications. The Commission seeks comment on how useful this 500-
megahertz bandwidth provision has been in practice in facilitating FDS
device deployment, given that radars typically achieve better
resolution with a wider bandwidth. What FDS applications currently are
being enabled using the higher power levels permitted in the 61.0-61.5
GHz band? Could the Commission expect that expanding Sec. 15.255(c)(2)
would result in new mobile FDS applications, and if so would they
perform functions that otherwise would not be possible under the
existing rules? How would expanding the rule affect the spectrum
environment for all users of the band? What costs and benefits would be
associated with such an action? In particular, the Commission seeks
comment and technical analyses on these issues to develop a
comprehensive record.
Section 15.255(c)(2) requires the average power of any emission
outside of the 61.0-61.5 GHz band, measured during the transmit
interval, to be less than or equal to 10 dBm, and similarly the peak
power of any emission to be less than or equal to 13 dBm. Because no
measurement bandwidth is currently specified in the rule, the
Commission seeks comment on whether this requirement is sufficiently
specific. Should these limits be specified in terms of power spectral
density (PSD)? If so, what are the required peak and average power
densities outside of the 61.0-61.5 GHz band? The reference bandwidth
that the Commission often uses for specification of the spurious domain
emission levels for frequency bands above 1 GHz is 1 megahertz. The
Commission seeks comment on the appropriate reference bandwidth for PSD
for emission outside of the 61.0-61.5 GHz band. Are any other
additional requirements necessary?
To the extent that the Commission retains provisions in Sec.
15.255 that specifically permit fixed FDS operations, the Commission
seeks comment on how the Commission should interpret ``fixed'' and
whether the Commission should incorporate a specific definition for the
term into the Commission's Part 15 rules. When OET granted the
automotive waivers, it noted that the Commission did not specifically
address whether the rule permits something that is inherently mobile
(such as an automobile) to be treated as fixed in certain
circumstances, and left any determination of what constitutes ``fixed''
and ``mobile'' operation under the rule for separate consideration. A
review of the 1998 Report and Order that first permitted fixed FDS use
in the band would suggest that the Commission was anticipating a narrow
set of applications that would be used in industrial settings where the

[[Page 46668]]

equipment would rarely if ever be moved. However, in light of the wide
range of potential FDS applications that now have been identified for
the 60 GHz band and the Commission's general inclination to provide as
expansive an opportunity for unlicensed operations in a particular band
as is practical, the Commission tentatively concludes that a broader
view is appropriate. The Commission tentatively concludes that the
Commission should interpret fixed FDS operations as those instances
where an FDS device is stationary and is operating at a discrete
location for an indefinite--i.e., more than mere transitory--period.
The Commission envisions this interpretation would allow for a device
that is used in a household and easily moved from room to room to
operate in different parts of the residence, but that an automotive-
mounted radar that operates when the car is stopped while the ignition
is engaged would be too transitory to qualify. The Commission seeks
comment on this proposal. Does it provide a sufficient bright-line rule
for device operation? Will it provide other unlicensed and authorized
users in the 60 GHz band with sufficient confidence that they will be
able to identify and resolve any degradation of the operational
environment caused by these fixed users? Are there other
interpretations that are more appropriate for defining fixed FDS
operations?
The Commission's third area of discussion relates to whether the
Commission could permit FDS devices to operate at a higher power
throughout the entire 57-71 GHz band. In its recommendation, the TAC
suggests that the Commission explores the possibility of allowing
radars that incorporate a sensing technology such as listen-before-talk
(LBT) to operate at the same emission limits as WLAN devices in the
band, i.e., 40 dBm EIRP and 27 dBm transmitter conducted output power.
The Commission seeks input regarding the effect such higher power
levels would have on authorized users who are entitled to interference
protection, as well as how those power levels would affect the ability
of unlicensed radar systems to coexist with unlicensed communications
systems. Are these EIRP and transmitter conducted output power levels
appropriate for radar applications, given the implied high antenna
gain/directivity? What antenna gain do radars need in various
applications? Are mobile radar applications limited by power
consumption such that they would not be able to leverage these higher
emission limits? With spectrum sensing capabilities, would a duty cycle
restriction be necessary? The Commission seeks input and feedback as
well as recommendations on these issues. Commenters should provide
technical details and/or studies to show that it is practical for
radars to operate at up to 40 dBm EIRP without causing harmful
interference to existing authorized services in the band. The
Commission notes that the 2021 TAC Recommendation only mentions the
listen-before-talk technique. Are there other spectrum contention
avoidance techniques that would serve the same purpose and how
effective are they? What are the costs and benefits of such techniques?
Have there been any completed or ongoing studies regarding coexistence
between radars and authorized 60 GHz users and, if so, what are the
results and recommendations? Should the same spectrum sensing technique
be required for all devices operating in the 57-71 GHz band with the
average power limit of 40 dBm EIRP? Have industry standards groups such
as the 802.11 Standards Committee considered the use of spectrum
sensing techniques for 60 GHz unlicensed devices? Will there be a need
to regulate energy detection and observation time for LBT sensing? If
so, what are the appropriate limits? Will usage of LBT provide higher
aggregate capacity? If so, does it justify the higher complexity
necessary to support LBT? The Commission solicits input on these issues
to develop a comprehensive record on these matters.
The Commission does not propose to alter the existing restrictions
relating to the use of 60 GHz band unlicensed devices on board aircraft
which are contained in Sec. 15.255(b) of its rules, but the Commission
nevertheless seeks comment as to whether the Commission should expand
the situations where such use is permissible. Currently, such operation
is limited to when the aircraft is on the ground, and, for airborne
use, only in closed exclusive communication networks within the
aircraft. To account for the important interest in protecting passive
EESS users that operate in the 57-59.3 GHz band, the rule limits this
use to aircraft with a high RF attenuation body (e.g., commercial
airliners), and cannot be used in wireless avionics intra-communication
applications where external structural sensors or external cameras are
mounted on the outside of the aircraft structure.
The Commission does not believe that retaining the existing
provisions regarding in-aircraft use of unlicensed devices would hinder
the initial successful deployment of new applications and devices under
the Commission's proposed rules. Many of the use opportunities that
have been identified to date--such as inside and outside vehicles, and
in personal safety, medical imaging, home automation, environmental
control, and robotic appliances devices, for example--are not dependent
on use on board an aircraft. Compliance options also exist for portable
electronic devices that may be brought aboard airplanes. These could
include, for example, activation of ``airplane mode'' during flight or
the use of sensors to disable operations when the device is above a
particular height above ground. The Commission seeks comment on this
tentative determination.
Currently the Commission has only authorized 60 GHz radars to
operate on board aircraft beyond the uses permitted in the rules via
two limited situations. Both were in conjunction with waiver grants
that carefully evaluated how specific devices would be deployed in
well-defined use cases. Leica Geosystems AG may operate a 60-64 GHz
radar on an unmanned aircraft, but with very restrictive conditions on
the number of deployed devices. The Google Soli radar incorporated into
a smartphone (e.g., the Google Pixel) allows control of a smartphone
via gestures without touching the phone, and is not intended to be part
of the aircraft communication network.
Although the Commission proposes to retain the existing rule, the
Commission nevertheless seeks comment on whether the Commission should
allow for expanded use of 60 GHz radars on board aircraft and, if so,
with what requirements and restrictions. Given that the Commission's
fundamental consideration has been and remains how to ensure that
passive EESS operations in the 57-59.3 GHz band continue to be
protected from harmful interference that could be caused by airborne
use of unlicensed 60 GHz devices, could airborne radar use be permitted
above 59.3 GHz? The Commission is not aware of any reports of harmful
interference being caused by Google Soli devices during airborne use.
Could the Commission permit 60 GHz radars to operate on board aircraft
for limited uses such as when incorporated into smartphones or similar
portable electronic devices that may be carried by air travelers? Would
the Commission need to limit such use to the power levels associated
with the Google Soli waiver, which operates at lower power levels than
those the Commission is proposing for 60 GHz radars? Are there other
narrow use cases that the Commission should allow? For

[[Page 46669]]

example, could the Commission's rules be modified to allow an
aircraft's entertainment system's in-seat display monitors to
incorporate radars that could be controlled remotely by air travelers'
gestures? Commenters addressing expanded airborne use should provide
detailed technical analyses, research, studies, etc. supporting
potential recommendations to address whether harmful interference to
authorized users in the band would result or if such systems can
coexist and under what conditions. Would any adverse effects be
anticipated from 60 GHz radars operating on aircraft? Would the risk of
harmful interference occurring to passive EESS be minimal from radars
in aircraft with high RF attenuation characteristics? What are the cost
and benefits of such use?
In addition, the Commission seeks comment on the ramifications of
permitting unlicensed 60 GHz radar operation on board aircraft with
little or no RF attenuation characteristics, such as unmanned aerial
systems (UAS)/drones and light and personal aircraft. The Commission
has given a limited waiver to Leica Geosystems AG to operate a radar in
the 60-64 GHz band on board a UAS to provide visual inspection of
structures in engineering and scientific applications to prevent the
UAS from colliding with the structure or other fixed objects that it is
surveying. The Commission has also received informal inquiries
indicating an interest in deploying unlicensed 60 GHz radar for
applications involving, as an example, use on board crop-spraying
aircraft. Commenters who support expanding the types of aircraft upon
which unlicensed 60 GHz devices could be deployed should address how
such use would not undermine the objective of preventing harmful
interference to EESS operations in the 57-59.3 GHz portion of the band.
Compliance testing of modulated CW (e.g., FMCW) and pulse/impulse-
based radar devices can be complex and typically requires careful
consideration to ensure the proper characterization of technical
parameters such as transmit bandwidth, output power and unwanted
emissions levels in the out-of-band and spurious domains. As such, the
Commission seeks comment on methodologies for performing such tests to
obtain the data necessary to demonstrate compliance with the specified
technical requirements for the types of radars anticipated to operate
under Sec. 15.255 rules. For example, should transmission bandwidth be
represented only by the chirp or pulse specifications or should it be
expressed as a measured occupied bandwidth, 20-dB bandwidth, or other
representation? Similarly, should peak power measurements be avoided to
eliminate potential for inaccurate amplitude results due to measurement
instrumentation desensitization? Measured power levels for radio
frequency (RF) pulses that are frequency modulated (chirped) vary as a
function of the bandwidth in which the measurement is performed; if
chirped pulses cause RF interference, the power levels of the pulses in
victim receivers will likewise vary as a function of receiver
bandwidth. NTIA Technical Report TR-12-488 provides both heuristic and
rigorous derivations of the relationships among chirped pulse
parameters and the measured peak and average power levels of chirped
pulses as a function of measurement bandwidth. These relationships may
be best understood via a single graph (Figure 3) presented in this
report. This report supplements NTIA Technical Reports TR-05-420, TR-
10-465 and TR-10-466, in which the formula for minimum bandwidth needed
for measurement of full peak power in chirped pulses is presented but
not derived. The Commission seeks comment on NTIA's technical report
and its applicability to measurements of chirped signals.
The Commission proposes to exempt FMCW and other similar swept-
frequency radars from the Sec. 15.31(c) requirement to stop the
frequency sweep when measuring the relevant technical parameters.
Stopping the sweep is physically impractical for most of these types of
devices and can result in inaccurate measurements. In addition, the
Commission proposes to remove the Sec. 15.255(c)(4) requirement to use
an RF detector with a detection bandwidth that encompasses the 57-71
GHz frequency range for performing peak power measurements. The
Commission believes that this requirement is superseded by the more
recent inclusion of Sec. 15.255(i), which sets out a flexible approach
toward measurement that can be adapted more effectively as the
technology of devices and test instrumentation evolve. Finally, the
Commission proposes to specify that the provision of Sec. 15.35(c)
that requires calculating average field strength over a complete pulse
train or 100 milliseconds is not applicable to pulsed or burst radars
that operate in the 60 GHz band. This measurement requirement was
originally designed for low frequency pulse-code modulated devices such
as garage door openers and the Commission believes it is not
appropriate for high frequency radars. The Commission seeks comment on
these proposals.
Initial Regulatory Flexibility Act. The Regulatory Flexibility Act
of 1980, as amended (RFA), requires that a regulatory flexibility
analysis be prepared for notice and comment rulemaking proceedings,
unless the agency certifies that ``the rule will not, if promulgated,
have a significant economic impact on a substantial number of small
entities.'' Accordingly, the Commission has prepared an Initial
Regulatory Flexibility Analysis (IRFA) concerning potential rule and
policy changes contained in this Notice of Proposed Rulemaking.
Initial Paperwork Reduction Act Analysis. This Notice of Proposed
Rulemaking does not contain potential new or revised information
collection requirements subject to the Paperwork Reduction Act of 1995,
Public Law 104-13. In addition, therefore, it does not contain any
proposed information collection burden for small business concerns with
fewer than 25 employees, pursuant to the Small Business Paperwork
Relief Act of 2002, Public Law 107-198, see 44 U.S.C. 3506(c)(4).
Ex Parte Rules--Permit-But-Disclose. This proceeding shall be
treated as a ``permit-but-disclose'' proceeding in accordance with the
Commission's ex parte rules. Ex parte presentations are permissible if
disclosed in accordance with Commission rules, except during the
Sunshine Agenda period when presentations, ex parte or otherwise, are
generally prohibited. 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. Memoranda must contain a
summary of the substance of the ex parte presentation and not merely a
listing of the subjects discussed. More than a one or two sentence
description of the views and arguments presented is generally required.
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,

[[Page 46670]]

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 Sec. 1.1206(b)
of the rules. In proceedings governed by Sec. 1.49(f) of the rules 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.
Additional Information. For additional information on this
proceeding, contact Anh T. Wride, <a href="/cdn-cgi/l/email-protection#3d5c5355134a4f5459587d5b5e5e135a524b">[email&#160;protected]</a>, (202) 418-0577,
Office of Engineering and Technology, Technical Rules Branch; or Thomas
Struble at (202) 418-2470 or <a href="/cdn-cgi/l/email-protection#ce9aa6a1a3afbde09dbabcbbaca2ab8ea8adade0a9a1b8">[email&#160;protected]</a>, Office of
Engineering and Technology, Office of the Chief Engineer.
Initial Regulatory Flexibility Analysis. As required by the
Regulatory Flexibility Act of 1980, as amended (RFA),\1\ the Commission
has prepared this present Initial Regulatory Flexibility Analysis
(IRFA) of the possible significant economic impact on a substantial
number of small entities by the policies and rules proposed in this
Notice of Proposed Rule Making (NPRM). Written public comments are
requested on this IRFA. Comments must be identified as responses to the
IRFA and must be filed by the deadlines for comments on the NPRM
provided in the item. The Commission will send a copy of the NPRM,
including this IRFA, to the Chief Counsel for Advocacy of the Small
Business Administration (SBA).\2\ In addition, the NPRM and IRFA (or
summaries thereof) will be published in the Federal Register.\3\
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\1\ 5 U.S.C. 603. The RFA, 5 U.S.C. 601-612, has been amended by
the Small Business Regulatory Enforcement Fairness Act of 1996
(SBREFA), Public Law 104-121, Title II, 110 Stat. 857 (1996).
\2\ 5 U.S.C. 603(a).
\3\ Id.
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A. Need for, and Objectives of, the Proposed Rules

The NPRM addresses issues raised in multiple waiver requests by
various field disturbance sensor (FDS)/radar manufacturers and is
partly in response to a recommendation from the Technical Advisory
Committee (TAC) that the Commission modify the rules for unlicensed 60
GHz devices in a number of respects. The TAC recommends that the FCC
initiates a rulemaking proceeding addressing potential areas of concern
in the 60 GHz band by requesting comment and response to the following
questions: (1) Should FCC rules allow greater radiated power for radar
applications than currently permitted?; (2) Should the parameters for
Google Soli, for which other entities have filed ``me-too'' requests,
be included in the rules?; (3) What changes to the recent waiver
parameters are needed to improve sharing with communications
applications?; (4) Should the FCC require 60 GHz communication
applications (and radar applications) to use a contention-based
protocol?; and (5) Should radar applications that perform listen-
before-talk be allowed to use the same power levels as communications
applications in this band?

B. Legal Basis

The proposed action is taken pursuant to sections 4(i), 201, 302,
and 303 of the Communications Act of 1934, as amended, 47 U.S.C.
154(i), 201, 302a, 303.

C. Description and Estimate of the Number of Small Entities to Which
the Proposed Rules Will Apply

The RFA directs agencies to provide a description of, and where
feasible, an estimate of the number of small entities that may be
affected by the proposed rules, if adopted.\4\ The RFA generally
defines the term ``small entity'' as having the same meaning as the
terms ``small business,'' ``small organization,'' and ``small
governmental jurisdiction.'' \5\ In addition, the term ``small
business'' has the same meaning as the term ``small business concern''
under the Small Business Act.\6\ A ``small business concern'' is one
which: (1) Is independently owned and operated; (2) is not dominant in
its field of operation; and (3) satisfies any additional criteria
established by the Small Business Administration (SBA).\7\
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\4\ 5 U.S.C. 603(b)(3).
\5\ 5 U.S.C. 601(6).
\6\ 5 U.S.C. 601(3) (incorporating by reference the definition
of ``small-business concern'' in the Small Business Act, 15 U.S.C.
632). Pursuant to 5 U.S.C. 601(3), the statutory definition of a
small business applies ``unless an agency, after consultation with
the Office of Advocacy of the Small Business Administration and
after opportunity for public comment, establishes one or more
definitions of such term which are appropriate to the activities of
the agency and publishes such definition(s) in the Federal
Register.''.
\7\ 15 U.S.C. 632.
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Radio and Television Broadcasting and Wireless Communications
Equipment Manufacturing. The proposed rules pertain to manufacturers of
unlicensed communications devices. The appropriate small business size
standard is that which the SBA has established for radio and television
broadcasting and wireless communications equipment manufacturing. This
industry comprises establishments primarily engaged in manufacturing
radio and television broadcast and wireless communications
equipment.\8\ Examples of products made by these establishments are:
Transmitting and receiving antennas, cable television equipment, GPS
equipment, pagers, cellular phones, mobile communications equipment,
and radio and television studio and broadcasting equipment.\9\ The SBA
has established a small business size standard for this industry of
1,250 employees or less.\10\ U.S. Census Bureau data for 2012 show that
841 establishments operated in this industry in that year.\11\ Of that
number, 828 establishments operated with fewer than 1,000 employees, 7
establishments operated with between 1,000 and 2,499 employees and 6
establishments operated with 2,500 or more employees.\12\ Based on this
data, we conclude that a majority of manufacturers in this industry are
small.
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\8\ See U.S. Census Bureau, 2017 NAICS Definition, ``334220
Radio and Television Broadcasting and Wireless Communications
Equipment Manufacturing,'' <a href="https://www.census.gov/naics/?input=334220&year=2017&details=334220">https://www.census.gov/naics/?input=334220&year=2017&details=334220</a>.
\9\ Id.
\10\ See 13 CFR 121.201, NAICS Code 334220.
\11\ See U.S. Census Bureau, 2012 Economic Census of the United
States, Table ID: EC1231SG2, Manufacturing: Summary Series: General
Summary: Industry Statistics for Subsectors and Industries by
Employment Size: 2012, NAICS Code 334220, <a href="https://data.census.gov/cedsci/table?text=EC1231SG2&n=334220&tid=ECNSIZE2012.EC1231SG2&hidePreview=false">https://data.census.gov/cedsci/table?text=EC1231SG2&n=334220&tid=ECNSIZE2012.EC1231SG2&hidePreview=false</a>.
\12\ Id. The available U.S. Census Bureau data does not provide
a more precise estimate of the number of firms that meet the SBA
size standard.
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D. Description of Projected Reporting, Recordkeeping, and Other
Compliance Requirements for Small Entities

Unlicensed 60 GHz devices operating in the 57-71 GHz frequency band
are regulated under section 15.255 of the Commission's rules. The
proposed rules in this NPRM pertain to field disturbance sensors (i.e.,
radar devices) that may be fixed or mobile. The proposed rules increase
the allowable transmitted power levels to promote

[[Page 46671]]

short-range radar applications without application restriction on
operating environments, i.e., they may operate indoors or outdoors, in
fixed or mobile applications, and be incorporated into any device,
e.g., personal safety, industrial and consumer robotics, home/
transportation automation (e.g., autonomous vehicles), environmental
control, health care monitoring. Specifically, the NPRM: (1) Proposes
to permit field disturbance sensors in the 57-64 GHz band to operate
with up to 20 dBm average EIRP, 10 dBm transmitter conducted output
power, 13 dBm/MHz average EIRP power spectral density and a 10% duty
cycle in every 33 millisecond (ms) interval; (2) investigates the
potential for mobile FDS devices to operate in the 61.0-61.5 GHz band
at the same 40 dBm EIRP at which fixed FDS devices currently are
permitted to operate; (3) ask whether the Commission could permit radar
devices that incorporate listen-before-talk, spectrum sensing, or other
methods of co-existence, to operate across the entire 57-71 GHz band at
the same power level (i.e., 40 dBm EIRP) as currently is permitted for
60 GHz communication devices; and (4) ask whether any of the provisions
proposed for FDS operation should be more broadly applied to all Part
15 devices operating in the 57-71 GHz band.
Most RF transmitting equipment, including 60 GHz devices, must be
authorized through the certification procedure. Certification is an
equipment authorization issued by a designated Telecommunication
Certification Body (TCB) based on an application and test data
submitted by the responsible party (e.g., the manufacturer or
importer).\13\ Existing FDS devices operating under section 15.255 of
the Commission's rules are already subject to the Certification
procedure. The NPRM does not propose to change the authorization
procedure for 60 GHz devices, but it does seek comment on methodologies
for performing tests to obtain the data necessary to demonstrate
compliance with the technical requirements for the types of radars
anticipated to operate under the modified rules. In addition, the NPRM
proposes to exempt frequency-modulated continuous wave and other swept
frequency radars from the section 15.31(c) requirement to stop the
frequency sweep when measuring the relevant technical parameters; \14\
(2) remove the section 15.255(c)(4) requirement to use an RF detector
with a detection bandwidth that encompasses the 57-71 GHz frequency
range for performing peak power measurements; \15\ and (3) not apply
the provision of section 15.35(c) that requires calculating average
field strength over a complete pulse train or 100 milliseconds to
pulsed or burst radars that operate in the 60 GHz band.\16\
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\13\ 47 CFR 2.907. The Commission or a TCB may test a sample of
a device to verify that it complies with the rules before granting
approval for the equipment to be marketed. Examples of devices
subject to certification include, but are not limited to, mobile
phones; wireless local area networking equipment, remote control
transmitters; land mobile radio transmitters; wireless medical
telemetry transmitters; cordless telephones; and walkie-talkies.
\14\ 47 CFR 15.31(c).
\15\ 47 CFR 15.255(c)(4).
\16\ 47 CFR 15.35(c).
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E. Steps Taken To Minimize the Significant Economic Impact on Small
Entities, and Significant Alternatives Considered

The RFA requires an agency to describe any significant,
specifically small business, alternatives that it has considered in
reaching its proposed approach, which may include the following four
alternatives (among others): ``(1) the establishment of differing
compliance or reporting requirements or timetables that take into
account the resources available to small entities; (2) the
clarification, consolidation, or simplification of compliance and
reporting requirements under the rule for such small entities; (3) the
use of performance rather than design standards; and (4) an exemption
from coverage of the rule, or any part thereof, for such small
entities.'' \17\
---------------------------------------------------------------------------

\17\ 5 U.S.C. 603(c)(1)-(c)(4).
---------------------------------------------------------------------------

The rule changes proposed in the NPRM for higher power to field
disturbance sensors and radars would provide greater flexibility to 60
GHz device operations. As these proposed changes provide greater
flexibility, the Commission does not believe they will have a
significant negative impact on small entities. In fact, the proposed
rules could benefit small entities. As operation of 60 GHz devices do
not require a license, small entities are able to operate 60 GHz
devices without the cost or inconvenience of obtaining a license. In
addition, the proposed rules partly align the technical parameters for
FDS/radar devices with international standards, which could save cost
to small entities who would now be able to avoid having to create
region-specific product designs.

F. Federal Rules That May Duplicate, Overlap, or Conflict With the
Proposed Rules

None.
Ordering Clauses. It is ordered, pursuant to the authority found in
sections 4(i), 201, 302, and 303 of the Communications Act of 1934, as
amended, 47 U.S.C. 154(i), 201, 302a, 303, and Sec. Sec. 1.407 and
1.411 of the Commission's rules, 47 CFR 1.407 and 1.411, that this
Notice of Proposed Rulemaking is adopted, as set forth above.
It is further ordered that the Commission's Consumer and
Governmental Affairs Bureau, Reference Information Center, shall send a
copy of this Notice of Proposed 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.

Federal Communications Commission.
Marlene Dortch,
Secretary.

Proposed Rules

For the reasons discussed in the preamble, 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 15.31 is amended by revising paragraph (c) to read as
follows:

Sec. 15.31 Measurement standards.

* * * * *
(c) Except as otherwise indicated in Sec. Sec. 15.255 and 15.256,
for swept frequency equipment, measurements shall be made with the
frequency sweep stopped at those frequencies chosen for the
measurements to be reported.
* * * * *
0
3. Section 15.35 is amended by revising paragraph (c) to read as
follows:

Sec. 15.35 Measurement detector functions and bandwidths.

* * * * *
(c) Unless otherwise specified, e.g., Sec. Sec. 15.255(c), and
15.256(l)(5), when the radiated emission limits are expressed in terms
of the average value of the emission, and pulsed operation is employed,
the measurement field strength shall be determined by averaging over
one complete pulse train, including blanking intervals, as long as the
pulse train does not exceed 0.1 seconds. As an alternative (provided
the

[[Page 46672]]

transmitter operates for longer than 0.1 seconds) or in cases where the
pulse train exceeds 0.1 seconds, the measured field strength shall be
determined from the average absolute voltage during a 0.1 second
interval during which the field strength is at its maximum value. The
exact method of calculating the average field strength shall be
submitted with any application for certification or shall be retained
in the measurement data file for equipment subject to Supplier's
Declaration of Conformity.
0
4. Section 15.255 is amended by revising the introductory text of
paragraphs (a), (c), and (c)(1), revising paragraph (c)(3), removing
paragraph (c)(4), paragraphs (e) introductory text and (e)(2) and
adding paragraph (e)(4) to read as follows:

Sec. 15.255 Operation within the band 57-71 GHz.

(a) Operation under the provisions of this section is not permitted
for equipment used on satellites.
* * * * *
(c) Radiated Power Limits. Within the 57-71 GHz band, emission
levels shall not exceed the following equivalent isotropically radiated
power (EIRP):
(1) Products other than field disturbance sensors shall comply with
one of the following power limits, as measured during the transmit
interval:
* * * * *
(3) Field disturbance sensors other than those operating under the
provisions of paragraph (c)(2) of this section shall comply with the
following, as measured during the transmit interval:
(i) For field disturbance sensors that limit their operation to the
57-64 GHz frequency band, the average power shall not exceed 20 dBm and
the average power spectral density shall not exceed 13 dBm/MHz. The
transmit duty cycle shall not exceed 10% during any 33 ms interval
(i.e., the device shall not transmit longer than a total of 3.3 ms).
(ii) For field disturbance sensors operating over the entire 57-71
GHz frequency band, the average power shall not exceed 10 dBm.
* * * * *
(e) Limits on transmitter conducted output power. Except as
specified paragraph (e)(1) of this section, the peak transmitter
conducted output power shall not exceed 500 mW. Depending on the gain
of the antenna, it may be necessary to operate the intentional radiator
using a lower peak transmitter output power in order to comply with the
EIRP limits specified in paragraph (c) of this section.
* * * * *
(2) Field disturbance sensors operating under the provisions of
paragraph (c)(3) of this section shall comply with the following:
(i) For field disturbance sensors that limit their operation to the
57-64 GHz frequency band, the peak transmitter conducted output power
shall not exceed 10 mW.
(ii) For field disturbance sensors operating over the entire 57-71
GHz frequency band, the peak transmitter conducted output power shall
not exceed 0.1 mW.
* * * * *
(4) Compliance measurements of frequency-agile field disturbance
sensors shall be performed with any related frequency sweep, step, or
hop function activated.
* * * * *
[FR Doc. 2021-16637 Filed 8-18-21; 8:45 am]
BILLING CODE 6712-01-P

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