[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 [www.gpo.gov]
[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:
     Electronic Filers: Comments may be filed electronically 
using the internet by accessing the ECFS: http://apps.fcc.gov/ecfs/.
     Paper Filers: Parties who choose to file by paper must 
file an original and one copy of each filing.
     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.
     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.
     U.S. Postal Service first-class, Express, and Priority 
mail must be addressed to 45 L Street NE, Washington, DC 20554
     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). https://www.fcc.gov/document/fcc-closes-headquarters-open-window-and-changes-hand-delivery-policy.
    People with Disabilities: To request materials in accessible 
formats for people with disabilities (braille, large print, electronic 
files, audio format), send an email to [email protected] 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, [email protected], or Thomas Struble at 202-
418-2470 or [email protected]

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: https://www.fcc.gov/document/fcc-seeks-enable-state-art-radar-sensors-60-ghz-band-0 or by using the search function for ET 
Docket No. 20-382 on the Commission's ECFS web page at www.fcc.gov/ecfs.

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, [email protected], (202) 418-0577, 
Office of Engineering and Technology, Technical Rules Branch; or Thomas 
Struble at (202) 418-2470 or [email protected], 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,'' https://www.census.gov/naics/?input=334220&year=2017&details=334220.
    \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, https://data.census.gov/cedsci/table?text=EC1231SG2&n=334220&tid=ECNSIZE2012.EC1231SG2&hidePreview=false.
    \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\
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    \17\ 5 U.S.C. 603(c)(1)-(c)(4).
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    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