[Federal Register Volume 89, Number 5 (Monday, January 8, 2024)]
[Rules and Regulations]
[Pages 874-891]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-28006]


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FEDERAL COMMUNICATIONS COMMISSION

47 CFR Part 15

[ET Docket No. 18-295 and GN Docket No. 17-183; FCC 23-86; FR ID 
190574]


Unlicensed Use of the 6 GHz Band; and Expanding Flexible Use in 
Mid-Band Spectrum Between 3.7 and 24 GHz

AGENCY: Federal Communications Commission.

ACTION: Final rule.

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SUMMARY: In this document, the Federal Communications Commission 
(Commission) builds on the 6 GHz band unlicensed rules by permitting 
very low power (VLP) devices in the U-NII-5 (5.925-6.425 MHz) and U-
NII-7 (6.525-6.875 MHz) portions of the 6 GHz band. The Commission will 
limit VLP devices to low power levels and subject them to other 
technical and operational requirements that will permit these devices 
to operate across the United States while protecting incumbent licensed 
services that operate in the 6 GHz band from harmful interference. The 
Commission also takes action in a Memorandum Opinion and Order on 
Remand that addresses a remand from the United States Court of Appeals 
for the District of Columbia Circuit concerning an issue raised by 
television broadcasters. The Commission finds that broadcasters' 
unsubstantiated claims of interference in the 2.4 GHz

[[Page 875]]

band do not warrant any changes to the 6 GHz rules.

DATES: This final rule is effective March 8, 2024. The Memorandum 
Opinion and Order on Remand in the SUPPLEMENTARY INFORMATION is 
effective February 7, 2024.

FOR FURTHER INFORMATION CONTACT: Nicholas Oros of the Office of 
Engineering and Technology, at [email protected] or 202-418-0636.

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Second 
Report and Order and Memorandum Opinion and Order on Remand, ET Docket 
No. 18-295 and GN Docket No. 17-183; FCC 23-86, adopted on October 19, 
2023 and released on November 1, 2023. The full text of this document 
is available for public inspection and can be downloaded at: https://docs.fcc.gov/public/attachments/FCC-23-86A1.pdf. Alternative formats 
are available for people with disabilities (Braille, large print, 
electronic files, audio format) by sending an email to [email protected] 
or calling the Commission's Consumer and Governmental Affairs Bureau at 
(202) 418-0530 (voice), (202) 418-0432 (TTY).

Procedural Matters

    Regulatory Flexibility Act. The Regulatory Flexibility Act of 1980, 
as amended (RFA), requires that an agency prepare a regulatory 
flexibility analysis for notice and comment rulemakings, unless the 
agency certifies that ``the rule will not, if promulgated, have a 
significant economic impact on a substantial number of small 
entities.'' Accordingly, we have prepared a Final Regulatory 
Flexibility Analysis (FRFA) concerning the possible impact of the rule 
changes contained in the Second Report and Order on small entities. The 
FRFA is set forth in Appendix C of the FCC document, https://docs.fcc.gov/public/attachments/FCC-23-86A1.pdf.
    Paperwork Reduction Act. The Second Report and Order does not 
contain new or modified information collection requirements subject to 
the Paperwork Reduction Act of 1995 (PRA), Public Law 104-13. In 
addition, therefore, it does not contain any new or modified 
information collection burden for small business concerns with fewer 
than 25 employees, pursuant to the Small Business Paperwork Relief Act 
of 2002, Public Law 107-198, see 44 U.S.C. 3506(c)(4).
    Congressional Review Act. The Commission has determined, and the 
Administrator of the Office of Information and Regulatory Affairs, 
Office of Management and Budget, concurs, that this rule is major under 
the Congressional Review Act, 5 U.S.C. 804(2). The Commission will send 
a copy of the Second Report and Order to Congress and the Government 
Accountability office, pursuant to 5 U.S.C. 801(a)(1)(A).
    Accessing Materials. 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).

Synopsis

    1. As discussed in greater detail below, the Commission adopts 
rules to permit very low power (VLP) devices to operate with up to -5 
dBm/MHz effective isotropic radiated power (EIRP) power spectral 
density (PSD) and 14 dBm EIRP across the U-NII-5 (5.925-6.425 MHz) and 
U-NII-7 (6.525-6.875 MHz) portions of the 6 GHz band. VLP devices will 
enable new innovative uses and will provide opportunities to enhance 
nascent applications, such as augmented reality/virtual reality, in-car 
connectivity, wearable on-body devices, healthcare monitoring, short-
range mobile hotspots, high accuracy location and navigation, and 
automation. The rules the Commission is adopting are designed to 
support innovation to bring exciting new applications to market while 
protecting the important licensed services that operate in the 6 GHz 
band from harmful interference. At this time, the Commission is 
limiting VLP devices to the U-NII-5 and U-NII-7 bands because the 
technical record has mainly focused on the potential for interference 
to fixed microwave links which are the predominate uses of these 
portions of the 6 GHz band. The Commission plans on proposing to expand 
VLP device operation to the U-NII-6 and U-NII-8 portions of the band 
which support mobile operations.

A. VLP Power Levels and Protection of the Fixed Microwave Services

    2. In making this decision to enable this new class of VLP 
unlicensed devices to operate in the 6 GHz band while protecting 
licensed incumbent operations from harmful interference, the Commission 
notes that this policy represents a careful balancing between enabling 
new services and protecting existing services. In response to comments 
reflecting incumbents' concerns regarding the potential for harmful 
interference as well as analysis in the record, the Commission is 
taking reasonable actions to minimize such potential. The Commission 
emphasizes the core principle from its Policy Statement (FCC 23-27, 
Apr. 21, 2023) that expresses the notion that data-driven approaches 
are necessary to promote co-existence. And while the Policy Statement 
generally addresses adjacent channel issues, it notes that many of the 
technical and policy principles articulated could be applied to co-
channel spectrum sharing as well, such as the sharing scenarios in the 
6 GHz band. The Commission's decision herein is consistent with its 
principles. In adopting rules to enable VLP devices to share the 6 GHz 
band, the Commission has followed this approach in anchoring its 
decision on an extensive technical record. The Commission recognizes 
the highly variable nature of the electromagnetic environment and 
relies on analyses that use a probabilistic approach to evaluating 
interference risk rather than basing our decision on worst-case 
examples.
    3. In considering the maximum power level for VLP devices, the 
Commission's goal is to balance competing factors. The Commission aims 
to permit as much power as possible for these devices so that the 
maximum benefit can be derived from their operation while minimizing 
the potential risk of harmful interference to licensed incumbent 
operations. As described below, the record is replete with many 
analyses and tests that come to widely different conclusions. These 
analyses and tests provide a basis for the Commission's understanding 
of the potential for VLP devices to cause harmful interference under a 
variety of conditions. As described in detail, the Commission believes 
based on the technical record that it can permit at this time VLP 
devices to operate at up to -5 dBm/MHz power spectral density (PSD) and 
14 dBm EIRP without presenting a significant risk of harmful 
interference to the licensed microwave incumbents that share the 6 GHz 
band.
1. Computer Simulations/Monte Carlo Analysis
    4. In considering the technical record, the Commission finds that 
two computer simulations based on Monte Carlo analysis submitted by 
Apple, Broadcom, et al. and by Apple provide sufficient support for 
permitting VLP operation at up to -5 dBm/MHz EIRP power spectral 
density (PSD) and 14 dBm EIRP across the U-NII-5 and U-NII-7 portions 
of the 6 GHz band. Relying on computer simulations is in harmony with 
the Commission's Policy Statement's directive to follow a data-driven 
approach to spectrum

[[Page 876]]

management rather than placing dispositive weight on worst-case 
examples that may be rare or never occur in practice. In relying on 
these computer simulations, the Commission follows the path of its 
previous decision in adopting rules for unlicensed 6 GHz low-power 
indoor (LPI) devices. For the LPI rules, the Commission characterized a 
computer simulation submitted by CableLabs as ``the best evidence in 
the record of the impact that unlicensed low-power indoor devices will 
have on incumbent operations.''
    5. A well-designed computer simulation can simultaneously model 
many probabilistic factors that determine whether harmful interference 
may occur. These factors include VLP device location variability in 
relation to the microwave receiver, height of the VLP device, whether 
the VLP device is operating co-channel, the VLP power level, and the 
radio propagation environment. In examining the potential for harmful 
interference to occur to microwave links from VLP devices, the 
characteristics of the microwave links must also be considered. 
Microwave links use highly directional antennas typically located on 
tall towers or building rooftops to transmit over distances up to 30 
kilometers. Because of the heights of these antennas and their 
directional nature, VLP devices only present a harmful interference 
risk if they are located within the main beam of the antenna and are 
close enough to the microwave receiver that a strong signal can be 
received. One important factor to consider when modeling interference 
to 6 GHz microwave receivers is atmospheric multipath fading. 
Atmospheric multipath fading is caused when stable air masses, such as 
warm and humid air, lead to stratification of the atmosphere. 
Atmospheric multipath fades can be very deep--30 dB or more. However, 
deep fades are rare while more mild fades occur more frequently. For a 
typical link, fades greater than 30 dB occur, on average, 15 seconds a 
month while fades greater than 10 dB occur, on average, 37 minutes a 
month. Because of this fading phenomenon, 6 GHz microwave links are 
designed with large ``fade margins'' that are typically 25-40 dB. This 
fade margin provides transmitted power beyond what is needed to 
maintain the link when no fading is occurring. Thus, the typical 
microwave link can operate with 5-nines availability (99.999%) despite 
the presence of fading. Because the links are designed with these large 
fade margins, even when a VLP device is located directly within the 
main beam of a microwave antenna at a close enough distance where it 
might be possible for it to cause harmful interference, the microwave 
link's operation will not be degraded unless a deep enough fade occurs 
so that the combination of received signal from the VLP device and fade 
depth is greater than the link's fade margin. Thus, VLP operation 
during the more frequent mild fades that occur which only consume a 
small portion of the fade margin will present only an insignificant 
harmful interference risk. An examination of the interference potential 
of VLP devices to microwave links must consider not only the position 
and transmit power of the VLP devices and the technical characteristics 
of the microwave links, but also include the effects of fading.
    6. A computer simulation submitted by Apple, Broadcom, et al. 
modeled the effect of VLP devices on two hundred forty-seven (247) 
fixed microwave links in the San Francisco area. Data from the 
Commission's licensing database was used to model each microwave link. 
For each iteration during this simulation, 1,146 VLP devices were 
randomly placed in the San Fransisco area where the distribution of 
devices was determined by the population data--i.e., it was more likely 
that the devices were placed in areas with higher population density. 
The San Francisco computer simulation indicates that for VLP devices 
transmitting at -5 dBm/MHz EIRP PSD the probability of the interference 
to noise power (I/N) ratio exceeding -6 dB was 0.003% and the 
probability of the I/N exceeding 0 dB was 0.001% over the one million 
simulation iterations. The simulation specifies that the same 
probability of exceeding -6 dB I/N results when the VLP PSD is 1 dBm/
MHz EIRP, but is correspondingly lower for -8 dBm/MHz and -18 dBm/MHz 
EIRP PSD levels and higher for the simulations that used 10 dBm/MHz 
EIRP.
    7. In addition to providing statistics on the I/N ratio, the 
simulation also evaluated the likelihood that the microwave link's fade 
margin will be exceeded by the combination of the interference power 
received from the VLP devices and the atmospheric multipath fading. For 
each of the 247 microwave links in the San Francisco area, the 
simulation calculated the fade margin by calculating the actual 
carrier-to-noise (C/N) ratio for the microwave link based on the link's 
technical parameters and subtracting the C/N ratio needed for the link 
to operate at the highest data rate listed in the Commission's database 
for that link. The simulation then determined the probability 
distribution for the atmospheric multipath fading for each link using 
the ITU-R P.530-17 model. The simulation then calculated a distribution 
of the noise floor increase for each link based on the I/N statistics 
and convolved that with the multipath fading distribution. For VLP 
devices operating at powers up to 1 dBm/MHz EIRP, the results indicate 
that the probability of the fade margin being exceeded by the 
combination of the interference power received from VLP devices plus 
the multipath fading is not materially different than the probability 
of the link margin being exceeded solely from multipath fading. 
According to the simulation results, of the 247 links assessed in the 
study, the presence of VLP devices transmitting at 1 dBm/MHz EIRP at 
the ``worst-case'' location for a microwave link would change the 
probability that the worst-case link will be degraded by 0.3%.
    8. The computer simulation submitted by Apple has many similarities 
to the San Francisco simulation. Apple's simulation modeled VLP to 
microwave receiver interactions in the Houston, Texas area by modeling 
a single microwave link while varying the VLP parameters for each 
simulation run based on the characteristics of microwave links that 
area. Two hundred twenty-four (224) VLP devices operating at 14 dBm 
EIRP within bandwidths varying from 20 megahertz to 320 megahertz were 
randomly placed within 23.49 kilometers of the microwave link on each 
of 10 million iterations.
    9. The Houston simulation found that for VLP devices operating at -
5 dBm/MHz EIRP PSD, the -6 dB I/N level was exceeded approximately 
0.06% of the time and 0 dB I/N was exceeded approximately 0.01% of the 
time. For VLP devices operating at 1 dBm/MHz EIRP PSD, the -6 dB I/N 
level was exceeded approximately 0.085% of the time and 0 dB I/N was 
exceeded approximately 0.02% of the time. Similar to the San Francisco 
simulation, the Houston simulation also examined the likelihood that 
the microwave link's fade margin will be exceeded by the combination of 
the interference power received from the VLP devices and the 
atmospheric multipath fading. These results, which were derived for 
various microwave transmitter heights, show that the presence of VLP 
devices have no noticeable impact on microwave link reliability 
compared to atmospheric multipath fading alone. The simulation for the 
Houston area also indicated that the chance of exceeding -6 dB I/N 
increased from 0.07% to 0.135% when both VLP and LPI devices were 
included as compared to just having LPI present. Finally, this 
simulation also

[[Page 877]]

examined the sensitivity of various inputs to the overall result. Apple 
claims that the results are sensitive to fixed service receiver antenna 
height, where higher microwave receiver antenna height above ground 
level results in a lower potential for impact to the microwave link and 
that the 35 meter antenna height assumed for the simulation represents 
a conservative value because such a height is significantly lower than 
the typical microwave receiver height in the Houston area. Likewise, 
Apple asserts that the assumed 44 dBi microwave receiver antenna gain 
and assumed ITU-R F.1245 antenna pattern do not represent typical 
antenna gains or antenna gain patterns and that more realistic inputs 
would result in the results showing a lower potential for exceeding -6 
dB I/N.
    10. AT&T argues that the approximate 0.1% chance that the Houston 
simulation indicates for the I/N to exceed -6 dB for a VLP device 
operating at 1 dBm/MHz EIRP PSD implies that 1,300 device deployments 
in the Houston area would impair the fade margin of a microwave link by 
more than 1 dB (i.e., produce an I/N greater than -6 dB) at any given 
moment. This contention is based on several misunderstandings of the 
Houston Monte Carlo simulation. The approximately 0.1% chance of the I/
N being greater than -6 dB means that on 10,000 of these 10 million 
iterations of the simulation, the calculated I/N at the microwave 
receiver from all 224 VLP devices was greater than -6 dB; the I/N 
contribution from any individual VLP device would be much less. As to 
AT&T's contention that this demonstrates a significant risk to the 
microwave links, this represents the likelihood that the aggregate 
signal from all 224 transmitting VLP devices causes the microwave link 
to receive a signal at greater than -6 dB I/N, which represents a 1 dB 
reduction in the fade margin of the link. The Commission reiterates 
that in the 6 GHz Order, 85 FR 31390 (May 26, 2020), the Commission 
stated that it was not making a determination that a signal received at 
greater than -6 dB I/N would constitute ``harmful interference.''
    11. These simulations examined the statistical relationship that 
the combination of the interference power received from VLP devices and 
atmospheric multipath fading could have on microwave receivers. Both 
the San Francisco analysis and the Houston analysis considered the 
summation of microwave receiver noise floor from VLP device 
transmissions and the occurrence of atmospheric multipath fading. 
Because atmospheric multipath fading and the signal levels received 
from the VLP devices are independent phenomenon, in accordance with a 
well-known statistical theorem the probability distribution of the 
combination of these two processes is the convolution of the 
probability distribution of each of the individual processes. The 
computer simulations used this mathematical convolution process to 
examine the combination of these two processes and illustrate that the 
presence of VLP devices does not result in a significant increase in 
the likelihood that the fade margin of the links will be exceeded by 
the combination of both atmospheric multipath fading and signals 
received from the VLP devices. Because the functioning of a microwave 
link is only interrupted when the combination of multipath fading and 
received VLP signals exceeds the fade margin, these results show that 
the presence of VLP devices will not significantly increase the 
potential for harmful interference to a microwave link over effects due 
to atmospheric fading alone.
    12. AT&T claims the data on fade margin exceedance from the 
combination of atmospheric multipath fading and VLP devices that the 
San Francisco Monte Carlo simulation presents is suspect. The 
Commission believes that Apple, Broadcom, et al. have sufficiently 
explained how they calculate this data. As they explain, for each link, 
the available C/N ratio was calculated based on the link's transmitted 
power, propagation distance, receiver antenna gain, receiver feeder 
loss, and receiver noise figure and the required C/N ratio was 
calculated based on the highest order modulation for the link as 
indicated in the Commission's licensing data. The fade margin is simply 
the difference between these two C/N ratios. The probability that the 
fade margin for a link will be exceeded by an atmospheric multipath 
fade was obtained from ITU-R P.530-17. As to whether some of the link 
availabilities are excessively low or high, as AT&T claims, the 
Commission does not find the range of link availabilities indicated by 
the San Francisco simulation to be unrealistic. As Apple, Broadcom, and 
Meta indicate, there are many factors that impact the calculated 
availability of the microwave links. AT&T also suggests that it would 
be useful for the San Francisco simulation to have listed the links 
that appear to be more susceptible to VLP interference to help 
understand what they have in common. Because none of the links appear 
to have an increased potential for the fade margin being exceeded by 
the combination of multipath fading and VLP devices operating at the -5 
dBm/MHz power level, the information is not necessary to reach a 
conclusion regarding the potential for harmful interference occurring.
    13. For the Commission to have confidence in the results of 
computer simulations, the assumptions and models that are used must be 
appropriate. The Commission finds that for both the San Francisco and 
Houston simulations, the assumptions are not only appropriate, but also 
represent reasonably conservative estimates of the potential impact on 
microwave receivers and that using more realistic input assumptions 
would produce results showing even less potential impact. Nevertheless, 
the Monte Carlo analyses results are important as they represent an 
upper bound on what could be expected under real-world conditions with 
the actual impact likely to be much lower. To reiterate this point, the 
Commission discusses these assumptions.
    14. Each of the simulations randomly distributed a number of VLP 
devices over the study area for each iteration. The Commission finds 
that the number of devices placed within the study area for each 
simulation iteration appears to be based on realistic assumptions. Both 
simulations assume that all simulated VLP devices will operate outdoors 
because indoor VLP devices are assumed to not present an interference 
risk to microwave links. The Commission agrees; such an assumption is 
consistent with its finding in the 6 GHz Order, which adopted rules 
permitting LPI devices to operate with 5 dBm/MHz PSD EIRP and up to 30 
dBm EIRP; at least 10 dB more than the Commission is permitting for VLP 
devices. The San Francisco simulation assumes that for the population 
within the study area, 6% of people will be outdoors, and that 25% of 
those people will be using VLP devices. Apple, Broadcom, et al. 
indicate that 6% is a realistic assumption because EPA and Department 
of Transportation statistics show that the average American spends 90% 
of the time indoors and, of the remaining 10%, 4% of the time is spent 
in vehicles, which leaves 6% with no attenuation of the signal from 
buildings or vehicles. As this assumption is based on Department of 
Transportation and Environmental Protection Agency statistics, the 
Commission finds that it is reasonable. The Commission believes that 
assuming 25% of people outdoors at any given time will be using a VLP 
device is a conservative assumption as

[[Page 878]]

even if 25% of the people are simultaneously using devices, many are 
apt to be operating using licensed spectrum and of the devices 
operating on an unlicensed basis, they are likely to be spread across 
the various bands that support unlicensed devices (e.g., U-NII bands 1-
5). Apple, Broadcom, et al. acknowledge this by further stating that 
they assume that 90% of the devices will operate on an unlicensed basis 
(rather than using licensed spectrum), that 50% of unlicensed devices 
will be capable of using the 6 GHz band, and that of these devices 
capable of using the 6 GHz band, 65% will actually be using the 6 GHz 
band. These appear to be reasonable assumptions. In addition, they 
assume that VLP devices will actively transmit 2% of the time. While 
VLP devices are not yet deployed, the Commission finds this assumption 
reasonable for analytical purposes. Thus, as the number of VLP devices 
placed in each iteration for the San Francisco simulation appears to be 
based on reasonable assumptions, the Commission concludes that placing 
1,146 devices per iteration was appropriate to model the interference 
potential of VLP devices.
    15. Apple placed 224 VLP devices during each iteration for its 
Houston area analysis. This number was based on a set of assumptions 
about VLP device use appear to be reasonable. The analysis places all 
224 VLP devices around a single microwave receiver resulting in a 
similar device density per microwave receiver for I/N computation as 
the 247 microwave receivers simulated in the San Francisco simulation; 
noting that the reported I/N for each analysis iteration is an 
aggregate of the individual I/Ns calculated for each device in that 
iteration. Even with a similar device density, the Commission finds 
that the fact that the Houston results show a 20 times increase in the 
potential for a VLP device to exceed -6 dB I/N is not cause for concern 
regarding an increase in the potential for actual harmful interference. 
The I/N probabilities calculated from the Houston analysis results from 
a worst-case analysis designed to ensure that any possible microwave 
receiver configuration is accounted for while the San Francisco 
analysis was predicated on the actual microwave receiver layout and 
characteristics from the Universal Licensing System (ULS) for that 
market and thus reflects a more real world analysis. Moreover, the 
Houston analysis assumed that every VLP device was operating co-channel 
with the microwave receiver. This situation is unlikely to occur under 
actual operating conditions. Second, the propagation models estimate 
clutter losses based on the mean for various statistical categories and 
are likely to underestimate these losses, especially in cities where 
tall buildings and urban canyons are likely to block signals from 
microwave receivers. Third, from a purely mathematical standpoint, it 
stands to reason that the more devices that are randomly placed around 
a microwave receiver, the greater the likelihood that the signal level 
received at the microwave receiver may exceed the interference 
protection criterion. However, as the Commission believes that the 
number of VLP devices used in each simulation run for Houston was 
higher than what would be reasonably expected under actual operating 
conditions, the Commission believes that the results similarly 
overestimate the actual number of devices that would exceed -6 dB I/N. 
And even if the results from the San Francisco and the Houston analyses 
represent lower and upper bounds, these percentages are sufficiently 
low as to pose an insignificant risk of harmful interference to 
microwave links. And fourth, as noted in the 6 GHz Order and herein, -6 
dB I/N is an interference protection criterion and exceeding that 
metric does not in and of itself represent harmful interference as 
microwave links are designed with significant fade margin. Lastly, many 
microwave links rely on multiple receive antennas that are physically 
separated from one another to provide spatial diversity as a method to 
mitigate multipath fading. This will make the receivers even more 
resistant to multipath fading meaning that the likelihood that the fade 
margin will be exceeded by the combination of fading and VLP 
interference is even lower than is indicated by the simulation.
    16. AT&T points out that for many VLP device use cases there will 
be at least two and maybe more VLP transmitters exchanging data at the 
same location. The Commission agrees with AT&T that many VLP device use 
cases, such as body worn devices and mobile hotspots, involve 
communication between multiple VLP devices. However, only one of these 
devices will be transmitting at a time. Furthermore, such usage will 
usually involve devices located in close proximity, in many cases on 
the same person's body, sharing the same channel through intermittent 
transmissions. Thus, these multiple devices can appropriately be 
considered a single device within the simulation. Moreover, if multiple 
proximate devices communicate over different channels, then only one of 
the simulated devices would be co-channel with a given microwave 
receiver, negating it from consideration within the simulation. 
Therefore, the Commission does not agree with AT&T that it is necessary 
for multiple proximate VLP devices communicating with each other to be 
specifically modeled by the simulations as such use is implicitly 
accounted for.
    17. One of the key parameters in computer simulations is the 
propagation model used to calculate the signal level received by the 
microwave receivers from the VLP devices. The Houston simulation uses 
the exact propagation models that the Commission specified for the 
automated frequency coordination (AFC) systems that manage access to 6 
GHz band spectrum by standard power access points, while the San 
Francisco simulation departs slightly from this framework. As the 
Commission concluded that these models are appropriate in preventing 
harmful interference from standard power devices in this band, the 
Commission agrees that these models are appropriate for a computer 
simulation for VLP devices. The San Francisco simulation departs from 
the Commission's AFC rules. As the difference in the propagation models 
used in the San Francisco simulation and the Commission's AFC rules 
produces a more conservative result--i.e., overpredict the possibility 
of interference--they are not only appropriate for evaluating the 
potential for exceeding -6 dB I/N, but also act to overprotect 
microwave receivers beyond the limits the Commission deems appropriate 
in its rules.
    18. Another input modeled within the simulations was attenuation to 
account for ``body loss'' due to scattering and absorption from a VLP 
device operating on or near a body or other object (e.g., a VLP device 
placed on a table). As VLP devices are envisioned to generally be small 
form factor body worn type devices or devices used in close proximity 
to people, this is an appropriate input for analysis. Body loss is a 
random variable and subject to variation due to a multitude of factors, 
such as whether a device is body-worn or not, what part of the body it 
is worn on, body type, and whether it is in a pocket. Thus, a body loss 
value for analytic purposes must reflect not just the body loss itself, 
but also the wide range of values possible, the varying behavior of VLP 
device users, and the variety of uses for which VLP devices may be 
employed. Considering the data placed on the record reflecting widely

[[Page 879]]

varying levels of body loss under different conditions, as well as the 
general consensus among studies relied on by other regulators, the 
Commission finds that the computer simulations' assumptions that there 
would be a mean attenuation of 4 dB for body and/or clutter loss and 
that this would follow a gaussian distribution is appropriate. The 
Commission believes that this is a reasonable approach as it is in the 
range specified by many commenters, is consistent with the measurements 
made by Meta, and is consistent with what was used by the International 
Telecommunication Union (ITU) and the European Conference of Postal and 
Telecommunications Administrations' (CEPT) Electronic Communications 
Committee (ECC) for interference analysis. While many commenters put 
data on the record purporting to show losses greater than 4 dB, the 
Commission notes that this data also shows, in some instances, losses 
less than this value.
    19. Because VLP devices are anticipated to be worn across a wide 
range of positions on the body or placed on a wide range of surfaces, 
the Commission believes that use of a gaussian distribution with a 4 dB 
mean as used by the computer simulations captures the wide range of use 
cases described by VLP proponents and is appropriate for analytical 
purposes. Gaussian distributions are commonly used to represent random 
processes that vary over a range such as far-field body loss. 
Considering that the body loss measurements submitted by Apple, 
Broadcom, et al. and Meta have a mean higher than 4 dB and some 
measured attenuations were much greater than the then 8 dB maximum of 
the truncated distributions used in the simulations, use of these 
distribution appears to be a conservative assumption. The Commission 
does not find merit in AT&T's criticism of the body loss distribution 
used by the simulations as not being justified or being ``abnormally'' 
truncated to plus/minus one standard deviation. While AT&T implies the 
distribution must be ``justified,'' it does not provide any information 
on what such a justification may entail or how body loss should 
otherwise be modeled. Use of a truncated distribution is reasonable as 
this prevents the distribution from unrealistically including a body 
loss less than 0 dB or incorporating very high body loss values (more 
than one standard deviation from the mean) which could be viewed as 
outliers and not realistic while maintaining the 4 dB mean.
    20. Both computer simulations assumed that 90% of VLP devices would 
operate at a 1.5 meter height above ground level. As the simulations 
are only modeling outdoor VLP devices, the VLP devices that are at 
greater heights will represent use on building balconies and rooftops. 
The Commission agrees with Apple, Broadcom, et al. that, assuming that 
10% are at heights greater than 1.5 meters appears to be a conservative 
assumption. For those 10% of VLP devices that are assumed to be above 
1.5 meters, both simulations base the height of the device on data for 
building heights in the cities they are modeling. The Commission 
concludes that this is a reasonable approach to modeling the VLP device 
heights.
    21. Both simulations used the ITU-R F.1245 antenna pattern to model 
microwave receiver antennas. This ITU recommendation provides an 
average antenna pattern to be used in interference assessments. AT&T 
criticizes the simulations for not using actual antenna patterns for 
the antennas specified in the Commission's licensing database and 
suggests that if the actual antenna patterns are not used that ``a 
better choice would have been to base the antenna pattern on F.699 and 
the FCC antenna mask in Part 101.115 as has been agreed within the 
WinnForum'' for the AFC specification.
    22. Given that the actual antenna model is not specified for many 
of the microwave link licensing records in the Commission's ULS 
database and the added complexity of obtaining and integrating into the 
simulation antenna patterns for microwave links where the antenna 
pattern is known, the Commission appreciates why the simulations did 
not use actual antenna patterns. In addition, as the Houston simulation 
did not model specific microwave links, using a particular actual 
antenna pattern would have been completely arbitrary. The Commission 
does not believe the Monte Carlo simulations using a different antenna 
pattern than the WinnForum AFC specification detracts from the 
simulation's accuracy for two reasons. First, because ITU-R F.699 is 
based on the peak envelope for the side lobes it will overestimate the 
level of interference from signals received in the side lobes because 
most actual antennas will have lower side lobe gain. ITU-R F.1245, 
which is based on the average side lobe levels for microwave antennas, 
appears to be a more appropriate choice given that the purpose of a 
Monte Carlo simulation is to determine the typical level of 
interference experienced by microwave receivers and that the 
simulations are summing the signals received at the microwave antenna 
at different arrival angles from multiple VLP devices. Second, the 
WinnForum AFC specification appears to use a mask based on Sec.  
101.115 of the Commission's rules for the side lobes because this 
permits use of different levels of attenuation for different categories 
of microwave antennas for angles of arrival outside the main beam of 
the antenna. Because the goal of the AFC systems is to protect specific 
fixed microwave receivers from harmful interference from standard power 
unlicensed devices, trying to more closely match the characteristics of 
particular classes of antennas is important for this purpose. In a 
Monte Carlo simulation the goal is to obtain overall statistics on the 
likelihood of occurrence of harmful interference to all the microwave 
links rather than determining exclusion zones around specific microwave 
receivers. Hence, trying to match the characteristics of individual 
antennas is of less importance. For this purpose, the Commission 
believes that use of the ITU-R F.1245 pattern, which represents an 
``average'' antenna pattern, is a reasonable alternative to using the 
actual antenna patterns or to following the approach used in the 
WinnForum AFC specification.
    23. AT&T also criticizes the Houston simulation for not using the 
actual microwave link data available in the Commission's ULS licensing 
database and instead using different antenna heights and either a 44 
dBi antenna gain or antenna gains selected from a distribution whose 
source was unspecified. While the San Francisco simulation used the 
data from the ULS for each individual link, the Houston simulation took 
a different, yet also valid, approach in which it simulated both the 
range of microwave receiver characteristics (antenna gain, antenna 
height, etc.) and VLP parameters over 10 million iterations to 
determine the probability of exceeding -6 dB I/N for any potential VLP 
to microwave receiver configuration. Contrary to AT&T's assertion, the 
parameters the Houston simulation used are based on distributions taken 
from the Commission's ULS licensing database for the Houston market and 
are based on real-world data representative of the Houston area. By 
choosing a microwave antenna height at the 10-percentile and a 
microwave antenna gain at the 90-percentile for the Houston market, the 
Houston simulation represents a conservative estimate of the potential 
for harmful interference to occur to microwave links from VLP devices 
in

[[Page 880]]

the Houston area. While the Commission believes the more complex 
approach taken by the San Francisco simulation does have some 
advantages over the approach taken in the Houston simulation, the 
Houston simulation is a reasonable approach for assessing VLP device 
operation in the Houston market.
    24. The San Francisco simulation used an antenna pattern for all 
VLP devices that is based on a model of consumer Wi-Fi devices 
developed by the CEPT SE45 working group. The Houston simulation used 
an antenna pattern for client devices from the ECC 302 report, which 
examined the interference potential of unlicensed 6 GHz devices. AT&T 
states that it has ``previously shown that assumptions made in 
simulations by [proponents of VLP devices] rely on inaccurate antenna 
patterns and illogical assumptions regarding [device] positioning.'' In 
making this broad statement, AT&T refers to its previous discussion of 
a Monte Carlo simulation for LPI devices conducted by CableLabs. The 
Commission does not believe AT&T's concerns have validity for the two 
simulations under consideration here. The Commission finds each of 
these studies provide independent grounds for its conclusions.
    25. Transmit power control is another important parameter that VLP 
devices will use and was appropriately included in the analyses. For 
transmit power control the San Francisco simulation used a gaussian 
distribution with a mean and standard deviation of 3 dB that is 
truncated at 0 and 6 dB. The Houston simulation used a gaussian 
distribution with 7 discrete steps from 0 to 6 dB for transmit power 
control. The Commission believes that transmit power control is likely 
to be implemented for most VLP devices, such as body worn devices, to 
save battery power. Consequently, modeling the transmit power control 
as a random variable in the computer simulations is appropriate. Given 
the ITU resolution and ECC regulation requiring an average power 
reduction of 3 dB from transmit power control for U-NII-2A and U-NII-2C 
devices and that the Commission previously required that U-NII-2A and 
U-NII-2C devices have the capability for at least 6 dB transmit power 
control, the Commission believes that the distributions used in the San 
Francisco and Houston simulations are reasonable approximations for the 
amount of transmit power control VLP devices are likely to employ for 
VLP devices.
    26. The Houston simulation used a noise figure of 5 dB and a feeder 
loss of 1.3 dB for the microwave receivers. AT&T claims that the 5 dB 
noise figure is ``larger than typical'' and suggests that using 4 dB 
for U-NII-5 and 4.5 dB for U-NII-7 microwave receivers, as in 
WinnForum's functional requirements document for AFC systems, would be 
a better choice. AT&T also claims that a 1.3 dB feeder loss may not be 
appropriate for all cases as many microwave radios are mounted directly 
to the antenna and have no feeder loss. Apple, Broadcom, and Meta have 
indicated that the simulation used 2 dB for waveguide feeder loss and 5 
dB for the noise figure. While the Commission agrees with AT&T that the 
noise figure numbers from the WinnForum AFC specification would have 
been a better choice than the 5 dB that both simulations used, this up 
to 1 decibel difference is not significant enough to make an 
appreciable difference in the simulation results. For feeder loss, when 
no feeder loss is available in the Commission's ULS database and the 
type of microwave radio is known, WinnForum's AFC specification 
document indicates that a value of 3 dB be used for radios that are 
identified as indoor units while no feeder loss should be used for 
outdoor units. Hence, according to WinnForum's AFC specification, a 1.3 
dB or 2 dB feeder loss would be too large for an outdoor radio and too 
small for indoor radio. As these simulations are designed to model the 
potential for harmful interference to occur to microwave links in 
general rather than explore the interference risk of a particular 
microwave receiver, the Commission believes that employing such an 
``in-between'' value for feeder loss is a reasonable approach for a 
Monte Carlo simulation.
    27. In sum, the Commission's review of Apple, Broadcom, et al.'s 
San Francisco Monte Carlo simulation examining the potential for VLP 
device interaction with microwave links and the similar Apple 
simulation for Houston provide a solid basis for concluding that VLP 
devices can coexist with incumbent services in the 6 GHz band with an 
insignificant potential for causing harmful interference. In fact, as 
noted, the Commission believes that the assumptions and thus, the 
results, err on the side of caution, are conservative, and overestimate 
the potential for any given VLP device to exceed -6 dB I/N. The worst-
case operating scenario occurs when the VLP device is in the main beam 
of a microwave receiver, at close distance, operating co-channel to the 
microwave receiver, and not significantly attenuated by terrain, body 
loss, or blocked by buildings, which is an event that the simulations 
show will be a rare occurrence.
2. Power Level for VLP Devices
    28. The computer simulations show virtually no impact on the 
microwave links even for VLP devices operating at 1 dBm/MHz EIRP PSD--
the Houston and San Francisco simulations indicate that a -6 dB I/N 
event occurs only at either 0.06% or 0.003% of the time, respectively. 
The San Francisco results show an identical outcome for VLP devices 
transmitting at -5 dBm/MHz PSD and for the Houston simulations, a 
slight decrease in occurrences that -6 dB I/N may be exceeded. Thus, as 
a conservative initial approach for permitting VLP devices to operate 
in the U-NII-5 and U-NII-7 portions of the 6 GHz band, the Commission 
will limit them to a maximum of -5 dBm/MHz PSD EIRP and 14 dBm EIRP at 
this time. The Commission believes the conservative nature of the 
analyses resulting in extremely low probabilities for exceeding -6 dB 
I/N justify this approach which balances the need to provide enough 
power for VLP devices to ensure manufacturers can provide useful 
devices with the requirement to protect licensed incumbent operations 
from harmful interference. This approach recognizes, as pointed out by 
licensed incumbents, that there are locations where VLP devices 
operating at these power levels could result in a signal with I/N 
ratios that may exceed -6 dB I/N. However, Apple, Broadcom, et al. and 
Broadcom argue that the risk of exceeding that interference protection 
criterion is low at even higher power levels. Therefore, the Commission 
believes that it is appropriate to be conservative at this time and 
permit the VLP devices to operate at no more than -5 dBm/MHz EIRP PSD. 
The Commission also limits total EIRP to no more than 14 dBm consistent 
with Apple, Broadcom, et al. and other VLP proponents' comments. While 
there may be some worst-case locations where harmful interference is 
possible, the Commission finds the overall risk insignificant. In 
addition, because (i) the Commission is concluding that VLP devices can 
operate at -5 dBm/MHz EIRP PSD with an insignificant potential of 
causing harmful interference to incumbent operations, and (ii) VLP 
devices are inherently mobile, communications between two VLP devices 
present no more harmful interference risk than a VLP device 
communicating with an access point. Thus, the Commission will permit 
VLP devices operating at this PSD level to directly communicate with 
each other. The Commission is examining additional steps that it could 
take to provide additional power or operating

[[Page 881]]

flexibility to VLP devices. However, given that no VLP devices have yet 
to be deployed, the Commission believes limiting operation to no more 
than -5 dBm/MHz EIRP PSD is appropriate at this time. Given the 
conservative PSD limit the Commission is adopting, we are confident 
that the harmful interference risk is insignificant.
    29. Southern Company cautions that to the extent the Commission is 
relying on computer simulations to inform its decisions for the 6 GHz 
band, it should require the underlying algorithms used by the 
simulation to be disclosed to all stakeholders consistent with the 
Commission's Policy Statement on spectrum management. The Utilities 
Telecom Council (UTC) et al. express similar views, arguing that 6 GHz 
band unlicensed use proponents relied on simulation information that is 
not reproducible by any party and that others have not been given the 
opportunity to review or fully understand the data and simulation 
methodology. In addition to echoing these views, AT&T suggests that the 
Commission should require the simulation code to be released consistent 
with the Commission's Policy Statement and the practices of NTIA, which 
released similar software for evaluation of 3.1 GHz network 
deployments. Both AT&T and Southern Company also criticize the 
Commission for not conducting its own computer simulations and instead 
relying on those submitted by interested parties.
    30. While Apple, Broadcom, et al. and Apple have not made their 
simulation code or the resulting raw data produced by the simulations 
publicly available, the Commission believes that they have provided 
sufficient information for knowledgeable engineers to understand the 
algorithms and models used in the simulations. Both Apple, Broadcom, et 
al. for the San Francisco simulation and Apple for the Houston 
simulation provided filings detailing the significant simulation 
assumptions. Apple has indicated that its simulation was prepared using 
the widely available and well understood Spectrum Engineering Advanced 
Monte Carlo Analysis Tool (SEAMCAT) simulation tool, while Apple, 
Broadcom, et al. indicated that its simulation was implemented using 
the C++ programming language using well-established Monte Carlo 
simulation techniques. Through these filings to the record, the 
Commission believes that Apple, Broadcom, et al. and Apple have 
provided enough technical details that engineers experienced in radio 
propagation modeling and coexistence analysis would be able to conduct 
identical simulations and obtain consistent results. Furthermore, the 
Commission observes that it is noteworthy that no opponents of VLP 
deployment have conducted their own simulations to confirm or refute 
the results. The Commission has no statutory obligation to conduct or 
commission [its] own empirical or statistical studies. The Commission 
therefore concludes that the results presented in the filings are 
adequate to inform its decision. The Commission's decision to authorize 
VLP devices will encourage innovative methods of using the 6 GHz band 
and the Commission is exercising its technical judgment in relying on 
the simulations from Apple, Broadcom, et al. and Apple in reaching this 
decision. The Commission notes that parties opposing its low-power 
indoor (LPI) rules raised a similar concern in a challenge to the 
previously adopted 6 GHz unlicensed rules in the United States Court of 
Appeals for the District of Columbia Circuit regarding a computer 
simulation conducted by CableLabs on which the Commission relied. The 
court rejected that challenge noting that ``requiring agencies to 
obtain and publicize the data underlying all studies on which they rely 
would be impractical and unnecessary.'' In accordance with this 
established precedent, the Commission finds that Apple, Broadcom, et 
al. and Apple provided ample information on the record such that any 
interested party could undertake similar analyses and that opponents' 
challenge on this point is meritless.
    31. Fade margin infringement. The Fixed Wireless Communications 
Coalition (FWCC) expresses a strong opinion that unlicensed devices 
should not be permitted to infringe on the fade margin of microwave 
links. FWCC claims that it has ``shown that interference from 
unlicensed (RLAN) operations will cut into the fade margin and leave FS 
systems vulnerable to data loss and outages.'' FWCC claims that because 
adding fade margin is expensive, system designers build only the 
necessary minimum, with a small safety margin, and that any unlicensed 
interference that encroaches into a microwave link's fade margin will 
reduce the link reliability.
    32. As the Commission stated in the 6 GHz Order which authorized 
LPI devices, it ``is not required to refrain from authorizing services 
or unlicensed operations whenever there is any possibility of harmful 
interference.'' Instead, ``the Commission may authorize operations in a 
manner that reduces the possibility of harmful interference to the 
minimum that the public interest requires, and it will then authorize 
the service or unlicensed use to the extent that such authorization is 
otherwise in the public interest.'' There is no prohibition in either 
previous Commission decisions or legal precedents on the Commission 
adopting rules that permit VLP devices to occasionally infringe upon 
the fade margins of microwave links. Instead, the Commission's 
responsibility is to ensure that the operation of the VLP devices might 
only impose an insignificant risk of harmful interference occurring to 
the microwave links to the minimum that the public interest requires. 
The Commission believes based on the computer simulations, which take 
into account both the technical characteristics of actual microwave 
links and reasonable technical assumptions for VLP devices, that the 
Commission's decision is within the bounds of this principle. 
Furthermore, noting that the 6 GHz band is populated by both microwave 
licensees representing commercial and public safety interests, the 
Commission observes that there is no appreciable difference between the 
systems operated by those different entities and finds that the rules 
we are adopting protects both commercial and public safety microwave 
systems in a comparable manner. Finally, the Commission reiterates that 
in its recent Policy Statement, the Commission noted that ``zero risk 
of occasional service degradation or interruption cannot be 
guaranteed'' whether from natural events or other spectrum users.
3. Fixed Infrastructure Prohibition
    33. As suggested by Apple, Broadcom, Google, and Meta, the 
Commission is prohibiting VLP devices from operating as part of a fixed 
outdoor infrastructure. The Commission notes that no commenters have 
opposed us adopting this prohibition. This measure is being adopted as 
an additional means of protecting incumbent operations to ensure that 
all VLP devices are subject to body and/or clutter loss, to add 
additional assurance that the simulation assumption that most outdoor 
devices will operate at 1.5 m above ground level is correct, and to 
force all devices to be itinerant consistent with the VLP devices 
simulated in the Monte Carlo analyses. Thus, VLP devices will be 
prohibited from attaching to outdoor infrastructure, such as poles or 
buildings, that would make any instances of potential interference more 
than fleeting. In addition, device mobility results in devices, even if 
remaining in a general location, constantly changing their orientation 
due to even subtle body movements.

[[Page 882]]

Such movements can result in widely varying VLP signal levels in any 
given direction. Thus, the maximum VLP signal level, which is likely to 
be less than the maximum the Commission's rules permit for a device in 
the worst-case location and operating co-channel to a microwave system, 
may only be oriented toward a microwave receiver for a short period of 
time, which also serves to keep the potential for causing harmful 
interference to a minimum.
4. Transmit Power Control Requirement
    34. The Commission is adopting a requirement that VLP devices 
employ a transmit power control mechanism that has the capability to 
operate at least 6 dB below the -5 dBm/MHz EIRP PSD level permitted for 
VLP devices. Both computer simulations, which the Commission have 
concluded is the best evidence that the potential for VLP devices to 
cause harmful interference is insignificant, assume that VLP devices 
would operate with a transmit power control mechanism with a range up 
to 6 dB and a mean power reduction of 3 dB. To ensure that actual VLP 
devices operate consistent with the simulations on which its relying, 
the Commission adopts this provision to provide confidence that such 
devices do indeed operate using transmit power control. The Commission 
is not placing any specific requirements in its rules as to how the VLP 
device transmit power control algorithm will function, but proof of 
such functionality must be provided with a device's application for 
equipment certification. The Commission does not expect that placing 
this transmit power control requirement will present an undue burden on 
device manufacturers as such functionality is routinely included in 
battery-powered device design to conserve battery power. In this 
connection, Broadcom states that transmit power control is enabled in 
100% of its portable products. In addition, Apple, Broadcom, Google, 
and Meta jointly suggested that the Commission adopt a VLP device 
transmit power control requirement that would require such devices to 
reduce their PSD by 3 dB on average. No commenters have opposed us 
mandating that VLP devices employ a transmit power control mechanism. 
While AT&T advocates that any limitation on VLP device use that was 
assumed in the computer simulations, such as average power due to 
transmit power control, should be subject to a specific rule, the 
Commission notes that it's adopting a rule requiring VLP devices to 
have transmit power control capability to reduce power by at least 6 
dB. While the exact power distribution that VLP devices will use is 
unknown at this time, the Commission believes this requirement is 
reasonable given the diversity in propagation environments in which VLP 
will operate.
5. Equipment Compliance and Enforcement Matters
    35. Consistent with the requirements for most other unlicensed 
transmitters, the Commission requires 6 GHz VLP transmitters to be 
approved under the Commission's certification procedure. This procedure 
requires that the equipment be tested by an accredited laboratory and 
approved by a designated Telecommunication Certification Body (TCB) to 
ensure that the equipment complies with all requirements that the 
Commission is adopting, e.g., maximum power (EIRP and PSD), transmit 
power control, contention based protocol, which are designed to ensure 
that the risk of harmful interference to licensed incumbent services is 
insignificant. As a general matter, only 6 GHz VLP devices certified as 
compliant by a TCB will be permitted to be imported into and marketed 
and operated within the United States.
    36. For reasons discussed throughout the Report and Order, the 
Commission is confident that the risk of harmful interference to 
licensed incumbent services is insignificant, based on the VLP 
technical rules adopted herein and on the compliance measures in place 
under the its equipment authorization rules. The Commission also 
emphasizes that 6 GHz VLP devices, like other part 15 devices, are not 
permitted to cause harmful interference and that any such interference 
is actionable for enforcement purposes. Section 15.5(b) of the 
Commission's rules provides that ``[o]peration of an intentional, 
unintentional, or incidental radiator is subject to the condition[ ] 
that no harmful interference is caused.'' In the unlikely event that 
harmful interference does occur due to VLP operations, Sec.  15.5(c) of 
the Commission's rules provides that ``[t]he operator of a radio 
frequency device shall be required to cease operating the device upon 
notification by a Commission representative that the device is causing 
harmful interference,'' even if the device in use was properly 
certified and configured, and that ``[o]peration shall not resume until 
the condition causing the harmful interference has been corrected.'' 
Although UTC asks the Commission to ``propose processes and procedures 
for the identification, reporting and resolution of interference from 
unlicensed operations as part of [future rulemaking],'' the Commission 
already have processes and procedures in place under which the 
Enforcement Bureau investigates complaints of harmful interference and 
takes appropriate enforcement action, as necessary. These processes and 
procedures have been effective in identifying and resolving harmful 
interference to licensed operations in other situations and are 
available for use in the 6 GHz band as well.
    37. Parties that believe particular 6 GHz VLP devices are not 
compliant with the Commission's rules or are causing harmful 
interference to licensed incumbent services can contact the Enforcement 
Bureau, which will address any rule violations, such as impermissible 
operations or marketing of non-compliant devices, as appropriate.
6. Cumulative Effect of Different Classes of Unlicensed Devices
    38. AT&T contends that 6 GHz unlicensed devices have been modeled 
under the erroneous presumption that each type of device--standard 
power, LPI, and VLP--can interfere with microwave links up to a 
threshold of -6 dB I/N, but as there is only one -6 dB I/N margin, the 
modeling must account for consumption of that margin by all three types 
of devices. AT&T points out that no computer simulation models the 
combined impact of all these different types of unlicensed devices. 
AT&T points to the CEPT computer simulation that addressed 6 GHz 
devices that did not include standard power devices, simulated LPI 
devices at a lower power level than the Commission's rules permit, and 
only assumed 1% of devices located outdoors as illustrating the error 
in the VLP proponents reasoning.
    39. As the Commission stated above, typical microwave link 
architecture results in 6 GHz band unlicensed devices only presenting a 
potential interference risk if they are in the microwave antenna's main 
beam at a close enough distance that a signal of sufficient strength 
will be received. The AFC systems that control standard power access 
points' spectrum access will prevent those devices from operating at 
locations where they present a risk of causing harmful interference. 
Therefore, the Commission does not believe that it is necessary for 
unlicensed proponents to provide a study that jointly considers the 
potential for harmful interference from the cumulative effect of 
standard power devices and other types of unlicensed 6 GHz devices. 
Regarding VLP and LPI devices, the Commission again points out that 
Apple's Monte Carlo analysis

[[Page 883]]

for devices operating in the Houston areas included results for the 
additive effect of LPI and VLP devices and concluded that the 
likelihood that there was no material effect on potential microwave 
degradation due to the presence of both the LPI and VLP devices.
7. Request for Higher Power
    40. While supporting comments advocating for a 14 dBm EIRP power 
level, a subset of VLP device advocates point out that allowing even 
higher power would enable VLP devices to communicate with higher order 
modulation, which would enable higher throughputs and lower latencies 
and request that the Commission authorize up to 21 dBm EIRP. They claim 
that the 14 dBm EIRP power level would be insufficient for untethered 
augmented reality/virtual reality, remote surgery, data center wireless 
flyways, educational applications requiring transmitting high 
resolution materials, and other demanding applications. They point to 
the computer simulation conducted by RKF to claim that operation at 
this power level would not cause harmful interference to licensed 
stations.
    41. As these commenters also support the more modest 14 dBm EIRP 
power level and the applications cited are more speculative than those 
generally cited as other use cases for VLP devices, the Commission 
declines to permit additional power for VLP devices at this time. The 
Commission also observes that devices delivering many of the cited 
applications, such as remote surgery, necessitate indoor operation and 
can be conducted under the LPI device rules that already permit more 
power than the Commission is permitting for VLP devices. Much of the 
Commission's decision is based on the computer simulations that are 
based on a maximum 14 dBm EIRP power level. Due to the undeveloped 
record on operations with up to aa 21 dBm EIRP, the Commission declines 
to permit VLP devices to operate at greater than 14 dBm EIRP. The 
Commission does not plan on seeking comment, however, on whether we 
can, under certain circumstances, increase the VLP power level without 
increasing the harmful interference risk to incumbent operations.
8. Request for Lower Power
    42. The Ultra Wide Band (UWB) Alliance expresses concern that VLP 
devices will radiate power uniformly in all directions even though they 
likely only need the maximum power in a specific direction and that 
this will result in unnecessary interference to other receivers, 
including other VLP devices. To address this issue, it suggests that 
VLP devices meet one of two alternate power limits: (1) a -32 dBm power 
spectral density with a peak power of 0 dBm; or (2) a -8 dBm power 
spectral density that is reduced by 2 dB for every dB that the antenna 
gain is less than 12 dBi as well as a peak power of 14 dBm that is 
reduced by 2 dB for every dB that the antenna gain is less than 7 dB. 
The UWB Alliance also suggests that dynamic transmit power control be 
required for VLP devices as the power needed for on-body locations can 
vary from nearly free space to over 70 dB. Other commenters such as 
Nokia, the National Association of Broadcasters (NAB), and AT&T suggest 
that we only permit VLP if we limit such devices to much lower power 
than what the Commission proposed.
    43. While several commenters request that the Commission only 
permits VLP devices to operate at lower power, for the reasons already 
articulated we decline to do so. First, the Commission concludes based 
on the computer simulations that VLP device operation at -5 dBm/MHz PSD 
will only pose an insignificant risk of harmful interference to 
incumbent operations. Additionally, the Commission appreciates the UWB 
Alliance's concern for improving spectrum efficiency and reducing the 
potential for interference by proposing rules that would incentivize 
the use of directional antennas. However, the Commission agrees with 
Apple, Broadcom, et al. that directional antennas are likely infeasible 
for small form factor portable devices, particularly when the device's 
orientation is constantly changing. The Commission does not believe 
that it would be appropriate to adopt rules that would likely make it 
impractical to manufacture devices for many of the proposed VLP use 
cases, such as small portable body-worn devices. As for the UWB 
Alliance's suggestion to require dynamic transmit power control, as 
explained above, the Commission is adopting such a requirement on VLP 
devices. Second, the Commission does not believe that tying the power 
level for VLP devices to the power levels for low-power indoor devices, 
as NAB and AT&T suggests, is appropriate, given the fundamental 
differences between these device classes. VLP devices will inherently 
be mobile rather than stationary like LPI access points, have smaller 
form factors, less efficient antennas due to the small form factors, 
and operate at low power levels to conserve battery. Finally, as the 
Commission specified in the 6 GHz Order, ultra-wideband and wideband 
devices operate under part 15 unlicensed rules, and providing specific 
accommodations would effectively provide those devices with a level of 
interference protection to which they are not entitled. Consequently, 
the Commission believes that the -5 dBm/MHz PSD EIRP and maximum 14 dBm 
EIRP are appropriate and will result in widespread coexistence within 
the 6 GHz band among the various devices that operate there. Thus, the 
Commission is not persuaded to reduce VLP device utility by 
artificially restricting their power levels to even lower levels.
9. VLP Devices and the AFC
    44. Many microwave incumbents advocate that VLP devices should be 
required to use an AFC system to control spectrum access based on their 
potential to cause harmful interference to microwave receivers. As the 
Commission concludes that the risk of harmful interference from VLP 
devices operating at -5 dBm/MHz is insignificant, the use of AFC 
systems to control spectrum access by VLP devices is unnecessary. Thus, 
the Commission sees no reason to impose such a requirement on VLP 
devices. While there is dispute on the record as to how much it would 
cost to impose AFC control on VLP devices, there clearly is some cost 
to imposing such a requirement without a requisite benefit. 
Furthermore, there will likely be some VLP devices, such as laptop 
computers that do not have geolocation capabilities and requiring such 
devices to operate under AFC control would limit the utility of the VLP 
rules. In addition, neither the standard power or LPI rules support the 
highly mobile applications envisioned for VLP devices as LPI devices 
are limited to indoor locations utilizing access points that are 
supplied power by a wired connection while standard power access points 
may not be mobile. The Commission does note that consistent with 6 GHz 
low-power indoor unlicensed devices as well as all client devices, the 
Commission will require VLP devices to include a contention-based 
protocol which will act to avoid channels on which incumbent systems 
are actively transmitting.
10. Link Budget Analysis
    45. As discussed in more detail below, a number of commenters 
submitted link budget analyses that they claim show that harmful 
interference will result from VLP device operation. The Commission 
disagrees with CTIA--

[[Page 884]]

The Wireless Association (CTIA), Southern Company, and others regarding 
the utility of link budget analysis in driving the Commission's 
decision regarding VLP devices. In determining whether to permit VLP 
devices to operate in the 6 GHz band, the controlling factor is the 
potential risk that VLP devices could cause harmful interference to 
microwave links. This is a function not just of the received power 
level from a VLP device at a ``worst-case'' location, but also of the 
likelihood that a device will be at the location at the same time that 
a severe enough atmospheric multipath fade occurs to overcome the 
microwave link's fade margin. This question is not one that a link 
budget analysis alone can answer. A link budget provides a calculation 
of the power received at a receiver at one instant of time based on 
deterministic quantities for quantities such as transmitted power 
level, propagation loss, antenna gain, polarization loss, feeder loss, 
etc. Such an analysis does not take into account probabilistic 
quantities such as multipath fading or the likelihood of a transmitting 
device being in a particular location or transmitting co-channel with a 
microwave links. One important factor that a link budget analysis 
cannot consider is the fact that, because the Commission is prohibiting 
VLP device use for fixed infrastructure purposes, the VLP devices will 
be mobile and will not remain in potentially problematic locations for 
significant periods of time. A computer simulation that takes into 
account the transient nature of VLP use is a better model for 
determining VLP device interference potential as compared to a link 
budget analysis. The Commission also disagrees with Southern Company's 
contention regarding the utility of computer simulations as the number 
of VLP devices reach the millions. In fact, that is exactly what Monte 
Carlo simulations are designed to analyze, especially when each device 
is subject to multiple probabilistic operating conditions. The 
assumptions used in the San Francisco simulation to determine the 
number of simultaneously transmitting devices in the San Fransisco area 
assumed millions of VLP devices present in that area, but that did not 
mean that all these devices were transmitting simultaneously co-
channel. As discussed above, that simulation starts with the 13,066,000 
people in the San Francisco area and calculates how many VLP devices 
will be simultaneously transmitting outdoors in the area based on 
assumptions as to how many people are outdoors, how many of these 
people use VLP devices, how many VLP devices are capable of using the 6 
GHz band, how many VLP devices actually use the 6 GHz band, and how 
many VLP devices are actively transmitting at a given moment.
    46. As already noted, the Commission believes that Monte Carlo 
analysis is the most appropriate method for evaluating the potential 
for VLP devices to exceed -6 dB I/N. Although the link budget analyses 
provided by commenters conclude that in some instances the I/N caused 
by a VLP device could exceed that interference protection criterion, 
these analyses suffer from one of the same fundamental flaws as the 
AT&T link budget analysis that the Commission rejected in the 6 GHz 
Order--that is, they rely on worst-case scenarios that overstate the 
potential for harmful interference. For example, Southern Company and 
Edison Electric Institute (EEI) submitted link budget analyses which 
assumed that all VLP devices are operating in locations within the main 
beam of the antenna. Nokia submitted a link budget analysis in which it 
similarly assumed that VLP devices were operating either in buildings 
directly beneath a microwave receiver and at street level within line-
of-sight to a 6 GHz microwave receiver. Furthermore, all the link 
budget analyses relied on inappropriate assumptions for certain values, 
such as antenna pattern mismatch, feeder line loss, and propagation 
model. Moreover, just the mere possibility that under certain 
circumstances and in certain locations an I/N may rise to a level 
greater than -6 dB I/N does not translate to any certainty that harmful 
interference will occur; several other independent factors must also 
simultaneously occur and the probability of those events occurring is 
sufficiently low to lead us to the Commission's conclusion that based 
on the analyses in the record, VLP devices can coexist with incumbent 
operations in the 6 GHz band with an insignificant risk of causing 
harmful interference.
11. Interference Studies
    47. Several utilities filed field test measurement reports directed 
at quantifying LPI device interference potential on actual microwave 
receivers. While the focus of those studies is on LPI devices that are 
located indoors, some of the results do have implications for 
understanding the potential for VLP devices to cause harmful 
interference. CTIA and Southern Company jointly conducted field 
measurements using a signal generator to emulate both LPI and VLP 
devices which they claim show the emulated VLP device reduced the 
microwave link fade margin between 5.2 dB and 10.9 dB. For its test, 
Evergy used a commercially purchased LPI access point. When the result 
is adjusted for the power difference between LPI and VLP devices, the 
test indicates the I/N could be 14.5 dB for a VLP device located next 
to a window in a school classroom. Other electric utilities also 
conducted field test measurements: First Energy reports I/N ratios as 
high as 9.1 dB and Southern Company reports I/N ratios at high as 25.7 
dB.
    48. Apple, Broadcom, et al. criticize these field tests for using 
an indirect methodology to measure the reduction in link fade margin 
and estimating the I/N ratio. Apple, Broadcom, et al. claim the field 
test methodology is unreliable and produces inconsistent results. They 
also claim that the test chose worst-case locations and set the LPI 
access point parameters to reflect only extreme worst-case scenarios 
with unrealistic data rates. In addition, NCTA--The internet & 
Television Association (NCTA) suggests that the field test should use a 
metric based on the microwave link's signal to interference-plus-noise 
ratio S/(I+N) rather than using an I/N ratio or a reduction in fade 
margin as an interference metric as the S/(I+N) ratio would take into 
account the characteristics of the microwave link.
    49. The Commission believes Apple, Broadcom, et al. and NCTA 
express valid points about the field test results, especially regarding 
the testing methodology. However, as the Commission's focus here is on 
the potential for VLP devices to cause harmful interference and the 
field tests were mainly directed to LPI devices, the Commission 
refrains from opining on how representative the tests are of LPI device 
use. As for their connection to assessing VLP interference potential, 
the Commission observes that they too rely on worst-case scenarios that 
overstate the potential for harmful interference and therefore suffer 
from the same flaw as the link budget analyses and as the AT&T study 
that was rejected in the 6 GHz Order. The field tests purport to 
measure the I/N ratio at a worst-case location directly within the main 
beam of a microwave receiver. Furthermore, as these tests do not take 
into the account the fade margin designed into the microwave link and 
the occurrence of atmospheric multipath fading, they are of limited 
utility in determining the likelihood that the microwave links will 
actually experience harmful interference from a mobile VLP device, 
which by nature is unlikely to remain at any specific location or in a 
fixed orientation for a significant interval of time. Thus, these field 
tests are not

[[Page 885]]

informative with respect to the impact that VLP devices could have on 
microwave link reliability.
12. Chain of Coincidences Rationale
    50. AT&T claims that the VLP device proponents make a flawed 
argument in claiming that ``a chain of improbable coincidences'' is 
necessary for interference to occur to microwave links and ``citing 
indoor use, device positioning, channel overlap, body loss, RLAN 
antenna gain, transmit power control, fade margin and itinerant use.'' 
The Commission agrees with AT&T to the extent that it intimates that 
merely mentioning each of these factors, claiming each is unlikely, and 
thus deducing that harmful interference is unlikely to occur is of 
little utility. Consequently, while these assertions may have some 
merit, the Commission did not rely on them in reaching our conclusions 
here. Instead, the Commission's conclusions rely heavily on the San 
Francisco and Houston Monte Carlo simulations, which considered the 
respective likelihood for different factors that could impact 
interference potential to quantify the overall risk of harmful 
interference occurring to 6 GHz microwave links. Based on these 
analyses, the Commission concludes that the risk is insignificant.

B. Fixed Satellite Services (FSS)

    51. The entire 6 GHz band is allocated for the FSS in the Earth-to-
space direction. Additionally, portions of the U-NII-7 and U-NII-8 
bands are allocated for FSS space-to-Earth (downlink) operations. 
However, there are no licensed downlink earth stations in the U-NII-7 
band. Sirius XM and Globalstar were the only FSS operators to file 
comments in response to the Further Notice of Proposed Rulemaking 
(FNPRM), 88 FR 43502 (July 10, 2023), but these comments were limited 
to their operations in the U-NII-8 band.
    52. In 6 GHz Order, the Commission concluded that FSS receivers in 
space would not receive harmful interference from either 6 GHz standard 
power or LPI devices. Considering that the satellites receiving in the 
6 GHz band are limited to geostationary orbits, approximately 35,800 
kilometers above the equator, the Commission found that it is unlikely 
the relatively low power unlicensed devices would cause harmful 
interference to the space station receivers. The only restriction that 
the Commission adopted to protect the satellite receivers was to 
require that outdoor standard-power access points limit their maximum 
EIRP above a 30 degree elevation angle to 21 dBm. Because VLP devices 
are limited to no more than 14 dBm EIRP, for the same reasons, the 
Commission concludes that no restrictions on VLP devices are necessary 
to protect FSS Earth-to-space operations.

C. Radio Astronomy Services

    53. Incumbent operations in the U-NII-7 band include several radio 
astronomy observatories, located in remote areas, that observe methanol 
spectral lines between 6.65-6.6752 GHz. To protect these radio 
observatories, the National Academy of Sciences' Committee on Radio 
Frequencies (CORF) requests that we implement exclusion zones for this 
band, as listed in Allocation Table footnote US385, if VLP devices are 
able to determine their locations. If the devices are not able to 
determine their locations, CORF claims that the radio observatories 
must be protected by notching out the VLP device's transmissions within 
this band.
    54. When the Commission adopted the rules for 6 GHz LPI devices, it 
did not implement exclusion zones or require the LPI devices to notch 
out the 6.65-6.6752 GHz band. Because VLP devices will operate at an 
even lower power than LPI devices, the Commission does not expect them 
to create an interference problem for the radio observatories. The 
Commission recognizes the importance of these observations to the 
scientific community but, as VLP devices will not operate under the 
control of an AFC system and will not be required to have a geolocation 
capability, the Commission is not able to adopt exclusion zones around 
these radio observatories. The radio observatories that receive in the 
6 GHz band are in remote locations, and it is unlikely that unlicensed 
VLP devices will be operating nearby. Furthermore, these observatories 
can restrict such devices from being used at their facilities. 
Consequently, the Commission concludes that radio astronomy operations 
will not be subject to harmful interference from unlicensed VLP 
devices. Given this conclusion, the Commission cannot justify requiring 
VLP devices to notch out this band as requested as this would increase 
device complexity and result in less efficient spectrum use.

D. Emission Mask and Out-of-Band Emission Limit

1. Limits for Very Low Power Devices in the U-NII-5 and U-NII-7 Bands
    55. In the FNPRM, the Commission sought comment on appropriate 
power levels and other technical parameters that VLP unlicensed devices 
in the 6 GHz band should have to meet. The Commission notes that there 
were no comments regarding the in-band emission mask for 6 GHz VLP 
devices. The Commission's previous decision in the 6 GHz Order found 
that the emission mask originally proposed by RKF engineering, with 
certain modifications, was necessary to protect incumbent microwave 
links and other services operating in the adjacent channel to 
unlicensed devices within the U-NII-5 through U-NII-8 bands. Because 6 
GHz VLP devices will operate in two of these same bands and on the same 
channels as LPI and standard power 6 GHz devices and need to protect 
the same incumbent operations, the Commission finds that using the same 
emission mask for VLP devices as adopted for LPI and standard power 
devices is appropriate. As the incumbent operations' protection 
requirements have not changed since the Commission's previous decision 
for this band, using the same mask ensures that those operations are 
fully protected from unlicensed adjacent channel operations. Moreover, 
by adopting the same emission requirements, the Commission anticipates 
that device manufacturers will be able to take advantage of economies 
of scale regarding filters necessary to meet these requirements which 
should help to reduce costs. Finally, the Commission takes this 
opportunity to again point out that the emission specification it's 
adopting represents the minimum requirement. The Commission encourages 
device manufacturers, consistent with the recent Commission Policy 
Statement, to design their devices to minimize energy transmitted into 
adjacent channels.
    56. Accordingly, the Commission is requiring emissions from VLP 
devices in the U-NII-5 and U-NII-7 bands to comply with the 
transmission emission mask adopted in the 6 GHz Order. That is, the 
Commission is requiring the power spectral density to be suppressed by 
20 dB at one megahertz outside of an unlicensed device's channel edge, 
suppressed by 28 dB at one channel bandwidth from an unlicensed 
device's channel center, and suppressed by 40 dB at one and one-half 
times the channel bandwidth away from an unlicensed device's channel 
center. At frequencies between one megahertz outside an unlicensed 
device's channel edge and one channel bandwidth from the center of the 
channel, the limits must be linearly interpolated between the 20 dB and 
28 dB suppression levels. At frequencies between one and one and one-
half times an unlicensed device's

[[Page 886]]

channel bandwidth from the center of the channel, the limits must be 
linearly interpolated between the 28 dB and 40 dB suppression levels. 
Emissions removed from the channel center by more than one and one-half 
times the channel bandwidth, but within the U-NII-5 and U-NII-7 bands, 
must be suppressed by at least 40 dB.
2. Emission Limits Outside the U-NII-5 and U-NII-7 Bands
    57. The Commission is adopting emissions limits at the edge of the 
U-NII-5 and U-NII-8 bands for VLP devices that are identical to the 
emissions limits that the Commission adopted in the 6 GHz Order. 
Specifically, the Commission is adopting a -27 dBm/MHz EIRP limit for 6 
GHz VLP devices at frequencies below the bottom of the U-NII-5 band 
(5.925 GHz) and above the upper edge of the U-NII-8 band (7.125 GHz), 
but will not require it between the sub-bands, i.e., between the U-NII-
5 and U-NII-6, the U-NII-6 and U-NII-7, and the U-NII-7 and U-NII-8 
bands; those emissions are subject to the emission mask and out-of-band 
emission (OOBE) limits discussed above. These limits are intended to 
protect cellular vehicle-to-everything (C-V2X) operations below the 6 
GHz band and Federal operations above the band. The Commission 
previously determined that the -27 dBm/MHz limit will sufficiently 
protect C-V2X operations from harmful interference from U-NII devices 
operating in other bands.
    58. The Commission notes here that it adopted rules that require 
Intelligent Transportation System (ITS) licensees to cease use of the 
5.850-5.895 GHz band and operate only in the 5.895-5.925 GHz band. In 
the 5.9 GHz Order, 83 FR 23281 (May 3, 2021), the Commission also 
required that dedicated short range communications (DSRC)-based 
technology operating in the ITS radio service transition to C-V2X-based 
technology. The FNPRM, 86 FR 23323 (May 3, 2021), in that proceeding 
addressed transitioning all ITS operations in the revised ITS band at 
5.895-5.925 GHz to C-V2X-based technology, including the appropriate 
timeline for the implementation and codification of C-V2X technical 
parameters for operation in the 5.895-5.925 GHz band. Since then, the 
C-V2X proponents requested and the Commission has begun granting 
waivers to allow immediate C-V2X deployment in the ITS bands prior to 
the initiation of final rules for CV2X operations.
    59. Several parties support the -27 dBm/MHz EIRP emission limit, 
while other parties make alternative proposals. A group of VLP 
proponents jointly propose a compromise out-of-band emission limit that 
would apply at the bottom of the U-NII-5 band. Specifically, they 
propose that VLP devices comply with a -37 dBm/MHz out-of-band emission 
limit at 5925 MHz measured by root mean square (RMS) to ensure 
coexistence when 6 GHz devices are operating in the lowermost channels 
and that VLP devices prioritize operations in channels above 6105 
megahertz.
    60. The Commission is not convinced at this time that a more 
stringent out-of-band emission limit nor operational restrictions 
suggested by C-V2X proponents are necessary to protect in-vehicle C-V2X 
devices from harmful interference. The Commission already determined 
that standard power and LPI 6 GHz devices must comply with this same -
27 dBm/MHz out-of-band emission limit and that emissions at or under 
that limit will protect adjacent band users from harmful interference. 
C-V2X devices must be designed to successfully operate in an 
interference-limited environment as they are subjected to co-channel 
and adjacent channel signals between each other that are higher than 
the -27 dBm/MHz out-of-band emission limit the Commission is adopting 
here for 6 GHz unlicensed VLP devices. C-V2X devices have to coexist 
with other C-V2X devices that operate in close proximity to each other, 
e.g., other on-board units (within vehicles) and roadside units. 
Finally, to the extent that commenters raised concerns about harmful 
interference from aggregate VLP device emissions, the Commission notes 
that the number of such devices present in any given vehicle is 
anticipated to be low and because transmissions between VLP devices 
would occur over very short distances, the transmit power levels and 
their associated out-of-band emissions are expected to be well below 
the maximum permitted. Thus, even if multiple out-of-band emissions 
were aggregated, the total out-of-band emissions in the local area 
would still be expected to be below C-V2X device's own signal levels. 
The Commission also believes that maintaining the -27 dBm/MHz emission 
limit is appropriate in part because the rules for C-V2X operation in 
the 5.895-5.925 GHz band are the subject of a pending rulemaking 
proceeding and current C-V2X operations are pursuant to conditional 
rule waivers.
    61. The Commission declines to adopt the -37 dBm/MHz out-of-band 
emissions limit suggested by some parties. However, the Commission 
plans on seeking additional information on the potential impact that 
VLP devices operating in motor vehicles could have on C-V2X performance 
and whether any modification of the out-of-band emission limit or other 
technical or operational requirements are appropriate. Likewise, the 
Commission finds the -60 dBm/MHz out-of-band emission limit suggested 
by the Alliance for Automotive Innovation (AAI) for application at the 
U-NII-5 band edge to be too restrictive. In addition, the Commission 
finds AAI's suggestion to require VLP devices to operate with a 1-2% 
duty cycle that is averaged over a range of tens of milliseconds is not 
reasonable. While duty cycle is an important parameter for system 
operation, the Commission typically does not make rules requiring 
adherence to specific duty cycle requirements as they may artificially 
restrict design choices and limit the applications that can be used by 
the American public. Similarly, the Commission declines to adopt a 
requirement advocated by Panasonic that VLP devices include sensing 
technology as it does not believe that such a complex solution is 
necessary to achieve the protection requirements needed for all users 
in the band. Moreover, any new sensing technology often requires long 
development cycles along with extended testing to ensure proper 
operation, which would only delay the benefits that VLP devices can 
provide.
    62. As discussed above, the Commission remains convinced that the -
27 dBm/MHz out-of-band emission level at the lower edge of U-NII-5 will 
protect C-V2X operations below 5925 MHz and adopt that level for VLP 
devices. This will create a consistent out-of-band limit for all 6 GHz 
unlicensed devices throughout the 6 GHz band.
3. Prioritization of Operations on Channels Above 6105 MHz
    63. The Commission is mindful of the concerns from the auto 
industry regarding the potential for harmful interference to automotive 
safety systems operating below the U-NII-5 band. For example, the 
proponents of the compromise proposal propose that VLP devices 
prioritize unlicensed operation in channels above 6105 MHz (i.e., the 
top edge of the first 160 megahertz wide channel in the Institute of 
Electrical and Electronics Engineers (IEEE) band plan) before operating 
below 6105 MHz and that manufacturers submit with their equipment 
authorization application a declaration that the equipment complies 
with this prioritization rule.

[[Page 887]]

    64. To ensure that safety of life services below the U-NII-5 band 
are protected from harmful interference, the Commission adopts the 
suggestion from the compromise proposal to require VLP devices to 
prioritize spectrum above 6105 MHz. The Commission disagrees with NAB 
that this is inconsistent with its previous decision not to exclude VLP 
devices from a portion of the 6 GHz band to protect electronic news 
gathering (ENG) operations as this requirement does not prohibit 
operation below 6105 MHz; it merely requires that devices seek to 
operate in the spectrum above that frequency first before operating 
below it. Although under this approach, there may be fewer VLP devices 
operating on the spectrum below 6105 MHz, many devices will still 
operate on that spectrum and the Commission does not expect abnormal 
concentrations of VLP devices in U-NII-6 and U-NII-8 where ENG operates 
as devices would still naturally spread across the available spectrum.

E. Other Matters

    65. Restrictions on Very Low Power Device Use on Aircraft, Boats, 
and Oil Platforms. Because VLP access points can operate in motion, 
unlike standard power and LPI devices that the rules limit to 
stationary operation, the Commission will permit VLP devices to operate 
in terrestrial land-based vehicles, including cars, buses, trains, etc. 
The Commission will also not prohibit VLP device use on boats in 
contrast to its decision to prohibit standard power and LPI devices 
from operating on boats. That decision stemmed from a request from the 
National Academy of Sciences' Committee on Radio Frequencies (CORF) 
seeking protection for Earth Exploration Satellite Service (EESS) 
remote sensing operations over oceans. Given that VLP devices will 
operate at much lower power levels than LPI and standard power devices, 
and many boaters, particularly recreational boaters operate either on 
inland lakes and waterways or in close proximity to the coastline, the 
Commission does not believe that they will present an interference 
threat to EESS sensing over the oceans. However, the Commission plans 
on seeking comment on whether any restrictions should be put in place 
for VLP operation on boats. The Commission will continue to prohibit 6 
GHz devices, including VLP devices, from operating on oil platforms 
because EESS operations in this band mainly include oceanic sensing, 
and operation of VLP devices on oil platforms could potentially 
interfere with passive and active sensing operations over the oceans 
and coastal where these oil rigs tend to be concentrated. The 
Commission also notes that ocean based oil platforms, are located 
anywhere from a few hundred meters to a few hundred miles off of the 
coast where EESS operations are monitoring critical data oceanographic 
and weather phenomenon. However, the Commission plans on seeking 
comment on whether this restriction should be eliminated.
    66. Consistent with the Commission's decision in the 6 GHz Order to 
prohibit standard power and LPI devices from operating in low flying 
aircraft and unmanned aircraft systems (UAS) (i.e., drones), the 
Commission similarly prohibits such operation for VLP devices. Use on 
such platforms presents novel propagation paths and introduces the 
potential for causing harmful interference to fixed microwave 
receivers, which are typically located on towers and rooftops. Unlike 
operation that may occur outside on a balcony above ground level, 
operation on a low flying aircraft or UAS may not have buildings or 
other structures nearby to attenuate signals and thus will have a 
higher probability of having a line-of-sight path to an incumbent 
receiver location resulting in a higher potential for causing harmful 
interference. Hence, the Commission will apply the same aircraft 
restriction to VLP devices as it adopted for LPI and standard power 
devices. VLP devices will not be permitted on aircraft, except in large 
aircraft while flying above 10,000 feet. Consistent with the 
Commission's decision in the 6 GHz Order, it believes that operating at 
those altitudes along with attenuation provided by an aircraft's 
fuselage will keep signal levels to such a low level at incumbents' 
receivers as to pose an insignificant harmful interference risk. The 
Commission will permit VLP devices operating on aircraft above 10,000 
feet to operate across the 5.925-6.425 GHz band. This is consistent 
with the 6 GHz Order, which restricted LPI operation on large aircraft 
flying above 10,000 feet to the U-NII-5 band to prevent harmful 
interference to radio astronomy and EESS operations in the U-NII-6, U-
NII-7, and U-NII-8 bands. VLP devices will also not be permitted to be 
used for control of or communications with unmanned aircraft systems.
    67. 57-71 GHz Band. CTIA opposes expanding AFC-free VLP unlicensed 
operations in the 6 GHz band and instead proposes that unlicensed 
proponents consider the 57-71 GHz band for VLP operations. We decline 
to prohibit VLP device operations in the U-NII-5 and U-NII-7 portions 
of the of the 6 GHz band in favor of the 57-71 GHz band. The 
Commission's policy has been to provide as much flexibility for 
spectrum users--both licensed and unlicensed--to use spectrum bands 
that best meet their needs based on their business case and expected 
use cases. VLP operations are no different and, as explained in the 
Second Report and Order, the Commission believes that permitting VLP 
operations in the 6 GHz band meets that goal. The rules the Commission 
is adopting provides flexibility for VLP operations while still 
protecting authorized services from harmful interference. Furthermore, 
the Commission notes that the 57-71 GHz band has flexible rules for 
unlicensed operations and that manufacturers could develop similar 
devices to 6 GHz VLP devices under those rules should they determine 
that it is both feasible and would meet consumer demand.
    68. LPI and standard power devices as substitute for VLP. AT&T 
points to claims by VLP device proponents that 90% of these devices 
will operate indoors to argue that VLP devices are not necessary to 
address the use cases purportedly supported by the VLP rules. AT&T also 
claims that VLP device proponents essentially concede that the burden 
of adding AFC capability to VLP devices would be minimal, pointing to a 
filing by Apple, Broadcom, Google, and Meta that discusses implementing 
exclusion zones for VLP devices.
    69. The Commission does not agree with AT&T's rationale that if 90% 
of VLP use is assumed to be indoors, there is no utility in enabling 
outdoor VLP device operation. VLP proponents describe portable battery-
powered consumer products as a primary use case for these devices, and 
apportioning significant battery resources to the overhead necessary to 
operate pursuant to an AFC could reduce utility of these devices to the 
point that they would be infeasible. In addition, as discussed above, 
the Commission disagrees with AT&T's assertion that there is no cost to 
implement an AFC capability in VLP devices. Adding AFC capability to 
these small battery-powered portable device would likely increase their 
complexity and, correspondingly, their cost. The Commission also agrees 
with Apple, Broadcom, and Meta that VLP devices will be suitable for 
applications that require direct communications between client devices 
and to support mobility that may require devices to transition between 
indoor and outdoor use. Therefore, the Commission finds AT&T's 
contention to be without merit.
    70. Rule Corrections. The Commission is making two minor changes to 
Sec.  15.407 to correct cross-references that were

[[Page 888]]

inadvertently not updated when the Commission previously renumbered 
paragraphs in this section. Specifically, the Commission corrects the 
cross-reference in the introductory text of Sec.  15.407(b) to 
reference paragraph (b)(10) rather than paragraph (b)(7), and the 
Commission corrects the cross-reference in Sec.  15.407(l)(2)(ii) to 
reference paragraph (b)(7) rather than paragraph (b)(6).

F. Benefits and Cost

    71. As discussed above, the Commission adopts rules to permit VLP 
devices to operate in the U-NII-5 and U-NII-7 portions of the 6 GHz 
band while protecting the licensed services that operate in the band 
from harmful interference. Enabling new unlicensed use types in the U-
NII-5 and U-NII-7 bands will yield important economic benefits and will 
allow more extensive use of technologies, such as Wi-Fi and Bluetooth, 
by American consumers. Consumers are using more and more data, on 
average, and this is expected to continue to grow significantly. One 
report estimated that in 2021, the economic benefits associated with 
Wi-Fi in the United States was valued at almost $979 billion and that 
by 2025, 40% of Wi-Fi traffic will rely on 6 GHz. Another report 
estimated that making the 6 GHz band accessible to VLP devices would 
produce over $39 billion in economic value over five years. Even if the 
rules that the Commission adopts herein lead to expected benefits of 5% 
of $39 billion, or approximately $2 billion--a figure the Commission 
finds to be below the likely benefits of these rules--the expected 
benefits will be well in excess of the costs that we estimate.
    72. Because there are presently no VLP devices in operation, the 
rules that the Commission promulgate does not have cost implications 
for the existing unlicensed device ecosystem. And because the harmful 
interference risk to incumbent operators is insignificant and the 
Commission is not imposing any specific requirements on any incumbent 
operator, there is also no cost implication on them. Thus, by 
promulgating these rules to enable VLP devices to operate in the U-NII-
5 and U-NII-7 portions of the 6 GHz band, significant economic benefits 
will be bestowed on the American public.

Memorandum Opinion and Order on Remand

    73. Introduction. In this order, the Commission addresses a remand 
from the United States Court of Appeals for the District of Columbia 
Circuit concerning the rules that govern the use of unlicensed devices 
in the 6 GHz band (AT&T Servs., Inc. v. FCC, 21 F.4th 841 (D.C. Cir. 
2021)). After rejecting a number of challenges to the rules, the court 
of appeals remanded a single narrow issue for further consideration. 
Specifically, the court directed us to consider whether, in light of 
broadcasters' claims that they have experienced interference from 
unlicensed devices in the 2.4 GHz band, a portion of the 6 GHz band 
should be reserved for mobile broadcast operations. For the reasons set 
forth below, the Commission concludes that broadcasters' 
unsubstantiated claims of interference in the 2.4 GHz band do not 
warrant any modification of our 6 GHz rules.
    74. Background. In the spring of 2020, the Commission adopted rules 
to make 1200 megahertz of spectrum available for use by unlicensed 
devices in the 6 GHz band (5.925-7.125 GHz). Several parties, including 
NAB, filed petitions for review of the rules in the D.C. Circuit. The 
court denied the petitions for review ``in all respects save one.'' The 
sole issue that the court remanded concerned NAB's assertion that 
``after the Commission allowed unlicensed access in the 2.4 GHz band, 
`a contention-based protocol . . . failed to protect . . . licensed 
users[,] . . . rendering that band partially unusable.' '' Based on 
broadcasters' concern that unlicensed devices could create similar 
problems in the 6 GHz band, NAB had asked the Commission to ``reserve a 
sliver of [the] 6 GHz band for licensed mobile [broadcast] operation.'' 
In the court's view, ``the Commission failed adequately to respond to 
[this] request'' because it ``never responded'' to NAB's concerns about 
interference in the 2.4 GHz band. ``Given the Commission's failure to 
respond'' to these concerns, the court concluded that ``further 
explanation is called for.'' Accordingly, the court ``remand[ed] to the 
Commission for it to respond to [NAB's] concerns about interference in 
the 2.4 GHz band.''
    75. Discussion. In response to the court's remand, the Commission 
has further examined NAB's claims concerning the 2.4 GHz band, and the 
Commission finds that those claims lack merit. The record in this 
proceeding contains no concrete evidence that unlicensed Wi-Fi devices 
have caused harmful interference to mobile broadcast operations in the 
2.4 GHz band. By contrast, the record contains concrete evidence that 
contention-based protocols would be effective in the 6 GHz band. 
Consequently, the Commission finds that NAB's claims of interference in 
the 2.4 GHz band do not warrant any modifications to its 6 GHz rules.
    76. In a series of letters filed before the 6 GHz rules were 
adopted, NAB told the Commission that a contention-based protocol 
requirement for unlicensed devices in the 2.4 GHz band had not 
protected broadcasters and that this experience should lead the 
Commission to conclude that a contention-based protocol likewise would 
not protect broadcasters from harmful interference in the 6 GHz band. 
NAB claimed that ``the penetration of Wi-Fi has so polluted the shared 
portion of the 2.4 GHz band as to render it unusable for'' ENG 
operations. But NAB offered no specific evidence to support this broad 
claim. Instead, NAB cited comments filed in this proceeding by the 
Engineers for the Integrity of Broadcast Auxiliary Services Spectrum 
(EIBASS) in February 2019.
    77. Although EIBASS asserted in its February 2019 comments that 
``part 15 devices have a long history of causing chronic interference 
to TV BAS [Broadcast Auxiliary Service] operations'' on certain 
channels in the 2.4 GHz band, it offered only two very specific pieces 
of evidence regarding this claim: an unsubstantiated account of an 
incident that allegedly occurred in a single market more than a decade 
ago and a spectrum analyzer screenshot from a specific location 
purporting to show that Wi-Fi caused an increase in the 2.4 GHz band 
noise floor. EIBASS described a presentation made by the BAS frequency 
coordinator for Phoenix, Arizona, during a conference of broadcast 
engineers in April 2004. According to EIBASS, the Phoenix coordinator 
stated during the April 2004 presentation that ``about every six months 
or so,'' one of the four ENG receive-only sites in the Phoenix area 
``becomes unusable'' for certain channels in the 2.4 GHz band ``because 
of the proliferation of 2.4 GHz WiFi devices at the site.''
    78. Even if the Commission were persuaded that broadcasters in the 
Phoenix area had experienced interference in the 2.4 GHz band nearly 
two decades ago, as EIBASS claimed, this isolated incident would not 
convince us that the Commission needs to take additional measures that 
would affect the entirety of the U.S. to protect broadcasters from 
harmful interference in the 6 GHz band. Even assuming that harmful 
interference did in fact occur, the Commission has no way of verifying 
that Wi-Fi devices caused the problem. If the alleged interference did, 
in fact, occur, the Commission notes that many unlicensed part 15 non-
Wi-Fi devices also operate in the 2.4 GHz band, and

[[Page 889]]

those devices do not use a contention-based protocol. Similarly, 
industrial, scientific, and medical (ISM) devices operate on a primary 
basis in the 2.4 GHz band. Because EIBASS does not attribute any 
alleged harmful interference to any specific Wi-Fi device(s) and does 
not appear to consider any of the other numerous devices operating in 
the band without using a contention-based protocol, the Phoenix 
incident does not support NAB's assertion that a contention-based 
protocol failed to prevent interference in the 2.4 GHz band.
    79. The other evidence that EIBASS provided was a spectrum analyzer 
screenshot that was captured at an ENG receive-only site in Phoenix in 
2013. While this screenshot shows that some type of signal could have 
been present in the 2.4 GHz band at that time, it does not provide 
evidence of what devices may be causing any noise floor increase nor 
that a contention-based protocol would have failed to protect BAS 
receivers in the band. Moreover, as this screenshot is merely an 
indication of the spectrum at a single point in time, it offers no 
indication as to the behavior of a device employing a contention-based 
protocol when in the vicinity of a BAS transmitter in the band. Given 
the limited information this screenshot conveys, it provides no grounds 
to support NAB's assertion that a contention-based protocol had failed 
to prevent interference in the 2.4 GHz band.
    80. Furthermore, even if the devices that EIBASS alleged were 
causing interference in Phoenix used a contention-based protocol, the 
Commission cannot determine from the sparse evidence in the record 
whether those devices were operating in compliance with the 
Commission's part 15 rules. Notably, the contention based protocol used 
by Wi-Fi devices is part of the IEEE 802.11 standard and not required 
by the Commission's rules nor do the Commission's rules limit such 
devices to indoor locations. Because of the lack of a Commission-
mandated requirement for a contention-based protocol or indoor 
operation on 2.4 GHz devices, and no insight into whether devices in 
the Phoenix area at the time of the alleged interference were actually 
using such a protocol or operating indoors, it is impossible to draw 
any conclusions from those operations and the operations anticipated in 
the 6 GHz band. Thus, the alleged Phoenix incidents shed no light on 
the relevant question raised by NAB: that is, whether the purported 
experience regarding potential harmful interference to BAS devices in 
the 2.4 GHz band has any relevance to the potential for such 
interference from LPI devices in the 6 GHz band. Additionally, as an 
added safeguard and as several commenters note, the 6 GHz rules impose 
much lower power limits on unlicensed LPI devices than the 2.4 GHz 
rules do.
    81. In contrast to NAB's unsubstantiated claims of harmful 
interference in the 2.4 GHz band, the record persuades us that ``the 
risk of harmful interference to indoor electronic news gathering 
receivers from indoor unlicensed devices'' in the 6 GHz band ``is 
insignificant.'' A study by Apple, Broadcom, et al. ``simulated the 
receive power level from electronic news gathering transmitters at 20 
unlicensed access points operating within the U.S. House of 
Representatives chamber. The results of this simulation demonstrate[d] 
that, even at the lowest electronic news gathering transmit power 
level, all unlicensed access points would detect the electronic news 
gathering signal at greater than -62 dBm and therefore not transmit co-
channel.'' This study ``confirm[ed]'' that contention-based protocols 
``could be used to mitigate interference to indoor electronic news 
gathering receivers'' in the 6 GHz band.
    82. Because the record contains no substantial evidence of harmful 
interference to broadcast operations in the 2.4 GHz band, the 
Commission finds no basis for NAB's assertion that a contention-based 
protocol failed to protect broadcasters from interference in that band, 
much less under the parameters established for operation in the 6 GHz 
band. As the Commission noted in the 6 GHz Order, ``Wi-Fi devices have 
been deployed'' in the 2.4 GHz band ``in abundance for well over 20 
years.'' For most of that time, the 2.4 GHz band was the primary band 
used by Wi-Fi devices. If (as NAB and others have claimed) interference 
from Wi-Fi devices prevented broadcasters from using portions of the 
2.4 GHz band, the Commission would expect the record to reflect 
evidence of numerous instances of such interference. Yet apart from an 
unsubstantiated account of an alleged incident in Phoenix almost two 
decades ago and a spectrum analyzer screenshot captured in Phoenix more 
than a decade ago, the record contains no specific evidence that any 
broadcaster has experienced harmful interference from unlicensed Wi-Fi 
devices in the 2.4 GHz band. Moreover, neither NAB nor any other party 
has cited a single complaint filed with our Enforcement Bureau by any 
broadcaster alleging interference by unlicensed Wi-Fi devices in the 
2.4 GHz band. The absence of any such complaints undermines NAB's 
contention that interference from unlicensed Wi-Fi devices is a serious 
problem for broadcasters in the 2.4 GHz band.
    83. Following the remand, the Society of Broadcast Engineers (SBE) 
and EIBASS attempted to supplement the record by presenting new 
evidence of harmful interference in the 2.4 GHz band. Such evidence 
falls outside the scope of this remand proceeding. The narrow question 
presented by the court's remand is whether the Commission adequately 
considered NAB's concerns about interference in the 2.4 GHz band when 
it adopted the 6 GHz rules. In this context, the relevant record is 
``the record before the agency at the time of its decision.''
    84. In any event, even assuming that the new evidence proffered by 
SBE and EIBASS were properly before us, this evidence does not persuade 
us that Wi-Fi devices have caused harmful interference to broadcast 
operations in the 2.4 GHz band, much less at the far lower power at 
which Wi-Fi operations are required to operate in the 6 GHz band. SBE 
asserts that it conducted an ``informal survey'' in which local 
frequency coordinators reported ``harmful interference from Wi-Fi 
systems [in the 2.4 GHz band] . . . in at least 13 markets.'' But as 
Apple, Broadcom, et al. point out, SBE's ``informal survey'' was 
``backed in most cases by no supporting evidence or incident 
descriptions.'' The only evidence offered by SBE to support its 
``informal survey'' is a spectrum plot that purports to show 
interference in Milwaukee. The Commission agrees with Apple, Broadcom, 
et al. that this spectrum plot does not constitute ``meaningful 
technical evidence'' because it contains ``no supporting detail'' 
concerning how the measurement of interference in Milwaukee was made. 
In particular, the Commission notes that SBE offers ``no explanation 
why'' it attributes the alleged interference in Milwaukee ``to Wi-Fi, 
rather than to the many other technologies operating in the 2.4 GHz 
band that do not use a contention-based protocol.'' The same is true of 
EIBASS's comparison of the noise floors for mobile broadcast operations 
at 2 GHz and 2.5 GHz. Although EIBASS claims that part 15 Wi-Fi devices 
are responsible for the higher noise floor at 2.5 GHz, the higher noise 
floor could also be attributable to ``the many other technologies 
operating in the 2.4 GHz band that do not use a contention-based 
protocol.''
    85. The post-remand submissions by SBE and EIBASS also fail to cite 
any complaints filed with our Enforcement

[[Page 890]]

Bureau claiming that Wi-Fi devices caused harmful interference to 
mobile broadcast operations in the 2.4 GHz band. The absence of any 
such complaints casts further doubt on the assertions made by NAB and 
its supporters that broadcasters have routinely experienced such 
interference.
    86. In sum, despite NAB's claims that interference issues in the 
2.4 GHz band are pervasive and longstanding, the record contains no 
credible evidence of such interference. The specific incident of 
alleged interference cited in the record occurred about two decades ago 
in Phoenix, and it was never reported to the Commission's Enforcement 
Bureau. EIBASS's sketchy description of the details of that incident 
does not provide us with enough information to draw any firm 
conclusions about how--or even whether--interference occurred. The 
spectrum analyzer screenshot showing an increase in the noise floor in 
Phoenix more than a decade ago also lacks the details needed to reach a 
conclusion about whether harmful interference was occurring. Given the 
absence of any concrete evidence that broadcasters have experienced 
harmful interference in the 2.4 GHz band or in the 6 GHz band, where 
LPI devices have been operating since December 2020, and in light of 
the substantial record evidence demonstrating that there is no 
significant risk of harmful interference given the constraints under 
which Wi-Fi devices are required to operate in the 6 GHz band, the 
Commission rejects NAB's contention that broadcasters' experience with 
interference in the 2.4 GHz band justifies the reservation of a portion 
of the 6 GHz band for mobile broadcast operations.
    87. Conclusion. For the foregoing reasons, the Commission concludes 
that NAB's unsubstantiated claims of interference in the 2.4 GHz band 
do not justify any modifications to its 6 GHz rules to provide 
broadcasters with further protections from harmful interference. The 
Commission reaffirms that the rules adopted in the 6 GHz Order 
eliminate any significant risk of harmful interference to mobile 
broadcast operations and other incumbent licensed services in the 6 GHz 
band. Therefore, the Commission declines to adopt NAB's proposal to 
reserve part of the 6 GHz band for the exclusive use of mobile 
broadcast operations.

Ordering Clauses

    1. Accordingly, it is ordered, pursuant to sections 2, 4(i), 302, 
and 303 of the Communications Act of 1934, as amended, 47 U.S.C. 152, 
154(i), 302a, and 303, the Second Report and Order and Memorandum 
Opinion and Order on Remand, is hereby adopted.
    2. It is further ordered, pursuant to sections 4(i), 4(j), 201, 
302, and 303 of the Communications Act of 1934, as amended, 47 U.S.C. 
154(i), (j), 201, 302a, 303, that the Memorandum Opinion and Order on 
Remand is hereby adopted.
    3. It is further ordered that the amendments of the Commission's 
rules as set forth in Appendix A of the Second Report and Order are 
adopted, effective 60 days from the date of publication in the Federal 
Register.
    4. It is further ordered that the Memorandum Opinion and Order on 
Remand shall become effective thirty (30) days after publication in the 
Federal Register.
    5. It is further ordered that the Office of the Secretary, 
Reference Information Center, shall send a copy of the Second Report 
and Order including the Final Regulatory Flexibility Analysis, to the 
Chief Counsel for Advocacy of the Small Business Administration.
    6. It is further ordered that the Office of Managing Director, 
Performance Program Management shall send a copy of the Second Report 
and Order in a report to be sent to Congress and the Government 
Accountability Office pursuant to the Congressional Review Act, 5 
U.S.C. 801(a)(1)(A).

List of Subjects in 47 CFR Part 15

    Communications equipment, Radio, Reporting and recordkeeping 
requirements.

Federal Communications Commission.
Marlene Dortch,
Secretary.

Final Rules

    For the reasons discussed in the preamble, the Federal 
Communications Commission amends 47 CFR part 15 as follows:

PART 15--RADIO FREQUENCY DEVICES

0
1. The authority citation for part 15 continues to read as follows:

    Authority:  47 U.S.C. 154, 302a, 303, 304, 307, 336, 544a, and 
549.


0
2. Section 15.403 is amended by adding the definition of ``Very low 
power device'' in alphabetical order, to read as follows:


Sec.  15.403  Definitions.

* * * * *
    Very low power device. For the purpose of this subpart, a device 
that operates in the 5.925-6.425 GHz and 6.525-6.875 GHz bands and has 
an integrated antenna. These devices do not need to operate under the 
control of an access point.

0
3. Section 15.407 is amended by:
0
a. Removing the headings from paragraphs (a)(1) and (3);
0
b. Redesignating paragraphs (a)(9) through (12) as paragraphs (a)(10) 
through (13);
0
c. Adding a new paragraph (a)(9);
0
d. Revising paragraphs (b) introductory text, (c), and (d)(1);
0
e. Removing and reserving paragraph (d)(2);
0
f. Revising paragraph (d)(6);
0
g. Adding paragraphs (d)(8) through (10); and
0
h. Revising paragraph (l)(2)(ii).
    The revisions and additions read as follows.


Sec.  15.407  General technical requirements.

    (a) * * *
    (9) For very low power devices operating in the 5.925-6.425 GHz and 
6.525-6.875 GHz bands, the maximum power spectral density must not 
exceed -5 dBm e.i.r.p in any 1-megahertz band and the maximum e.i.r.p 
must not exceed 14 dBm.
* * * * *
    (b) Undesirable emission limits. Except as shown in paragraph 
(b)(10) of this section, the maximum emissions outside of the frequency 
bands of operation shall be attenuated in accordance with the following 
limits:
* * * * *
    (c) Transmission discontinuation requirement. The device shall 
automatically discontinue transmission in case of either absence of 
information to transmit or operational failure. The provisions in this 
paragraph (c) are not intended to preclude the transmission of control 
or signaling information or the use of repetitive codes used by certain 
digital technologies to complete frame or burst intervals. Applicants 
shall include in their application for equipment authorization a 
description of how the requirement in this paragraph (c) is met.
    (d) * * *
    (1) Operational restrictions include:
    (i) Oil platforms. Operation of standard power access points, fixed 
client devices, very low power devices, and indoor access points in the 
5.925-7.125 GHz band is prohibited on oil platforms.
    (ii) Land vehicles. Operation of standard power access points, 
fixed client devices, and indoor access points in the 5.925-7.125 GHz 
band is prohibited on vehicles (e.g., cars, trains).
    (iii) Boats. Operation of standard power access points, fixed 
client

[[Page 891]]

devices, and indoor access points in the 5.925-7.125 GHz band is 
prohibited on boats.
    (iv) Aircraft. Standard power access points, fixed client devices, 
very low power devices, and indoor access points in the 5.925-7.125 GHz 
band are prohibited from operating on aircraft, except that very low 
power devices and indoor access points are permitted to operate in the 
5.925-6.425 GHz bands in large aircraft while flying above 10,000 feet.
    (v) Unmanned aircraft systems. Operation of transmitters in the 
5.925-7.125 GHz band is prohibited for control of or communications 
with unmanned aircraft systems.
* * * * *
    (6) All U-NII transmitters, except for standard power access 
points, operating in the 5.925-7.125 GHz band must employ a contention-
based protocol.
* * * * *
    (8) Very low power devices may not employ a fixed outdoor 
infrastructure. Such devices may not be mounted on outdoor structures, 
such as buildings or poles.
    (9) Very low power devices must prioritize operations on 
frequencies above 6.105 GHz prior to operating on frequencies between 
5.925 GHz and 6.105 GHz.
    (10) Very low power devices operating in the 5.925-6.425 and 6.525-
6.875 GHz bands shall employ a transmit power control (TPC) mechanism. 
A very low power device is required to have the capability to operate 
at least 6 dB below the maximum EIRP power spectral density (PSD) value 
of -5 dBm/MHz.
* * * * *
    (l) * * *
    (2) * * *
    (ii) The AFC system must use -6 dB I/N as the interference 
protection criteria in determining the size of the adjacent channel 
exclusion zone, where I (interference) is the signal from the standard 
power access point or fixed client device's out of channel emissions at 
the fixed microwave service receiver and N (noise) is background noise 
level at the fixed microwave service receiver. The adjacent channel 
exclusion zone must be calculated based on the emissions requirements 
of paragraph (b)(7) of this section.
* * * * *
[FR Doc. 2023-28006 Filed 1-5-24; 8:45 am]
BILLING CODE 6712-01-P