Unlicensed White Space Device Operations in the Television Bands, 32682-32692 [2023-10166]

Agencies

• FEDERAL COMMUNICATIONS COMMISSION

[Federal Register Volume 88, Number 98 (Monday, May 22, 2023)]
[Rules and Regulations]
[Pages 32682-32692]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-10166]


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FEDERAL COMMUNICATIONS COMMISSION

47 CFR Parts 15

[ET Docket Nos. 20-36 and 14-165; FCC 23-24; FRS 139311]


Unlicensed White Space Device Operations in the Television Bands

AGENCY: Federal Communications Commission.

ACTION: Final rule.

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    In this document, the Federal Communications Commission 
(Commission) continues taking steps to sustain and spur growth within 
the white space ecosystem and adopts three orders addressing pending 
issues associated with white space devices. These actions will provide 
additional certainty to white space device users and manufacturers to 
enable unlicensed white space devices to operate efficiently while 
protecting other spectrum users. In the Report and Order the Commission 
adopts rules specifying the database re-check interval for the new 
categories of mobile and narrowband white space devices established in 
2020. In the Order on Reconsideration, the Commission dismisses in part 
and, on alternative and independent grounds, denies a petition for 
reconsideration of two rule changes for white space devices operating 
in the broadcast television (TV) bands. In the Memorandum Opinion and 
Order, the Commission declines to modify the rules to permit white 
space databases to use more complex terrain-based models to determine 
the available frequencies for white space devices and will instead 
continue to rely on the simpler established model that has worked 
reliably to prevent interference to TV and other protected services.

DATES: Effective June 21, 2023.

FOR FURTHER INFORMATION CONTACT: Hugh Van Tuyl, Office of Engineering 
and Technology, (202) 418-7506 or [email protected].

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's 
document, Order on Reconsideration, Report and Order and Memorandum 
Opinion and Order, ET Docket Nos. 20-36 and 14-165; FCC 23-24, adopted 
April 11, 2023 and released April 12, 2023. The full text of this 
document is available for public inspection and can be downloaded at: 
https://www.fcc.gov/document/fcc-adopts-white-spaces-order. 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

    Final Regulatory Flexibility Analyses. The Regulatory Flexibility 
Act of 1980 (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, the Commission has prepared a Final Regulatory 
Flexibility Analysis (FRFA) concerning the possible impact of the rule 
changes contained in this Order on Reconsideration, Report and Order 
and Memorandum Opinion and Order on small entities. As required by the 
RFA, an Initial Regulatory Flexibility Analysis (IRFA) was incorporated 
in the Notice of Proposed Rulemaking (NPRM) (86 FR 38969, July 23, 
2021). The Commission sought written public comment on the proposals in 
the NPRM, including comments on the IRFA. No comments were filed 
addressing the IRFA. Accordingly, the Commission has prepared a Final 
Regulatory Flexibility Analysis (FRFA) concerning the possible impact 
of the rule changes contained in the document on small entities. The 
present FRFA conforms to the RFA and can be viewed under Appendix E of 
the item at: https://www.fcc.gov/document/fcc-adopts-white-spaces-order.
    Paperwork Reduction Act. This document does not contain new or 
modified information collection requirements subject to the Paperwork 
Reduction Act of 1995 (PRA), Public Law 104-13. In addition, therefore, 
it does not contain any new or modified information collection burden 
for small business concerns with fewer than 25 employees, pursuant to 
the Small Business Paperwork Relief Act of 2002, Public Law 107-198, 
see 44 U.S.C. 3506 (c)(4).
    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 ``non-
major'' under the Congressional Review Act, 5 U.S.C. 804(2). The 
Commission will send a copy of this Order on Reconsideration, Report 
and Order and Memorandum Opinion and Order to Congress and the 
Government Accountability Office pursuant to 5 U.S.C. 801(a)(1)(A).
    People with Disabilities: To request materials in accessible 
formats for people with disabilities (braille, large print, electronic 
files, audio format), send an email to [email protected] or call the 
Consumer & Governmental Affairs Bureau at 202-418-0530 (voice), 202-
418-0432 (tty).
    Additional Information. For additional information on this 
proceeding, contact Hugh L. Van Tuyl, [email protected], (202) 418-
7506 or Syed Hasan, [email protected], (202) 418-2454.

Synopsis

Background

    Unlicensed white space devices, which operate in the TV broadcast 
bands and portions of the 600 MHz band at locations where frequencies 
are not in use by licensed services or other protected entities, 
provide a variety of wireless services to the public. For example, 
Wireless internet Service Providers (WISPs) use fixed white space 
devices to provide internet connectivity in rural and underserved 
areas, including broadband data for schools and libraries, and on 
tribal lands. These devices obtain a list of available channels and 
data on power levels that may be used at their particular locations 
from databases administered by private entities approved by the 
Commission. Fixed and mobile white space devices must incorporate a 
geo-location capability and a means to access a database. Personal/
Portable white space devices can either acquire a list of available 
channels via another white space device (Mode I), or themselves include 
geo-location and database access capabilities (Mode II). Once the white 
space device acquires channel and power information for its location, 
it selects an appropriate frequency from that list for transmitting.
    Since 2008 when the Commission first authorized unlicensed white 
space

[[Page 32683]]

device operations in the VHF and UHF TV bands, it has taken a number of 
further actions to make the white space rules more flexible while 
protecting incumbent services to facilitate improved broadband services 
to all Americans, particularly those in rural, Tribal and other 
underserved areas. Operating in the TV and 600 MHz Service bands allows 
these devices to operate over long distances at moderate power levels 
making them ideal for connecting these areas. The Commission continues 
to examine and modify, as needed, the white space device rules to 
maximize their efficiency and ensure that the American public continues 
to reap their benefits.
    In its 2015 White Spaces Order, the Commission modified the 
technical rules for white space device operations in the spectrum that 
continues to be TV band spectrum following the incentive auction. It 
maintained the requirement for fixed and Mode II personal/portable 
devices to re-check the white space database at least once per day, but 
it also adopted additional requirements intended to better protect 
licensed wireless microphone operations registered in the white space 
database. Specifically, the Commission required the white space 
databases to ``push'' changes in channel availability information to 
fixed and Mode II personal/portable devices when a licensed wireless 
microphone is registered on a previously vacant TV channel (``push 
notifications''). In response to petitions for reconsideration arguing 
that the push notification requirement was overly burdensome and would 
need modifications to be effective, the Commission waived this 
requirement pending final action on the petitions for reconsideration. 
The Commission, acting on these petitions in 2022, removed the push 
notification requirement.
    In the 2020 White Spaces Order and FNPRM, the Commission made 
targeted changes to the rules for white space devices in the TV bands 
to provide improved broadband coverage for American consumers in rural 
and underserved areas and improved access to narrowband Internet of 
Things (IoT) applications in all areas. Specifically, the Commission 
permitted higher equivalent isotropically radiated power (EIRP) and 
higher antenna height above average terrain (HAAT) for fixed white 
space devices in ``less congested'' geographic areas, i.e., those areas 
where at least half the TV channels in a device's band of operation are 
vacant. In addition, the Commission permitted higher power mobile 
device operation within defined geo-fenced areas in ``less congested'' 
areas and adopted rule changes designed to facilitate the development 
of new and innovative narrowband IoT services. Mobile devices, which 
operate within a bounded area at power levels comparable to fixed 
devices, were implemented as a new class of white space device. 
Narrowband devices are a subset of fixed or personal/portable devices, 
and are subject to technical rules which permit narrower channel 
bandwidths than other fixed and personal/portable devices. The 
Commission, consistent with existing rules, required narrowband and 
mobile devices to comply with a once daily database check.
    Shure Incorporated filed a petition for reconsideration of two 
Commission decisions in the 2020 White Spaces Order and FNPRM, 
expressing concern about possible interference to wireless microphones. 
Shure believes that the 16-watt EIRP limit that the Commission 
permitted for geo-fenced mobile devices is too high and requests that 
this limit be reduced. Shure also objects to narrowband IoT devices 
being permitted to operate anywhere rather than limited to ``less 
congested'' areas, and wants the Commission to consider imposing 
additional requirements on narrowband IoT devices, such as requiring 
device operators to register the times, locations and technical 
operating parameters in the white space database.
    The Commission sought comment in the 2020 White Spaces Order and 
FNPRM on whether it should allow the use of a terrain-based propagation 
model such as the Longley-Rice Irregular Terrain Model for determining 
white space channel availability. It sought to develop a record on 
whether or not to implement such a model, the effect use of such a 
model would have on white space device channel availability, how a 
terrain-based model could be implemented within the current white space 
device framework, the technical parameters necessary to use such a 
model for identifying available spectrum while protecting incumbents 
from harmful interference, and various database and device 
implementation issues.
    Unlicensed proponents support permitting the use of terrain-based 
models by white space database administrators as an optional 
alternative to the current model that requires white space devices to 
comply with minimum separation distances outside the protected service 
contours of co-channel and adjacent channel TV stations. These parties 
generally argue that the current protection model can be overly 
conservative and that permitting terrain-based models would make more 
spectrum available for white space devices. However, TV broadcast 
interests oppose allowing the use of terrain-based models for 
determining white space channel availability due to concerns about 
interference to TV reception.
    In its 2022 White Spaces Order and FNPRM, the Commission addressed 
the 2015 petitions for reconsideration of the push notification 
requirement. It replaced this requirement with a simpler requirement 
that all fixed and Mode II personal/portable devices, with the 
exception of narrowband devices, must comply with a more frequent 
database re-check interval (once per hour instead of once per day). The 
Commission did not apply the more frequent re-check requirement to the 
newer classes of mobile and narrowband white space devices established 
in 2020 but instead sought comment on what database re-check interval 
should apply to mobile and narrowband devices, e.g., once per hour, 
once per day, or some other interval. Commenters support an hourly 
database re-check interval for mobile devices, but are divided on the 
appropriate re-check interval for narrowband devices. Unlicensed 
interests support a once daily re-check interval for narrowband 
devices, while broadcasters and wireless microphone interests support 
an hourly re-check interval.

Order on Reconsideration

    In this Order on Reconsideration, the Commission dismisses in part 
and, on alternative and independent grounds, denies Shure's petition 
for reconsideration and upholds the Commission's decisions allowing 
mobile devices to operate at 16 watts EIRP and permitting narrowband 
white space devices to operate in all areas rather than limiting them 
to ``less congested'' areas.

Mobile Device Power Limits

    Background. In the 2020 White Spaces Order and FNPRM, the 
Commission established a new class of mobile white space device which 
is permitted to operate within defined geo-fenced areas in ``less 
congested'' areas. It permitted these mobile devices to operate with up 
to 16 watts EIRP, which is the same power level permitted for fixed 
devices in ``less congested'' areas. The white space database must 
determine channel availability in the geo-fenced area using the same 
separation distances applicable to 16 watt fixed devices, and the 
database may indicate a channel as being available for a mobile device 
only if it

[[Page 32684]]

is available at the same power level throughout the entire geo-fenced 
area. A mobile device must incorporate a geo-location capability and 
check its location at least once every 60 seconds to determine whether 
it is still within the geo-fenced area where its operating channel is 
available. It must cease operation if it moves to within 1.9 kilometers 
of the boundary of the geo-fenced area or is outside of the area.
    Shure filed a petition for reconsideration of this decision, 
expressing concern about possible interference to unlicensed wireless 
microphones. Shure believes that the 16-watt EIRP limit that the 
Commission permitted for geo-fenced mobile devices is too high and 
recommends that the power limit be reduced to 100 milliwatts, but in no 
case greater than 4 watts. It argues that the Commission's decision to 
authorize high power mobile white space devices is irreconcilable with 
a 2010 decision denying a request for higher power mobile operation and 
is not in the public interest. Shure also argues that the 2020 White 
Spaces Order and FNPRM misguidedly conflates the interference profiles 
of fixed and mobile white space devices, fails to consider substantial 
risks of harm to the many users of unlicensed wireless microphones in 
less congested areas, and indefensibly deviates from the Commission's 
consistent policy of exercising caution when introducing new white 
space services. Microsoft opposes Shure's petition, arguing that the 
Commission's decision to adopt a 16-watt EIRP limit for mobile devices 
operating within geo-fenced areas was well-reasoned, cautious, and 
consistent with precedent.
    The Commission upholds its decision to allow the new class of 
mobile white space devices to operate at up to 16 watts EIRP. It 
disagrees with Shure's contention that this decision is irreconcilable 
with past Commission actions. The Commission made the 2010 decision 
that Shure cites in response to a Motorola petition for reconsideration 
of the 100 milliwatt power limit for personal/portable devices that the 
Commission established in 2008. Motorola had requested on 
reconsideration that the Commission establish a new class of vehicle 
mounted portable devices that could operate at up to four watts EIRP 
either under the control of a fixed device or by contacting a white 
space database to obtain a list of available channels, i.e., analogous 
to the operation of Mode I and Mode II personal/portable devices, but 
at a higher power level. The Commission denied Motorola's request, 
stating that personal/portable devices generally pose a greater risk of 
harmful interference to authorized operations than fixed devices 
because these devices will change locations, making identification of 
both unused TV frequencies and the devices themselves, if interference 
occurs, more complex and difficult. The Commission also noted the 
significant distances at which interference could occur from a 
personal/portable device operating at greater than 100 milliwatts would 
make it very difficult to identify a device that is the source of 
interference. However, the rules the Commission adopted in the 2020 
White Spaces Order and FNPRM to allow higher power mobile devices are 
different from what Motorola previously suggested in that they contain 
requirements to minimize the likelihood of interference that were not 
considered in 2010.
    Specifically, mobile devices must operate within a pre-defined 
(geo-fenced) area in which the white space database has determined in 
advance that at least one TV channel is available at all locations 
within the area. A channel is considered available for a mobile device 
if it meets the minimum required separation distances applicable to 16-
watt fixed devices from all protected services in the TV bands, 
including TV broadcast services (full power, Class A and low power), 
licensed wireless microphones, land mobile radio services, and 
registered TV and broadcast auxiliary service receive sites. In 
addition to the geo-fencing requirement, mobile devices are limited to 
operation in ``less congested'' areas, which are defined as those areas 
where at least half the channels within the band of operation are 
vacant. For example, for devices operating in the UHF TV band (channels 
14 through 36), a location is considered ``less congested'' if at least 
12 of the 23 UHF TV channels are vacant. These two requirements, 
limiting the new class of higher power mobile device to areas with more 
available spectrum, substantially reduces the likelihood of harmful 
interference to authorized services in the TV bands, and enables all 
unlicensed devices, including other white space devices and unlicensed 
wireless microphones, to have an opportunity to access spectrum in the 
TV bands. Limiting operation of mobile devices to geo-fenced areas also 
addresses the concern the Commission previously noted about 
difficulties mobile devices may have in identifying vacant spectrum 
because the database will determine in advance which channels are 
available over an entire geo-fenced area. Thus, mobile devices will 
have flexibility to move freely within the area without causing harmful 
interference. The requirement for mobile devices to comply with the 
same separation distances as fixed devices, which have the same power 
limits as mobile devices, will ensure that mobile devices have no 
greater interference potential than fixed devices, and that services in 
the TV bands are adequately protected, even at the larger separation 
distances required from higher power mobile devices. The potential for 
mobile devices to interfere with unlicensed wireless microphones could 
in some cases be lower than fixed devices because mobile devices will 
generally operate with an antenna height above ground of no more than 4 
meters due the necessity for vehicle clearance under bridges, power 
lines, trees, etc., so a mobile device signal could be attenuated by 
clutter such as buildings, trees and hills between a mobile device and 
a wireless microphone. In addition, because a mobile device may operate 
at the maximum 16 watts EIRP only if it uses a highly directional 
antenna with a gain of at least 12 dBi, which would require use of an 
electrical antenna beam steering system, mobile device operators may 
choose the less costly option of operating with an omnidirectional 
antenna which would have a lower gain, resulting in an EIRP of less 
than 16 watts.
    The Commission disagrees with Shure's contention that the technical 
limits for mobile devices (maximum in-band power, antenna gain, power 
spectral density, adjacent channel and out-of-band emissions) require 
additional study by the Commission. Shure's petition focuses on the 
EIRP limit for mobile devices, which is a function of the in-band 
conducted power and antenna gain. While it requests a lower EIRP limit 
for mobile devices which the Commission declines to adopt, it does not 
request specific changes to the in-band conducted power and antenna 
gain limits and does not raise specific concerns about the suitability 
of any other technical limits, e.g., power spectral density, adjacent 
channel and out-of-band emissions, nor does it suggest any 
modifications to them. The Commission therefore makes no changes to the 
technical limits for mobile devices adopted in the 2020 White Spaces 
Order and FNPRM.
    The Commission recognizes that the white space database does not 
have the capability to track the exact location of a mobile device, 
making it more difficult to identify an interfering mobile device than 
a registered fixed device. However, the database will contain 
information on the devices

[[Page 32685]]

operating within the boundaries of each geo-fenced area, and can 
determine the TV channel(s) that are available within that area. This 
information could be used to help identify potentially interfering 
devices if the need arises. Because mobile devices will operate 
primarily within rural areas where it is likely that there will be only 
a single or very limited number of white space devices operating within 
a geo-fenced area, the Commission expects that it should not be 
difficult to find out which device is causing interference. Also, the 
rules require the white space database administrator to cease providing 
lists of available channels to specific white space devices upon 
request by the Commission. The Commission could request that the 
database administrator stop providing lists of available channels to 
all mobile devices operating within a specific geo-fenced area where 
interference has occurred. As discussed in the Report and Order below, 
the Commission is requiring mobile white space devices to re-check the 
database at least once per hour, which will ensure a device ceases 
operation quickly if the database ceases providing lists of available 
channels to it.
    The Commission also recognizes Shure's concern about potential 
interference from high power mobile devices to unlicensed wireless 
microphones operating in ``less congested'' areas. The Commission does 
not believe it is appropriate to lower the mobile device power limit to 
a level (e.g., 100 milliwatts EIRP) intended to allow coexistence with 
co-channel wireless microphones at short distances since that would 
severely limit the utility of mobile devices. The Commissions disagrees 
that Shure's example of a white space device made by Redline 
Communications, which purportedly has a range of 50 kilometers, 
supports a lower power limit for mobile devices. The web page Shure 
referenced for Redline is no longer active, but the power levels Shure 
cites for these devices (100 milliwatts for the CPE and 1 watt for the 
base unit) are conducted power levels, whereas the white space device 
power limits for both fixed and mobile devices are specified in terms 
of EIRP, i.e., a maximum of one watt conducted power plus antenna gain. 
Thus, the Redline devices could operate with high gain antennas to 
achieve an EIRP much higher than 100 milliwatts or 1 watt. 
Additionally, fixed devices can be mounted with both the transmit and 
receive antennas high above ground to clear terrain and other obstacles 
to achieve long range, whereas mobile device antennas are limited to 
approximately four meters above ground. The Commission expects that a 
device operating with 100 milliwatts or 1 watt of conducted power would 
require both high gain transmit and receive antennas and high antenna 
heights to achieve a range of 50 kilometers.
    The Commission decided to limit operation of mobile devices to less 
congested areas to enable all unlicensed devices, including other white 
space devices and unlicensed wireless microphones, to have an 
opportunity to access spectrum in the TV bands. Because mobile devices 
operate only in ``less congested'' areas, there will, by definition, be 
multiple vacant TV channels available where unlicensed wireless 
microphones can operate, e.g., at least 12 in the UHF band. Thus, if 
mobile devices operate on one or even several TV channels in an area, 
there will still be multiple vacant channels available for use by 
unlicensed wireless microphones where mobile white space devices do not 
operate. As noted above, the white space database will contain 
information on geo-fenced areas used for mobile devices, and this 
information could be used by unlicensed wireless microphone users to 
determine whether any mobile devices could operate in their area. The 
Commission also points out that unlicensed wireless microphones operate 
on an equal basis with white space devices in the TV bands and that 
neither one has priority over the other. As with all unlicensed devices 
operating under the Commission's part 15 rules, unlicensed wireless 
microphones are subject to the condition that they may receive 
interference--including interference from other unlicensed devices. As 
such, while the presence of multiple vacant channels in ``less 
congested'' areas indicates that there will likely be spectrum 
available for both white space devices and unlicensed wireless 
microphones, the unlicensed wireless microphones operate under the same 
spectrum access provisions as all part 15 unlicensed devices where all 
such devices have equal access to the spectrum and must accept 
interference that may be caused by the operation of an authorized radio 
station, by another intentional or unintentional radiator, by 
industrial, scientific and medical (ISM) equipment, or by an incidental 
radiator.

Narrowband Devices

    Background. The Commission established a new class of ``narrowband 
white space device'' that can be used in IoT applications, which it 
defined as a type of fixed or personal/portable white space device 
operating in a bandwidth of no greater than 100 kilohertz. The 
Commission's rules require narrowband devices to comply with the same 
power spectral density (PSD), antenna gain and adjacent channel 
emission limits as four watt EIRP fixed devices, and limit them to a 
one percent duty cycle (36 seconds per hour). It also requires 
narrowband devices to comply with a channelization plan (55 narrowband 
carriers within the center 5.5 megahertz of a TV channel) which ensures 
that the maximum instantaneous power within a TV channel can never be 
greater than four watts EIRP. The Commission noted that because the 
transmission time is limited to no more than thirty-six seconds per 
hour, the interference potential of narrowband white space devices will 
actually be significantly less than that of four-watt EIRP fixed 
devices, since it is extremely unlikely that devices would transmit at 
maximum power on all 55 narrowband channels simultaneously, and even if 
they did, that would occur for no more than 36 seconds per hour. The 
Commission decided not to limit narrowband device operation to ``less 
congested'' areas as suggested by wireless microphone interests, noting 
that the white space database will ensure that narrowband devices do 
not operate on channels at locations where registered licensed wireless 
microphones operate. It also noted that unlicensed wireless microphones 
must already share spectrum with four watt EIRP white space devices, 
and that narrowband devices will generally have a significantly lower 
interference potential in the vast majority of cases.
    Shure believes that the Commission erred in authorizing narrowband 
IoT white space device operations on a nationwide basis. It argues that 
the Commission failed to justify authorizing a new nationwide class of 
IoT services within a rural access proceeding and that it did not 
consider the negative public interest impact nationwide narrowband 
white space devices will have on coequal unlicensed users scanning for 
available spectrum. Shure further argues that the Commission failed to 
consider mitigation measures that would ease the feasibility of 
coexistence with other spectrum users, such as disclosing the times, 
locations, and technical operating parameters to the white space 
database, or requiring IoT devices to incorporate a transmission signal 
that would enable wireless microphone users to better identify clear 
and occupied channels. Microsoft responds that the Commission 
appropriately authorized nationwide IoT mobile device operations and is 
not

[[Page 32686]]

required to restrict these devices to rural areas, and that the rules 
adopted in the 2020 White Spaces Order and FNPRM consider and mitigate 
the impact on coequal unlicensed users.
    Discussion. The Commission affirms its decision to allow narrowband 
devices to operate in all areas and decline to adopt additional 
requirements for narrowband devices suggested by Shure that are 
intended to facilitate their detection or that would require additional 
information to be submitted to the white space database. As an initial 
matter, the Commission previously noted that narrowband devices have no 
greater interference potential than four watt EIRP devices, and that as 
a practical matter their interference potential will be significantly 
lower because a device is unlikely to transmit on all possible 55 
narrowband channels simultaneously, and if it did the transmissions are 
limited to a one percent maximum duty cycle. Unlicensed wireless 
microphones are already required to share spectrum with white space 
devices operating at up to four watts EIRP (outside of ``less 
congested'' areas) on an equal basis, and the 2020 White Spaces Order 
and FNPRM made no changes to this sharing regime. Unlicensed wireless 
microphones must accept interference from white space devices, and 
conversely, white space devices must accept interference from both 
licensed and unlicensed wireless microphones. However, as discussed 
below, the Commission expects that there will generally be spectrum 
available for unlicensed wireless microphones in areas where narrowband 
white space devices are used, and there are steps that wireless 
microphone users can take under the current rules to help identify 
where narrowband devices may be in use.
    The Commission disagrees with Shure's contention that the 
Commission should not have permitted nationwide deployment of 
narrowband devices in this proceeding. The fact that this proceeding 
focuses primarily on rural areas does not preclude the Commission from 
adopting rules that benefit persons in all areas. While Microsoft noted 
that several major narrowband IoT use cases and applications are 
predominately in rural areas, it did not suggest, and the Commission 
did not propose or even seek comment on whether to limit narrowband 
white space device operation to only less congested areas. Thus, Shure 
had notice that the Commission was considering allowing narrowband 
devices to operate in all areas. In adopting rules to permit the new 
class of narrowband devices, the Commission already considered and 
rejected requests by wireless microphone interests to limit narrowband 
devices to ``less congested'' areas, noting that these devices have no 
greater interference potential than four watt EIRP white space devices 
that were already permitted to operate in any area.
    The Commission expects that there will generally be spectrum 
available for unlicensed wireless microphones at locations where 
narrowband devices are used outside of ``less congested'' areas for 
several reasons. First, narrowband white space devices must comply with 
the same separation distances from TV contours and other protected 
services as four watt EIRP fixed devices. These rules require that a 
four watt EIRP device operate outside the protected contours of both 
co-channel and adjacent channel TV stations, which means that a 
narrowband device can operate only at a location where there are at 
least three contiguous vacant TV channels, with the white space device 
operating in the center 6 megahertz channel and both adjacent channels 
vacant. Thus, at a location where a narrowband white space device is 
being used outside of a ``less congested'' area, there will be a 
minimum of 12 megahertz of spectrum available for wireless microphones 
that cannot be used by a narrowband white space device. Further, a 
narrowband white space device would not preclude operation of 
unlicensed wireless microphones over large distances. Licensed wireless 
microphones are protected to a one kilometer distance from co-channel 
white space devices operating with up to ten watts EIRP. Since a 
narrowband device will generally have a much lower interference 
potential than a four watt EIRP device, and therefore even less than a 
ten watt EIRP device, the distance at which it could potentially 
interfere with wireless microphones will be significantly less than one 
kilometer.
    Because narrowband devices have a lower interference potential than 
other fixed white space devices with which unlicensed wireless 
microphones must already share spectrum, and because there will 
continue to be spectrum available for unlicensed wireless microphones 
at locations where narrowband devices operate, the Commission declines 
to adopt additional requirements for narrowband devices as suggested by 
Shure. The Commission recognizes Shure's concern about the difficulty 
in scanning spectrum for the presence of white space devices that 
transmit for short periods of time, but there is no clear solution to 
this concern. The white space rules have never specified any 
requirements on the time interval over which devices may transmit, and 
establishing a minimum transmission time to facilitate detection by 
wireless microphone users could require devices to transmit 
unnecessarily, potentially affecting battery life in battery-powered 
devices or impacting the use of spectrum by other white space devices 
and unlicensed wireless microphones. Similarly, requiring white space 
devices to transmit a beacon signal could also affect the battery life 
of battery powered devices, and depending on the nature of the signal 
transmitted could also impact spectrum use by other white space devices 
or wireless microphones.
    The Commission will not require operators of narrowband devices to 
register additional information in the white space database. The 
Commission previously rejected requests to require white space devices 
to provide additional information to the white space database, 
including their specific operating channel, in the interest of keeping 
the rules simple and avoiding the imposition of unnecessary 
requirements that could hamper innovation. These same considerations 
lead us to decline to require operators of narrowband devices to 
register additional information in the white space database. However, 
unlicensed wireless microphone operators can use the white space 
database to identify locations where fixed devices, including 
narrowband devices, are in use. This information is publicly available 
and can allow unlicensed wireless microphone users to determine whether 
any fixed devices are in their vicinity, e.g., less than 1 kilometer. 
In addition, the white space database can provide a list of available 
channels at an unlicensed wireless microphone's location, which can 
indicate where narrowband devices could potentially operate (i.e., 
groups of three vacant channels) and thus, where they could not.

Report and Order

    In this Report and Order, the Commission requires mobile white 
space devices, which operate on TV channels 2 through 35, to comply 
with the same hourly database re-check interval that the Commission 
recently required for most fixed and Mode II personal/portable white 
space devices. The Commission continues to require narrowband white 
space devices, which also operate on TV channels 2 through 35, to re-
check the white space database once per day rather than once per hour 
due to their lower potential for causing

[[Page 32687]]

harmful interference to protected services in the TV bands, including 
licensed wireless microphones.

Mobile Devices

    Background. Because of the technical similarities between fixed and 
mobile devices, the Commission proposed in the 2022 White Spaces Order 
and FNPRM to require mobile devices to comply with the same hourly 
database re-check interval as fixed devices (excluding narrowband) that 
operate in the TV bands to more effectively protect licensed wireless 
microphones. The Commission also proposed to require mobile devices to 
comply with the other database re-check requirements for fixed devices 
(excluding narrowband) in the TV bands, specifically, the requirement 
to cease operation no more than 120 minutes after the last successful 
database contact in the event a device is no longer able to 
successfully contact the database, and the requirement to adjust their 
use of TV channels in accordance with wireless microphone scheduling 
information provided by the white space database for the two hour 
period beginning when the device last contacted the database. The 
Commission further proposed that any modified rules would become 
effective six months after publication in the Federal Register. NAB, 
Shure, and Sennheiser support an hourly re-check interval for mobile 
white space devices, and Shure also suggests decreasing the amount of 
time that a mobile device can continue to operate from 60 minutes to 10 
minutes in the event it is unable to make its hourly contact with the 
database. Microsoft states that it has no objection to an hourly 
database re-check requirement for mobile devices.
    The Commission will require mobile devices to re-check the white 
space databases at least once per hour; the same re-check interval 
required for fixed devices (excluding narrowband). The Commission 
believes this is an appropriate re-check interval due to the technical 
similarities between mobile and fixed devices, e.g., maximum 
transmitter power, power spectral density, antenna gain, requirement to 
connect to a database to obtain a list of available channels, and 
protection criteria for other services in the TV bands. The Commission 
will also require mobile devices to comply with the other database re-
check requirements applicable to fixed devices, specifically, the 
requirement to cease operation no later than 120 minutes after the last 
successful database contact and the requirement to adjust their use of 
TV channels in accordance with wireless microphone scheduling 
information provided by the white space database for the two hour 
period beginning when the device last contacted the database. The 
Commission is implementing this change by removing the mobile device 
database re-check requirements from Sec.  15.711(k)(9) and replacing 
them with a cross-reference to Sec.  15.711(h), which will specify the 
database re-check requirements applicable to fixed, mobile, and Mode II 
personal/portable devices.
    The Commission disagrees with Shure that it is necessary to shorten 
the time period that a mobile device can continue to operate if it is 
unable to make its hourly contact with the database. There is 12 
megahertz of spectrum available for wireless microphones nationwide in 
the 600 MHz duplex gap and guard band where they can be immediately 
operated without advance registration. Further, as discussed above, 
since mobile white space devices may operate only in ``less congested'' 
areas where at least half the TV channels in the band of operation are 
vacant, there will by definition be at least 12 unused TV channels out 
of the 23 in the UHF TV band, so there will be multiple TV channels 
available for wireless microphones in addition to the 12 megahertz of 
spectrum available nationwide in the 600 MHz duplex gap and guard band. 
Therefore, a potentially slightly longer time interval for operation 
after a failed database re-check (60 minutes as opposed to Shure's 
suggestion of 10 minutes) should not be problematic for licensed 
wireless microphone operators as it will not substantially increase the 
potential of harmful interference because other spectrum is available 
where licensed wireless microphones can operate until a TV channel 
occupied by a white space device is cleared. In the case of large 
events held in ``less congested'' areas where a licensed wireless 
microphone operator registers TV channels in advance, this slightly 
longer time interval is even less likely to be problematic because 
operators will have the information necessary to register wireless 
microphones (e.g., location, times, dates, channels required) well in 
advance of an event, so a small amount of extra time needed to release 
a channel after registration is insignificant. Finally, the Commission 
notes that the extra time that a device is permitted to operate beyond 
a failed database re-check is expected to be an infrequent occurrence 
limited to those instances when a device is unable to contact the 
database; it is not a device's normal mode of operation.
    While the Commission proposed a 6-month transition period for 
parties to comply with a changed database re-check interval for mobile 
devices, upon further consideration it does not believe that a 
transition period is necessary since the white space database is not 
yet capable of supporting mobile devices and there are as of yet no 
certified mobile white space devices. No party indicated a need for a 
transition period. Accordingly, the Commission makes the rules changing 
the database re-check interval for mobile white space devices effective 
30 days after publication in the Federal Register.

Narrowband Devices

    Background. The rules currently require narrowband white space 
devices to re-check the database at least once daily and permit them to 
operate until 11:59 p.m. the following day if they are unable to 
contact the database on a given day. Microsoft previously argued that 
requiring narrowband fixed white space devices used for IoT 
applications to comply with an hourly database re-check would 
negatively impact battery life, limit potential form factors, and 
increase the cost of those devices. It requests that the Commission 
maintain its existing requirement that narrowband fixed devices check 
the white space database once per day to ensure capturing wireless 
microphone reservations rather than hourly.
    The Commission sought comment in the 2022 White Spaces Order and 
FNPRM on the database re-check interval that should be required for 
narrowband white space devices. It sought comment on whether to retain 
the current requirement for a once daily database check and allow 
continued operation until 11:59 p.m. the following day if a device is 
temporarily unable to contact the database, or whether narrowband 
devices should comply with the same hourly re-check interval as other 
fixed and Mode II personal/portable devices. The Commission further 
sought comment on the types of devices to which a different re-check 
interval should apply, e.g., both fixed and Mode II personal/portable 
narrowband devices, battery-powered devices only or to AC powered 
devices as well. It also sought comment on the impact of the database 
re-check interval on the protection of licensed wireless microphones.
    Microsoft, CTA, and OTI/PK support a once daily database re-check 
requirement for narrowband devices, generally arguing that a more 
frequent re-check interval (e.g., once per hour) would be overly 
burdensome, have a negative impact on device design,

[[Page 32688]]

including battery life, and is not necessary to prevent harmful 
interference to licensed wireless microphones. Microsoft and OTI/PK 
argue that because narrowband devices can only be used in areas where 
there are at least three contiguous vacant channels, operation will be 
precluded in urban and most suburban locations, and this three-channel 
requirement means channels adjacent to one used by a narrowband device 
will remain available for wireless microphone use. They also argue that 
the low duty cycle of narrowband devices (36 seconds per hour) further 
reduces the likelihood of harmful interference to wireless microphones. 
However, NAB, Shure and Sennheiser support an hourly re-check interval 
for narrowband devices. NAB does not believe that an hourly re-check is 
burdensome, while Shure and Sennheiser express concern about the 
potential for interference to licensed wireless microphones from a 
longer re-check interval.
    The Commission declines to require narrowband white space devices 
to re-check the database on an hourly basis instead of once daily. 
However, the Commission believes that modifying the rule to eliminate 
the grace period that permits narrowband white space devices to operate 
until 11:59 p.m. the following day if they are unable to successfully 
contact a database will provide a better balance among competing 
interests for spectrum access in this band. Instead, the Commission 
will require narrowband white space devices to successfully contact the 
database at least once within each 24-hour period it will be operating. 
Microsoft urges the Commission to retain the current rules specifying a 
once per day recheck interval along with a grace period permitting 
continued operation until 11:59 p.m. the following day absent a 
successful contact with the database. OTI/PK also urges the Commission 
to retain the current recheck rules for narrowband white space devices. 
In contrast, Shure notes that operation under the existing rules could 
result in a white space device operating for a nearly 48-hour period 
where there is no communication with the database and in addition to 
modifying the recheck time to once per hour, recommends changing the 
grace period to 10 minutes. By modifying the rules to eliminate the 
grace period that could extend narrowband white space device usage up 
to almost an entire day without contacting the database, the Commission 
believes it can provide more certainty to wireless microphone operators 
regarding their ability to access spectrum to cover late breaking news 
events without detrimental impact to narrowband white space device 
operation.
    First, with respect to narrowband white space devices, the rules 
require frequency selection based on accessing a white space database. 
Inherent in that requirement is the expectation that the device has 
established a good, stable, long lasting connection with the database. 
In addition, the Commission is not aware that the database has 
experienced any significant downtime to date. Thus, the Commission does 
not foresee many, if any, situations where a narrowband white space 
device will be impacted by a lack of connectivity to a white space 
database. Even if a device was unable to contact a database, the 
Commission notes that it still may transmit for 24-hours since its last 
successful connection which should provide ample time to transmit any 
data the device has collected. Moreover, the Commission expects that 
most IoT information that will be transmitted on these data links is 
not time critical information and can tolerate some delay in the event 
that the database cannot be contacted. And in such situations, the 
Commission does not expect any outages or loss of connection to a 
database to persist over a significant amount of time. Finally, the 
Commission notes that as an unlicensed device, narrowband white space 
devices already operate under a best effort framework with no guarantee 
regarding quality of service. For these reasons, the Commission does 
not believe that eliminating the grace period will negatively impact 
narrowband white space device operation nor does the Commission believe 
it will alter users' expectations.
    The Commission does believe that changing the recheck time to one 
hour from the current once per day requirement will have significant 
impact on narrowband white space devices that could render them 
impractical and deprive their utility to users. As noted by Microsoft, 
requiring narrowband devices to re-check the database once daily rather 
than once hourly will provide longer battery life and a smaller form 
factor for battery-powered devices. Although the transmission time and 
amount of data sent by a narrowband device when re-checking the 
database may be small as suggested by NAB, requiring hourly checks will 
require 24 times the battery power of once daily checks, which could 
have a negative impact on battery life of very small battery-powered 
devices. While the Commission has no specific data regarding the impact 
on battery size or cost, the Commission notes that many IoT devices 
(e.g., optical sensors for streetlights or internal sensors embedded in 
machinery) are designed to be very small due to environmental 
constraints (e.g., size of the structure or machine they are attached 
to) and correspondingly necessitate small batteries that must last for 
long periods of time as the IoT device's location may make replacement 
difficult and costly. Thus, size and form factor are essential 
characteristics that may drive device design and in turn limit maximum 
battery size. Given that a battery's capacity is at maximum levels at 
installation, decreases over time with use, and that more use 
intuitively causes the battery to drain faster and necessitate 
replacement sooner, the Commission agrees with Microsoft that the 
Commission's rules should accommodate such applications. The 
alternative would be either larger devices that cannot be installed 
where needed or devices that have inadequate battery life and must be 
serviced more frequently which could be costly and may be impractical 
for many locations.
    The Commission believes that by making this change, it will provide 
a more predictable spectrum environment for wireless microphones and 
continue to maintain a low potential for harmful interference. As an 
initial matter, the Commission notes that licensed wireless microphones 
have access to a registration system in which users can preregister 
locations to ensure that white space devices do not operate on certain 
television channels during specific times. In contrast, unlicensed 
wireless microphones operate on an equal basis with white space devices 
and neither device type has any spectral rights over the other. The 
Commission also notes that wireless microphones are generally used for 
two types of events--preplanned events known well in advance (such as 
sporting events, concerts, shows and conventions) and late breaking 
events (such as on-site news reporting). For the former case, the 
Commission expects licensed wireless microphone users to use the tools 
available to them and register their usage well in advance of these 
events to ensure that the television channels they intend to use are 
clear when they need them. With respect to the latter case, wireless 
microphone users have always operated in an environment where many 
microphone users converge on an area and on-the-scene frequency 
coordination and management must be accomplished in real time; users 
often

[[Page 32689]]

have flexibility to choose among several television channels on which 
to tune their microphones. In such situations, the Commission's rules 
ensure that ample spectrum should be available even if a narrowband 
white space device is operating nearby.
    Because narrowband white space devices must comply with the same 
separation distances from co-channel and adjacent channel TV station 
contours as four-watt fixed white space devices, they may only operate 
when there are at least three contiguous television channels available 
and may not operate on the lowest or highest channel. Thus, for late 
breaking events where licensed microphone users may not have ample time 
to register their usage, there will still be spectrum available. 
Wireless microphones could operate on the available television channels 
adjacent to the channel being used by the narrowband white space 
device, or on any other vacant TV channels where narrowband devices 
cannot operate, i.e., channels on which one or both of the adjacent 
channels are occupied. In addition, as noted above other spectrum will 
also be available for wireless microphone usage, including 12 megahertz 
in the 600 MHz guard band and duplex gap. In all cases, fixed white 
space devices, including narrowband devices, must be registered in the 
white space database and those registrations are publicly available, 
thus allowing prospective wireless microphone users to determine the 
precise locations where fixed narrowband devices are in use. The white 
space database can also show which channels cannot be used by 
narrowband devices, i.e., those where four-watt fixed devices cannot 
operate due to occupied adjacent channels and thus, are available for 
microphone use.
    For late breaking events where licensed microphone users are unable 
to preregister their usage, it is not apparent that changing the 
database recheck requirement from once per day to once per hour would 
result in any difference regarding the channels on which narrowband 
white space devices operate as in many cases, microphone users may not 
be able to register their usage at all as they are focused on getting 
to the scene, not on registering their usage. However, even in 
instances where a wireless microphone may operate in the vicinity of a 
narrowband white space device, the potential for harmful interference 
is low. As discussed above, the interference potential of a narrowband 
device is significantly less than that of a four watt EIRP device due 
to the fact that it operates intermittently with narrowband carriers 
with a duty cycle of less than one percent. These rules working in 
tandem will provide a spectrum environment where wireless microphones 
users, that for whatever reason cannot operate on one of the available 
channels or chooses not to, will be able to operate in close proximity 
to a narrowband white space device without experiencing any detrimental 
effect. In this regard, the Commission's rules require fixed white 
space devices operating at up to 40 dBm (10 watts) EIRP to maintain a 1 
kilometer buffer from registered wireless microphone locations. 
Narrowband white space devices operate with maximum 18.6 dBm/100 kHz 
EIRP. In the unlikely situation that all narrowband channels are in use 
at any given time, the total equivalent energy is no worse than a 36 
dBm (4 watts) white space device and the duration of any such situation 
will be extremely short due to the one percent duty cycle limit. Also, 
because the rule requiring geographic separation is based on devices 
operating at maximum antenna height (250 meters generally and 500 
meters in less congested areas) and devices operating at lower antenna 
heights have shorter line-of-sight distance and experience more clutter 
losses, coupled with the extremely low potential of all narrowband 
white space devices operating at the same time, the Commission expects 
that wireless microphones will be able to operate without experiencing 
harmful interference at much closer distances. Due to this low 
interference potential, the Commission does not see a need to require a 
more frequent database re-check interval than once daily. Sennheiser 
does not clearly state why it believes narrowband devices have a higher 
potential for causing interference than other white space devices. 
Also, the primary use case of narrowband devices is in rural and other 
less populated areas where there is less likelihood that one will be 
used in close proximity to a licensed wireless microphone. The fact 
that narrowband devices can operate only at locations where there are 
three contiguous channels will help ensure that they are used only in 
areas where there are fewer TV stations in operation and thus more 
spectrum available for wireless microphones.
    In sum, the Commission finds that a once daily database check will 
facilitate a wide variety of IoT devices, will not affect the potential 
for narrowband white space devices to cause harmful interference and 
will continue to allow widespread wireless microphone use. The 
Commission is therefore maintaining the current daily re-check interval 
for all types of narrowband devices (e.g., AC and battery-powered). No 
party indicated a need for different requirements for different types 
of devices. The Commission finds that an hourly re-check interval is 
not necessary for narrowband devices due to the very low likelihood of 
them to cause harmful interference to licensed wireless microphones and 
because other protected services in the TV bands such as broadcast TV 
change operating parameters on a less frequent basis. In the rare event 
of a conflict between narrowband white space devices and licensed 
wireless microphones used in applications that require immediate 
spectrum access, there will typically be other spectrum available where 
the microphones can operate until a newly registered TV channel is 
cleared of white space devices. In cases where a channel is reserved 
more than a day in advance for large planned events, a daily re-check 
interval will be sufficient to ensure that licensed wireless 
microphones have access to that TV band spectrum. However, to better 
accommodate licensed microphone usage when such usage is registered a 
day in advance, the Commission is eliminating the grace period that 
would otherwise permit narrowband white space devices to operate until 
11:59 p.m. the following day if it does not successfully contact a 
database. The Commission finds that due to the expected use cases for 
narrowband white space devices, such a change will not adversely impact 
their ability to deliver their intended services. Accordingly, the 
Commission is modifying the rules to require narrowband white space 
devices to successfully contact a database at least once every 24-hours 
or cease operating until such time at it does communicate with a 
database and obtains an up-to-date available channel list.

Memorandum Opinion and Order

    In this Memorandum Opinion and Order, the Commission declines to 
allow the white space database to use terrain-based models, such as the 
Longley-Rice Irregular Terrain Model (Longley-Rice) to determine which 
TV channels are available for white space device operation at a 
particular location. The Commission instead requires that white space 
databases continue to use only the current model for determining TV 
channel availability.

Background

    Under current rules, white space devices must generally operate 
outside the defined protected contours of co-

[[Page 32690]]

channel and adjacent channel TV stations. The rules provide a table of 
separation distances beyond the protected contour that white space 
devices must meet that is based on the white space device's EIRP and 
HAAT. These distances are based on a desired-to-undesired (D/U) signal 
ratio of 23 dB at the edge of the protected contour for co-channel 
operation, and -33 dB at the edge of the protected contour for adjacent 
channel operation, with a 14 dB allowance for TV receive antenna front-
to-back ratio.
    The Longley-Rice propagation model is used to make predictions of 
radio signal field strength using the median attenuation calculated as 
a function of distance and the signal variability in time and space. 
The model can be run in point-to-point mode where it examines a 
specific radio signal path between a transmitter and a receiver, or in 
area mode in which it predicts field strength at many geographic points 
within a specified area. Each operational mode uses a terrain elevation 
profile in making predictions; in the point-to-point mode path-specific 
parameters can be determined from the terrain profile between the 
transmitter and receiver, and in area mode the elevation profile 
between the transmitter and each specific reception point is examined. 
The model may require a large number of reception points to be 
individually examined. It also requires a large set of input parameters 
encompassing system parameters (e.g., frequency, polarization, antenna 
heights), environmental parameters (e.g., terrain irregularity, 
electrical ground constants, surface refractivity, climate 
information), deployment parameters, and statistical parameters (e.g., 
reliability and confidence level). Based on the predicted radio signal 
attenuation and using additional factors such as transmitter power and 
antenna directivity, the D/U signal ratio can be estimated and compared 
against the 23 dB co-channel and -33 dB adjacent channel standards used 
as the basis when developing the white space device rules to predict 
whether harmful interference is likely to occur to television 
reception.
    In the 2020 White Spaces Order and FNPRM, the Commission sought 
comment on whether the use a terrain-based model such as Longley-Rice 
for determining white space channel availability would better serve the 
white space device community as well as television broadcasters and 
other protected entities in the television bands. In particular, it 
sought comment on how the Longley-Rice propagation model could be used 
to determine available white space channels and whether it could be 
used to protect other services in the TV bands (e.g., licensed wireless 
microphones, translator receive sites, land mobile stations) in 
addition to TV. The Commission also sought comment on whether the use 
of a terrain-based model should be mandatory or an optional alternative 
to the current protection model and on the technical parameters that 
would be necessary to use such a model for identifying available 
spectrum while protecting incumbents from harmful interference. In 
addition, the Commission sought comment on various white space database 
and device implementation issues that would need to be addressed if the 
Commission were to allow or require use of a terrain-based model.
    Unlicensed proponents support permitting the use of terrain-based 
models by white space database administrators as an optional 
alternative to the current model. These parties generally argue that 
the current protection model can be overly conservative and that 
permitting terrain-based models would make more spectrum available for 
white space devices. They also state that the increased computer 
resources to make the calculations are not an issue with current 
technology. Microsoft suggests limiting use of terrain-based models to 
locations outside of a TV station's protected contour, while WISPA and 
DSA suggest also allowing use within an adjacent channel station's 
protected contour. RED Technologies, the only currently active white 
space database administrator, suggests using a terrain-based model only 
for the purpose of calculating TV station protected contours and 
leaving the current separation distances beyond the contour unchanged.
    TV broadcast interests oppose allowing the use of terrain-based 
models by the white space database due to concerns about interference 
to TV reception. Commenters argue that a terrain-based model does not 
work well for protecting individual TV receivers. Commenters also argue 
that now is not a good time to change the white space protection 
requirements due to TV broadcasters transitioning to ATSC 3.0 and 
recent rule changes regarding distributed transmission systems and 
white space devices.
    Discussion. The Commission declines at this time to permit use of 
terrain-based models in place of, or as an alternative to, the current 
method of protecting TV and other services using minimum distance 
separations from defined protected service contours or defined 
geographic points. The Commission finds that it lacks a sufficient 
record to adopt rules on issues such as whether a terrain-based model 
is an appropriate method for protecting TV services from white space 
devices, and if so, the exact technical parameters that would need to 
be specified to implement the model, whether a terrain-based model 
should be used only outside of a TV station's protected contour or 
whether it could also be used within a protected contour, whether it 
should be used only for protecting TV services or for protecting other 
services as well (e.g., land mobile stations, licensed wireless 
microphones).
    The record does not show whether allowing use of a more complex 
terrain-based model for determining channel availability would yield 
any significant increase in spectrum for white space devices. While 
unlicensed interests state that this could be the case in some 
instances, no party provided analysis to substantiate this claim. TV 
spectrum available for white space devices became more limited after 
the broadcast incentive auction due to the reduction in size of the UHF 
TV band and the re-packing of UHF TV stations into the remaining 
portion of the band (channels 14 through 36). The need to protect 
adjacent channel TV stations means that a fixed white space device may 
operate at higher power levels (up to four watts EIRP generally, 16 
watts EIRP in ``less congested'' areas) only at locations where there 
are at least three contiguous vacant channels, with the white space 
device operating on the center channel and both adjacent channels 
vacant. After the incentive auction, there are fewer groups of three 
vacant TV channels in most areas, particularly in urban and suburban 
areas, as well as fewer single or pairs of vacant TV channels where 
white space devices could operate at lower power levels. There is no 
evidence in the record that allowing the use of terrain-based models to 
determine white space channel availability could address these spectrum 
limitations.
    The record does not adequately address broadcaster concerns that 
terrain-based models are not an appropriate method of determining white 
space channel availability and that their use could result in harmful 
interference to TV. While the Commission does not conclude that 
terrain-based models are necessarily inappropriate for determining 
white space channel availability, it notes that there are differences 
between how these models are currently used as compared to their 
potential use in determining

[[Page 32691]]

white space channel availability. For example, the Longley-Rice 
methodology is used by the Commission for evaluating TV service 
coverage and interference within a TV station's protected contour. The 
area within a protected contour is divided into a grid with 1 kilometer 
by 1 kilometer cells and the station's coverage and any interference 
received from other TV stations are calculated at a single point within 
each grid cell. While the Commission has successfully used this method 
for determining TV station coverage, it is not clear from the record 
that it is sufficiently precise to be used in determining white space 
channel availability since TV receivers are spread over a wide area 
where their locations are not known, which increases the possibility of 
interference if a terrain-based model cannot accurately predict TV 
signal levels at all potentially affected receiver locations. There are 
also differences in the interference environment for TV reception 
compared to other applications where the Commission allows calculation 
of potential interference using terrain-based models, such as for 
unlicensed devices in the 6 GHz bands and devices in the Citizens 
Broadband Radio Service. The record lacks sufficient information on 
these differences and how broadcasters' interference concerns could be 
addressed.
    The Commission also believes that implementing terrain-based models 
could create burdens on the white space database administrator, the 
Commission and other parties. The white space database administrator 
would have to develop and test new, more complex computer code to 
determine channel availability and also to upgrade its computer system. 
Even after updated code is developed, the Commission or another party, 
e.g., a test laboratory, would have test and validate that the code 
provides accurate channel availability information. Because there is 
currently only one active white space database administrator and fewer 
than 300 registered fixed devices, the implementation costs, including 
any third party testing, would have to be spread over a relatively 
small user base or borne by the white space database administrator. In 
comparison, there are five spectrum access system (SAS) administrators 
in the Citizens Broadband Radio Service with hundreds of thousands of 
devices in use, and the Commission recently conditionally approved 
thirteen 6 GHz automated frequency coordination system (AFC) operators 
and the Commission expects that 6 GHz device deployment will 
substantially exceed white space device deployment due to the greater 
amount of spectrum available. The Commission notes that the white space 
database administrator suggests only a very limited implementation of a 
terrain-based model, specifically, to calculate TV station protected 
contours while making no other changes to the current protection model.
    In sum, while the Commission believes the use of a terrain-based 
propagation model for calculating whether the potential for causing 
harmful interference exists is appropriate in some instances, it is not 
clear that it would be beneficial to allow use of a terrain-based model 
in determining white space channel availability. As noted above, there 
are unresolved interference concerns as well as implementation costs 
that may outweigh any potential benefits of the changes. Further, there 
is already a simple, well-defined model for determining white space 
channel availability which no party argues is inadequate for protecting 
services in the TV bands. For these reasons, the Commission declines at 
this time to permit the use of terrain-based models in determining 
white space channel availability.
    Rule correction. The Commission is making a ministerial correction 
to Sec.  15.713(e)(6) of the rules, which contains a requirement that 
white space databases not provide a list of available channels to fixed 
white space devices that exceed specific antenna height limits.
    Prior to 2019, fixed white space devices were generally limited to 
a maximum antenna height above ground of 30 meters and a maximum HAAT 
of 250 meters. In the 2019 White Spaces Order on Reconsideration, the 
Commission raised the antenna height above ground limit to 100 meters 
in ``less congested'' areas while retaining the 30 meter height above 
ground and 250 meter HAAT limits in all other areas. In the 2020 White 
Spaces Order and FNPRM, the Commission increased the HAAT limit to 500 
meters in ``less congested'' areas, retained the 250 meter HAAT limit 
in all other areas, and removed the antenna height above ground limit 
for most fixed white space devices. The Commission revised Sec. Sec.  
15.709(g)(1) and 15.713(e)(6) to reflect these decisions, but in doing 
so it inadvertently continued to include an outdated reference to the 
former 30 meter antenna height above ground limit in Sec.  
15.713(e)(6). Accordingly, the Commission modifies Sec.  15.713(e)(6) 
to remove this reference and conform the text of the rule to the 
Commission's decision.

Ordering Clauses

    Accordingly, it is ordered that, pursuant to the authority 
contained in sections 4(i), 302, 303(b), (c), (e), (f), (r), and 307 of 
the Communications Act of 1934, as amended, and sections 6403 and 6407 
of the Middle Class Tax Relief and Job Creation Act of 2012, Public Law 
112-96, 126 Stat. 156, 47 U.S.C. 154(i), 302, 303(b), (c), (e), (f), 
(r), 307, 1452, 1454, this Order on Reconsideration, Report and Order, 
and Memorandum Opinion and Order is hereby adopted.
    It is further ordered that the petition for reconsideration filed 
by Shure Incorporated on February 11, 2021 in ET Docket No. 20-36 is 
dismissed in part on procedural grounds and, as an independent and 
alternative basis, denied.
    It is further ordered that the amendments of the Commission's rules 
as set forth in Appendix A are adopted, effective thirty days from the 
date of publication in the Federal Register.
    It is further ordered that the Commission's Consumer and 
Governmental Affairs Bureau, Reference Information Center, shall send a 
copy of this Order on Reconsideration, Report and Order, and Memorandum 
Opinion and Order, including the Final Regulatory Flexibility Analysis, 
to the Chief Counsel for Advocacy of the Small Business Administration.
    It is further ordered that the Commission's Consumer and 
Governmental Affairs Bureau, Reference Information Center, shall send a 
copy of this Order on Reconsideration, Report and Order, and Memorandum 
Opinion and Order, including the Final Regulatory Flexibility Analysis, 
to Congress and the Government Accountability Office pursuant to the 
Congressional Review Act, see 5 U.S.C. 801(a)(1)(A).

List of Subjects in 47 CFR Part 15

    Communications equipment.

Federal Communications Commission.
Marlene Dortch,
Secretary.

Final Rules

    For the reasons set forth 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:


[[Page 32692]]


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


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2. Amend Sec.  15.711 by revising paragraph (h)(1) introductory text 
and paragraph (h)(2) introductory text, adding paragraph (h)(3) and 
revising paragraph (k)(9) to read as follows:


Sec.  15.711  Interference avoidance methods.

* * * * *
    (h) * * *
    (1) Mobile devices and fixed and Mode II personal/portable devices, 
excluding narrowband devices, operating in the television bands.
* * * * *
    (2) Fixed and Mode II personal/portable devices operating outside 
of the television bands.
* * * * *
    (3) Narrowband devices operating in the television bands.
    (i) A device that has been in a powered-on state shall access the 
database at least once each 24-hour period to verify that the operating 
channel(s) and associated maximum power levels continue to be available 
at its location.
    (ii) A device must cease operating if it fails to successfully 
access the database once 24 hours from its last successful contact 
elapses until it re-establishes contact with the white space database 
and re-verifies its list of available channels and corresponding power 
levels.
* * * * *
    (k) * * *
    (9) A mobile white space device shall access the database at least 
as frequently as specified in paragraph (h) of this section to verify 
that the operating channel(s) and corresponding power levels continue 
to remain available.
* * * * *

0
3. Amend Sec.  15.713 by revising paragraph (e)(6) to read as follows:


Sec.  15.713  White space database.

* * * * *
    (e) * * *
    (6) A fixed device with an antenna height above average terrain 
(HAAT) that exceeds 250 meters generally, or 500 meters in less 
congested areas, shall not be provided a list of available channels. 
The HAAT is to be calculated using computational software employing the 
methodology in Sec.  73.684(d) of this chapter.
* * * * *
[FR Doc. 2023-10166 Filed 5-19-23; 8:45 am]
BILLING CODE 6712-01-P