[Federal Register Volume 78, Number 69 (Wednesday, April 10, 2013)]
[Proposed Rules]
[Pages 21320-21337]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-08033]


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FEDERAL COMMUNICATIONS COMMISSION

47 CFR Part 15

[ET Docket No. 13-49; FCC 13-22]


Unlicensed National Information Infrastructure (U-NII) Devices in 
the 5 GHz Band

AGENCY: Federal Communications Commission.

ACTION: Proposed rule.

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SUMMARY: This document proposes to amend the Commission's rules 
governing the operation of Unlicensed National Information 
Infrastructure (U-NII) devices in the 5 GHz band. The Commission has 
gained much experience with U-NII devices since it first made spectrum 
available in the 5 GHz band for U-NII in 1997. The Commission believes 
that the time is now right to revisit the rules. The initiation of this 
proceeding satisfies the requirements of the ``Middle Class Tax Relief 
and Job Creation Act of 2012'' which requires the Commission to begin a 
proceeding to modify the rules to

[[Page 21321]]

allow unlicensed U-NII devices to operate in the 5350-5470 MHz band. 
The Commission believes that an increase in capacity gained from 195 
megahertz of additional spectrum, combined with the ease of deployment 
and operational flexibility provided by its U-NII rules would continue 
to foster the development of new and innovative unlicensed devices, and 
increase wireless broadband access and investment.

DATES: Comments must be filed on or before May 28, 2013, and reply 
comments must be filed on or before June 24, 2013.

FOR FURTHER INFORMATION CONTACT: Aole Wilkins, Office of Engineering 
and Technology, (202) 418-2406, email: Aole.Wilkins@fcc.gov, TTY (202) 
418-2989.

ADDRESSES: You may submit comments, identified by ET Docket No. 13-49, 
by any of the following methods:
    [squf] Federal Communications Commission's Web site: http://fjallfoss.fcc.gov/ecfs2/. Follow the instructions for submitting 
comments.
    [squf] Mail: Aole Wilkins, Office of Engineering and Technology, 
Room 7-A431, Federal Communications Commission, 445 12th SW., 
Washington, DC 20554.
    [squf] People with Disabilities: Contact the FCC to request 
reasonable accommodations (accessible format documents, sign language 
interpreters, CART, etc.) by email: FCC504@fcc.gov or phone: 202-418-
0530 or TTY: 202-418-0432.

For detailed instructions for submitting comments and additional 
information on the rulemaking process, see the SUPPLEMENTARY 
INFORMATION section of this document.

SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Notice 
of Proposed Rule Making, ET Docket No. 13-49; FCC 13-22, adopted 
February 20, 2013, and released February 20, 2013. The full text of 
this document is available for inspection and copying during normal 
business hours in the FCC Reference Center (Room CY-A257), 445 12th 
Street SW., Washington, DC 20554. The complete text of this document 
also may be purchased from the Commission's copy contractor, Best Copy 
and Printing, Inc., 445 12th Street SW., Room, CY-B402, Washington, DC 
20554. The full text may also be downloaded at: www.fcc.gov.
    Pursuant to Sec. Sec.  1.415 and 1.419 of the Commission's rules, 
47 CFR 1.415, 1.419, interested parties may file comments and reply 
comments on or before the dates indicated on the first page of this 
document. Comments may be filed using the Commission's Electronic 
Comment Filing System (ECFS). See Electronic Filing of Documents in 
Rulemaking Proceedings, 63 FR 24121 (1998).
    [squf] Electronic Filers: Comments may be filed electronically 
using the Internet by accessing the ECFS: http://fjallfoss.fcc.gov/ecfs2/.
    [squf] Paper Filers: Parties who choose to file by paper must file 
an original and one copy of each filing. If more than one docket or 
rulemaking number appears in the caption of this proceeding, filers 
must submit two additional copies for each additional docket or 
rulemaking number.
    Filings can be sent by hand or messenger delivery, by commercial 
overnight courier, or by first-class or overnight U.S. Postal Service 
mail. All filings must be addressed to the Commission's Secretary, 
Office of the Secretary, Federal Communications Commission.
    [squf] All hand-delivered or messenger-delivered paper filings for 
the Commission's Secretary must be delivered to FCC Headquarters at 445 
12th St. SW., Room TW-A325, Washington, DC 20554. The filing hours are 
8:00 a.m. to 7:00 p.m. All hand deliveries must be held together with 
rubber bands or fasteners. Any envelopes and boxes must be disposed of 
before entering the building.
    [squf] Commercial overnight mail (other than U.S. Postal Service 
Express Mail and Priority Mail) must be sent to 9300 East Hampton 
Drive, Capitol Heights, MD 20743.
    [squf] U.S. Postal Service first-class, Express, and Priority mail 
must be addressed to 445 12th Street SW., Washington DC 20554.

People with Disabilities: To request materials in accessible formats 
for people with disabilities (braille, large print, electronic files, 
audio format), send an email to fcc504@fcc.gov or call the Consumer & 
Governmental Affairs Bureau at 202-418-0530 (voice), 202-418-0432 
(tty).

Summary of Notice of Proposed Rulemaking

    1. By the Notice of Proposed Rulemaking (NPRM), the Commission 
proposes to amend part 15 of its rules governing the operation of 
Unlicensed National Information Infrastructure (U-NII) devices in the 5 
GHz band. U-NII devices are unlicensed intentional radiators that 
operate in the frequency bands 5.15-5.35 GHz and 5.47-5.825 GHz, and 
which use wideband digital modulation techniques to provide a wide 
array of high data rate mobile and fixed communications for 
individuals, businesses, and institutions. Since the Commission first 
made available spectrum in the 5 GHz band for U-NII in 1997, it has 
gained much experience with these devices. The Commission believes that 
the time is now right to revisit the part 15 rules, and, in the NPRM, 
proposes to modify certain technical requirements for U-NII devices to 
ensure that these devices do not cause harmful interference and thus 
can continue to operate in the 5 GHz band and make broadband 
technologies available for consumers and businesses.
    2. The Commission also seeks comment on making available an 
additional 195 megahertz of spectrum in the 5.35-5.47 GHz and 5.85-
5.925 GHz bands for U-NII use. This could increase the spectrum 
available to unlicensed devices in the 5 GHz band by approximately 35 
percent and would represent a significant increase in the spectrum 
available for unlicensed devices across the overall radio spectrum. The 
initiation of this proceeding satisfies the requirements of section 
6406 (a) of the ``Middle Class Tax Relief and Job Creation Act of 
2012'' which requires the Commission to begin a proceeding to modify 
part 15 of title 47, Code of Federal Regulations, to allow unlicensed 
U-NII devices to operate in the 5350-5470 MHz band. The Commission 
believes that an increase in capacity gained from 195 megahertz of 
additional spectrum, combined with the ease of deployment and 
operational flexibility provided by its U-NII rules would continue to 
foster the development of new and innovative unlicensed devices, and 
increase wireless broadband access and investment.

Background

    3. Part 15 of the Commission's rules permits the operation of radio 
frequency devices without issuing individual licenses to operators of 
these devices. The Commission's part 15 rules are designed to ensure 
that there is a low probability that these devices will cause harmful 
interference to other users of the same or adjacent spectrum. 
Typically, unlicensed devices operate at very low power over relatively 
short distances, and often employ various techniques, such as dynamic 
spectrum access or listen-before-talk protocols, to reduce the 
interference risk to others as well as themselves. The primary 
operating condition for unlicensed devices is that the operator must 
accept whatever interference is received and must correct whatever 
interference it causes. Should harmful interference occur, the operator 
is required to

[[Page 21322]]

immediately correct the interference problem or cease operation.
    4. In 1997, the Commission made available 300 megahertz of spectrum 
at 5.15-5.25 GHz (referred to hereinafter as U-NII-1), 5.25-5.35 GHz 
(referred to hereinafter as U-NII-2A), and 5.725-5.825 GHz (referred to 
hereinafter as U-NII-3) for use by a new category of unlicensed 
equipment, called U-NII devices which are regulated under part 15, 
Subpart E of the Commission's rules. In 2003, the Commission made an 
additional 255 megahertz of spectrum available in the 5.47-5.725 GHz 
(referred to hereinafter as U-NII-2C) for U-NII devices. These actions 
align the frequency bands used by U-NII devices in the United States 
with the frequency bands used by U-NII devices in other parts of the 
world, thus decreasing development and manufacturing costs by allowing 
for the same products to be used in most parts of the world.
    5. The U-NII-1 band is allocated on a primary basis to the 
Aeronautical Radionavigation Service for both Federal and non-Federal 
operations and on a primary basis for Fixed Satellite Service (Earth-
to-space) for non-Federal operations. The U-NII-2A band is allocated on 
a primary basis to the Earth Exploration Satellite (active), 
Radiolocation, and Space Research (active) Services for Federal 
operation, and for non-Federal operation on a secondary basis.
    6. The U-NII-2C band is allocated on a primary basis to the 
Radiolocation Service for Federal operation. The sub-band at 5.47-5.65 
GHz band is allocated on a primary basis to the Radiolocation Service 
for non-Federal operation, and on a primary basis to the Maritime 
Radionavigation Service for both Federal and non-Federal operations. 
The 5.47-5.570 GHz band segment is allocated on a primary basis to the 
Earth Exploration-Satellite (active) and Space Research (active) 
Services for Federal operation and on the secondary basis for non-
Federal operation. The 5.6-5.65 GHz band segment is allocated on a 
primary basis to the Meteorological Aids Service for both Federal and 
non-Federal operations. The band segment at 5.65-5.725 GHz is allocated 
on a secondary basis to the Amateur Radio Service for non-Federal 
operation.
    7. The U-NII-3 band is allocated on a primary basis to the 
Radiolocation Service for Federal operation, and is allocated on a 
secondary basis to the Amateur Radio Service for non-Federal operation.
    8. In early 2009, Federal Aviation Administration (FAA) reported 
interference to their Terminal Doppler Weather Radar (TDWR) that 
operates within the 5.60-5.65 GHz band. Early field studies performed 
by the National Telecommunications and Information Administration's 
(NTIA's) Institute for Telecommunications Sciences (ITS) and FAA staff 
indicated the interference sources were unlicensed U-NII devices that 
incorporated dynamic frequency selection (DFS), from different 
manufacturers, and operated in the same frequency band as these Federal 
radar systems.
    9. The Commission brought together all of the principal parties 
including NTIA, FAA, industry participants and the FCC's Enforcement 
Bureau and Office of Engineering and Technology to analyze the 
interference situation. Based on these investigations, the Commission 
has taken actions to mitigate the interference situation, including 
issuing enforcement advisories to heighten users' awareness of TDWR 
interference issues, and the Office of Engineering and Technology has 
placed conditions on U-NII device certifications to curtail the 
interference risk. The Commission also has sent enforcement teams to 
work with FAA staff in the field, and has taken enforcement actions 
against operators of U-NII devices that caused interference to TDWR 
installations including issuing Letters of Inquiry and Notices of 
Apparent Liability for Forfeitures to operators found to be causing 
interference. Most of these interference cases were caused by devices 
not certified for operation in the U-NII-2C band, which includes the 
5.6-5.65 GHz band used by the TDWRs. Instead, these devices had been 
certified for operation in the U-NII-3 band, either as U-NII devices 
under Sec.  15.407 of the Commission's rules or as digitally modulated 
intentional radiators under Sec.  15.247 of the Commission's rules, and 
which were operating at high power levels in elevated locations. The 
Commission's investigations found that most U-NII devices are 
manufactured to enable operation across a wide range of frequencies, 
extending down into the 4-GHz bands and up to almost 6 GHz. In many 
cases, the interference was caused by third parties modifying software 
configurations to enable operation in frequency bands other than those 
for which the device had been certified but without meeting the 
technical requirements for operation in those frequency bands. There 
was also an issue with devices that employed frame based architectures 
that allowed operators to reconfigure the talk/listen ratio of their 
devices.
    10. In recent years, there has been an industry wide push to 
increase the amount of spectrum available for unlicensed use. In June 
2010, the President issued an Executive Memorandum that encouraged the 
Commission to work closely with the Department of Commerce, through 
NTIA, to make available a total of 500 megahertz for commercial mobile 
and fixed wireless broadband use by the year 2020. The FCC's 2010 
National Broadband Plan recommended that the Commission make available 
500 megahertz of new spectrum for wireless broadband within 10 years. 
In analyzing the need for broadband spectrum, the Commission also 
concluded that nearly 300 megahertz of spectrum is needed by 2014, and 
that making available additional spectrum for mobile broadband would 
create value in excess of $100 billion through avoidance of unnecessary 
costs.
    11. In addition, Congress has enacted legislation that addresses 
unlicensed use of the 5 GHz band. The Spectrum Act requires the 
Commission to begin a proceeding to modify part 15 title 47, Code of 
Federal Regulations (CFR), to allow unlicensed U-NII devices to operate 
in the 5.35-5.47 GHz band (referred to hereinafter as U-NII-2B) no 
later than 1 year after the date of the enactment of the Act if, in 
consultation with the Assistant Secretary of Commerce (i.e., the NTIA 
Administrator), it determines that licensees will be protected by 
technical solutions and that the primary mission of Federal spectrum 
users in the band will not be compromised by the introduction of 
unlicensed devices in this band.
    12. The Spectrum Act also requires NTIA, in consultation with the 
Department of Defense and other impacted agencies, to conduct a study 
evaluating known and proposed spectrum sharing technologies and the 
risks to Federal users if unlicensed U-NII devices were allowed to 
operate in the U-NII-2B band as well as in the 5.85-5.925 GHz band 
(referred to hereinafter as U-NII-4). NTIA was required to publish a 
report on the U-NII-2B band no later than 8 months after the date of 
enactment of the Spectrum Act and a report on the 5.85-5.925 GHz band 
(referred to hereinafter as U-NII-4) no later than 18 months after the 
date of enactment of the Spectrum Act. NTIA published a report 
(hereinafter referred to as ``NTIA 5 GHz Report'') on both the U-NII-2B 
and U-NII-4 bands on January 25, 2013.

Notice of Proposed Rulemaking

    13. In the NPRM, the Commission took the first steps towards 
ensuring the U-NII bands continue to meet the demand for broadband 
spectrum, while ensuring protection of authorized

[[Page 21323]]

operations, by proposing modifications to the part 15 rules. In 
particular, the Commission is proposing to align the provisions for 
operation of digitally modulated devices in the 5.725-5.85 GHz band, 
now permitted under Sec.  15.247 of its rules, with the rules for the 
U-NII-3 band under Sec.  15.407. This will expand the U-NII-3 band by 
25 megahertz and provide consistent rules across 125 megahertz of 
spectrum. The Commission also seeks comment on aligning the power 
limits and permissible location for operations in the U-NII-1 and U-
NII-2A bands to permit the introduction of a new generation of wireless 
devices in 200 megahertz of contiguous spectrum.
    14. The Commission also addresses ways to ensure compliance with 
its rules across all of the U-NII bands and, in particular, the U-NII-
2A and U-NII-2C bands to curtail interference to incumbent Federal 
operations (e.g. TDWR installations). The Commission seeks comment on 
various ways to prevent unlawful modification and operation of 
unlicensed devices in the U-NII bands as well as compliance issues that 
are likely to arise as the Commission moves toward wider bandwidth 
systems operating across multiple U-NII bands. Although some of the 
methods discussed would ensure that manufacturers and users comply with 
the Commission's requirements across any of the U-NII band segments, 
the Commission also seeks comment on some techniques that may be useful 
mainly in curtailing interference to incumbent Federal operations, such 
as Terminal Doppler Weather radar (TDWR) installations, in the U-NII-2A 
and U-NII-2C bands, such as geo-location and database registration, 
unwanted emissions limits, and guard band requirements. The Commission 
also seeks comment on several issues specific to the U-NII-2A and U-
NII-2C bands regarding DFS functionality, the sensing threshold for co-
channel operation, and revised DFS measurement procedures. The 
Commission asks that commenters address the benefits of adopting any of 
the proposals in the NPRM as well as the costs to do so, and that they 
weigh and compare the benefits and costs in each case. This assessment 
should address which costs should be borne by U-NII device 
manufacturers, U-NII device operators or other third parties, as 
appropriate.
    15. In the NPRM, the Commission also seeks comment on modifying 
part 15 Subpart E of the Commission's rules governing the operation of 
U-NII devices to make available an additional 195 megahertz of spectrum 
in the 5.350-5.470 GHz (U-NII-2B) and 5.850-5.925 GHz (U-NII-4) bands. 
This would increase the spectrum available to unlicensed devices in the 
5 GHz band by nearly 35 percent and would represent a significant 
increase in spectrum available for unlicensed operations. Finally, The 
Commission seeks comment on transition periods for requiring compliance 
with any modified rules that the Commission ultimately adopts in this 
proceeding.

A. The Current U-NII Bands

1. Unlicensed Operations in the U-NII-3 Band
    16. The Commission believes that now is an appropriate time to 
review its rules to eliminate the disparity and decrease the complexity 
associated with interpreting its rules for digitally modulated devices 
operating in the U-NII-3 band under Sec.  15.407 and in the 5.725-5.85 
GHz band under Sec.  15.247 The Commission believes the changes 
proposed will ensure compliance with requirements designed to protect 
authorized services in the U-NII bands, simplify the Commission's 
authorization procedures, and reduce certification cost for 
manufacturers of these devices. The spectrum ecosystem has changed 
considerably since the Commission allowed the certification of 
``digitally modulated'' devices. For example, the standards for 
wireless broadband devices are now capable of producing data rates in 
excess of 1 Gbits/s. In addition, devices are now able to utilize 
advances in antenna technology that allow the multiple data streams to 
be transmitted over multiple antennas. This provides an opportunity for 
the Commission to reflect on recent industry developments and propose 
new rules that have the potential to increase consistency in the 
process of certifying 5 GHz wireless broadband devices, while 
continuing to protect authorized services.
    17. The Commission is proposing two changes that will eliminate the 
disparity in its rules for 5.7 GHz digitally modulated devices. First, 
the Commission proposes to extend the upper edge of the U-NII-3 band 
from 5.825 GHz to 5.85 GHz to match the amount of spectrum available 
for digitally modulated devices under Sec.  15.247. The Commission 
believes that this change would eliminate the complexity and costs 
associated with multiple rule part certifications for these devices 
which are technically similar. Adopting this proposal would not 
increase the potential for harmful interference because this 25 
megahertz segment is already available for devices certified under 
Sec.  15.247. The Commission seeks comment on the potential benefits of 
expanding the U-NII-3 band to include an additional 25 megahertz of 
spectrum at the upper band edge. The Commission invites comment on 
whether there are cost advantages of this proposal. The Commission asks 
that commenter's assessment of adopting the proposal weigh and compare 
the benefits and costs to do so. This assessment should address which 
costs should be borne by U-NII device manufacturers, U-NII device 
operators or other third parties, as appropriate.
    18. Second, the Commission proposes to consolidate all equipment 
authorizations for digitally modulated devices in the 5.725-5.85 GHz 
band under the U-NII rules, while maintaining many of the technical 
rules that currently make equipment authorization under Sec.  15.247 
more attractive for equipment manufacturers. The Commission also 
proposes to remove the 5.725-5.85 GHz band for digital modulation 
devices from Sec.  15.247. By doing this, the Commission will ensure 
that all digitally modulated equipment, which is technically similar, 
operates under a single rule part using identical technical rules. The 
Commission proposes to modify Sec.  15.407 for digitally modulated 
devices and it seeks comment on all of these proposed rule changes. The 
Commission invites comment on the benefits of adopting any of the 
proposed rule changes below as well as the costs to do so. The 
Commission asks that commenter's assessment of adopting the proposals 
weigh and compare the benefits and costs to do so. This assessment 
should address which costs should be borne by U-NII device 
manufacturers, U-NII device operators or other third parties, as 
appropriate.
    19. Frequency Band. Section 15.247 allows operation throughout the 
5.725-5.85 GHz band, while Sec.  15.407 allows operation only in the 
5.725-5.825 GHz band. The extra 25 megahertz of spectrum that is 
allowed under Sec.  15.247 provides incentive for device manufacturers 
to certify devices under that rule rather than under Sec.  15.407. The 
Commission proposes to expand the frequency band of operation in Sec.  
15.407 to include the 5.825-5.85 GHz band. This will allow U-NII-3 
devices to operate across the full range of spectrum that can currently 
be accessed by digitally modulated devices under Sec.  15.247.
    20. Power. Section 15.247 allows 1 Watt of total peak conducted 
power (alternate measurement procedures are permitted), whereas Sec.  
15.407 limits

[[Page 21324]]

maximum conducted output power to the lesser of 1 Watt or 17 dBm + 10 
log B (in MHz, alternate measurement procedure in Sec.  15.247 is 
required). In addition to the 1 watt power limit, there is a separate 
power spectral density (PSD) limit in both Sec. Sec.  15.247 and 15.407 
such that 1 Watt of total power is available only when the 6-dB 
bandwidth is 500 kilohertz or more under Sec.  15.247 and when the 26-
dB bandwidth is 20 megahertz or more under Sec.  15.407. Because the 
Commission is trying to accommodate digitally modulated devices that 
are currently permitted under both rules, the Commission proposes to 
remove the bandwidth dependent term (i.e., remove 17 + 10 log B) from 
Sec.  15.407 so that the power limit will be 1 Watt. The Commission 
does not believe removing the variable power limit in Sec.  15.407 
would increase any potential for interference, because under current 
rules manufacturers are able to certify equipment that uses up to 1 
Watt of power under Sec.  15.247.
    21. Power Spectral Density. Section 15.247 requires a maximum PSD 
of 8 dBm/3 kHz (33 dBm/MHz), whereas Sec.  15.407 requires a maximum 
PSD of 17 dBm/MHz. The only difference between these two PSD limits is 
the bandwidth at which the 1 Watt total power, rather than the PSD, 
becomes the limiting factor. Specifically, Sec.  15.247 allows a higher 
PSD when the device emission bandwidth is between 0.5 to 20 megahertz. 
Above 20 megahertz emission bandwidth, the 1 Watt power limit becomes 
the limiting parameter, and PSD is the same for both Sec. Sec.  15.247 
and 15.407. The Commission proposes to modify Sec.  15.407 to require 
the PSD limit used in Sec.  15.247 (i.e., 8 dBm/3 kHz (33 dBm/MHz)), so 
that digitally modulated devices designed to meet this limit will 
continue to comply with the new PSD requirement in Sec.  15.407. This 
will ease the transition of all digitally modulated devices in the 
5.725-5.85 GHz band to authorization and compliance under Sec.  15.407. 
The only change for digitally modulated devices will occur when 
emission bandwidth is between 500 kilohertz and 20 megahertz. High-
bandwidth devices like those typically used in U-NII applications will 
still be limited by 1 Watt total power, and thus the proposed change in 
PSD limits would not increase the risk of any potential interference. 
However, the Commission does realize that limiting the PSD to 8 dBm/kHz 
(33 dBm/MHz) would result in a PSD that is higher than the total power 
limit of 1 watt (30dBm). In addition, the Commission realizes that 
requiring devices that employ wider bandwidths to utilize a measurement 
bandwidth of 3 kHz may unnecessarily increase the time that it takes to 
complete measurement tests. The Commission seeks comment on whether it 
should increase the measurement bandwidth to 1 megahertz to reduce the 
complexity in measurement tests. The Commission notes that changing the 
measurement bandwidth would promote consistency within the U-NII rules. 
Should the Commission consider implementing a different PSD limit and 
measure this limit across differing bandwidths, e.g. 500 kHz or 100 kHz 
measurement bandwidths?
    22. Emission Bandwidth. Section 15.247 requires a minimum 6-dB 
bandwidth of 500 kilohertz. No minimum or maximum bandwidth is required 
under Sec.  15.407, but the emission bandwidth is defined and measured 
as the 26-dB down points of the U-NII signal and is used to determine 
the total power allowed under that rule. Because the Commission is 
proposing to eliminate the bandwidth-dependent limit on total power, 
the Commission proposes to modify Sec.  15.407 to eliminate the 26-dB 
bandwidth requirement and to add the minimum 6-dB bandwidth requirement 
from Sec.  15.247.
    23. Antenna Gain. Under Sec.  15.247, the assumed antenna gain is 6 
dBi, with a 1 dB reduction in power required for every 1 dB that the 
antenna gain exceeds 6 dBi. For fixed point-to-point systems, no power 
reduction is required. Section 15.407 assumes the same antenna gain of 
6 dBi, with 1 dB reduction in power required for every 1 dB that gain 
exceeds 6 dBi. For fixed point-to-point systems, a 1 dB reduction in 
power is required for every 1 dB that gain exceeds 23 dBi. The only 
difference between the two rule parts is the maximum antenna gain that 
can be deployed without a penalty in transmitter power. The Commission 
proposes to apply the more stringent 23 dBi maximum antenna gain that 
is currently required under Sec.  15.407. The Commission believes that 
using the more stringent antenna gain requirement will ensure that 
there is no increase in the potential for interference from unlicensed 
devices operating under the new combined rule parts.
    24. Unwanted Emissions. Section 15.247(d) requires 20 dB of 
attenuation (30 dB if the alternate measurement procedure detailed in 
Sec.  15.247(b)(3) is used). In restricted bands, emissions must meet 
the Sec.  15.209 general emission limits. Section 15.407 requires 
unwanted emissions to be below -17 dBm/MHz within 10 megahertz of the 
band edge, and below -27 dBm/MHz beyond 10 megahertz of the band edge. 
Also, all emissions below 1 GHz must comply with the Sec.  15.209 
general emission limits. The unwanted emission limits in Sec.  15.407 
are somewhat more restrictive than those in Sec.  15.247. Because 
unwanted emission can be reduced without affecting the utility of the 
device, and because using the more stringent unwanted emissions 
requirement will ensure that there is no increase in the potential for 
interference from unlicensed devices operating under the new combined 
rule parts, the Commission is proposing that the more restrictive 
limits in Sec.  15.407 be required for digitally modulated devices.
    25. Peak to Average Ratio. Section 15.407 contains a requirement to 
maintain a peak-to-average ratio of no more than 13 dB across any 1 
megahertz band, whereas Sec.  15.247 does not contain any peak-to-
average ratio requirement. The Commission believes that using the more 
stringent peak-to-average requirement will ensure that there is no 
increase in the potential for interference from unlicensed devices 
operating under the new combined rule parts, thus the Commission is 
proposing to keep the peak-to-average ratio requirement that is 
currently in Sec.  15.407.
2. Unlicensed Operations in the U-NII-1 Band
    26. The Commission adopted technical rules for the U-NII-1 band in 
1997 that it believed would provide sufficient flexibility for the 
introduction of a variety of short-range communication devices within 
localized indoor settings. Although that vision was reasonable at the 
time, the Commission finds that today--over 15 years since those rules 
were adopted--the wireless device market has changed dramatically and 
the assumptions made in 1997 may not be valid for today's market. 
Unlicensed communication links are included in a wide variety of 
devices which are increasingly mobile or portable in nature, not easily 
limited to indoor locations, and often needing more power to link with 
other networks at farther locations.
    27. At the same time, the Commission must protect incumbent 
authorized services, both Federal and non-Federal. A global network of 
satellite systems in non-geostationary satellite orbit (NGSO) in the 
mobile satellite service (MSS) operates feeder links in the U-NII-1 
band. These NGSO/MSS feeder links require co-channel interference 
protection. The Commission also needs to consider the potential for 
interference to services in the bands immediately

[[Page 21325]]

adjacent to the U-NII-1 band. Microwave landing systems operate below 
5.15 GHz, and the Commission has proposed to add an allocation for 
Aeronautical Mobile Telemetry at 5.091-5.15 GHz.
    28. The Commission seeks comment on whether the rules for the U-
NII-1 band should be modified to harmonize with the rules for the U-
NII-2A band in three areas. Specifically, the Commission seeks comment 
on whether it should increase the power limits to those applicable in 
the U-NII-2A band, i.e., 250 mW with a maximum EIRP of 30 dBm with 6 
dBi antenna gain. The Commission also invites comment on whether the 
rules for the U-NII-1 band should be modified to increase the PSD 
limits to those applicable in the U-NII-2A band, i.e., 11 dBm/MHz. 
Finally, the Commission seeks comment on whether the rules for the U-
NII-1 band should be modified to eliminate the restriction on outdoor 
operation, and, if the Commission were to do so, whether it should 
allow outdoor operation only under the current power and PSD limits for 
the band or under the limits now permitted only in the U-NII-2 bands. 
The Commission believes that these changes would permit a new 
generation of wireless devices to be developed in the U-NII bands, 
particularly if industry develops wider bandwidth devices that would 
operate across multiple U-NII band segments. Harmonizing the power and 
use conditions across the lower 200 megahertz of U-NII spectrum would 
likely permit the introduction of a wide-range of new broadband 
products capable of operating at higher data rates than is now 
possible. The Commission seeks comment on these assumptions, and on the 
potential impacts to incumbent services, including any suggestions for 
mitigating interference.
    29. The Commission also seek comment on whether the rules for the 
U-NII-1 band should be modified to harmonize with the rules for the U-
NII-3 band to: (a) increase the power limits to 1 W with a maximum EIRP 
of 36 dBm with 6 dBi antenna gain; (b) increase the PSD limits to 17 
dBm; and (c) limit out-of-band emissions to an EIRP of -27 dBm/MHz and 
(d) eliminate the restriction on outdoor operation. The Commission 
believes that these changes would permit for wider bandwidth devices 
that would not rely on contiguous spectrum under new Wi-Fi standards, 
and would permit the introduction of more outdoor access points for 
broadband use. The Commission seeks comment on these assumptions, and 
on the potential impacts to incumbent services, including any 
suggestions for mitigating interference.
    30. The Commission invites comment on the benefits of adopting 
either of these approaches as well as the costs of doing so. The 
Commission asks that commenter's assessment of adopting either approach 
weigh and compare the benefits and costs to do so. This assessment 
should address which costs should be borne by U-NII device 
manufacturers, U-NII device operators or other third parties, as 
appropriate.
3. Ensuring Compliance With the Rules for the U-NII Bands
    31. The Commission's Enforcement Bureau working cooperatively with 
the FAA has been successful in finding and resolving a large number of 
interference cases. In some cases, equipment that met the Commission's 
certification standards nonetheless caused interference, due to a 
variety of factors such as the configuration of the transmitter, its 
height and azimuth relative to the TDWR, and the device's failure to 
detect and avoid the radar signal. In many cases, however, the 
Commission staff found that the interfering devices were not certified 
or otherwise were not compliant with the Commission's rules. For 
example, the Commission found that devices that were certified as 
digital devices under Sec.  15.247 for operation in the 5.725-5.850 GHz 
band had been unlawfully modified to transmit in the U-NII-2C band 
without demonstrating compliance with the DFS and TPC requirements for 
those bands. Typically, these modifications are made by operators of 
the devices, but manufacturers have produced equipment that is easily 
modified, especially through software changes, to permit devices to 
operate in non-compliant modes. The Enforcement Bureau is continuing to 
take action against companies for operating devices that cause 
interference to the TDWRs. The Commission notes that, while the TDWRs 
have been the focus of Commission investigations, DFS was designed to 
protect all incumbent radar operations and modification of devices as 
described poses a risk of interference to more than just TDWRs.
    32. Interference studies conducted by NTIA and the FAA indicate 
that there may be some potential for interference from U-NII devices 
operating in frequencies occupied by or adjacent to radar systems. In 
its Third Technical Report regarding the interference into the TDWRs, 
NTIA explores frequency separations, distance separations, and maximum 
U-NII emissions limits needed to preclude harmful interference into the 
TDWR. The report analyzes the distances at which U-NII transmissions 
can be expected to routinely interfere with TDWR receivers. U-NII 
devices on rooftops, towers, and other high points that are 153 m to 
305 m (500 to 1000 ft.) above ground level, as NTIA observed in San 
Juan, PR, will interfere with a TDWR mainbeam at distances within 25 km 
to 41 km (16 mi to 25 mi), respectively, of a TDWR station. The report 
also specifies frequency separations necessary to protect TDWR from 
interference due to unwanted emissions from U-NII devices.
    33. As a result of its ongoing discussions with NTIA, FAA and 
industry representatives, as well as the results of investigations 
conducted by the Commission, NTIA and FAA, and, the Office of 
Engineering and Technology has provided applicants for certification a 
representative way for demonstrating that their U-NII devices should 
not cause harmful interference to TDWR installations operating in the 
U-NII-2C band and accordingly can be authorized for manufacture and 
use. Specifically, OET has advised applicants that it will approve such 
devices upon assurance by the applicant that: (a) U-NII devices may not 
operate co-frequency with TDWR operations at 5.6-5.65 GHz; (b) grantee 
will provide owners, operators and installers of these devices with 
instructions that a master or client device within 35 km of a TDWR 
location must be separated by at least 30 megahertz (center-to-center) 
from the TDWR operating frequency and procedures for registering the 
devices in an industry-sponsored database; (c) the device does not 
include configuration controls to change the frequency of operation to 
any frequency other than those specified in the grant of certification; 
and (d) the device's software configurations do not allow for ad hoc 
networking, country code selection, or other mode of operation that 
would disable the DFS functionality of the U-NII device.
    34. The interference cases the Commission has seen to date raise 
serious concerns with ensuring compliance with the Commission's rules 
in the U-NII-2C band, but there are other circumstances that also make 
this an opportune time for the Commission to consider compliance issues 
across the 5 GHz U-NII bands. For example, unlicensed wireless 
broadband device manufactures are now designing devices employing wider 
bandwidths (e.g., IEEE 802.11ac standard currently in development) 
using transmitters that are capable of operating across two or more U-
NII bands. When devices are designed to operate across multiple 
frequency

[[Page 21326]]

bands, the Commission's rules require that applicants demonstrate 
compliance with the rules for each of the individual frequency bands in 
which they intend to operate in order to be certified for operation in 
each band.
    35. The Commission expects that more and more devices with even 
wider bandwidths will continue to be introduced in the 5 GHz band in 
the not too distant future as a result of new technical standards. The 
introduction of wider bandwidths under the IEEE 802.11ac standard 
presents complex issues for emissions testing to demonstrate compliance 
with the various requirements in the different U-NII bands. The Office 
of Engineering and Technology has published two guidance documents 
addressing these issues for testing of devices designed under this new 
standard as well as ``pre-ac'' devices, taking into account the current 
rules that permit authorization of digitally modulated devices under 
both Sec. Sec.  15.407 and 15.247.
    36. The Commission, NTIA, and the FAA have been working with 
manufacturers of U-NII devices and the WISPA to fully understand the 
causes of interference to TDWR systems and to identify ways to mitigate 
and significantly reduce the likelihood of interference. The Commission 
believes the rules proposed herein, in addition to continuing 
enforcement efforts, will enable us to achieve this goal while allowing 
U-NII devices to continue to operate successfully in the 5 GHz band.
    37. Wireless networking devices that operate within the 5 GHz band 
typically have similar operational parameters, so that a device 
certified for operation in any one of the 5 GHz frequency bands, 
whether a U-NII band or not, can be easily tuned to another frequency 
band in the same spectrum range through software modifications. The 
Commission's experience with these devices shows that some of these 
devices are designed so that end-users can modify them to operate in 
bands for which they are not certified and thus do not meet the 
specific requirements intended to protect sensitive incumbent services. 
For example, in some recent interference cases investigated by the 
Commission's Enforcement Bureau, operators of devices certified under 
Sec.  15.247 were tuned down into the U-NII-2C frequency band and 
operated with a higher gain antenna than what is permitted by the 
Commission's U-NII rules. The modification of devices in this manner 
resulted in both in-band and out-of-band emissions that were far in 
excess of what Sec.  15.407 allows in the U-NII-2C band. Such unlawful 
modification and operation of these devices could considerably increase 
the distance at which these non-compliant devices cause harmful 
interference to incumbent services. The Commission believes that its 
proposals, discussed to authorize all digitally modulated devices under 
identical rules in a modified Sec.  15.407 will allow the Commission to 
more effectively and efficiently address interference risk to incumbent 
operations in the U-NII-2C and U-NII-3 bands.
    38. The Commission believes that it should consider additional 
steps to further reduce the likelihood of interference not only to TDWR 
systems but to all other incumbent services in the 5 GHz bands as more 
composite and wideband devices are introduced across the 5 GHz band. 
The Commission recognizes that one of the difficulties in ensuring 
compliance with its current rules comes from the fact that these 
devices can easily be re-configured by operators modifying the software 
that controls the device's operational parameters, such as frequency 
band. This makes it difficult for the Commission not only to ensure 
compliance with its rules but also to enforce those rules.
    39. Because the current and future use of the 5 GHz bands is 
heavily reliant on the successful implementation of the Commission's 
technical rules, the Commission proposes to require that manufacturers 
implement security features in any digitally modulated device capable 
of operating in the U-NII bands, so that third parties are not able to 
reprogram the devices to operate outside the parameters for which the 
device was certified. The Commission proposes and seeks comment on 
adopting this safeguard regardless of whether or how it modifies Sec.  
15.247 or Sec.  15.407. The Commission is particularly concerned that 
U-NII devices--which are not certified under the rules as software 
defined radios (SDRs) and thus may lack safeguards that are required 
for certified SDRs--may nevertheless be susceptible to manipulation by 
third parties who can modify the operating parameters of country code, 
frequency range, modulation type, maximum output power or the 
circumstances under which the transmitter has been approved. 
Specifically, the Commission seeks comment on whether it should require 
manufacturers to make it difficult for third parties to reprogram the 
embedded transmitter chip in certified devices. For example, should the 
Commission require that manufacturers ensure that modifying or 
reconfiguring firmware or software will make a device inoperable in 
certain bands? The Commission also seeks comment on whether it should 
require U-NII devices to transmit identifying information so that, in 
the event interference to authorized users occurs, the Commission can 
identify the source of interference and its location. What type of 
information should be transmitted and in what format?
    40. Although the Commission believes that requiring manufacturers 
to secure the software in their radios to prevent modifications by 
third parties provides a clear public benefit in ensuring that these 
devices comply with the rules as more devices are introduced and the 
number of users increases, the Commission recognizes that this 
requirement will add some cost to these devices. The Commission seeks 
comment on the proposals discussed, particularly information on the 
costs to manufacturers for implementing them. The Commission invites 
comment on the benefits of adopting these proposals as well as the 
costs to do so. The Commission asks that commenter's assessment of 
adopting the proposals weigh and compare the benefits and costs to do 
so. This assessment should address which costs should be borne by U-NII 
device manufacturers, U-NII device operators or other third parties, as 
appropriate.
    41. The Commission believes that its proposals to modify the 
technical rules in the U-NII-3 band, along with its proposal to enhance 
the security requirements of all U-NII devices, would have prevented 
most of the interference cases that the Commission has observed to 
date. The Commission also notes, however, that the NTIA Third Technical 
Report and its own discussions with NTIA, FAA and industry 
representatives have identified additional techniques that could 
mitigate in-band and adjacent band interference to incumbents. These 
include using a database registration process combined with geo-
location technology to determine whether there is any potential 
interference to radar systems such as the TDWR; limiting the unwanted 
emission levels of the U-NII devices; or increasing the sensing 
frequency range (e.g., detection bandwidth) of U-NII devices operating 
in the U-NII-2A and U-NII-2C bands. These other techniques, could 
supplement or replace the assurances (described in paragraph 45 of the 
NPRM) that OET has accepted from certification applicants on an ad-hoc 
basis as sufficient to address interference concerns that might 
otherwise warrant denial of equipment certification requests for U-NII 
devices in the U-NII-2C band. The Commission

[[Page 21327]]

also observes that these techniques would place responsibility on 
users, rather than on manufacturers, for mitigating interference. The 
Commission invites comment on whether the security requirements it is 
proposing to place on U-NII devices, along with the more stringent 
unwanted emission limits that it is proposing for devices that would 
previously have been certified under Sec.  15.247, are sufficient to 
protect incumbent radar operations, including TDWR installations, from 
interference, or whether the Commission should further modify its rules 
to require implementation of other techniques. In particular, the 
Commission seeks comment on the likely effectiveness of each technique 
discussed in reducing the incidence of interference to TDWR systems or 
other incumbent operations by ensuring compliance with and in 
facilitating enforcement of its rules. The Commission invites comment 
on whether any of these techniques would be beneficial in protecting 
other incumbents from interference, not only in the U-NII-2C band but 
also in other segments of the 5 GHz band. The Commission invites 
comment on the benefits of adopting any of the methods discussed as 
well as the costs to do so. The Commission asks that commenters' 
assessment of adopting any of the methods weigh and compare the 
benefits and costs to do so. This assessment should address which costs 
should be borne by U-NII device manufacturers, U-NII device operators 
or other third parties, as appropriate.
    42. Geo-Location/Database: The NTIA Third Technical Report 
specifies the frequency separations and distance separations needed to 
preclude interference from U-NII devices into the TDWR under the study 
conditions used for NTIA's investigation. The separation requirements 
differ for the various types of devices, but, in general, as the 
frequency separation increases the required separation distance between 
the U-NII devices and the TDWR decreases. For example, with main-beam 
coupling and 30 megahertz of frequency separation from 20 
megahertz-wide 802.11-based U-NII devices operating at an EIRP of 17 
dBm, a TDWR needs a protection distance of 11 km. For 40 megahertz-wide 
802.11 devices with a frequency separation of 30 megahertz, 
the distance is 35 km; that distance is reduced to 15 km at a frequency 
separation of 50 megahertz above the center frequency and 10 km below 
the center frequency with a 50 megahertz frequency separation. As 
noted, the Office of Engineering and Technology has implemented these 
geographic and frequency separations as part of its equipment 
authorization program. Industry representatives have recommended to 
Commission staff that the Commission should implement these protections 
for high power point-to-point systems, and have argued that no 
additional limits or requirements are necessary for lower power, indoor 
systems. The Commission seeks comment on whether it should require 
these geographic and frequency separations from TDWR and other Federal 
radars operating in the U-NII-2C band for high power outdoor U-NII 
devices authorized for operation in this band. How should the 
Commission define and distinguish outdoor versus indoor U-NII devices, 
or high power versus low power U-NII devices? How would the Commission 
enforce compliance with these distinctions?
    43. One way to implement frequency and distance separation 
requirements is to require geo-location and database registration. 
Because the TDWR locations are known and somewhat limited in number, 
implementation of geo-location and database registration might be very 
straightforward and easy to accomplish. With this interference 
avoidance method, the location of an unlicensed device could be 
determined by a professional installer or by using geo-location 
technology such as GPS incorporated within the device. Using either of 
these methods, a user could determine from either an internal or 
external database whether the unlicensed device is located far enough 
from the TDWR to avoid causing harmful interference; if not, it could 
transmit on a frequency farther away from the TDWR's center frequency. 
CSMAC, for example, recommends implementing a Dynamic Database approach 
to device authorization. On a going-forward basis, devices and systems 
sharing a band would be ``connected'' devices and a geo-location/
database approach could enforce permission and terms-of-use updates on 
an automated basis. The concept of database-enabled cognitive radios 
can lend itself to many applications, including ultimately sharing 
spectrum with Federal users. As noted, a voluntary database has been 
implemented by WISPA, which disseminates the location of TDWR to WISPs 
and encourages operators that install devices within 35 km or the line-
of-sight of a TDWR, to operate at least 30 megahertz away from the TDWR 
operation frequencies. WISPA has also agreed to voluntarily provide a 
database where WISPs can register the locations of the outdoor 
transmitters that they use. The Commission seeks comment on whether, 
given the limited number of TDWR locations, a geo-location/database 
approach could be effectively implemented and maintained for numerous 
U-NII devices that would operate in the 5.6-5.65 GHz band. How will 
this approach protect other incumbent operations?
    44. The Commission recognizes that its rules already require radar 
avoidance via the DFS mechanism. The Commission further recognizes that 
requiring the implementation of a database for TDWR could increase the 
complexity of U-NII devices if the Commission were to require that they 
include a geo-location capability. Alternatively, the Commission could 
modify its rules to specifically require professional installation and 
permit manufacturers to pass on this cost to the user of the device. In 
addition, a database for registering TDWR locations and, perhaps, U-NII 
device users and locations as well would entail some cost to establish 
and maintain. The Commission seeks comment on what the cost would be to 
implement geo-location/database protection, what the requirements 
should be, and how to define ``professional installation.'' The 
Commission also seeks comment on whether requiring the implementation 
of both DFS and geo-location interference protection mechanisms would 
be overly burdensome for equipment manufacturers and whether it is 
necessary to require both. Are there alternative approaches that can be 
implemented to protect the incumbent radar systems? Because higher 
power outdoor devices (such as those used by Wireless Internet Service 
Providers) in the U-NII-2C band have a greater potential to cause 
harmful inference as compared to lower power consumer type devices, the 
Commission requests comment on whether a geo-location/database 
requirement should apply only to those devices or to lower power indoor 
U-NII devices as well.
    45. Unwanted emission limits. Emissions outside of the U-NII 
device's occupied bandwidth may have the potential to cause harmful 
interference into TDWR. Aside from increasing frequency separation or 
distance separation, U-NII devices may avoid causing interference by 
lowering the emissions on the radar's fundamental frequency. This 
equates to lowering all emissions from U-NII devices at the frequencies 
outside of the device's operating bandwidth. The Commission seeks 
comment as to whether TPC also contributes to reductions in unwanted 
emissions. For example, if the TPC

[[Page 21328]]

function reduces the fundamental power level by 1 dB, is there a 
corresponding 1 dB reduction in unwanted emissions?
    46. NTIA's report details the measurements and analysis that 
determine the power levels at which TDWR receivers experience 
interference from U-NII emissions at an interference-to-noise (I/N) 
ratio of -8 dB. In its report, NTIA finds that the maximum allowable 
co-channel interference power that can be received in the TDWR without 
exceeding the I/N level of -8 dB is shown to be -119 dBm/MHz at the 
antenna terminals. This equates, for example, to a mainbeam-to-mainbeam 
interference power density of 43 dBm/MHz between TDWR and U-NII 
transmitters at a distance of 8 km, or an interference power density of 
-22 dBm/MHz when the mainbeam of the U-NII device is in the TDWR 
sidelobe at a distance of 2 km. These power density thresholds are a 
function of separation distance between TDWR receivers and U-NII 
transmitters as well as the receive antenna gain of the TDWR in the 
direction of the U-NII transmitter.
    47. The Commission's existing rules for the U-NII-2C band specify 
that the peak power spectral density shall not exceed 11 dBm in any 1 
megahertz band. If transmitting antennas of directional gain greater 
than 6 dBi are used, both the maximum conducted output power and the 
peak power spectral density must be reduced by the amount in dB that 
the directional gain of the antenna exceeds 6 dBi. These rules 
implicitly allow a maximum EIRP of 17 dBm/MHz in the U-NII-2C band. 
Additionally, for devices operating within the U-NII-2C band, the 
Commission's rules specify that all emissions transmitted outside of 
the U-NII-2C band shall not exceed an EIRP of -27 dBm/MHz. The 
Commission recognizes, based on NTIA's report, that these two limits 
may not be sufficient to protect the TDWR from adjacent channel 
emissions from U-NII devices. Accordingly, the Commission seeks comment 
on whether requiring new unwanted emission limits for U-NII devices 
operating in the U-NII-2A and UNII-2C bands is appropriate and whether 
the Commission should modify its emission limits to reflect NTIA's 
findings.
    48. If the Commission were to impose new limits on U-NII devices, 
as suggested, the Commission believes that different limits can be set 
for lower power indoor and higher power outdoor devices. For indoor 
devices, the Commission believes that setting an out-of-channel 
emissions limit of -27dBm/MHz maximum EIRP may be appropriate because 
building materials would likely further attenuate these emissions. When 
measured outside of the building, the emissions from an indoor device 
would likely drop to a level that would appear as no more than -41dbm/
MHz. An out-of-channel emissions limit of -41 dBm/MHz for outdoor 
devices may be appropriate as well. The Commission seeks comment on 
modifying its rules to adopt these out-of-channel limits for indoor 
versus outdoor U-NII devices, including how the Commission should 
define the terms ``indoor'' and ``outdoor'', and how different 
operating requirements for indoor versus outdoor operations can be 
accommodated through the Commission's equipment authorization and the 
Commission's enforcement procedures.
    49. As an alternative, if the Commission determines that reductions 
in unwanted emissions are necessary, the Commission could allow outdoor 
devices to operate with an out-of-channel emissions limit of -27 dBm/
MHz peak EIRP as long as the separation distance between the device and 
the TDWR is at least 53 km. Should the Commission impose this new out-
of-channel limit based on the maximum power levels of the devices 
rather than whether a device is based indoor or outdoor? For instance, 
the Commission recognizes that lower power device devices provide 
short-range communications, such as those between computing devices 
within a very local area and therefore pose less of a potential risk to 
TDWR operations. Higher power devices, however, are intended to be used 
in an outdoor environment for longer-range communications. The 
Commission seeks comment on the assumptions made in its analysis.
    50. Sensing. If the Commission decides to require that a U-NII 
device move more than 30 megahertz in frequency from the TDWR, one way 
to enable this is to require the U-NII device to sense for radar in the 
channels adjacent to its occupied bandwidth. This will ensure that the 
unwanted emissions from U-NII devices are placed far enough away in 
frequency from the TDWR fundamental frequency to preclude harmful 
interference. The Commission seeks comment on this alternative 
approach.
    51. The DFS mechanism is designed to avoid co-channel interference 
to the TDWR by dynamically detecting radar signals and avoiding co-
channel operation with those systems. The efficacy of the DFS mechanism 
is dependent upon the U-NII device's ability to detect and avoid a 
radar pulse within a region of its occupied bandwidth. Specifically, 
the current measurement procedures require that a U-NII device sense 
for radar across 80 percent of its occupied bandwidth. With respect to 
the remaining 20 percent, the Commission does not require sensing in a 
10 percent region above or below the occupied bandwidth. The Commission 
recognizes that currently implementation of the sensing bandwidth will 
ensure co-channel interference protection only when the radar signal 
falls within 80 percent of the U-NII device's occupied bandwidth. 
Therefore, it is possible for the U-NII device to transmit on the same 
frequency as the radar when the radar signal falls within the 20 
percent of occupied bandwidth that does not require sensing. When the 
radar signal falls within the region of occupied bandwidth that does 
not require sensing, the U-NII device will continue to transmit. This 
could result in simultaneous and overlapping transmissions from the U-
NII device and the TDWR, which would increase the potential for harmful 
interference.
    52. In addition, NTIA's Third Technical Report suggests that 
adjacent channel interference is possible when the frequency separation 
between the radar and the U-NII device is less than a specified amount. 
For example, when a radar signal falls outside of the sensing bandwidth 
and occupied bandwidth, and is within 30 megahertz from the U-NII 
devices' fundamental frequency, the unwanted emissions from the U-NII 
devices could still cause harmful interference to the TDWR. If the 
Commission requires that U-NII devices sense for radar on the 
frequencies immediately adjacent to the occupied bandwidth, the 
Commission would ensure that the fundamental frequency is more than 30 
megahertz away from the radar.
    53. The Commission seeks comment on whether it should implement a 
rule requiring that U-NII devices sense for radar signals at or 
exceeding 100 percent of its occupied bandwidth, or whether the 
Commission should continue to reference this, as it does now, as part 
of the U-NII measurement procedures. The Commission believes that 
expanding the sensing bandwidth will prevent the co-channel operations 
between U-NII devices and radars receiver and thus will reduce the 
potential for harmful interference. The Commission also invites comment 
on the technical difficulty and cost of implementing this capability in 
U-NII devices.

[[Page 21329]]

4. The U-NII-2A and U-NII-2C Bands
    54. DFS is an essential element allowing U-NII devices to share the 
U-NII-2A and U-NII-2C bands successfully with vital government and 
military radar systems. As the Commission has gained experience with 
these devices and the implementation of DFS in the field, it is 
proposing changes in three areas to improve the utility and reliability 
of this function, thus ensuring that incumbent services in these bands 
are protected from interference. These changes include lowering the 
permitted PSD for lower power devices that use the relaxed sensing 
threshold, and modifying the Bin-1 radar simulating waveform used in 
the measurement procedures. The Commission believes that these changes 
will reduce the potential for co-channel interference to the TDWR and 
other radar systems. The Commission is also proposing to remove the 
uniform channel loading requirement found in the U-NII measurement 
procedures.
    55. DFS Functionality. To be certified for operation in the U-NII-
2A and U-NII-2C bands, devices must include a DFS radar detection 
function. In its field investigations, the Commission's Enforcement 
Bureau found that certain models of devices certified for use in these 
bands were designed so that users could disable the DFS mechanism by 
setting the device's operating mode to ``Compliance test.'' In other 
cases, the device's DFS mechanism could be turned off by manually 
changing the ``Country Code'' for the device. If the DFS mechanism is 
not active, the device could transmit on an active radar channel and 
cause harmful interference. The Commission therefore proposes that 
manufacturers prevent the DFS mechanism from being disabled in devices 
certified to operate in the U-NII-2A and U-NII-2C bands. The Commission 
also proposes that U-NII devices certified to operate in these bands 
must be operated with the DFS function on.
    56. Recently, the Office of Engineering and Technology has had to 
clarify which types of U-NII devices are required to demonstrate 
compliance with the DFS requirement. The Commission knows that many U-
NII devices operate in a master-client configuration, i.e., the master 
device controls the operational parameters of the client devices. 
Typically, DFS-enabled master devices would include both the radar 
sensing and DFS functions, but new configurations are being designed. 
For example, radios can operate in a network configuration with the 
sensing function distributed among various ``client'' devices. Also, 
some radios are designed so that they can communicate directly with 
each other, rather than through a control point, and thus they could 
function as either a ``master'' that initiates a network or as a 
``client'' device within the network. The Commission proposes that any 
U-NII device that is subject to the DFS requirements in Sec.  15.407 
that is capable of initiating a network must have radar detection 
functionality and must be approved with that capability.
    57. The Commission believes that responsible operation of U-NII 
devices in these bands is a joint responsibility of both manufacturers 
and users. The Commission seeks comment on these proposals regarding 
DFS functionality as well as information on costs to implement them. 
The Commission also invites comment on whether the DFS requirement has 
limited in any way the types of applications that have been or could be 
implemented in the U-NII-2A and U-NII-2C bands, particularly if wider 
bandwidth devices are deployed in this spectrum. The Commission invites 
comment on the benefits of adopting this proposal as well as the costs 
to do so. The Commission asks that commenters' assessments of adopting 
the proposal weigh and compare the benefits and costs to doing so. This 
assessment should address which costs should be borne by U-NII device 
manufacturers, U-NII device operators or other third parties, as 
appropriate.
    58. Sensing Threshold for Co-channel operation: The current rules 
require that the DFS mechanism continuously monitor the device's 
environment for the presence of radar, both prior to and during 
operation. The Commission further requires that U-NII devices certified 
under the rules use two detection thresholds to ascertain whether radar 
signals were present. The required threshold levels are:
    (a) 62 dBm for lower power devices with a maximum EIRP less than 
200 mW (23 dBm), and (b) -64 dBm for higher power devices with a 
maximum EIRP between 200 mW (23 dBm) and 1 W (30 dBm), averaged over 1 
[micro]s. The Commission also requires that the conducted peak power 
spectral density shall not exceed 11 dBm in any 1 megahertz band. If 
transmitting antennas of directional gain greater than 6 dBi are used, 
the Commission requires that both the maximum conducted output power 
and the power spectral density be reduced by the amount in dB that the 
directional gain of the antenna exceeds 6 dBi. Thus, the implicit limit 
on the EIRP spectral density is 17 dBm in any 1 megahertz band.
    59. The lower power U-NII devices are permitted to use the relaxed 
sensing threshold because the range at which these devices can 
potentially cause interference is reduced and thus they are allowed to 
operate closer to the radar. In order to ensure that interference 
potential does not increase with the use of the relaxed sensing 
threshold, the Commission believes that applying a reduction in EIRP 
spectral density for devices that use the -62 dBm sensing threshold is 
appropriate. The Commission proposes that devices must operate with 
both an EIRP of less than 200 mW (23 dBm), and an EIRP spectral density 
of less than 10 dBm/MHz (10 mW/MHz), in order to use the relaxed 
sensing detection threshold of -62 dBm. Devices that do not meet the 
proposed EIRP and EIRP spectral density requirements must use the -64 
dBm sensing threshold. The proposed changes will further enhance 
protection for radars from co-channel interference by reducing both the 
range and the in-band spectral density emissions of the U-NII device. 
The Commission seeks comment on this proposal, including the cost to 
manufacturers to implement it. The Commission notes that a reduction in 
the EIRP spectral density limit would be consistent with recent actions 
taken by European Telecommunications Standards Institute (ETSI). 
Specifically, ETSI chose to restrict a device's use of the relaxed 
sensing threshold by reducing both the EIRP and the EIRP spectral 
density by 7 dB to 23 dBm (200 mW) and 10 dBm/MHz (10 mW/MHz), 
respectively. The Commission invites comment on the benefits of 
adopting this proposal as well as the costs to do so. The Commission 
asks that commenter's assessment of adopting the proposal weigh and 
compare the benefits and costs to do so. This assessment should address 
which costs should be borne by U-NII device manufacturers, U-NII device 
operators or other third parties, as appropriate.
    60. Measurement and Testing Procedures. Under Sec.  2.947(a) of the 
rules, the Commission will accept data that is measured in accordance 
with (1) procedures or standards set forth in bulletins or reports 
prepared by the Commission's Office of Engineering and Technology 
(OET), (2) procedures or standards that are acceptable to the 
Commission and are published by a national engineering society, or (3) 
any other measurement procedure acceptable to the Commission. With 
respect to the first option, OET's most recent bulletin on measurement 
procedures for U-NII devices with DFS

[[Page 21330]]

capabilities was published in 2006. NTIA has recommended modifications 
to these 2006 measurement procedures, to further enhance protection for 
the TDWR. The Commission invites interested parties to comment on these 
modifications to the measurement procedures, which are set forth in 
Appendix B of the NPRM, and to propose any additional modifications 
that are appropriate. Consistent with the Commission's rules and prior 
practice, the Office of Engineering and Technology will evaluate 
comments on the recommended changes to the measurement procedures and 
will issue updated measurement procedures in the future as needed.
    61. The Commission's current rules and measurement procedures 
require that the DFS function provide a uniform spreading of loading 
over all available channels. The measurement procedure further explains 
this provision by stating that ``Uniform Channel Spreading'' is the 
spreading of U-NII devices operating over the DFS bands to avoid dense 
clusters of devices operating on the same channel. Some manufacturers 
comply with this requirement by using random channel selection, but the 
Commission believes that similar benefits could be obtained by manual 
selection of channels and may actually result in better spectrum usage 
at a given location. In particular, the Commission notes that enhanced 
spectrum use may be possible when devices use a very high bandwidth and 
the number of usable channels is small. The Commission also notes that 
the trend for U-NII devices is to operate with ever wider bandwidths. 
Operation over wider bandwidths causes U-NII energy to be spread 
throughout the frequency band in which the device is operating, rather 
than concentrated in a narrow bandwidth. This potentially makes the 
uniform channel spreading requirement unnecessary. The Commission 
proposes to remove the ``Uniform Channel Spreading'' requirement from 
the rules and measurement procedures. The Commission also proposes to 
permit either random channel selection or manual selection of the 
initial channel. For example, should the Commission permit a device to 
create a master list of available channels that it would use if they 
continue to be available? The Commission seeks comment on whether these 
changes will, in any way, negatively impact spectrum reuse or 
potentially increase interference to incumbent users. In addition, the 
Commission's measurement procedures require that system testing be 
performed with an MPEG test file that streams full motion video at 30 
frames per second for channel loading. Experience certifying U-NII 
devices has indicated that not all U-NII devices are designed for video 
transmission or support the specific coding format, and so other 
methods of channel loading are used. The Commission seeks comment on 
whether specifying video streaming as the preferred channel loading 
method for compliance measurements is as appropriate today as it was 
when the measurement procedures were created, or whether the channel 
loading requirement in the Commission's test procedures should be 
specified in a more general manner so as only to specify that 
measurements be conducted with the device under test operating in a 
loaded condition. The Commission seeks comments on how it should 
specify alternate means of channel loading for measurement purposes. 
Additionally, the Commission seeks comment on the effects of wider U-
NII device bandwidths on channel loading requirements.

B. Future Unlicensed Operations at 5 GHz

    62. The 5.35-5.47 GHz (U-NII-2B) and 5.85-5.925 GHz (U-NII-4) bands 
have great potential for fostering ongoing technological innovation, 
expanding broadband access, and encouraging competitive entry. The 
additional spectrum also would expand opportunities for innovative 
spectrum access models by creating new avenues for opportunistic and 
unlicensed use of spectrum and increasing research into new spectrum 
technologies. Creating ways to access spectrum under a variety of new 
models, including unlicensed uses, increases opportunity for 
entrepreneurs and other new market entrants to develop wireless 
innovations that may not have otherwise been possible under licensed 
spectrum models.
    63. These bands currently are used for various Federal and non-
Federal services, and the Spectrum Act requires that the Commission 
begin a proceeding to modify the part 15 rules to permit unlicensed 
devices in the U-NII-2B band if, in consultation with NTIA, it 
determines that licensed users will be protected by technical solutions 
and that the primary mission of Federal spectrum users will not be 
compromised by the introduction of unlicensed devices in these bands. 
Thus, the Commission's goal in this proceeding is to promote efficient 
use of radio spectrum through spectrum sharing. As part of this 
collaborative effort and as required by the Spectrum Act, NTIA has 
published a report, prepared in consultation with Department of Defense 
and other impacted Federal agencies, evaluating spectrum-sharing 
technologies and the risk to Federal users of unlicensed operations in 
the U-NII-2B and U-NII-4 bands.
    64. The Commission explores the potential for future unlicensed 
operations in the 5 GHz band, incumbent operations in the U-NII-2B and 
U-NII-4 bands, and the technical requirements and sharing technologies 
and techniques that could be used to protect Federal and non-Federal 
incumbent operations. The Commission also invites comments on the NTIA 
5 GHz Report itself, including its underlying assumptions and risk 
assessments.
1. Future Unlicensed Operations at 5 GHz
    65. The current U-NII bands are already being used for a variety of 
different commercial uses such as wireless internet services, cordless 
phone, scientific and medical applications, etc. In this proceeding, 
the Commission seeks comment on what types of uses could be deployed in 
the U-NII-2B and U-NII-4 bands, used either independently of the 
current U-NII bands or in conjunction with them. The Commission is 
interested in knowing how companies of different types might deploy U-
NII devices, what types of services they might offer, and where they 
might deploy them. The Commission is particularly interested in 
gathering information on ongoing industry standards activity and 
international efforts to harmonize uses of the 5 GHz band to make more 
efficient use of the 5 GHz spectrum.
    66. The Commission knows, for example, that unlicensed and licensed 
broadband networks often complement one another in important ways. The 
availability of unlicensed Wi-Fi networks in many locations enables 
licensed wireless providers to take data traffic off of their networks, 
thus reducing network congestion and delivering a better overall 
quality of service. Wi-Fi technology also can be ``networked'' to 
provide wider geographic coverage and, when configured this way, may be 
used by some service providers in offering broadband service.
    67. The introduction of the IEEE 802.11ac standard, can open new 
windows to wireless broadband for many users. The deployment of wide 
channel bandwidths with higher data rates in the 5 GHz band can help 
meet the challenge that rapid growth in

[[Page 21331]]

demand has posed for the wireless industry which has called for more 
spectrum to increase network capacity. The new standard has the 
potential to create new avenues for opportunistic use of spectrum in 
diverse broadband services. Some forecasts predict that in 2015, 
shipments of mobile phones with embedded Wi-Fi are projected to 
approach 800 million and by the same time 100 percent of mobile hotspot 
shipments will be 802.11ac enabled. Infonetics forecasts the global 
carrier Wi-Fi equipment market to grow significantly at least through 
2016, when it will hit $2.1 billion. The Commission seeks comment on 
how the introduction of this new standard might be implemented in the U 
NII bands and how these developments should inform the Commission's 
consideration of technical requirements for these bands and sharing 
technologies and techniques. The Commission also invites comment on 
whether some technologies or techniques, such as DFS, might limit the 
types of applications that could be implemented in the U-NII bands, 
particularly if wider bandwidth devices are deployed in this spectrum.
    68. Also, at the 2012 World Radio Conference, the United States 
along with other countries agreed that the next World Radio Conference 
in 2015 (WRC-15) should consider additional spectrum allocations to the 
mobile service for the development of terrestrial mobile broadband 
applications. In preparation for WRC-15, the International 
Telecommunications Union initiated spectrum sharing studies that 
consider possible expansion of the existing international allocations 
to the mobile services in the 5 GHz band which are used primarily by 
the radio local area network (RLAN) devices. The Commission seeks 
comment on how these activities should inform the Commission's 
consideration of technical requirements for these bands and sharing 
technologies and techniques in the following paragraphs. The Commission 
also seeks comment on importance and benefits of harmonization between 
the Commission's U-NII rules and the international radio regulations.
2. Incumbent Services in the U-NII-2B Band
    69. The 5.35-5.47 GHz band is allocated on a primary basis to the 
Earth Exploration Satellite, Space Research, and Radiolocation Services 
for Federal operations and on a secondary basis for non-Federal 
operations. The 5.35-5.46 GHz band segment is allocated on a primary 
basis to the Aeronautical Radionavigation Service for both Federal and 
non-Federal operations. The 5.46-5.47 GHz band segment is allocated on 
a primary basis to the Radionavigation Service for both Federal and 
non-Federal operations.
    a. Overview of Federal Systems
    70. RADAR Systems. The DoD uses the 5.35-5.47 GHz band for a wide 
variety of ground-based, shipborne, and airborne radars. These military 
radars have the operational capability to tune across the entire 5.25-
5.725 GHz frequency range and can operate on a fixed frequency or can 
employ frequency hopping techniques. In the past, these radars have 
operated on or near military installations. However, situations may 
arise where these radars have to be used more widely in support of 
homeland security. One of the areas of concern in assessing 
interference to military radars stems from future radar deployments and 
the expanding role of military radars in support of homeland defense. 
This expanded role could result in a requirement to deploy military 
radars in cities and metropolitan areas where unlicensed devices will 
have their highest usage. In addition to DoD, several other agencies 
operate radar systems in the band. The Coast Guard operates shipborne 
radars, which are vital sensors for safe navigation of waterways. NASA 
uses this band for test and launch range instrumentation radars to 
track rockets, missiles, satellites, launch vehicles, and other 
targets. NOAA operates radar systems in this band on ``Hurricane 
Hunter'' aircraft. The Department of Energy operates radar systems and 
associated transponders in the band at two test ranges in the United 
States.
    71. Spaceborne Altimeter Radar Systems. NASA, in joint ventures 
with the French agency, Centre National d'Etudes Spatiales (CNES), 
operates a space-based altimeter system in the 5.14-5.46 GHz band that 
is used to obtain measurements of the Earth's ocean surface height.
    72. Earth Exploration Satellite. Synthetic aperture radar (SAR) 
systems in the 5.35-5.47 GHz band perform space-based observations and 
measurements of surface topography, soil moisture, and sea surface 
height. The higher quality data collected using wideband SARs allow 
scientists to gain new insights into the prediction of climatic 
changes. These wideband SARs also provide the higher resolution 
necessary for commercial applications, such as high-resolution surface 
mapping. Canada operates an Earth exploration-satellite, known as 
RADARSAT, in the 5.35-5.47 GHz band to provide mission critical data in 
support of national security, public safety, law enforcement, and 
civilian applications in Canada and the United States. These 
applications include disaster management, response and recovery for 
safety of life, ice monitoring, surveillance, hydrology, mapping, and 
geology, safety of navigation, agriculture, and forestry. For example, 
the United States Coast Guard International Ice Patrol uses RADARSAT 
data operationally to detect and track icebergs.
    73. Unmanned aircraft systems (UAS). DoD utilizes this band for the 
testing and operation of unmanned aircraft system (UAS) datalinks from 
aircraft-to-ground and from ground-to-aircraft. The command link, a 
ground data terminal transmitter, operates at 5.625-5.85 GHz and the 
return link (UAS transmitter) transmits at 5.25-5.475 GHz. The Army, 
Navy, and Air Force operate UASs in the 5 GHz frequency range for 
intelligence, surveillance, and reconnaissance; combat search and 
rescue; and real-time full-motion video for target development. The 
Department of Homeland Security also operates UASs in this band for 
drug interdiction and border surveillance operations. In addition, NASA 
also operates a limited number of systems in the 5.35-5.47 GHz band 
that are used for downlink transmissions of data to ground control 
receivers.
b. Overview of Non-Federal Systems
    74. The types of Federal and non-Federal systems in the 5.35-5.47 
GHz band are similar except that non-Federal users in the Earth 
Exploration Satellite, Space Research, and Radiolocation Services 
operate on a secondary basis. Broadcast and media entities use radars 
operating in the 5.35-5.47 GHz band for tracking storms and providing 
weather radar information to the public via news and weather reporting. 
Weather radars are employed by broadcasters throughout the USA and used 
to detect supercell storms capable of developing tornados and severe 
weather. Local TV stations throughout the country utilize 5.35-5.47 GHz 
band providing viewers with weather maps, weather pictures, and 
informing the public on a range of local and regional weather warnings. 
Part 90 of FCC rules permit the operation of weather radar services in 
the 5.35-5.47 GHz band.
3. Incumbent Services in the U-NII-4 Band
    75. The 5.85-5.925 GHz band is allocated on a primary basis to the 
Radiolocation Service for Federal operations and to the Fixed Satellite

[[Page 21332]]

(Earth to space) and Mobile Services for non-Federal operations. This 
band is also allocated on a secondary basis to the Amateur Service for 
non-Federal operations.
a. Overview of Federal Systems
    76. The radars that operate in the 5.825-5.925 GHz band are 
primarily military surveillance and test range instrumentation systems 
and can be either mobile or transportable. In addition to the DoD 
operation, NASA, NOAA, and Department of Energy operate radar systems 
in the 5.85-5.925 GHz band throughout the United States.
b. Overview of Non-Federal Systems
    77. Fixed Satellite Services (FSS). The C-band is divided into a 
heavily-used ``conventional'' segment (3.7-4.2 GHz downlink and 5.925-
6.425 GHz uplink) and a lightly-used ``extended'' segment (3.6-3.7 GHz 
downlink and 5.85-5.925 GHz and 6.425-7.075 GHz uplink). The non-
Federal fixed-satellite service allocation in the extended C-band FSS 
(5.85-5.925 GHz) is limited to international inter-continental systems 
and is subject to case-by-case electromagnetic compatibility analysis. 
Earth stations in stationary locations communicate uplink with 
geostationary satellites such as Intelsat, Inmarsat, JCSAT-2, Mabuhay, 
New Skies, and Galaxy. The earth stations and satellites use 
directional antennas which, along with the separation between the 
satellites, prevent interference with earth stations communicating with 
adjacent satellites. The FSS operations in the 5.85-5.925 GHz band are 
authorized under Part 25 of the FCC rules.
    78. The FSS is widely used to provide a variety of commercial 
services domestically and internationally. For example, the FSS 
supports video distribution both on point-to-point basis and point-to-
multipoint bases. The FSS also provides network services consisting of 
``backbone'' capacity for point-to-point trunking for voice, data or 
Internet traffic; backhaul of communications services; and redundancy 
and restoration of communications services when other primary 
technologies fail. Further, the FSS is used to provide corporate, 
government, and military voice and data communications, as well as 
broadband and video services directly to the home.
    79. Intelligent Transportation Service (ITS). The non-Federal 
Mobile allocation is limited to Dedicated Short Range Communications 
Service (DSRC) systems operating in the Intelligent Transportation 
System radio service. ITS is a national program aimed at using state-
of-the-art communications system to make travel more efficient, safer 
and convenient for motorists, transit riders, commercial vehicle 
operators and public safety providers. Through the use of technologies 
such as roadside and/or overhead Variable Message Signs, Closed Circuit 
TV, Highway Advisory Radio transmitters, traffic counter loops and 
Transcom's System for Managing Incidents and traffic flow monitors, 
real-time traffic information is collected and conveyed to the 
traveling public. This multi-modal information then allows motorists to 
make smarter choices about how, when and where to travel.
    80. DSRC is a wireless ITS system designed for automotive use. In 
October 1999, the FCC allocated 75 megahertz of spectrum in the 5.85-
5.925GHz band for DSRC to be used by ITS. DSRC is a two-way short- to- 
medium-range wireless communications capability that permits very high 
data transmission critical in communications-based active safety 
applications. DSRC which involves vehicle-to-vehicle (V2V) and vehicle-
to-infrastructure (V2I) communications can save lives by warning 
drivers of an impending dangerous condition or event in time to take 
corrective or evasive actions. Vehicle safety applications that use V2V 
and V2I communications need secure, wireless interface dependability in 
extreme weather conditions, and short time delays; all of which are 
facilitated by DSRC. FCC grants licenses for state and regional 
transportation agencies to operate DSRC roadside units, while DSRC 
onboard units are licensed by rule under Part 95.
    81. Amateur Radio. Amateur service stations are permitted to 
transmit in the 5.85-5.925 GHz frequency segment on a secondary basis. 
Operation of these stations in this frequency segment must not cause 
harmful interference to, and must accept interference from, authorized 
stations in the fixed-satellite (earth to space) and mobile services 
(DSRC) and also stations authorized by other nations in the fixed 
service. The FCC does not have detailed information on use of this band 
by amateur service stations.
4. Technical Requirements for U-NII-2B and U-NII-4 Bands
    82. The technical requirements for U-NII devices operating in the 
U-NII-2B and U-NII-4 bands will depend ultimately on a determination of 
the types of unlicensed operations that can be supported while 
maintaining interference protection to incumbent Federal and non-
Federal users. Nonetheless, the Commission believes that because the 
types of incumbent services across the 5 GHz spectrum share similar 
characteristics, the technical requirements for unlicensed devices also 
could share similar characteristics.
    83. U-NII-2B Band. The U-NII-2B band falls between the existing U-
NII-2A and U-NII-2C bands. Most significantly, all three bands are 
allocated for Federal Earth Exploration Satellite, Space Research and 
Radiolcoation Services on a primary basis, and sensitive services such 
as Federal radar systems operate across all three bands. This suggests 
that U-NII devices could likely operate under the same technical 
framework specified in rule Sec.  15.407 in all three bands ranging 
from 5.25-5.725 GHz. Thus, U-NII devices could operate across 475 
megahertz either indoors or outdoors under the following power and 
emission limits: maximum output power limit is the lesser of 250 
milliwatts and 11dBm+10 Log (B), where B is 26 dB emission bandwidth; 
antenna gain requirement is 6 dBi for non-point to-point systems and 23 
dBi for point-to-point system; and power and power spectral density 
reduction is applied if the antenna gain exceeds these values. The 
maximum power spectral density should not exceed 11 dBm in any 1 
megahertz band, and the out-of-band emission limit shall not exceed an 
EIRP limit of -27 dBm/MHz. The out-of-channel emissions limit for an 
outdoors device should not exceed -41 dBm/MHz. The Commission invites 
comment on these technical parameters for U-NII-2B devices.
    84. U-NII-4 Band. The U-NII-4 band is situated 25 megahertz above 
the U-NII-3 band. A primary Federal allocation for Radiolocation 
Services and a non-Federal secondary allocation for Amateur Services 
range across the U-NII-3 and U-NII-4 bands, including the 25 megahertz 
located between them at 5.825-5.85 GHz. This suggests that U-NII 
devices should operate under the same framework and technical 
requirements specified in Sec.  15.407 in all three bands ranging from 
5.725-5.925 GHz. The Commission proposes that the U-NII-3 rules be 
applied to the upper adjacent 25 megahertz band segment at 5.825-5.85 
GHz. If the Commission adopts this proposal, it believes that the same 
framework and technical requirements specified in Sec.  15.407 should 
apply across the expanded U-NII-3 and the U-NII-4 bands. Thus, U-NII 
devices could operate across 200 megahertz either indoors or outdoors 
under the following power and emission limits: maximum output power 
limit is the lesser of 1Watt and 17dBm+10 Log (B) where B is 26 dB 
emission

[[Page 21333]]

bandwidth; antenna gain requirements is 6 dBi for non-point to-point 
systems and 23 dBi for point-to-point systems; and power and power 
spectral density reduction is applied if the antenna gain exceeds these 
values. The maximum power spectral density should not exceed 17 dBm in 
any 1 megahertz band, and out-of-band emissions within the frequency 
range from the band edge to 10 megahertz above or below the band edge 
should not exceed an EIRP limit of -17 dBm/MHz, and for frequencies 10 
megahertz or greater, the emissions should not exceed an EIRP of -27 
dBm/MHz. The Commission invites comment on these technical parameters 
for U-NII-4 devices.
    85. Spectrum Sensing/DFS and TPC. The rules require that U-NII 
devices operating in the U NII-2A and U-NII-2C bands employ Dynamic 
Frequency Selection (DFS) in order to avoid causing interference to 
Federal radar systems. The Commission seeks comment whether and how to 
integrate a DFS algorithm into U-NII-2B and U-NII-4 bands. What are the 
advantages and/or disadvantages of utilizing DFS in these bands? What 
are the technical challenges of DFS technology implementation in the U-
NII-2B and U-NII-4 bands? What changes are necessary in the existing 
DFS model to mitigate possible interference with incumbent radar system 
in the new bands? What radar parameters/signal detection threshold 
should be used for DFS to avoid assigning the occupied radar channel to 
U-NII device? If the U-NII device would have to perform sensing outside 
its occupied bandwidth (adjacent channel sensing), what would be the 
technical and cost implications of such deployment? Should the radar 
signal detection be sensed by base/fix stations, mobile stations or 
all? Are there technical solutions other than DFS that would prevent 
interference to Federal radar systems? Could database access offer any 
benefits for providing access to this spectrum while protecting 
incumbent services against harmful interference?
    86. The signal detection technology currently used by U-NII-2A and 
U-NII-2C DFS devices senses radar signals whose parameters (such as 
pulsewidth, pulse repetition interval, and the number of pulses per 
burst) are well-known and can be used to improve signal detection. To 
improve range resolution and accuracy, some radar systems operating in 
the U-NII-2B and U-NII-4 bands employ short (sub-microsecond) pulse 
widths. The smallest pulsewidth used in the development of the existing 
U-NII DFS regulations was 1 microsecond. A narrower radar pulsewidth 
used in conjunction with the higher data rates associated with the 
802.11ac standard could affect a device's ability to detect pulsed 
radar signals. The Commission seeks comment on the ability of signal 
sensing spectrum-sharing technologies to detect sub-microsecond pulses 
and whether the current DFS mechanism would protect the current and 
future radars that employ sub-microsecond pulses. Are there other 
detection mechanisms that could be considered?
    87. In addition, some fielded and in-development radar systems in 
the U-NII-2B and U-NII-4 bands include low-power modes or are designed 
to avoid detection to meet their mission requirements. The Commission 
seeks comment on whether DFS or any other spectrum-sharing technology 
would be capable of protecting such radar systems from possible 
interference.
    88. Finally, what measures should be taken to protect non-radar 
systems that operate in the U-NII-2B and U-NII-4 bands and what is the 
cost implication for manufacturers, vendors and consumers? The 
Commission seeks comment on what types of sharing technology or 
techniques could be used to protect non-radar systems, such as the 
DSRCS which includes both road side units (RSU-fixed) and on board 
units (OBU-mobile) operating under a primary allocation. For example, 
U-NII signal detection technologies used for DFS may not be able to 
detect signals from incumbents other than radar systems. Could U-NII 
devices detect signals from both DSRC fixed and mobile stations? The 
Commission seeks comments on evolving technologies that may help to 
detect non-radar signals and to protect those operations from harmful 
interference.
5. NTIA 5 GHz Report
    89. NTIA has published a report of its initial study on the 
potential for U-NII devices to share the U-NII-2B and U-NII-4 bands 
with incumbent Federal operations. The report includes an initial 
evaluation of known and proposed spectrum-sharing technologies and also 
completed a high-level evaluation of the risk to Federal users if the 
Commission allows U-NII devices to operate in the U-NII-2B and U-NII-4 
bands.
    90. NTIA, in collaboration with the Federal agency members of the 
Policy and Plans Steering Group (PPSG), developed a work plan for 
evaluating the risks to Federal systems operating in the U-NII-2B and 
U-NII-4 bands. The plan outlined the technical and operational 
information necessary to perform the evaluation. Several Federal 
agencies also conducted preliminary electromagnetic compatibility and 
interference analyses to begin to quantify risks to their systems. NTIA 
also used input from industry stakeholders related to their projected 
technical and deployment parameters for U-NII devices, and reviewed 
domestic and international technical studies used in the development of 
the existing U-NII regulations in performing their study. For the 
study, NTIA assumed that the FCC's existing U-NII TPC and DFS 
regulations would be extended to the U-NII-2B and U-NII-4 bands, and 
that the Federal agencies will not have to alter their systems or 
operations to accommodate U-NII devices. The report concludes that 
additional analysis is needed to determine the feasibility of 
introducing U-NII devices into these two bands and includes a tentative 
schedule and milestones for quantitative study consistent with the 
ongoing work for WRC-15.
    91. The Commission seeks comments on all aspects of the NTIA 5 GHz 
Report, particularly the spectrum sharing technologies and risk 
analysis described in the following paragraphs.
a. Spectrum Sensing Technologies
    92. The report addresses three spectrum sharing technologies that 
might be used as reference models in the U-NII-2B and U-NII-4 bands. 
These are classified as sensing based, geo-location based, and 
beaconing/pilot channel technologies.
    93. Sensing based technology. Sensing based spectrum sharing 
approaches enable radio devices to identify unused spectrum by 
assessing and determining current use of a particular frequency 
through, for example, transmitter detection, cooperative sensing, or 
interference detection. Transmitter detection is the capability of 
determining if a signal from another transmitter is using a frequency 
nearby by correlating a known signal with an unknown signal (matched 
filter detection), measuring signal energy (signal detection), or 
utilizing statistical means. Cooperative sensing incorporates 
information about the spectral environment from multiple sensing 
devices to accurately determine if spectrum is in use. Interference 
detection refers to sensing changes in the local noise floor to 
determine if additional traffic can be tolerated by primary users.
    94. Geo-Location based technology. This approach requires the 
development of a database infrastructure that contains information 
about incumbent spectrum users which, when used in combination

[[Page 21334]]

with a geo-location system (e.g., the Global Positioning System (GPS)) 
and an interference-free location-data communications link, provides a 
mechanism to facilitate spectrum sharing with incumbents operating at 
fixed or known locations with known technical parameters. Geo-location 
spectrum-sharing technologies can be used in conjunction with a well 
maintained updated database to define geographic areas where device 
operation will and will not be permitted, or where limitations should 
be placed on the operating parameters to enable spectrum sharing.
    95. Beaconing/pilot channel technology. In a beacon spectrum 
sharing approach, a new entrant's transceiver must have the ability to 
receive a control signal sent continuously by incumbent systems at 
times when transmissions by the new entrant are permitted. The new 
entrant may not commence transmissions if beacon signals are not 
received. If any beacon signal is present but then stops while the new 
entrant is transmitting, transmissions must cease within a specified 
time interval. The beacons could be a radio frequency signal sent by 
incumbents on designated control frequencies, or they may be signals 
received over a physical connection such as fiber, copper, or coaxial 
cable. Transmission by the new entrant would cease if any beacon signal 
suffers from unfavorable propagation conditions or the physical 
connection is lost such that the beacon signals are not properly 
received by the new entrant. In other words, if the new entrant cannot 
hear the beacon signal, it must cease transmission.
b. Risk Analysis
    96. The NTIA 5 GHz Report provides an overview of the risk elements 
to each type of Federal operation and suggests some mitigation 
strategies associated with each risk element for further investigation.
    97. Description of risk elements in U-NII-2B band. The report 
indicates that changes in radar signal parameters may impact U-NII 
device detection of radar and changes in U-NII device deployment and 
technical parameters may result in harmful interference into radar 
systems. The report also emphasizes that the current U-NII regulations 
may introduce hidden node interference and may not adequately protect 
current and future radar systems while changes in the existing U-NII 
DFS detection parameters, including channel response time, may not 
sufficiently shield current and future radar systems from serious 
degradation. The report extends the risk element to the U-NII devices 
operating on an adjacent channel and states this may cause harmful 
interference into radar systems. The report also specifies that the 
radar receiver interference protection criteria used to develop 
existing U-NII DFS regulations may not address low-level interference 
effects.
    98. The report states that the existing U-NII signal detection 
technologies may not be capable of detecting UAS signals because the 
existing U-NII regulations were not developed to detect such signals 
(there is no UAS signal in the bands governed by the existing U-NII 
regulations) and changes to U-NII DFS detection parameters may not 
protect UAS operations from performance degradation. The report also 
points out that existing U-NII regulations were not developed to 
protect spaceborne receivers. The report also states that the density 
of U-NII devices is one of the key parameters in determining the amount 
of potential interference to the incumbent Federal systems.
    99. Description of risk elements in U-NII-4 band. The report cites 
the same risks to radar systems operating in the U-NII-4 band as it 
cites for the U-NII-2B band discussed above. The report also states 
that the existing U-NII signal detection technologies may not be 
capable of detecting DSRC signals because the existing U-NII 
regulations were not originally developed to detect such signals (there 
is no DSRC signal in the bands governed by the existing U-NII 
regulations) and changes to U-NII DFS detection parameters may not 
protect DSRC operations from performance degradation.

C. Other Issues

1. Miscellaneous Rule Modifications
    100. The Commission also believes that there are a number of other 
changes that need to be considered to simplify and clarify part 15 of 
the rules. The Commission's analysis revealed several sections of the 
rules that reference procedures or provisions that are no longer in use 
and therefore, may no longer be necessary. The Commission has also 
identified sections of the rules that need to be updated with minor 
revisions.
2. Transition Periods
    101. The Commission proposes to establish a 12-month timetable 
after the effective date of any new or modified rules that the 
Commission eventually decides to adopt in this proceeding for 
manufacturers to produce U-NII devices that comply with new or modified 
rules. The Commission also proposes to establish a 2 year timetable 
after the effective date of any new or modified rules for requiring 
that any U-NII devices manufactured in or imported into the United 
States for sale comply with the new or modified rules. The Commission 
believes that a 12-month transition period should provide sufficient 
time for manufacturers to design equipment that complies with any new 
or modified rules and to obtain equipment certification. Therefore, the 
Commission would provide transitional provisions in its rules to allow 
for the certification of U-NII devices under the current rules for up 
to 12 months after the new or modified rules are published in the 
Federal Register. Beginning 12 months after the effective date of the 
new or modified rules, equipment certification could no longer be 
obtained for U-NII devices that do not meet the new requirements. 
However, until the end of the 2 year transition period, the Commission 
would permit Class II permissive changes for equipment certified prior 
to the 12-month transition date as well as their continued manufacture, 
marketing, installation, and importation. After the end of the 2-year 
transition period, Class II permissive changes for such devices would 
not be permitted nor would their manufacture, marketing, installation, 
or importation. The Commission finds that these requirements would 
facilitate the transition to new requirements without unduly impairing 
the availability or cost of U-NII devices or imposing undue burdens on 
manufacturers, translation services providers, or the public. Comments 
are requested on these proposed transition provisions.
    102. The Commission also proposes that U-NII devices that are 
already installed or in use should be grandfathered for the life of the 
equipment. Requiring the immediate upgrade or replacement of existing 
U-NII devices would be a financial burden on operators of these 
devices. The Commission believes that grandfathering equipment that is 
installed and operating will ensure that entities will be permitted to 
operate their existing U-NII devices until replacement is necessary or 
desired due to age, malfunction, or other concerns. The Commission 
seeks comments on this proposal.

Initial Regulatory Flexibility Analysis

    103. As required by the Regulatory Flexibility Act of 1980, as 
amended (RFA), the Commission has prepared this present Initial 
Regulatory Flexibility Analysis (IRFA) of the possible significant 
economic impact on small entities by the policies and rules

[[Page 21335]]

proposed in this Notice of Proposed Rule Making (NPRM). Written public 
comments are requested on this IRFA. Comments must be identified as 
responses to the IRFA and must be filed by the deadlines specified in 
the NPRM for comments. The Commission will send a copy of this NPRM, 
including this IRFA, to the Chief Counsel for Advocacy of the Small 
Business Administration (SBA). In addition, the NPRM and IRFA (or 
summaries thereof) will be published in the Federal Register.

A. Need for, and Objectives of, the Proposed Rules

    104. This NPRM proposes to amend part 15 of the FCC's rules 
governing the operation of unlicensed National Information 
Infrastructure (U-NII) devices in the 5 GHz band. U-NII devices are 
unlicensed intentional radiators that operate in the frequency bands 
5150-5350 MHz and 5470-5825 MHz that use wideband digital modulation 
techniques to provide a wide array of high data rate mobile and fixed 
communications for individuals, businesses, and institutions. The NPRM 
proposes to modify certain technical requirements for U-NII devices to 
ensure that these devices can continue to operate successfully while 
protecting incumbent spectrum users.

B. Legal Basis

    105. This action is authorized under Sections 1, 4(i), 302, 303(f) 
and (r), 332, and 337 of the Communications Act of 1934, as amended, 47 
U.S.C. 1, 4(i), 154(i), 302, 303(f) and (r), 332, 337.

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

    106. The RFA directs agencies to provide a description of, and, 
where feasible, an estimate of, the number of small entities that may 
be affected by the rules adopted herein. The RFA generally defines the 
term ``small entity'' as having the same meaning as the terms ``small 
business,'' ``small organization,'' and ``small governmental 
jurisdiction.'' In addition, the term ``small business'' has the same 
meaning as the term ``small business concern'' under the Small Business 
Act. A ``small business concern'' is one which: (1) Is independently 
owned and operated; (2) is not dominant in its field of operation; and 
(3) satisfies any additional criteria established by the Small Business 
Administration (SBA).
    107. Radio and Television Broadcasting and Wireless Communications 
Equipment Manufacturing. The Census Bureau defines this category as 
follows: ``This industry comprises establishments primarily engaged in 
manufacturing radio and television broadcast and wireless 
communications equipment. Examples of products made by these 
establishments are: transmitting and receiving antennas, cable 
television equipment, GPS equipment, pagers, cellular phones, mobile 
communications equipment, and radio and television studio and 
broadcasting equipment.'' The SBA has developed a small business size 
standard for Radio and Television Broadcasting and Wireless 
Communications Equipment Manufacturing, which is: all such firms having 
750 or fewer employees. According to Census Bureau data for 2007, there 
were a total of 939 establishments in this category that operated for 
part or all of the entire year. Of this total, 912 had less than 500 
employees and 17 had more than 1000 employees. Thus, under that size 
standard, the majority of firms can be considered small.

D. Description of Projected Reporting, Record Keeping, and Other 
Compliance Requirements

    108. The NPRM proposes to establish a 12-month timetable after the 
effective date of any new or modified rules that we eventually decide 
to adopt in this proceeding for manufacturers to produce U-NII devices 
that comply with new or modified rules. We also propose to establish a 
2-year timetable after the effective date of any or modified rules for 
requiring that any U-NII devices manufactured in or imported into the 
United States for sale comply with the new or modified rules. We 
believe that a 12-month transition period should provide sufficient 
time for manufacturers to design equipment that complies with any new 
or modified rules and to obtain equipment certification. Therefore, we 
would provide transitional provisions in our rules to allow for 
certification of U-NII devices under the current rules for up to 12 
months after the new or modified rules are published in the Federal 
Register. Beginning 12 months after the effective date of the new or 
modified rules, equipment certification could no longer be obtained for 
U-NII devices that do not meet the new requirements. However, until the 
end of the 2-year transition period, we would permit Class II 
permissive changes for equipment certified prior to the 12-month 
transition date as well as their continued manufacture, marketing, 
installation, and importation. After the end of the 2-year transition 
period, Class II permissive changes for such devices would not be 
permitted nor would their manufacture, marketing, installation, or 
importation. We find that these requirements would facilitate the 
transition to new requirements without unduly impairing the 
availability or cost of U-NII devices or imposing undue burdens on 
manufacturers, translation services providers, or the public.

E. Steps Taken To Minimize Significant Economic Impact on Small 
Entities, and Significant Alternatives Considered

    109. The RFA requires an agency to describe any significant 
alternatives that it has considered in reaching its proposed approach, 
which may include the following four alternatives (among others): (1) 
The establishment of differing compliance or reporting requirements or 
timetables that take into account the resources available to small 
entities; (2) the clarification, consolidation, or simplification of 
compliance or reporting requirements under the rule for small entities; 
(3) the use of performance, rather than design, standards; and (4) an 
exemption from coverage of the rule, or any part thereof, for small 
entities.
    110. The proposals contained in this Notice of Proposed Rulemaking 
(NPRM) are aimed at improving the sharing of the spectrum between U-NII 
devices and other spectrum users. This NPRM proposes to amend Part 15 
of our rules governing the operation of Unlicensed National Information 
Infrastructure (U-NII) devices in the 5 GHz band. U-NII devices are 
unlicensed intentional radiators that operate in the frequency bands 
5.15-5.35 GHz and 5.47-5.825 GHz, and which use wideband digital 
modulation techniques to provide a wide array of high data rate mobile 
and fixed communications for individuals, businesses, and institutions. 
Since the Commission first made available spectrum in the 5 GHz band 
for U-NII in 1997, we have gained much experience with these devices. 
We believe that the time is now right for us to revisit our rules, and, 
in this NPRM, we propose to modify certain technical requirements for U 
NII devices to ensure that these devices do not cause harmful 
interference and thus can continue to operate in the 5 GHz band and 
make broadband technologies available for consumers and businesses.
    111. We also seek comment on making available an additional 195 
megahertz of spectrum in the 5.35-5.47 GHz and 5.85-5.925 GHz bands for 
U-NII use. This could increase the spectrum available to unlicensed 
devices in the 5 GHz band by approximately 35 percent and would 
represent a significant increase in the

[[Page 21336]]

spectrum available for unlicensed devices across the overall radio 
spectrum. The initiation of this proceeding satisfies the requirements 
of Sec.  6406 (a) of the ``Middle Class Tax Relief and Job Creation Act 
of 2012'' which requires the Commission to begin a proceeding to modify 
part 15 of title 47, Code of Federal Regulations, to allow unlicensed 
U-NII devices to operate in the 5350-5470 MHz band. We believe that an 
increase in capacity gained from 195 megahertz of additional spectrum, 
combined with the ease of deployment and operational flexibility 
provided by our U-NII rules, would continue to foster the development 
of new and innovative unlicensed devices, and increase wireless 
broadband access and investment.

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

    112. None.

Ordering Clauses

    113. Pursuant to sections 1, 4(i), 7(a), 301, 303(f), 303(g), 
303(r), and 307(e) of the Communications Act of 1934, as amended, 47 
U.S.C. 151, 154(i), 157(a), 301, 303(f), 303(g), 303(r), and 307(e), 
and section 6406(a) of the Middle Class Tax Relief and Job Creation Act 
of 2012, Public Law 112-96, Sec.  6406(a), 126 Stat. 156, 231 (2012), 
the Notice of Proposed Rule Making is adopted.
    114. The Commission's Consumer and Governmental Affairs Bureau, 
Reference Information Center, shall send a copy of the Notice of 
Proposed Rule Making, including the Initial Regulatory Flexibility 
Analysis, to the Chief Counsel for Advocacy of the Small Business 
Administration.

List of Subjects in 47 CFR Part 15

    Communications equipment.

Federal Communications Commission.
Marlene H. Dortch,
Secretary.
    For the reasons discussed in the preamble, the Federal 
Communications Commission proposes to amend 47 CFR part 15 as follows:

PART 15--RADIO FREQUENCY DEVICES

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

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

0
2. Section 15.215 is amended by adding a second sentence to paragraph 
(c) to read as follows:


Sec.  15.215  Additional provisions to the general radiated emission 
limitations.

* * * * *
    (c) * * * In the case of intentional radiators operating under the 
provisions of Subpart E, the emission bandwidth may span across 
multiple frequency bands identified in that Subpart. * * *
0
3. Section 15.247 is amended by:
0
a. Revising the first sentence of paragraphs (a)(2) and (b)(3);
0
b. Removing paragraphs (b)(4)(i) through (iii);
0
c. Revising paragraph (c)(1)(ii) and the last sentence of paragraph (f) 
to read as follows:


Sec.  15.247  Operation within the bands 902-928 MHz, 2400-2483.5 MHz, 
and 5725-5850 MHz.

* * * * *
    (a) * * *
    (2) Systems using digital modulation techniques may operate in the 
902-928 MHz, and 2400-2483.5 MHz bands. * * *
    (b) * * *
    (3) For systems using digital modulation in the 902-928 MHz, and 
2400-2483.5 MHz bands: 1 Watt. * * *
* * * * *
    (c) * * *
    (1) * * *
    (ii) Frequency hopping systems operating in the 5725-5850 MHz band 
that are used exclusively for fixed, point-to-point operations may 
employ transmitting antennas with directional gain greater than 6 dBi 
without any corresponding reduction in transmitter conducted output 
power.
* * * * *
    (f) * * * The power spectral density conducted from the intentional 
radiator to the antenna due to the digital modulation operation of the 
hybrid system, with the frequency hopping operation turned off, shall 
not be greater than 8 dBm in any 3 kHz band during any time interval of 
continuous transmission.
* * * * *
0
4. Section 15.403 is amended by revising paragraph (m) to read as 
follows:


Sec.  15.403  Definitions.

* * * * *
    (m) Maximum Power Spectral Density. The maximum power spectral 
density is the maximum power in the specified measurement bandwidth, 
within the U-NII device operating band.
* * * * *
0
5. Section 15.407 is amended by:
0
a. Revising paragraphs (a)(3) through (6) and (b)(4);
0
b. Redesignating paragraphs (f) through (h) as paragraphs (g) through 
(i), and;
0
c. Adding new paragraph (f) and paragraph (j) to read as follows:


Sec.  15.407  General technical requirements.

    (a) * * *
    (3) For the band 5.725-5.850 GHz, the maximum conducted output 
power over the frequency band of operation shall not exceed 1 W. In 
addition, the maximum power spectral density shall not exceed 8 dBm in 
any 3-kHz band. If transmitting antennas of directional gain greater 
than 6 dBi are used, both the maximum conducted output power and the 
maximum power spectral density shall be reduced by the amount in dB 
that the directional gain of the antenna exceeds 6 dBi. However, fixed 
point-to-point U-NII devices operating in this band may employ 
transmitting antennas with directional gain up to 23 dBi without any 
corresponding reduction in the transmitter peak output power or maximum 
power spectral density. For fixed, point-to-point U-NII transmitters 
that employ a directional antenna gain greater than 23 dBi, a 1 dB 
reduction in peak transmitter power and maximum power spectral density 
for each 1 dB of antenna gain in excess of 23 dBi would be required. 
Fixed, point-to-point operations exclude the use of point-to-multipoint 
systems, omnidirectional applications, and multiple collocated 
transmitters transmitting the same information. The operator of the U-
NII device, or if the equipment is professionally installed, the 
installer, is responsible for ensuring that systems employing high gain 
directional antennas are used exclusively for fixed, point-to-point 
operations.

    Note To Paragraph (a)(3): The Commission strongly recommends 
that parties employing U-NII devices to provide critical 
communications services should determine if there are any nearby 
Government radar systems that could affect their operation.

    (4) The maximum conducted output power must be measured over any 
interval of continuous transmission using instrumentation calibrated in 
terms of an rms-equivalent voltage.
    (5) The maximum power spectral density is measured as a conducted 
emission by direct connection of a calibrated test instrument to the 
equipment under test. If the device cannot be connected directly, 
alternative techniques acceptable to the Commission may be used. 
Measurements are made over a bandwidth of 1 MHz or the 26-dB emission 
bandwidth of the device, whichever is less. A resolution bandwidth less 
than the measurement bandwidth can be used, provided that the measured 
power is integrated to

[[Page 21337]]

show total power over the measurement bandwidth. If the resolution 
bandwidth is approximately equal to the measurement bandwidth, and much 
less than the emission bandwidth of the equipment under test, the 
measured results shall be corrected to account for any difference 
between the resolution bandwidth of the test instrument and its actual 
noise bandwidth.
    (6) The ratio of the maximum peak excursion of the modulation 
envelope (measured in a 1 MHz bandwidth using a peak hold function) to 
the maximum power spectral density during an interval of continuous 
transmission (measured in a 1 MHz bandwidth) shall not exceed 13 dB. 
Each of the two maxima shall be separately determined across the full 
emission bandwidth. If the emission bandwidth is less than 1 MHz, the 
measurement may be performed in a resolution bandwidth narrower than 1 
MHz but wider than or equal to the emission bandwidth.
    (b) * * *
    (4) For transmitters operating in the 5.725-5.850 GHz band: all 
emissions within the frequency range from the band edge to 10 MHz above 
or below the band edge shall not exceed an e.i.r.p. of -17 dBm/MHz; for 
frequencies 10 MHz or greater above or below the band edge, emissions 
shall not exceed an e.i.r.p. of -27 dBm/MHz.
* * * * *
    (f) Within the 5.725-5.85 GHz band, the minimum 6 dB bandwidth of 
U-NII devices shall be at least 500 kHz.
* * * * *
    (j) All U-NII Devices must contain security features to protect 
against modification of software by unauthorized parties.
[FR Doc. 2013-08033 Filed 4-9-13; 8:45 am]
BILLING CODE 6712-01-P