[Federal Register Volume 78, Number 233 (Wednesday, December 4, 2013)]
[Proposed Rules]
[Pages 72851-72858]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-28254]
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FEDERAL COMMUNICATIONS COMMISSION
47 CFR Part 95
[GN Docket No. 12-354; FCC 13-144]
Commission Seeks Comment on Licensing Models and Technical
Requirements in the 3550-3650 MHz Band
AGENCY: Federal Communications Commission.
ACTION: Proposed rule.
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SUMMARY: In this notice of proposed rulemaking, the Commission seeks
comment on some specific variations of the licensing and technical
proposals for the 3550-3650 MHz band (3.5 GHz Band) originally set
forth in Amendment of the Commission's rules with Regard to Commercial
Operations in the 3550-3650 MHz Band.
DATES: Submit comments on or before December 5, 2013 and reply comments
on or before March 20, 2013.
ADDRESSES: You may submit comments, identified by GN Docket No. 12-354,
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: 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. 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.
U.S. Postal Service first-class, Express, and Priority mail must be
addressed to 445 12th Street 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: [email protected] or phone: 202-418-
0530 or TTY: 202-418-0432.
For detailed instructions for submitting comments and additional
[[Page 72852]]
information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document.
FOR FURTHER INFORMATION CONTACT: Paul Powell, Attorney Advisor,
Wireless Bureau--Mobility Division at (202) 418-1613 or
[email protected].
SUPPLEMENTARY INFORMATION: This is a summary of the Commission's Public
Notice in GN Docket No. 12-354, FCC 13-144A1, Notice of Proposed
Rulemaking, 78 FR 1188 (January 8, 2012) (NPRM or 3.5 GHz NPRM),
adopted and released November 1, 2013. The full text of this document
is available for inspection and copying during normal business hours in
the FCC Reference Center, 445 12th Street SW., Washington, DC 20554.
The complete text may be purchased from the Commission's copy
contractor, Best Copy and Printing, Inc., 445 12th Street SW., Room CY-
B402, Washington, DC 20554, (202) 488-5300, facsimile (202) 488-5563,
or via email at [email protected]. The full text may also be downloaded
at: www.fcc.gov. Alternative formats are available to persons with
disabilities by sending an email to [email protected] or by calling the
Consumer & Governmental Affairs Bureau at 202-418-0530 (voice), 202-
418-0432 (tty).
Comment Filing Instructions:
Pursuant to Sec. Sec. 1.415 and 1.419 of the Commission's rules,
47 CFR 1.415 and 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 [email protected] or call the
Consumer & Governmental Affairs Bureau at 202-418-0530 (voice), 202-
418-0432 (tty).
Ex Parte Rules
As noted in the NPRM, this proceeding has been designated as a
``permit-but-disclose'' proceeding in accordance with the Commission's
ex parte rules.
Initial Paperwork Reduction Act Analysis
The NPRM included a separate request for comment from the general
public and the Office of Management and Budget on the information
collection requirements contained therein, as required by the Paperwork
Reduction Act of 1995, Public Law 104-13, and the Small Business
Paperwork Relief Act of 2002, Public Law 107-198. This Public Notice
seeks further comment on some proposals and alternatives initially
raised in the NPRM. We invite supplemental comment on these
requirements in light of the details and issues raised in the Public
Notice.
Synopsis of the Public Notice of Proposed Rulemaking
I. Introduction
In December 2012, the Commission released a Notice of Proposed
Rulemaking (NPRM) seeking comment on a new Citizens Broadband Service
in the 3550-3650 MHz band (3.5 GHz Band) for shared, commercial uses,
including small cell networks. The NPRM proposed a three-tier, license-
by-rule authorization framework that would facilitate rapid broadband
deployment while protecting existing incumbent users of the 3.5 GHz
Band. See 3.5 GHz NPRM, 78 FR 1188. The NPRM solicited comment on all
aspects of this proposal, including the appropriate licensing framework
and the potential uses of each service tier and the Commission has
received extensive comment from a wide range of stakeholders in
response. The Commission also held a workshop on March 14, 2013 to
bring together diverse perspectives on the band and foster productive
discussion on the NPRM. Based upon our review of the substantial record
before us, we have determined that it would be in the public interest
to solicit further comment on specific alternative licensing proposals
inspired by some of the suggestions made by commenters and workshop
participants to facilitate use of the band for a diverse array of
applications.
This proposed rule builds on the NPRM and elaborates on some
alternative licensing concepts described in that document. We refer to
these elaborated licensing concepts as the Revised Framework. The
Revised Framework describes an integrated approach to dynamically
authorizing access to the Priority Access and General Authorized Access
(GAA) tiers of the 3.5 GHz Band and represents one logical approach
towards implementing the next generation of spectrum management systems
in light of the proposals and alternative proposals set forth in the
NPRM, the presentations made at the workshop, and the record in this
proceeding. This proposed rule also includes examples of possible
technical specifications, which could enable multiple networks to
coexist in the band within a given geographic area. We seek detailed
comment on the Revised Framework and the possible technical criteria.
We request that commenters provide technical and cost-benefit analyses
to support their positions.
Our goal in seeking comment on the Revised Framework is to
supplement the record with focused comment on licensing and
authorization concepts for the 3.5 GHz Band. This Public Notice does
not discuss issues related to shared operations with incumbent federal
and Fixed Satellite System (FSS) users, potential out-of-band
interference issues, or any potential geographic restrictions on
commercial use of the 3.5 GHz Band.
II. Discussion
With this notice of proposed rulemaking, we seek comment on some
specific variations of the licensing and technical proposals set forth
in the NPRM. The Revised Framework discussed below synthesizes elements
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from the NPRM and various commenter proposals into an integrated
authorization scheme for the 3.5 GHz Band. In doing so, we seek to
advance the discussion about how new technologies can facilitate
coexistence between different kinds of users with different rights in
the band. The Revised Framework retains the three-tier model proposed
in the NPRM but, consistent with alternative authorization methods
raised in the NPRM, expands the eligibility criteria for the Priority
Access tier and explores innovative means of assigning exclusive
authorizations within the tier. Like the NPRM's main proposal, the
Revised Framework would leverage the unique capabilities of small cell
and SAS technologies to enable sharing between users in the Priority
Access and GAA tiers. Specifically, the Revised Framework contains the
following core concepts: (1) An SAS to dynamically manage frequency
assignments and automatically enforce access to the Priority Access and
GAA tiers; (2) open eligibility for Priority Access tier use; (3)
granular but administratively-streamlined licensing of the Priority
Access tier; (4) mutually exclusive spectrum rights for Priority Access
subject to licensing by auction, coupled with; (5) a defined ``floor''
of GAA spectrum availability, to ensure that GAA access is available
nationwide (subject to Incumbent Access tier use); (6) additional GAA
access to unused Priority Access bandwidth, as identified and managed
by the SAS, to maximize dynamic use of the unutilized portion of the
band and ensure productive use of the spectrum; (7) opportunities for
critical infrastructure facilities to obtain targeted priority spectrum
use within specific facilities (such as a building) that meet certain
requirements to mitigate the potential for interference to and from
other band users; and (8) a set of baseline technical standards to
prevent harmful interference and ensure productive use of the spectrum.
A. Priority Access Tier
The Revised Framework further develops some alternative proposals
contained in the NPRM with respect to the Priority Access tier. The
approach to the Priority Access tier described in the Revised Framework
reflects many commenters' desire to open the Priority Access tier to a
broader class of potential users. At the same time, the Revised
Framework retains a significant amount of spectrum for GAA uses and
incorporates innovative features designed to integrate with the unique
aspects of the Citizens Broadband Service and the 3.5 GHz Band. The
Revised Framework balances the benefits of exclusive licensing and open
eligibility with the need to preserve GAA spectrum access and promote
productive small cell use of the band. In this section, we describe
concepts related to: (1) Licensee qualifications for access to the
Priority Access tier; (2) the elements of the Priority Access Licenses
(PALs) which could be used to authorize access to the Priority Access
tier; and (3) potential methods for assigning access to the Priority
Access tier when mutually exclusive applications are received. We seek
comment, including costs and benefits, on the revised approach to the
Priority Access tier described below.
The Revised Framework would expand access to the Priority Access
tier to a broad class of potential users. The NPRM proposed limiting
Priority Access eligibility to certain ``mission critical'' users. In
the alternative, we also proposed a more open eligibility model. In
response to the NPRM, many commenters supported the ``open''
eligibility alternative. Several others endorsed restricted
eligibility, tailored to specific users or industries. Under the
Revised Framework, any prospective licensee who meets basic FCC
qualifications would be eligible to apply for Priority Access licenses.
We seek detailed comment on this approach, including the potential
range of eligible users and any associated costs and benefits.
1. Priority Access Licenses
In the NPRM, we asked for comment on the technical licensing and
regulatory ramifications of our proposal for Priority Access users.
Under the Revised Framework, a set of PALs would define and control
spectrum use in the Priority Access tier. PALs are intended to ensure
flexible and efficient use of the Priority Access tier, given the
characteristics of small cell networks and advanced capabilities of an
SAS. We envision a ``building block'' approach in which relatively
granular PALs could be aggregated--in space, time, and frequency--to
meet diverse spectrum needs. We seek specific comment below on the
geographical, temporal, and frequency dimensions of potential PALs and
on the administrability of PALs in the context of the broader Revised
Framework.
Time. Under the Revised Framework, PALs would have a one year, non-
renewable, term but licensees would be able to aggregate multiple
consecutive PALs to obtain multi-year rights to spectrum within a given
geographic area. PALs would automatically terminate after one year and
would not be renewed. While shorter than the 10- or 15-year terms
typically associated with area-licensed wireless services, a 1-year
term may be more appropriate in this case. First, multiple 1-year terms
could be aggregated together to replicate the predictability of a
longer-term license while providing much of the flexibility inherent in
shorter-term spectrum authorizations. Second, the use of a shorter,
non-renewable license term could simplify the administration of the
Priority Access tier by obviating the need for some administratively-
intensive rules that are common to longer-term licenses. These include
renewal, discontinuance, and performance requirements associated with a
traditional spectrum license. Third, shorter terms would allow for a
wider variety of innovative uses and encourage consistent and efficient
use of spectrum resources. Finally, short term licenses could promote
greater fungibility and liquidity in the secondary market. In light of
these factors, we seek comment on the appropriate duration of PALs and
any associated costs and benefits of this or other proposals.
Geography. Our goal is to establish the geographic component of
PALs in a way that allows flexible, micro-targeted network deployments,
promoting intensive and efficient use of the spectrum, but also
allowing easy aggregation to accommodate a larger network footprint.
Due to their low power and small size, small cells can provide
broadband coverage and capacity in targeted geographic areas. This
applies whether small cells are used to offer independent broadband
service, supplemental coverage for a macrocell network, or private
network functions.
We envision that PALs would be authorized in a highly localized
fashion, such as at the census tract level. Census tracts may provide
an appropriately high level of geographic resolution for small cell
deployments, while also presenting a number of other benefits.
Currently, there are over 74,000 census tracts in the United States
targeted to an optimum population of 4,000. Census tracts vary in size
depending on the population density of the region, with tracts as small
as one square mile or less in dense urban areas and up to 85,000 square
miles in sparsely populated rural regions. They generally nest into
counties and other political subdivisions and, in turn, into the
standardized license areas commonly used by the Commission (e.g.,
Cellular Market Areas and Economic Areas). Census tracts could be
aggregated into those or other larger areas. Census tracts generally
align with the borders of
[[Page 72854]]
political boundaries (e.g., city lines) and often to natural features,
which may affect population density (e.g., rivers). Census tracts,
therefore, may naturally mirror key considerations in small cell
deployment by service providers, such as tracking existing customers,
plant, and permits or rights-of-way. In addition, the inclusion of
census tracts in census geospatial databases could ease the
incorporation of geographic and demographic data into an SAS.
We seek comment on considerations regarding the size of the
geographic component of the PALs. Are census tracts an appropriate
geographic unit for PALs? If not, what standard geographic unit would
best promote the Commission's goals? Should other geographic areas
(e.g., counties, census block groups) or licensing units (e.g.,
Cellular Market Areas), be used instead? Would a standardized grid
(e.g., 1 kilometer x 1 kilometer or 2 kilometer x 2 kilometer square)
overlaid on the United States be a more appropriate geographic unit?
Alternately, could a standardized high-resolution grid be ``nested''
within a larger grid or a political boundary such as a county?
Commenters should identify any costs or benefits, including a detailed
technical analysis regarding the geographic size of the PALs.
Frequency/Bandwidth. We identify 10 megahertz unpaired channels as
a standard PAL bandwidth that balances several objectives. First, 10
megahertz channels provide a practically deployable and scalable
bandwidth for high data rate technologies. Second, 10 megahertz
channels divide evenly into either the 100 megahertz (10 channels)
available in the 3.5 GHz Band or the 150 megahertz of spectrum (15
channels) that would be available if the supplemental plan is adopted,
providing flexibility for either proposal. Third, 10 megahertz channels
are sufficiently granular to license multiple Priority Access users in
each geographic area, particularly where protection of incumbents
limits the amount of spectrum available for commercial use. Fourth, we
expect that 10 megahertz licenses would provide useful ``building
blocks'' for licensees that might wish to aggregate larger amounts of
spectrum in a given area. We seek comment on the appropriate bandwidth
for PALs and, in particular, whether 10 megahertz blocks appropriately
balance the needs of potential Priority Access users and the policy
objectives identified herein. Commenters should identify any costs or
benefits, including a detailed technical analysis of any proposed
bandwidth unit.
License Flexibility and Fungibility. The purpose of the PAL
approach is to encourage flexible use of the 3.5 GHz Band for an array
of applications and end users. Such applications could include not only
small cell commercial broadband use, but private networks, non-line of
sight backhaul, and other innovative uses. Spectrum users would need to
comply with certain technical criteria, such as those discussed in
section III (e) below, to ensure their effective coexistence. These
requirements are intended to be minimal to encourage diverse spectrum
use. We seek comment on how much technical flexibility is possible in
the 3.5 GHz Band given the licensing model proposed in the NPRM and
elaborated upon in the Revised Framework.
Administrability. The PAL concept is intended to reduce the
complexity associated with administering and automating licensing
processes for a large number of granular licenses by eliminating the
need for a number of regulatory requirements associated with longer
term licenses. We seek comment on the implications of the PAL concept
on existing Commission licensing and authorization processes as well as
for the design of an SAS.
We also seek comment on the amount and type of information that
would need to be collected from potential Priority Access licensees.
The Communications Act establishes certain categories of eligibility
for license applications, while giving the Commission broad discretion
to determine specific eligibility criteria. See 47 U.S.C. 308 (b). In
the auctions context, the Commission typically requires applicants for
spectrum licenses to submit short and long form applications detailing
their qualifications and any supplemental information the Commission
deems necessary. See 47 CFR 1.2105. The Communications Act also limits
foreign ownership of FCC licenses, See 47 U.S.C. 310, and comprehensive
ownership information is required for all license applications, whether
or not they are subject to competitive bidding. See 47 CFR 1.2112.
Certain additional qualifications are prescribed by statute. See 21
U.S.C. 862; 47 CFR 1.2001.
Given our goal of a more fungible and administratively streamlined
licensing regime for the 3.5 GHz Band, we seek comment on the
information that must be collected from prospective licensees in an
open eligibility environment. What is the minimum amount of licensee
data that must be directly collected and maintained by the Commission
to meet the requirements of the Communications Act? Are there any legal
or other impediments to collection and maintenance of such information
by a third party, such as an SAS operator under Commission supervision?
What requirements, such as for information security, would need to be
imposed on such third parties? What processes and standards, and what
Commission review mechanism, should be applied to ensure that licensee
information is collected in accordance with Commission rules and all
licensees meet appropriate eligibility requirements?
2. Assignment of Priority Access Licenses
In the NPRM, the Commission sought comment on a proposed license-
by-rule authorization regime as well as alternative licensing schemes,
including auctions for Priority Access tier use within defined
geographic service areas and other assignment methodologies. Under the
Revised Framework, the number of applications for Priority Access
rights could exceed the number of available PALs in a given area or
timeframe and, in that event, we would need to provide for a means of
resolving mutually exclusive applications. Section 309(j) of the
Communications Act generally requires the Commission to resolve
mutually exclusive applications via competitive bidding. See 47 U.S.C.
309 (j)(1). Given the unique nature of the PAL-based licensing
framework, we see an opportunity with the 3.5 GHz Band to develop more
flexible and dynamic auction mechanisms than we have used thus far for
assigning authorizations, consistent with the requirements of section
309(j). Therefore, we seek comment on approaches to spectrum assignment
and auction that could be used to productively manage use of the
Priority Access tier while allowing SAS authorized opportunistic use of
the GAA tier as described in the NPRM.
One authorization method that could serve the goals of this Revised
Framework would be a combination of the license-by-rule approach
proposed in the NPRM and a more traditional auction process. Under such
an approach, GAA users would be licensed by rule under part 95,
requiring registration with the SAS for operation as set forth in the
NPRM. Separate licenses would not be required for individual GAA users.
For Priority Access users, the Commission would not license use by
rule. Instead, on a regular basis (perhaps annually), the Commission
would open windows for applications for available PALs. To accommodate
the ability of licensees to aggregate consecutive one-year terms, the
Commission could offer multiple consecutive years of PAL rights
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simultaneously. At the close of such a ``window,'' the Commission would
hold an auction to assign PALs where there are mutually exclusive
applications pending. Mutual exclusivity would be triggered when more
applications are submitted than can be accommodated geographically,
temporally, or spectrally.
We expect that Priority Access authorizations would be issued on a
PAL basis, as defined above. Licensees would have no renewal
expectancy, would automatically terminate at the end of their one-year
terms and would be non-renewable. We do not anticipate adopting
construction or service requirements for Priority Access licensees due
to the impracticability of enforcing such requirements across 74,000 or
more license areas with, potentially, multiple licensees in each area
if we base PALs on census tracts. However, to encourage deployment and
long term network planning, we anticipate allowing potential licensees
to bid for multiple consecutive years of PAL rights in a given
geographic area at a single auction, up to a predetermined cap. Payment
for each consecutive PAL could be due annually prior to the license
start date and a license would terminate automatically if the payment
is not made. Additionally, licensees may be permitted to trade future
PAL rights via secondary market transactions. As noted below, we
anticipate that annual auctions, combined with microtargeted licensing
and annual pre-payment requirements would sufficiently incentivize
construction of network facilities and intensive spectrum use for a
diverse range of uses in the public interest while discouraging
warehousing.
We anticipate that this spectrum assignment process would require a
greater degree of automation and, potentially, more third-party
participation than the Commission has employed in past auctions. Given
the large number of license areas and relatively short license terms
envisioned in the Revised Framework, more flexible and dynamic auction
mechanisms may be required to effectively manage use of the Priority
Access tier. We also foresee an opportunity for third-parties to add
value to the auction process by developing tools to help bidders manage
their inventory of PALs and structure bids in regular auctions. We seek
comment on the degree to which such an auction could be automated and
administered by a third party. What kind of auction format would be
most appropriate? Should SAS managers be permitted to administer
auction process as well or should these functions be kept separate?
What level of automation would be required to process the volume of
applications and bids that such an auction would entail? To what degree
could the Commission assign the responsibility for administering this
type of auction to a qualified third party and, if it did so, what
safeguards would be required to ensure the integrity of the auction
process? What lessons can be drawn from prior Commission reliance on
third-parties in auction or other contexts, including selection
criteria for and supervision of such third parties? See, e.g., 47
U.S.C. 251(e)(10); 47 CFR 52.12; 47 CFR 54.701.
We seek comment on the auction and licensing mechanisms discussed
above, including their economic and technical viability, whether they
are consistent with the requirements of section 309(j), and any other
potential legal issues that may arise. Commenters should identify any
costs or benefits associated with the proposal. Would such an approach
properly incentivize targeted use of the Priority Access tier by a
diverse group of users? How many consecutive years of PALs should the
Commission offer in a single auction? What, if any, limits should be
placed on the aggregation of PALs--in time, location, or frequency--by
a single licensee?
We also seek comment on alternative licensing and authorization
mechanisms. For instance, could a license-by-rule regime encompass both
the GAA and Priority Access tiers, as they are envisioned in the
Revised Framework? Are other models preferable? Commenters advocating
alternative assignment models should identify any costs or benefits
associated with these approaches and should include a detailed
technical analysis.
B. Band Plan
We seek comment on a band plan that would balance SAS-authorized
opportunistic access to the GAA tier with targeted exclusive access to
the Priority Access tier, as described above. Under the Revised
Framework, a minimum amount of spectrum would be designated for GAA
access in each geographic area, leaving the remaining bandwidth
available for assignment to priority access users on a PAL basis. We
seek comment on whether a minimum GAA reservation should be defined in
terms a proportional ratio that can scale with the quantity of spectrum
available in a given location or time after protecting incumbent uses,
rather than a fixed (megahertz) bandwidth. Would a ratio assigning a
minimum of, for example, 40 or 50 percent of available bandwidth for
GAA use further the public interest or would another ratio be more
appropriate? We emphasize that such ratio would constitute the
``floor'' for GAA use. Under the Revised Framework, GAA use would be
authorized and managed by the SAS, as proposed in the NPRM. In
addition, when Priority Access rights have not been issued (e.g., due
to lack of demand) or the spectrum is not actually in use by a Priority
Access licensee, the SAS would automatically make that spectrum
available for GAA use locally. Therefore, in any given location, the
quantity of spectrum available for GAA use could exceed the reserved
amount--sometimes by a significant margin. This approach would ensure
that the greatest possible portion of the 3.5 GHz Band would be
intensively used.
We seek comment on the public interest benefits of balancing GAA
and Priority Access use in the 3.5 GHz Band in the manner described
above. We also acknowledge that, if the supplemental proposal to
include the 3650-3700 MHz band is adopted, an even split between
Priority Access and GAA use would result in a fractional PAL and seek
comment on the appropriate ratio to apply in this situation. We also
seek comment on implementation details, including, for example, how the
``use-it-or-share-it'' concept described above could be implemented.
What does ``use'' mean in this context? How should it be measured? How
would such dynamically changing rights be enforced? Commenters should
identify any costs and benefits associated with any proposed
implementation approach.
We also envision that, in place of a static channel model, the SAS
would dynamically assign specific frequencies within given geographic
areas. The SAS would assign GAA users and Priority Access licensees
shares of the band but the exact spectral location of a given
transmission authorization within the band would not be fixed. For
example, a licensee might have Priority Access rights for a single PAL,
as defined above, but the specific frequencies assigned to that user
would be managed by the SAS and could be reassigned from time to time
(e.g., from 3550-3560 MHz to 3630-3640 MHz). The SAS would assign and
maintain appropriate frequency assignments and ensure that lower tier
users do not interfere with higher tier users and to minimize
interference among users in the same tier. Under this approach, we ask
whether authorized base stations, handsets, and other user equipment
should be required to be capable of operating across the entire 3.5 GHz
Band. How would a requirement to include capability to operate across
the
[[Page 72856]]
entire band affect equipment design, performance and cost?
We acknowledge that there may be benefits for Priority Access tier
licensees and GAA users to ensuring that contiguous blocks of spectrum
are made available for each tier and even individual licensees with
multiple PALs in a given geographic area. We seek comment on whether it
would be technologically feasible and in the public interest to ensure
that contiguous spectrum is made available on a tier-by-tier and
licensee-by-licensee basis.
We seek comment on this dynamic approach to frequency assignment.
We acknowledge that this interactive approach would require the SAS to
go well beyond the parameters of the current TV White Spaces databases
to manage multiple users on a dynamic, real time or near real time
basis. Is this spectrum management approach feasible using current or
developing technologies? Are there any technical parameters that would
need to be codified in Commission rules? How do the public interest
benefits of such an approach compare to a more traditional channel
block band plan? Commenters should identify any costs or benefits and
include a detailed technical analysis to support their positions on
dynamic assignment of frequency bands.
C. Ensuring Productive Spectrum Use
The Revised Framework leverages the unique characteristics of small
cells and the capabilities of modern database technologies to ensure
that the 3.5 GHz Band is used intensively for a wide variety of
potential applications. We seek comment on whether the PAL-based
allocation model outlined above could, by assigning priority spectrum
rights in a targeted and dynamic fashion, help to ensure that Priority
Access rights are allocated to the parties that would make the most
productive use of quality-assured spectrum within a given geographic
area. Moreover, short term licenses with no renewal expectancy would
provide licensees with incentives to make actual and consistent use of
the spectrum and significantly reduce the risk of spectrum warehousing.
This paradigm could also obviate the need for performance and
construction requirements that could be especially burdensome and
difficult to administer in the small cell context.
In the Revised Framework, the GAA tier plays an important role in
ensuring that the 3.5 GHz Band is used consistently and productively.
Ensuring that a significant GAA ``floor'' is maintained in all
geographic areas where commercial use of the 3.5 GHz Band is permitted,
regardless of the number of Priority Access tier users in the area,
should encourage widespread deployment of base stations and handsets
that would operate opportunistically in the band under the control of
the SAS. Moreover, under the Revised Framework, PALs that are not in
actual use would be added to the pool of available GAA spectrum, as
determined by the SAS. Thus, the GAA tier could be used to supplement
the spectrum available to active Priority Access users and as a source
of spectrum for opportunistic users as determined by the SAS. These
complementary functions should maximize the utility of the 3.5 GHz Band
for a diverse set of applications.
We seek comment on this approach to promoting productive use of the
3.5 GHz Band. Would the PAL concept provide strong incentives for
licensees to productive use their priority rights? What technical
metrics are appropriate to measure ``use'' in a portion of or the
entirety of a PAL? How can the SAS effectively monitor actual use of
the Priority Access tier to determine whether additional spectrum is
available for GAA use?
D. Localized Critical Access Use
As explained in the NPRM, a variety of critical services in the
United States have urgent current as well as future spectrum needs.
While there is currently insufficient spectrum available to efficiently
allocate dedicated spectrum bands to all of these users, we continue to
believe that the 3.5 GHz Band can be used to provide localized,
protected spectrum to entities with a need for reliable, interference
protected spectrum access throughout much of the country. Many parties,
including Motorola Solutions, UTI, EEI, and Microsoft submitted
comments supporting such access to the 3.5 GHz Band for various
critical access users. Even as we explore methods for expanding access
to the Priority Access tier, we continue to believe that ``the high
spatial reuse characteristics of low-power 3.5 GHz transmissions,
combined with access management facilitated by the SAS, should allow
the 3.5 GHz Band to be utilized on a shared, licensed basis by a
variety of critical users to provide high quality services to localized
facilities.'' Under the authorization method described above, critical
access users would be eligible to register and, in the case of mutually
exclusive applications, bid for access to Priority Access tier PALs.
However, many such facilities (e.g., hospitals) generally only need
access within specific buildings and therefore may not require
exclusive access to even a full census tract of Priority Access tier
spectrum. Moreover, these users would likely be unable to outbid well
capitalized commercial interests for competitive PALs. As such, we seek
comment on whether it would be possible to allow such critical users to
receive interference protections, akin to Priority Access users, within
a limited portion (e.g., 20 megahertz) of the GAA pool inside the
confines of their facilities.
Under this approach, qualified critical access facilities would be
eligible to operate indoor small cell networks on a quality-assured
basis. These licensees would be required to register their networks in
the SAS and comply with applicable technical rules, including low power
limits. In addition, while the SAS could manage GAA use in the area to
provide a measure of protection for critical access users, such users
might also be required to employ interference mitigation techniques to
ensure a properly interference-limited environment. Such techniques
could include physical shielding or building modifications around
eligible facilities. Alternatively, there may be standard
specifications for building efficiency or radio frequency (RF)
shielding that go beyond those applicable to normal construction that
could provide enough certainty against interference from surrounding
Priority Access or GAA use so as to provide an interference ``safe
harbor'' for those seeking critical access protections. We note that
some modern building standards may incorporate materials that result in
some degree of RF shielding.
We seek comment on methods to provide quality-assured spectrum for
critical access users. Does the Revised Framework adequately address
the needs of such critical access users? Would the SAS be able to
effectively manage spectrum use by a large number of microtargeted
facilities? What interference mitigation techniques should be required
to ensure that these facilities do not interfere with or receive
interference from other 3.5 GHz Band users? How would compliance with
technical rules and interference mitigation requirements be managed?
What RF emission limits would be appropriate for a ``safe harbor'' as
described above? Would this plan unacceptably encumber GAA spectrum? We
ask that commenters identify any costs and benefits and provide a
detailed technical analysis to support their arguments.
We also ask whether this approach should be limited to ``critical
access'' facilities. Could quality assured, microtargeted indoor
networks be employed generally by property owners
[[Page 72857]]
subject to appropriate technical and interference mitigation
requirements? What types of mitigation techniques would such buildings
need to employ to effectively prevent exterior interference? Could such
buildings coexist in close proximity without unacceptably interfering
with one another? Would an SAS be able to effectively manage a large
number of these locations?
E. Technical Issues
While we expect that the SAS would coordinate much of the
interaction between disparate users in the 3.5 GHz Band, some minimal
technical requirements will be necessary to ensure that multiple
networks can effectively coexist in the band. As such, we seek comment
on certain technical issues related to implementing the Revised
Framework. In responding to questions in this section, we ask that
commenters identify any costs and benefits and provide detailed
technical analysis to support their proposals. We also recognize that
these issues may need to be explored in greater depth in the future
and, to that end, we may seek additional comment on specific technical
rules in future notices.
1. Technical Implementation of the Revised Framework
The effectiveness of dynamic spectrum sharing depends on the proper
application of interference mitigation and spectrum management
techniques for operating in the shared band. The Commission addressed
some of the technical features of small cells in the NPRM, including
allowable power limits for small cell base stations, and solicited
comment on these and other potential technical rules. Below, we seek
additional comment on technical rules and assumptions appropriate to
implementing the Revised Framework or variations supported by
commenters. We ask that commenters identify any costs and benefits and
provide detailed technical analysis to support their proposals.
Building on the approach taken in the TV White Space proceeding, we
expect that the SAS would manage and configure the use of authorized
spectrum and policy related parameters, and communicate updates
regarding spectrum availability and operational requirements to
existing and new users. The SAS could extend the TV White Spaces
paradigm with a greater degree of dynamism--by incorporating
information about spectrum utilization from other Citizen's Broadband
users to manage access to the band on a real-time or near-real time
basis. For example, infrastructure nodes, such as base stations, access
points, or core network elements could interact with the SAS and
provide end user devices with operational parameters and recent
changes. Given these factors, we seek comment on the essential high-
level requirements for the SAS and the nature of its interactions with
the different technologies and network topologies in the 3.5 GHz Band.
Compared to typical macrocell deployments, small cell networks are
generally characterized by: Lower transmit power, lower local RF
transmissions, and an ability to operate in a relatively high
interference environment (relative to thermal noise; Interference-over-
Thermal (IoT)). In addition, recent advancements in network self-
organization and interference management technologies are expected to
allow for new spectrum sharing paradigms, which are difficult to
implement or impractical in traditional noise-limited environments.
Given the variety of possible network deployments and the wide range of
potential network parameters and RF configurations, we anticipate that
many of the parameters of systems operating in the 3.5 GHz Band will be
managed by the SAS. However, some preliminary estimated values for
transmission power levels, whether field strength or power flux density
(PFD) limits should be imposed. With regard to the Revised Framework,
the key technical considerations include: (1) Base station transmit
power; (2) acceptable interference environment; and (3) technical
flexibility. In light of the Revised Framework described here and
additional staff analysis, we seek comment on some preliminary values
defining some of these technical parameters and criteria.
Base Station Transmit Power. As a baseline, we seek comment on
limiting small cell base stations operating in the 3.5 GHz Band to a
maximum 24dBm transmit power along with maximum antenna gain of 6dBi.
These values are consistent with the 30dBm EiRP commonly assumed in
various studies for small cell base stations. The maximum operational
EiRP of individual base stations might be reduced by the SAS to prevent
interference and promote efficient network operation. In addition, we
assume end user devices to have configurable maximum power levels below
typical 23dBm values and support for some form of power control to
ensure effective spectrum sharing.
We seek comment on the power levels which should be considered as a
baseline for spectrum sharing evaluation and if the SAS can regulate
the use of such power levels. We also seek comment on the degree to
which power levels in excess of 24 dBm may be appropriate to enable
other use cases, such as the rural coverage case contemplated in our
NPRM. Should we consider additional higher and lower base station
(e.g., eNodeB or Access Point) power classes for operation in the 3.5
GHz Band to address different network deployments? What values should
be assumed for EIRP? Should power control function and capability at
the base station and user device be service rule requirements?
Acceptable Interference Environment. Another key factor to consider
is the acceptable interference environment in which multiple small cell
networks would be able to coexist. The acceptable interference rise
over thermal noise for small deployments has been studied with
operational values around 20dB for picocells and even higher (e.g.,
greater than 40dB) for femtocells. A common understanding of tolerable
IoT levels and extending them to estimate maximum acceptable
intersystem co-channel interference and adjacent channel interference
appear key to realizing and quantifying the potential in spectrum
sharing. What are appropriate values for IoT given the Revised
Framework we envision for the 3.5 GHz Band? In addressing this
question, commenters should focus not only on interference issues
between similar type systems (e.g., LTE to LTE), but also on
coexistence issues between disparate systems (e.g., LTE to Wi-Fi). Are
different considerations necessary for each of these situations? Can
such an approach be integrated with the imposition of some minimal
receiver standards on equipment in the band? How could such policies be
implemented and enforced at licensees' geographic boundary for a single
PAL or a collection of aggregated PALs? Similarly, one can estimate the
maximum signal level received from each system in adjacent channels. We
seek comment on noise figures, aggregate and intra and inter-system IoT
thresholds, and receiver desensitization with focus on 3.5 GHz Band
small cells. In addition, we seek comment on whether an approach based
on field strength or PFD would be more appropriate and easier to
administer and comply with. If so, at what location(s) should such
limits be imposed (e.g., at ground level, at some height above ground)?
What additional consideration is needed if two adjacent systems use
different radio access technologies or have no or poor synchronization?
Technical Flexibility. The Revised Framework is designed to
flexibly
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accommodate different types of end users and a variety of use cases. To
what extent could technical rules facilitate the effective coexistence
of disparate technologies and network topologies in the band? Should we
also accommodate point to multipoint radios for wireless backhaul and
WISP applications as suggested by some commenters? If so, how would
their coexistence with small cells in nearby locations or adjacent
channels be managed? Could spectrum coordination between different
networks and technologies be automated in whole or in part and managed
by the SAS? How can the SAS facilitate coexistence of disparate
systems?
2. Additional Technical Considerations
We acknowledge that there may be additional technical
considerations beyond those addressed in the NPRM and this Public
Notice that would need to be incorporated into any technical rules
adopted in this proceeding. We seek comment on what additional
technical issues may need to be addressed in this proceeding to promote
efficiency and intensive use of the 3.5 GHz Band. We encourage
commenters to address these issues as thoroughly as possible. To the
extent we see commenters identify common issues that require further
discussion, we may seek additional comment as appropriate. As noted
above, we envision holding a workshop on the technical aspects of the
SAS in the near future. The Bureaus will solicit further input on SAS
requirements in conjunction with that event.
We note that the FCC's Technological Advisory Council (TAC) has
been studying spectrum interference policy and receiver standards in
general, and it recommends that the Commission consider forming one or
more multi-stakeholder groups to study such standards and interference
limits policy at suitable service boundaries, such as those related to
the 3.5 GHz band. Should the Commission encourage the formation of one
or more groups to investigate interference limit policy for the 3.5 GHz
band? If so, what should be the scope of such a group or groups?
F. Extension of Revised Framework to the 3650-3700 MHz Band
The NPRM described the possibility of extending the proposed
licensing framework to the 3650-3700 MHz band. Although our primary
objective here is to describe how the Revised Framework would operate
in the context of the 3.5 GHz Band, we also seek comment on whether and
how it could be extended to the 3650-3700 MHz band. What, if any,
additional considerations would apply if the Revised Framework were to
be applied to the 3650-3700 MHz band? What provisions would need to be
made for incumbent operators? How much transition time would be
required?
Federal Communications Commission.
Marlene H. Dortch,
Secretary.
[FR Doc. 2013-28254 Filed 12-3-13; 8:45 am]
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