Commission Seeks Comment on Licensing Models and Technical Requirements in the 3550-3650 MHz Band, 72851-72858 [2013-28254]

Agencies

• FEDERAL COMMUNICATIONS COMMISSION

[Federal Register Volume 78, Number 233 (Wednesday, December 4, 2013)]
[Proposed Rules]
[Pages 72851-72858]
From the Federal Register Online via the Government Printing 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: https://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: FCC504@fcc.gov 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 
Paul.Powell@fcc.gov.

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 fcc@bcpiweb.com. The full text may also be downloaded 
at: www.fcc.gov. Alternative formats are available to persons with 
disabilities by sending an email to fcc504@fcc.gov 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: https://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).

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

[[Page 72853]]

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

[[Page 72855]]

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]
BILLING CODE 6712-01-P