Repurposing 3.1-3.55 GHz Spectrum: Issues for Congress
link to page 1 
March 16, 2023
Repurposing 3.1-3.55 GHz Spectrum: Issues for Congress
Wireless technologies use radio waves, or frequencies, to
that protects DOD operations, supports expansion of
transmit and receive voice and data signals. The radio
wireless services, and maximizes spectrum use and value.
spectrum is the range of frequencies used for wireless
mobile, satellite, television, AM and FM radio, military
3.1-3.55 GHz Band Background
radar, and aviation communications. Increases in wireless
The reallocation of segments of the 3.1-3.55 GHz band has
technology use have led to increased demand for spectrum.
been considered since 2010. This section provides a
Because it is a limited resource, the U.S. government
timeline of key actions taken during these considerations.
promotes spectrum sharing and the use of spectral
efficiency technologies to increase access for new wireless
March 2010: Federal Communications Commission
technologies, while accommodating incumbent users.
(FCC) Issued National Broadband Plan.
In the 2010 National Broadband Plan, the FCC, which
This In Focus discusses the 3.1-3.55 gigahertz (GHz) radio
manages nonfederal spectrum use, recommended that the
spectrum band, including the reallocation and auction of the
U.S. government make 500 megahertz (MHz) of spectrum
3.45-3.55 GHz segment, and congressional proposals to
available for mobile use within the next 10 years.
reallocate the 3.1-3.45 GHz segment (Figure 1). The
Department of Defense (DOD) uses the 3.1-3.45 GHz
June 2010: President Obama Called on Agencies to
segment for radar systems. The DOD Chief Information
Make Spectrum Available for Broadband.
Officer (CIO) acknowledged the potential for shared federal
President Obama signed a memorandum that called on the
and nonfederal use, but stated that DOD cannot fully vacate
National Telecommunications Information Administration
the segment without significant operational impact.
(NTIA), which manages federal spectrum use, to coordinate
with the FCC to make 500 MHz of spectrum available for
Figure 1. 3.1-3.55 GHz Band
wireless broadband use within 10 years.
October 2010: NTIA Ten-Year Plan.
NTIA published a Ten-Year Plan to make 500 MHz of
spectrum available for wireless broadband use. NTIA
identified more than 20 potential bands for repurposing.
The 3.1-3.5 GHz segment was one of the largest identified.
Source: CRS.
Notes: The graphic shows general use of the 3.1-3.45 GHz band and
March 2018: Congress Directed NTIA to Study the
3.45-3.55 GHz band in March 2023. DOD=Department of Defense.
Entire 3.1-3.55 GHz Band.
In the MOBILE NOW Act (P.L. 115-141, §605), Congress
The 117th Congress enacted legislation (P.L. 117-58,
required the Commerce Secretary, through NTIA and in
§90008) providing DOD funds to study its use of the 3.1-
consultation with the FCC and the head of each affected
3.45 GHz band to make spectrum available for shared
federal agency, to submit a report by March 23, 2020,
federal and nonfederal use, and allowed DOD to determine
evaluating the feasibility of allowing commercial wireless
frequencies that may be shared with nonfederal users. The
services to share use of the 3.1-3.55 GHz segment. The
House then passed legislation (H.R. 7624) that would have
report (described below), published in July 2020, assessed
repealed §90008 and provided funds for any affected
federal use, the impact of nonfederal users on federal
agency operating in the band to conduct studies to make the
operations, actions to avoid interference, and frequencies
band available for nonfederal, shared federal and
most conducive to sharing.
nonfederal, or combination use. This meant a portion could
be reallocated for exclusive commercial use, which some
July 2020: NTIA Report on the 3.1-3.55 GHz band.
DOD officials do not support. Similar legislation was
In response to the MOBILE NOW Act of 2018, NTIA
introduced in the Senate (S. 4117). Neither was enacted.
conducted technical studies, and in July 2020, released a
Senator Cantwell offered an amendment (S.Amdt. 6585) to
feasibility report on the 3.1-3.55 GHz band. It found that
the Consolidated Appropriations Act, 2023 (P.L. 117-328)
(1) the 3.45-3.55 segment is suitable for potential spectrum
that included, among many things, a study of the band for
sharing and (2) some spectrum sharing below 3.45 GHz
nonfederal, shared federal and nonfederal, or combination
may be possible, but additional analysis was necessary to
use, with protections for DOD. It did not advance.
address specific challenges. First, there are classified and
unclassified federal operations below 3.45 GHz, which
In the 118th Congress, debate has centered on whether to
could make sharing challenging. Second, if federal
make all or a portion of the band available for nonfederal
operations in 3.45-3.55 GHz segment are shifted into the
use or shared use, and the role of DOD in the process. A
3.1-3.45 GHz segment, it may become congested.
potential challenge for Congress may be finding a solution
https://crsreports.congress.gov
Repurposing 3.1-3.55 GHz Spectrum: Issues for Congress
August 2020: President Trump Announced the
Sharing Models
Availability of the 3.45-3.55 GHz Segment for 5G.
Spectrum may be shared by multiple users, through
On August 10, 2020, a White House fact sheet stated that at
roaming or leasing agreements; use of the same frequencies
the President’s direction, in coordination with DOD, the
but in different locations to avoid interference; and use of
3.45-3.55 GHz segment would be available for 5G services.
frequency coordination. DOD works with federal partners
through Emerging Mid-Band Radar Spectrum Sharing
December 2020: Congress Required the FCC to
(EMBRSS), an initiative to develop ways to share the 3.1-
Auction the 3.45-3.55 GHz Segment.
3.45 GHz segment. It works with industry and academia
On December 27, 2020, in the Consolidated Appropriations
through Partnering to Advance Trusted and Holistic
Act, 2021 (P.L. 116-260), Congress required the FCC to
Spectrum Solutions (PATHSS) under the National
commence competitive bidding (i.e., auction) of the 3.45-
Spectrum Consortium, an organization of industry experts
3.55 GHz segment no later than December 31, 2021.
that supports the government in developing new spectrum
initiatives to develop ways to share the 3.1-3.45 GHz band.
March 2021: 3.45-3.55 GHz Auction.
In March 2021, the FCC adopted rules giving nonfederal
The FCC instituted a sharing model in the 3.55-3.7 GHz
entities use of the 3.45-3.55 GHz segment, stipulating that
band (known as the Citizen Broadband Radio Service or
federal systems may not cause interference to nonfederal
CBRS) that created a three-tiered approach for sharing
users except in certain areas where incumbent federal
among federal and nonfederal users. Tier 1 users—
systems will remain in this segment. The auction began
incumbent federal users—continue to operate in the band.
October 5, 2021, and ended January 4, 2022, resulting in
Tier 2 users—commercial providers with auctioned rights
over 4,000 licenses and generating more than $22 billion.
for specific frequencies in certain locations—hold Priority
Access Licenses (PAL), but cannot interfere with Tier 1
November 15, 2021: The Infrastructure Investment
users. Tier 3 users—General Authorized Access (GAA)
and Jobs Act (IIJA) Provided Funds for DOD to
users—can use the band at no charge, when frequencies are
Study Shared Use in the 3.1-3.45 GHz Segment.
not in use. Tier 3 users cannot interfere with Tier 1 or Tier 2
IIJA (P.L. 117-58), §90008 provided DOD $50 million to
users, and may be subject to interference from them. An
study, analyze, and plan for making spectrum in the 3.1-
automated frequency coordinator, known as a Spectrum
3.45 GHz segment available for shared federal and
Access System (SAS), manages spectrum use.
nonfederal use, in order to identify frequencies for auction.
Some spectrum users view the CBRS model as an effective
April 28, 2022: Bills to Repeal IIJA, §90008.
approach for protecting federal users and enabling
On April 28, 2022, H.R. 7624 and S. 4117 were introduced.
commercial access. Most commercial wireless providers
The bills would have repealed §90008 of P.L. 117-58 and
prefer licenses that grant exclusive use of spectrum. Hence,
funded affected agencies to study the potential for
auctions of exclusive use licenses often generate more
nonfederal, shared federal and nonfederal, or combination
revenue than auctions for shared use. Thus, while the CBRS
use, meaning all or a portion of the 3.1-3.45 GHz segment
auction generated more than $4.5 billion, the C-band
could be reallocated for exclusive nonfederal use. H.R.
auction (3.7-4.2 GHz) of exclusive use licenses, yielded
7624 passed the House on July 28, 2022, but neither bill,
$81 billion.
nor a compromise bill, was enacted.
Congressional Considerations
September 2022: DOD oOficials Reiterated the
One congressional option is to keep IIJA, §90008, allowing
Importance of the Band to Military Operations.
DOD to complete its study and determine the frequencies it
At a September 2022 NTIA Spectrum Policy Symposium,
can share with nonfederal users. This could protect DOD
DOD’s CIO noted, “We have many radars [in the 3.1-3.45
operations, but may not make enough spectrum available
GHz segment] ... that are critical for our service members to
for providers to meet wireless demands, or generate the
train on before they deploy into harm’s way overseas, and
maximum in auction revenues for deficit reduction or
also to protect our homeland.” He stressed the need to share
public interest programs (e.g., 9-1-1). Another option could
rather than relinquish spectrum, noting “it would take us
be legislation like H.R. 7624, S. 4117, or S.Amdt. 6585,
two decades and hundreds of billions of dollars to be able to
requiring DOD to study the potential to make the 3.1-3.45
refactor and move those radars out of there.”
GHz segment available for nonfederal use. In a March 5,
2023, letter to committee chairs and ranking members, the
December 2022: Senate Amendment 6585.
Secretaries of Defense and Commerce supported S.Amdt.
On December 20, 2022, Senator Cantwell offered an
6585, provided any decision to make the segment available
amendment (S.Amdt. 6585) to the Consolidated
for commercial use be contingent on a thorough study of
Appropriations Act, 2023. It would have provided agencies
potential impact on federal operations. Although an auction
funds to study nonfederal, shared federal and nonfederal, or
of the segment for commercial use could drive wireless
combination use in the 3.1-3.45 GHz segment; directed the
expansion and generate significant revenues, technical
Secretary of Commerce to identify frequencies for auction;
experts assert reallocation of the band from federal to
and given DOD authority to elevate concerns about
nonfederal use would require complex and high-cost
reallocation to the President. Members seeking to preserve
modifications to DOD systems and affect DOD operations.
DOD’s access to the band opposed it. It was not included in
the act.
Jill C. Gallagher, Analyst in Telecommunications Policy
IF12350
https://crsreports.congress.gov
Repurposing 3.1-3.55 GHz Spectrum: Issues for Congress
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF12350 · VERSION 2 · NEW
March 16, 2023
Repurposing 3.1-3.55 GHz Spectrum: Issues for Congress
Wireless technologies use radio waves, or frequencies, to
that protects DOD operations, supports expansion of
transmit and receive voice and data signals. The radio
wireless services, and maximizes spectrum use and value.
spectrum is the range of frequencies used for wireless
mobile, satellite, television, AM and FM radio, military
3.1-3.55 GHz Band Background
radar, and aviation communications. Increases in wireless
The reallocation of segments of the 3.1-3.55 GHz band has
technology use have led to increased demand for spectrum.
been considered since 2010. This section provides a
Because it is a limited resource, the U.S. government
timeline of key actions taken during these considerations.
promotes spectrum sharing and the use of spectral
efficiency technologies to increase access for new wireless
March 2010: Federal Communications Commission
technologies, while accommodating incumbent users.
(FCC) Issued National Broadband Plan.
In the 2010 National Broadband Plan, the FCC, which
This In Focus discusses the 3.1-3.55 gigahertz (GHz) radio
manages nonfederal spectrum use, recommended that the
spectrum band, including the reallocation and auction of the
U.S. government make 500 megahertz (MHz) of spectrum
3.45-3.55 GHz segment, and congressional proposals to
available for mobile use within the next 10 years.
reallocate the 3.1-3.45 GHz segment (Figure 1). The
Department of Defense (DOD) uses the 3.1-3.45 GHz
June 2010: President Obama Called on Agencies to
segment for radar systems. The DOD Chief Information
Make Spectrum Available for Broadband.
Officer (CIO) acknowledged the potential for shared federal
President Obama signed a memorandum that called on the
and nonfederal use, but stated that DOD cannot fully vacate
National Telecommunications Information Administration
the segment without significant operational impact.
(NTIA), which manages federal spectrum use, to coordinate
with the FCC to make 500 MHz of spectrum available for
Figure 1. 3.1-3.55 GHz Band
wireless broadband use within 10 years.
October 2010: NTIA Ten-Year Plan.
NTIA published a Ten-Year Plan to make 500 MHz of
spectrum available for wireless broadband use. NTIA
identified more than 20 potential bands for repurposing.
The 3.1-3.5 GHz segment was one of the largest identified.
Source: CRS.
Notes: The graphic shows general use of the 3.1-3.45 GHz band and
March 2018: Congress Directed NTIA to Study the
3.45-3.55 GHz band in March 2023. DOD=Department of Defense.
Entire 3.1-3.55 GHz Band.
In the MOBILE NOW Act (P.L. 115-141, §605), Congress
The 117th Congress enacted legislation (P.L. 117-58,
required the Commerce Secretary, through NTIA and in
§90008) providing DOD funds to study its use of the 3.1-
consultation with the FCC and the head of each affected
3.45 GHz band to make spectrum available for shared
federal agency, to submit a report by March 23, 2020,
federal and nonfederal use, and allowed DOD to determine
evaluating the feasibility of allowing commercial wireless
frequencies that may be shared with nonfederal users. The
services to share use of the 3.1-3.55 GHz segment. The
House then passed legislation (H.R. 7624) that would have
report (described below), published in July 2020, assessed
repealed §90008 and provided funds for any affected
federal use, the impact of nonfederal users on federal
agency operating in the band to conduct studies to make the
operations, actions to avoid interference, and frequencies
band available for nonfederal, shared federal and
most conducive to sharing.
nonfederal, or combination use. This meant a portion could
be reallocated for exclusive commercial use, which some
July 2020: NTIA Report on the 3.1-3.55 GHz band.
DOD officials do not support. Similar legislation was
In response to the MOBILE NOW Act of 2018, NTIA
introduced in the Senate (S. 4117). Neither was enacted.
conducted technical studies, and in July 2020, released a
Senator Cantwell offered an amendment (S.Amdt. 6585) to
feasibility report on the 3.1-3.55 GHz band. It found that
the Consolidated Appropriations Act, 2023 (P.L. 117-328)
(1) the 3.45-3.55 segment is suitable for potential spectrum
that included, among many things, a study of the band for
sharing and (2) some spectrum sharing below 3.45 GHz
nonfederal, shared federal and nonfederal, or combination
may be possible, but additional analysis was necessary to
use, with protections for DOD. It did not advance.
address specific challenges. First, there are classified and
unclassified federal operations below 3.45 GHz, which
In the 118th Congress, debate has centered on whether to
could make sharing challenging. Second, if federal
make all or a portion of the band available for nonfederal
operations in 3.45-3.55 GHz segment are shifted into the
use or shared use, and the role of DOD in the process. A
3.1-3.45 GHz segment, it may become congested.
potential challenge for Congress may be finding a solution
https://crsreports.congress.gov
Repurposing 3.1-3.55 GHz Spectrum: Issues for Congress
August 2020: President Trump Announced the
Sharing Models
Availability of the 3.45-3.55 GHz Segment for 5G.
Spectrum may be shared by multiple users, through
On August 10, 2020, a White House fact sheet stated that at
roaming or leasing agreements; use of the same frequencies
the President’s direction, in coordination with DOD, the
but in different locations to avoid interference; and use of
3.45-3.55 GHz segment would be available for 5G services.
frequency coordination. DOD works with federal partners
through Emerging Mid-Band Radar Spectrum Sharing
December 2020: Congress Required the FCC to
(EMBRSS), an initiative to develop ways to share the 3.1-
Auction the 3.45-3.55 GHz Segment.
3.45 GHz segment. It works with industry and academia
On December 27, 2020, in the Consolidated Appropriations
through Partnering to Advance Trusted and Holistic
Act, 2021 (P.L. 116-260), Congress required the FCC to
Spectrum Solutions (PATHSS) under the National
commence competitive bidding (i.e., auction) of the 3.45-
Spectrum Consortium, an organization of industry experts
3.55 GHz segment no later than December 31, 2021.
that supports the government in developing new spectrum
initiatives to develop ways to share the 3.1-3.45 GHz band.
March 2021: 3.45-3.55 GHz Auction.
In March 2021, the FCC adopted rules giving nonfederal
The FCC instituted a sharing model in the 3.55-3.7 GHz
entities use of the 3.45-3.55 GHz segment, stipulating that
band (known as the Citizen Broadband Radio Service or
federal systems may not cause interference to nonfederal
CBRS) that created a three-tiered approach for sharing
users except in certain areas where incumbent federal
among federal and nonfederal users. Tier 1 users—
systems will remain in this segment. The auction began
incumbent federal users—continue to operate in the band.
October 5, 2021, and ended January 4, 2022, resulting in
Tier 2 users—commercial providers with auctioned rights
over 4,000 licenses and generating more than $22 billion.
for specific frequencies in certain locations—hold Priority
Access Licenses (PAL), but cannot interfere with Tier 1
November 15, 2021: The Infrastructure Investment
users. Tier 3 users—General Authorized Access (GAA)
and Jobs Act (IIJA) Provided Funds for DOD to
users—can use the band at no charge, when frequencies are
Study Shared Use in the 3.1-3.45 GHz Segment.
not in use. Tier 3 users cannot interfere with Tier 1 or Tier 2
IIJA (P.L. 117-58), §90008 provided DOD $50 million to
users, and may be subject to interference from them. An
study, analyze, and plan for making spectrum in the 3.1-
automated frequency coordinator, known as a Spectrum
3.45 GHz segment available for shared federal and
Access System (SAS), manages spectrum use.
nonfederal use, in order to identify frequencies for auction.
Some spectrum users view the CBRS model as an effective
April 28, 2022: Bills to Repeal IIJA, §90008.
approach for protecting federal users and enabling
On April 28, 2022, H.R. 7624 and S. 4117 were introduced.
commercial access. Most commercial wireless providers
The bills would have repealed §90008 of P.L. 117-58 and
prefer licenses that grant exclusive use of spectrum. Hence,
funded affected agencies to study the potential for
auctions of exclusive use licenses often generate more
nonfederal, shared federal and nonfederal, or combination
revenue than auctions for shared use. Thus, while the CBRS
use, meaning all or a portion of the 3.1-3.45 GHz segment
auction generated more than $4.5 billion, the C-band
could be reallocated for exclusive nonfederal use. H.R.
auction (3.7-4.2 GHz) of exclusive use licenses, yielded
7624 passed the House on July 28, 2022, but neither bill,
$81 billion.
nor a compromise bill, was enacted.
Congressional Considerations
September 2022: DOD oOficials Reiterated the
One congressional option is to keep IIJA, §90008, allowing
Importance of the Band to Military Operations.
DOD to complete its study and determine the frequencies it
At a September 2022 NTIA Spectrum Policy Symposium,
can share with nonfederal users. This could protect DOD
DOD’s CIO noted, “We have many radars [in the 3.1-3.45
operations, but may not make enough spectrum available
GHz segment] ... that are critical for our service members to
for providers to meet wireless demands, or generate the
train on before they deploy into harm’s way overseas, and
maximum in auction revenues for deficit reduction or
also to protect our homeland.” He stressed the need to share
public interest programs (e.g., 9-1-1). Another option could
rather than relinquish spectrum, noting “it would take us
be legislation like H.R. 7624, S. 4117, or S.Amdt. 6585,
two decades and hundreds of billions of dollars to be able to
requiring DOD to study the potential to make the 3.1-3.45
refactor and move those radars out of there.”
GHz segment available for nonfederal use. In a March 5,
2023, letter to committee chairs and ranking members, the
December 2022: Senate Amendment 6585.
Secretaries of Defense and Commerce supported S.Amdt.
On December 20, 2022, Senator Cantwell offered an
6585, provided any decision to make the segment available
amendment (S.Amdt. 6585) to the Consolidated
for commercial use be contingent on a thorough study of
Appropriations Act, 2023. It would have provided agencies
potential impact on federal operations. Although an auction
funds to study nonfederal, shared federal and nonfederal, or
of the segment for commercial use could drive wireless
combination use in the 3.1-3.45 GHz segment; directed the
expansion and generate significant revenues, technical
Secretary of Commerce to identify frequencies for auction;
experts assert reallocation of the band from federal to
and given DOD authority to elevate concerns about
nonfederal use would require complex and high-cost
reallocation to the President. Members seeking to preserve
modifications to DOD systems and affect DOD operations.
DOD’s access to the band opposed it. It was not included in
the act.
Jill C. Gallagher, Analyst in Telecommunications Policy
IF12350
https://crsreports.congress.gov
Repurposing 3.1-3.55 GHz Spectrum: Issues for Congress
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF12350 · VERSION 2 · NEW