Overview of Department of Defense Use of the Electromagnetic Spectrum

Changes from February 10, 2021 to March 18, 2021

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Overview of Department of Defense Use of the ~~February 10~~March 18, 2021 , 2021
Electromagnetic Spectrum
John R. Hoehn,
Communication using the electromagnetic spectrum (“the spectrum”) enables a number Communication using the electromagnetic spectrum (“the spectrum”) enables a number
~~Analyst in Military~~Coordinator
of modern military capabilities. The Department of Defense (DOD) uses of modern military capabilities. The Department of Defense (DOD) uses
~~Capabilities and Programs~~Analyst in Military
electromagnetic radiation to enable military communications, navigation, radar, electromagnetic radiation to enable military communications, navigation, radar,

Capabilities and Programs nonintrusive inspection of aircraft, and other equipment. DOD also heavily relies on nonintrusive inspection of aircraft, and other equipment. DOD also heavily relies on
~~Jill C. Gallagher~~
~~electromagnetic radiation for intelligence, surveillance~~ electromagnetic radiation for intel igence, surveil ance, and reconnaissance (ISR) , and reconnaissance (ISR)
~~Analyst in~~Jill C. Gallagher
applications such as missile early warning and signals applications such as missile early warning and signals ~~intelligence~~intel igence. Individual branches . Individual branches
~~Telecommunications~~Analyst in
of the military (e.g., the Air Force, Army, Marine Corps, Navy and Space Force) of the military (e.g., the Air Force, Army, Marine Corps, Navy and Space Force)
~~Policy~~Telecommunications
currently are currently are ~~allotted~~al otted significant ranges of frequency bands to enable various equipment significant ranges of frequency bands to enable various equipment

Policy and applications that support military operations. and applications that support military operations.
Kelley M. Sayler
~~Analyst in Advanced~~
Potential adversaries like China and Russia have observed how the United States wages Potential adversaries like China and Russia have observed how the United States wages
~~Technology and Global~~Analyst in Advanced
war through conflicts ranging from Desert Storm to war through conflicts ranging from Desert Storm to ~~Allied~~Al ied Force, Iraqi Freedom, and Force, Iraqi Freedom, and
Technology and Global Security ~~Security~~

Enduring Freedom over the past 30 years. These potential adversaries have identified the Enduring Freedom over the past 30 years. These potential adversaries have identified the
DOD’s use of the spectrum as a critical enabler, and, as a result, have developed weapon DOD’s use of the spectrum as a critical enabler, and, as a result, have developed weapon

systems, particularly electronic warfare (EW) platforms, designed to systems, particularly electronic warfare (EW) platforms, designed to ~~challenge~~chal enge the ~~the~~
DOD’s ability to effectively use the spectrum. These technologies designed to deny access to the spectrum are DOD’s ability to effectively use the spectrum. These technologies designed to deny access to the spectrum are
part of a series of systems and technologies that are commonly referred to as anti-access/area denial capabilities. part of a series of systems and technologies that are commonly referred to as anti-access/area denial capabilities.
Several new and emerging technologies and methods to employ existing Several new and emerging technologies and methods to employ existing technologies (technologies (~~called~~cal ed concepts) are being concepts) are being
developed to counter these developed to counter these ~~challenges~~chal enges. These new technologies include directed energy, artificial . These new technologies include directed energy, artificial ~~intelligence~~intel igence, and , and
counter-unmanned aircraft systems. Concepts like Joint counter-unmanned aircraft systems. Concepts like Joint ~~All~~ Al Domain Command and Control (JADC2) and Mosaic Domain Command and Control (JADC2) and Mosaic
Warfare look to change the nature of how the DOD communicates and uses the spectrum. Warfare look to change the nature of how the DOD communicates and uses the spectrum.
The U.S. government manages access to and use of spectrum. As the nation continues to experience significant The U.S. government manages access to and use of spectrum. As the nation continues to experience significant
growth in commercial wireless services (e.g., mobile phones, mobile applications, video streaming, Wi-Fi), growth in commercial wireless services (e.g., mobile phones, mobile applications, video streaming, Wi-Fi),
demand for spectrum has increased. Congress has enacted policies to make additional spectrum available for demand for spectrum has increased. Congress has enacted policies to make additional spectrum available for
commercial use, in some cases commercial use, in some cases ~~reallocating~~real ocating spectrum from federal agency use to commercial use. As Congress spectrum from federal agency use to commercial use. As Congress
considers policies that considers policies that ~~reallocate~~real ocate spectrum from DOD to commercial use, it may spectrum from DOD to commercial use, it may ~~consider~~c onsider the following issues: the following issues:
  Interoperability (i.e., the ability of one radio or computer system to talk to another). Each of the (i.e., the ability of one radio or computer system to talk to another). Each of the
military services has developed robust networks of their own; however, many are often unable to military services has developed robust networks of their own; however, many are often unable to
communicate with one another. communicate with one another.
  DOD’s ability to keep pace with technological advances by potential adversaries.
Adversaries such as Russia, China, Iran, and North Korea have developed systems to Adversaries such as Russia, China, Iran, and North Korea have developed systems to ~~challenge~~chal enge
the U.S. military’s abilitythe U.S. military’s ability to access the spectrum and to reduce the effectiveness of future to access the spectrum and to reduce the effectiveness of future
technologies. technologies.
  The private sector’s increasing interest in using frequencies traditionally reserved for the
military. The advent of fifth generation communications technologies (5G) has increased the The advent of fifth generation communications technologies (5G) has increased the
demand for multiple different frequency bands, which has the potential to disrupt military demand for multiple different frequency bands, which has the potential to disrupt military
operations. For example, in 2020 the Federal Communications Commission (FCC) authorized the operations. For example, in 2020 the Federal Communications Commission (FCC) authorized the
Ligado 5G network, which could affect the global positioning system’s radio signals. Ligado 5G network, which could affect the global positioning system’s radio signals.
  Spectrum sharing. Emerging technologies and policies are demonstrating that DOD and Emerging technologies and policies are demonstrating that DOD and
commercial systems are able to use the same frequencies without degrading DOD’s capabilities. commercial systems are able to use the same frequencies without degrading DOD’s capabilities.
The process for identifying such potential spectrum-sharing frequencies and the ability to develop The process for identifying such potential spectrum-sharing frequencies and the ability to develop
technologies quickly may also be of interest to Congress. technologies quickly may also be of interest to Congress.
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  The interagency process for spectrum allocation. Questions about the interagency process Questions about the interagency process
emerged after the FCC authorized Ligado’s 5G network to operate, despite the fact that DOD and emerged after the FCC authorized Ligado’s 5G network to operate, despite the fact that DOD and
several other federal agencies disagreed with that decision. several other federal agencies disagreed with that decision.
  Anticipating future spectrum needs for both commercial and military users. Much attention Much attention
has focused on 5G technologies. However, new technologies—like a future sixth generation (6G) has focused on 5G technologies. However, new technologies—like a future sixth generation (6G)
of communications technologies—of communications technologies—~~will~~ wil increase demand for additional spectrum. Moreover, new increase demand for additional spectrum. Moreover, new
military technologies may change how DOD uses the spectrum and may require a different military technologies may change how DOD uses the spectrum and may require a different
spectrum spectrum ~~allocation~~al ocation. .
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he Department of Defense (DOD) is the largest federal user of the electromagnetic he Department of Defense (DOD) is the largest federal user of the electromagnetic
spectrum (“the spectrum”). It holds frequencies across multiple bands to support a number spectrum (“the spectrum”). It holds frequencies across multiple bands to support a number
T of technologies and uses. DOD utilizes spectrum on a day-to-day basis, for training, and T of technologies and uses. DOD utilizes spectrum on a day-to-day basis, for training, and
for military operations. Thus, any changes to spectrum could affect DOD operations, both for military operations. Thus, any changes to spectrum could affect DOD operations, both
~~domestically~~domestical y and with and with ~~allies~~al ies abroad. Further, DOD has invested significantly in spectrum- abroad. Further, DOD has invested significantly in spectrum-
dependent technologies. A summary of some of these technologies, including wireless dependent technologies. A summary of some of these technologies, including wireless
communications, communications, ~~satellites~~satel ites, radar technologies that support situational awareness, signal , radar technologies that support situational awareness, signal
~~intelligence~~ intel igence and electronic warfare technologies, is provided below. Changes in spectrum may and electronic warfare technologies, is provided below. Changes in spectrum may
affect how DOD can use, manipulate, or develop these technologies. affect how DOD can use, manipulate, or develop these technologies.
The Department of Defense (DOD), partly through congressional action, has begun to re- The Department of Defense (DOD), partly through congressional action, has begun to re-
prioritize its management and use of the spectrum. Since 2018, the DOD has created new prioritize its management and use of the spectrum. Since 2018, the DOD has created new
organizational structures and is in the process of developing new strategies and policies, organizational structures and is in the process of developing new strategies and policies,
recognizing the importance the spectrum plays in military operations. A recognizing the importance the spectrum plays in military operations. A ~~recent~~rec ent Joint Joint
Electromagnetic Spectrum Operations publication states: Electromagnetic Spectrum Operations publication states:
[t]he electromagnetic spectrum (EMS) is a maneuver space essential for facilitating control [t]he electromagnetic spectrum (EMS) is a maneuver space essential for facilitating control
within the operational environment (OE) and impacts all portions of the OE and military within the operational environment (OE) and impacts all portions of the OE and military
operations ... Just as in the physical domains and in cyberspace, military forces maneuver operations ... Just as in the physical domains and in cyberspace, military forces maneuver
andand conduct operationsconduct operations ~~within the EMS to achieve tactical, operational, and strategic~~
~~advantage. Freedom of maneuver and action within the EMS are essential to~~ within the EMS to achieve tactical, operational, and strategic advantage. Freedom of maneuver and action within the EMS are essential to US and US and
multinational operations.1 multinational operations.1
What Is the Electromagnetic Spectrum?2
The electromagnetic spectrum is the range of wavelengths or frequencies of electromagnetic The electromagnetic spectrum is the range of wavelengths or frequencies of electromagnetic
radiation. It includes radio waves, microwaves, visible light, X-rays, and gamma rays (seradiation. It includes radio waves, microwaves, visible light, X-rays, and gamma rays (see Figure
1). Electromagnetic radiation is . Electromagnetic radiation is ~~all~~ al around us. It can be produced by natural sources, such as around us. It can be produced by natural sources, such as
lightning or the sun, or by man-made sources, such as radio transmitters, microwave ovens, lightning or the sun, or by man-made sources, such as radio transmitters, microwave ovens,
lasers, and X-ray machines. Electromagnetic radiation travels through space, air, and sometimes lasers, and X-ray machines. Electromagnetic radiation travels through space, air, and sometimes
solid materials in the form of waves. These waves are solid materials in the form of waves. These waves are ~~called~~cal ed electromagnetic waves because they electromagnetic waves because they
have both electric and magnetic properties. Such waves vary in frequency,3 wavelength,4 and have both electric and magnetic properties. Such waves vary in frequency,3 wavelength,4 and
energy. Scientists classify electromagnetic waves by their wavelength or frequency. Waves with energy. Scientists classify electromagnetic waves by their wavelength or frequency. Waves with
shorter wavelengths (e.g., gamma rays) have higher frequencies and higher energy; waves with shorter wavelengths (e.g., gamma rays) have higher frequencies and higher energy; waves with
longer wavelengths (e.g., radio waves) have lower frequencies and lower energy. longer wavelengths (e.g., radio waves) have lower frequencies and lower energy.

1 Department of Defense, 1 Department of Defense, Joint Electromagnetic Spectrum Operations, JP 3-85, Washington, DC, March 22, 2020, p. v, , JP 3-85, Washington, DC, March 22, 2020, p. v,
https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp3_85.pdf?ver=2020-04-09-140128-347. https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp3_85.pdf?ver=2020-04-09-140128-347.
2 2 ~~This~~T his section was section was written by John R.written by John R. Hoehn. For more information, see CRSHoehn. For more information, see CRS In Focus IF11155, In Focus IF11155, Defense Primer:
Military Use of the ~~Electromagnetic~~Electrom agnetic Spectrum , by John R. Hoehn. , by John R. Hoehn.
3 Frequency is the property of a wave that describes 3 Frequency is the property of a wave that describes how many wave patterns orhow many wave patterns or cycles pass by in a period of time. cycles pass by in a period of time.
Frequency isFrequency is ~~measured~~ measured in Hertz (Hz). A wavein Hertz (Hz). A wave with a frequency of 1 Hz means that one wave (peakwith a frequency of 1 Hz means that one wave (peak -to-peak) passes by -to-peak) passes by
each second. each second.
4 Wavelength is the distance between adjacent peaks in a series of periodic waves.4 Wavelength is the distance between adjacent peaks in a series of periodic waves.
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Overview of Department of Defense Use of the Electromagnetic Spectrum

Figure 1. The Electromagnetic Spectrum

Source: National Aeronautics and Space Administration,National Aeronautics and Space Administration, “The Electromagnetic Spectrum,” 2020, “The Electromagnetic Spectrum,” 2020,
https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html. https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html.
Scientists and engineers have discovered many practical uses for electromagnetic radiation. For Scientists and engineers have discovered many practical uses for electromagnetic radiation. For
example, mobile phones convert human voice and digital information into signals that can be example, mobile phones convert human voice and digital information into signals that can be
transmitted by low frequency, low energy radio waves to enable wireless communications. transmitted by low frequency, low energy radio waves to enable wireless communications.
Medical professionals use machines to focus high frequency, high energy gamma rays to Medical professionals use machines to focus high frequency, high energy gamma rays to ~~kill~~
kil cancerous cancerous ~~cells~~cel s. Thus, common technologies use electromagnetic radiation to enable a wide . Thus, common technologies use electromagnetic radiation to enable a wide
variety of uses. In applications across civil, commercial, and government sectors, the variety of uses. In applications across civil, commercial, and government sectors, the
characteristics of the waves used often drive the use. Below are examples of electromagnetic characteristics of the waves used often drive the use. Below are examples of electromagnetic
radiation uses and applications. radiation uses and applications.
 Radio frequency waves can be used to transmit messages between electronic  Radio frequency waves can be used to transmit messages between electronic
devices. Radio waves have varying wavelengths and characteristics that affect devices. Radio waves have varying wavelengths and characteristics that affect
how much, how far, and in what conditions data can be transmitted between a how much, how far, and in what conditions data can be transmitted between a
sender and a receiver. Some very low frequency radio waves can travel long sender and a receiver. Some very low frequency radio waves can travel long
distances, and can penetrate seawater, but cannot support high data rates. These distances, and can penetrate seawater, but cannot support high data rates. These
waves are useful for communications with submarines. Other radio waves can waves are useful for communications with submarines. Other radio waves can
travel a long distance and pass through solid objects, like buildings and trees, travel a long distance and pass through solid objects, like buildings and trees,
making them useful for mobile communications. making them useful for mobile communications. ~~Still~~ Stil other radio waves can other radio waves can
travel short distances and cannot penetrate dense objects, but offer greater travel short distances and cannot penetrate dense objects, but offer greater
bandwidth and speed. These radio waves may be useful for high-data bandwidth and speed. These radio waves may be useful for high-data
applications, such as downloading or streaming videos within a home or office. applications, such as downloading or streaming videos within a home or office.
 Microwaves have higher throughput—data upload and download rates—than  Microwaves have higher throughput—data upload and download rates—than
radio waves and therefore are able to transmit more data. However, microwaves radio waves and therefore are able to transmit more data. However, microwaves
are more limited in range and can be disrupted by solid objects. Hence, are more limited in range and can be disrupted by solid objects. Hence,
microwaves are often used for point-to-point transmissions. Microwaves are also microwaves are often used for point-to-point transmissions. Microwaves are also
used in radars—systems that send out pulses of high frequency waves that reflect used in radars—systems that send out pulses of high frequency waves that reflect
off an object and back to the source. This technology capitalizes on the fact that off an object and back to the source. This technology capitalizes on the fact that
the waves cannot penetrate solid objects, and uses this characteristic to gauge the waves cannot penetrate solid objects, and uses this characteristic to gauge
time and distance to an object. Microwaves are also used in time and distance to an object. Microwaves are also used in ~~satellite~~satel ite
communications, which experience few obstacles in their transmission path.communications, which experience few obstacles in their transmission path.
 Infrared radiation (IR) is used in household items such as remote controls.  Infrared radiation (IR) is used in household items such as remote controls.
Remote controls shoot pulses of IR energy to a receiver in a TV, for example. The Remote controls shoot pulses of IR energy to a receiver in a TV, for example. The
receiver converts the light signals to electrical signals, instructing receiver converts the light signals to electrical signals, instructing
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Overview of Department of Defense Use of the Electromagnetic Spectrum

microprocessors to carry out commands.5 Similarly, infrared lasers can be used microprocessors to carry out commands.5 Similarly, infrared lasers can be used
for point-to-point communications over short distances to provide high-speed, for point-to-point communications over short distances to provide high-speed,
reliablereliable connections. Infrared signals can travel only short distances and can be connections. Infrared signals can travel only short distances and can be
blocked by obstacles. blocked by obstacles.
 X-rays can penetrate  X-rays can penetrate ~~optically~~optical y opaque materials and are routinely used in aircraft opaque materials and are routinely used in aircraft
maintenance to identify cracks in airframes. X-rays are high-energy, high- maintenance to identify cracks in airframes. X-rays are high-energy, high-
frequency ionizing radiation; they have enough energy to remove an electron frequency ionizing radiation; they have enough energy to remove an electron
from (ionize) an atom or molecule, which could lead to mutations in a human from (ionize) an atom or molecule, which could lead to mutations in a human
~~cell~~cel ’s DNA, and could lead to cancer.6 ’s DNA, and could lead to cancer.6
 Certain technologies can detect gamma rays—high-energy radiation—to help  Certain technologies can detect gamma rays—high-energy radiation—to help
identify potential nuclear events. Similar to X-rays, gamma rays present identify potential nuclear events. Similar to X-rays, gamma rays present
biological risks. biological risks.
Federal Spectrum Allocation
In the United States, the National Telecommunications and Information Administration (NTIA) In the United States, the National Telecommunications and Information Administration (NTIA)
and the Federal Communications Commission (FCC) jointly manage use of the radio spectrum (3 and the Federal Communications Commission (FCC) jointly manage use of the radio spectrum (3
Hz to 300 GHz) to balance U.S. government interests, private interests, and the public good.7 Hz to 300 GHz) to balance U.S. government interests, private interests, and the public good.7
NTIA manages radio spectrum use by federal agencies,8 while the FCC manages nonfederal NTIA manages radio spectrum use by federal agencies,8 while the FCC manages nonfederal
use—that is, radio spectrum use of the private sector, including broadcasting, mobile use—that is, radio spectrum use of the private sector, including broadcasting, mobile
communication use, commercial, industrial, personal uses, and state and local government uses.9 communication use, commercial, industrial, personal uses, and state and local government uses.9
Both agencies coordinate on frequency Both agencies coordinate on frequency ~~allocation~~al ocation and assignment, and in setting technical and assignment, and in setting technical
requirements to avoid interference.10requirements to avoid interference.10
The The allocation of radio spectrum involves designating certain frequency segments for specific of radio spectrum involves designating certain frequency segments for specific
uses, such as mobile communications, uses, such as mobile communications, ~~satellite~~satel ite, and TV broadcasting. The , and TV broadcasting. The assignment of radio of radio
frequencies occurs after the spectrum has been frequencies occurs after the spectrum has been ~~allocated~~al ocated for a specific use. The FCC assigns for a specific use. The FCC assigns
frequencies and grants licenses to nonfederal users to use certain segments or certain frequencies and grants licenses to nonfederal users to use certain segments or certain
frequencies.11 The NTIA assigns frequencies to federal agencies, authorizing them to operate in a frequencies.11 The NTIA assigns frequencies to federal agencies, authorizing them to operate in a
specific segment of the radio spectrum.12 The two agencies coordinate on radio spectrum specific segment of the radio spectrum.12 The two agencies coordinate on radio spectrum

5 Jim Lucas, “What is Infrared,” 5 Jim Lucas, “What is Infrared,” Live Science, February 27, 2019, https://www.livescience.com/50260-infrared-, February 27, 2019, https://www.livescience.com/50260-infrared-
radiation.html. radiation.html.
6 American Cancer Society, 6 American Cancer Society, What are x-rays and gamma rays?, accessed February 26, 2019, https://www.cancer.org/, accessed February 26, 2019, https://www.cancer.org/
cancer/cancer-causes/radiation-exposure/x-rays-gamma-rays/whatcancer/cancer-causes/radiation-exposure/x-rays-gamma-rays/what -are-xrays-and-gamma-rays.html. -are-xrays-and-gamma-rays.html.
7 7 ~~The NTIA~~T he NT IA and FCC and FCC also represent U.S. interests at international forums, such as the World Radiocommunication also represent U.S. interests at international forums, such as the World Radiocommunication
Conference (WRC) that works to globalize and harmonize spectrum allocation to facilitate international Conference (WRC) that works to globalize and harmonize spectrum allocation to facilitate international
communications. communications. ~~Thus~~T hus, allocation decisions are also dependent on agreements, treaties, and regulations that drive , allocation decisions are also dependent on agreements, treaties, and regulations that drive
international use of the spectrum. For more information, see international use of the spectrum. For more information, see ~~NTIA~~NT IA, “Spectrum Sharing,” accessed, “Spectrum Sharing,” accessed February 26, 2020, February 26, 2020,
https://www.ntia.doc.gov/legacy/osmhome/EPS/openness/sp_rqmnts/sharing7.html. https://www.ntia.doc.gov/legacy/osmhome/EPS/openness/sp_rqmnts/sharing7.html.
8 P.L. 102-538. 8 P.L. 102-538.
9 47 U.S.C.9 47 U.S.C. §303. §303.
10 Spectrum decisions are also driven by10 Spectrum decisions are also driven by international decisions to coordinate spectrum use and facilitate global international decisions to coordinate spectrum use and facilitate global
communications. communications.
11 11 ~~The~~T he FCC also designates FCC also designates some bandssome bands for unlicensedfor unlicensed ~~use. These bands~~ use. T hese bands are open for usersare open for users (e.g., medical(e.g., medical device device
makers, Wi-Fi equipment makers) who agree to adhere to certain technical requirements so that their equipment does makers, Wi-Fi equipment makers) who agree to adhere to certain technical requirements so that their equipment does
not interfere with other unlicensed usesnot interfere with other unlicensed uses or nearby licensed uses.or nearby licensed uses.
12 12 ~~NTIA~~NT IA, , Federal Government Spectrum Compendium, Washington, DC, August, Washington, DC, August 21, 2017, https://www.ntia.doc.gov/21, 2017, https://www.ntia.doc.gov/
other-publication/2017/federal-government-spectrum-compendium. other-publication/2017/federal-government-spectrum-compendium.
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~~allocation and reallocation~~al ocation and real ocation as specified in a Memorandum of Understanding (MOU).13 The MOU, as specified in a Memorandum of Understanding (MOU).13 The MOU,
which dates back to 1940,14 establishes a framework for compliance with the statutory which dates back to 1940,14 establishes a framework for compliance with the statutory
requirements and stipulates that the Chairman of the FCC and Assistant Secretary for requirements and stipulates that the Chairman of the FCC and Assistant Secretary for
Communications and Information (i.e., the lead administrator for the NTIA), Communications and Information (i.e., the lead administrator for the NTIA), ~~shall meet~~
~~biannually~~shal meet biannual y to conduct joint spectrum planning. to conduct joint spectrum planning.
The NTIA uses the Interdepartment Radio Advisory Committee (IRAC) as an interagency radio The NTIA uses the Interdepartment Radio Advisory Committee (IRAC) as an interagency radio
spectrum coordination body which consists of technical representatives from many agencies.15 spectrum coordination body which consists of technical representatives from many agencies.15
The IRAC advises the NTIA on federal radio spectrum needs so that it can represent the interests The IRAC advises the NTIA on federal radio spectrum needs so that it can represent the interests
of federal agencies in discussions with the FCC. The FCC engages with the NTIA on spectrum of federal agencies in discussions with the FCC. The FCC engages with the NTIA on spectrum
discussions when changes in discussions when changes in ~~allocation~~al ocation or use may affect federal agency activities. After or use may affect federal agency activities. After
~~allocation~~al ocation occurs, federal users obtain authorization from NTIA— occurs, federal users obtain authorization from NTIA—~~usually~~usual y referred to as a referred to as a
frequency assignment. The DOD Chief Information Officer participates in the IRAC. The DOD’s frequency assignment. The DOD Chief Information Officer participates in the IRAC. The DOD’s
participation is guided by department policy.16 participation is guided by department policy.16
Current Military Applications of the Spectrum17
Nearly every modern weapons system—such as those used by airplanes, Nearly every modern weapons system—such as those used by airplanes, ~~satellites~~satel ites, tanks, ships, , tanks, ships,
and radios—depends on the spectrum to function. The military uses applications across the and radios—depends on the spectrum to function. The military uses applications across the
electromagnetic spectrum to support communications, situational awareness, military operations, electromagnetic spectrum to support communications, situational awareness, military operations,
and emerging technologies. These applications range from using very lowand emerging technologies. These applications range from using very low -frequency radio waves -frequency radio waves
to communicate with submarines underwater, to microwaves for datalinks to connect weapons to communicate with submarines underwater, to microwaves for datalinks to connect weapons
systems (e.g., aircraft, systems (e.g., aircraft, ~~satellites~~satel ites, ground forces, ships), ground forces, ships). Figure 2 shows various applications in the shows various applications in the
radio segment of the electromagnetic spectrum.18 segment of the electromagnetic spectrum.18

13 “Memorandum of Understanding Between the Federal Communications Commission and the National 13 “Memorandum of Understanding Between the Federal Communications Commission and the National
~~Telecommunications~~T elecommunications and Information Administration,” signed on January 31, 2003 by Michael K. Powell, and Information Administration,” signed on January 31, 2003 by Michael K. Powell, ~~Chairman~~Chairma n of of
the FCCthe FCC and Nancy J. Victory, Assistant Secretary for Communications and Information, U.S. Department of and Nancy J. Victory, Assistant Secretary for Communications and Information, U.S. Department of
Commerce, available at https://www.ntia.doc.gov/files/ntia/publications/fccntiamou_01312003.pdf. Commerce, available at https://www.ntia.doc.gov/files/ntia/publications/fccntiamou_01312003.pdf.
14 14 ~~The~~T he MOU includes MOU includes ~~This~~ T his MOU establishes MOU establishes a framework for compliance with the statutory requirements and stipulates a framework for compliance with the statutory requirements and stipulates
that the Chairman of the FCC and Assistant Secretary for Communications and Information shall that the Chairman of the FCC and Assistant Secretary for Communications and Information shall ~~meet~~mee t biannually to biannually to
conduct joint spectrum planning. conduct joint spectrum planning.
15 15 ~~NTIA~~NT IA, “Interdepartment Radio Advisory Committee (IRAC),” accessed, “Interdepartment Radio Advisory Committee (IRAC),” accessed ~~February~~ February 26, 2020, 26, 2020,
https://www.ntia.doc.gov/page/interdepartmenthttps://www.ntia.doc.gov/page/interdepartment -radio-advisory-committee-irac. -radio-advisory-committee-irac.
16 Combined Communications-Electronics Board (CCEB), 16 Combined Communications-Electronics Board (CCEB), Guide to Spectrum Management in Military Operations
APC 190(C), September 2007, http://www.acqnotes.com/Attachments/, September 2007, http://www.acqnotes.com/Attachments/
ACP%20190(C)%20Guide%20to%20Spectrum%20Managing%20in%20Military%20Operations.pdfACP%20190(C)%20Guide%20to%20Spectrum%20Managing%20in%20Military%20Operations.pdf , and , and ~~Thomas~~T homas P. P.
KiddKidd III, “Military Spectrum Management,” Presentation, November 2019, http://ustti.org/wp-content/uploads/2019/III, “Military Spectrum Management,” Presentation, November 2019, http://ustti.org/wp-content/uploads/2019/
11/Day-4-1_Military-Spectrum-Management_20180-0907.pdf. 11/Day-4-1_Military-Spectrum-Management_20180-0907.pdf.
17 17 ~~This~~T his section was section was written by John R.written by John R. Hoehn. For more information on DOD spectrum operations, see CRSHoehn. For more information on DOD spectrum operations, see CRS In Focus In Focus
IF11155, IF11155, Defense ~~Primer~~Prim er: Military Use of the ~~Electromagnetic~~Electrom agnetic Spectrum , by John R. Hoehn. , by John R. Hoehn.
~~18 The~~18 T he radio segment is radio segment is typically describedtypically described as those frequencies between 3 as those frequencies between 3 ~~kilohertz~~kilo hertz (kHz) and 300 gigahertz (GHz). (kHz) and 300 gigahertz (GHz).
~~The~~T he highest frequency radio waves, highest frequency radio waves, from 300 megahertz (MHz) to 300 GHz, are calledfrom 300 megahertz (MHz) to 300 GHz, are called microwaves.microwaves.
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Figure 2. U.S. Department of Defense (DOD) Use of Radio Spectrum
Examples of DOD Systems Operating in the Radio Spectrum (3 kHz – 300 GHz) Examples of DOD Systems Operating in the Radio Spectrum (3 kHz – 300 GHz)

Source: U.S. GovernmentU.S. Government Accountability Office,Accountability Office, Spectrum Management: Federal Relocation Costs and Auction
Revenues, 13-472, May 2013, p. 6, https://www.gao.gov/assets/660/654794.pdf. , 13-472, May 2013, p. 6, https://www.gao.gov/assets/660/654794.pdf.
Notes: The figure shows The figure shows ~~allocated~~al ocated radio spectrum for DOD applications, with multiple radio spectrum for DOD applications, with multiple uses operating in one uses operating in one
band (1755-1850 MHz) and microwave systemsband (1755-1850 MHz) and microwave systems in the upper bands (300 MHz-300 GHz). in the upper bands (300 MHz-300 GHz).
Although the majority of military communications capabilities use radio waves and microwaves, Although the majority of military communications capabilities use radio waves and microwaves,
the military also uses the infrared and ultraviolet spectrums for laser technologies and the military also uses the infrared and ultraviolet spectrums for laser technologies and ~~intelligence~~intel igence
collection (collection (~~see~~see Figure 3). Infrared and ultraviolet lasers have greater bandwidth than radio . Infrared and ultraviolet lasers have greater bandwidth than radio
frequencies, enabling the dissemination of large volumes of data (e.g., video) across long frequencies, enabling the dissemination of large volumes of data (e.g., video) across long
distances due to signal strength. The military can also use lasers offensively, to dazzle distances due to signal strength. The military can also use lasers offensively, to dazzle ~~satellite~~
satel ite sensors, destroy drones, and for other purposes.19sensors, destroy drones, and for other purposes.19

19 Hemani Kaushal19 Hemani Kaushal and Georgesand Georges Kaddoum,Kaddoum, “Applications of Lasers for “Applications of Lasers for ~~Tactical~~T actical Military Operations,” Military Operations,” IEEE Access, ,
vol. 5 (September 22, 2017), pp. 20736-20753, doi: 10.1109/ACCESS.2017.2755678. vol. 5 (September 22, 2017), pp. 20736-20753, doi: 10.1109/ACCESS.2017.2755678.
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Figure 3. Spectrum Used for DOD Laser Technologies
Infrared and Ultraviolet Radiation Used for Laser Technologies Infrared and Ultraviolet Radiation Used for Laser Technologies

Source: Marczak, Jan & Andrzej,Marczak, Jan & Andrzej, Koss & Targowski,Koss & Targowski, Piotr & Michalina, GÃƒÂ³raPiotr & Michalina, GÃƒÂ³ra & Strzelec,& Strzelec, Marek & Antoni, Marek & Antoni,
SarzyÃ…Â„skiSarzyÃ…Â„ski & Wojciech,& Wojciech, ~~Skrzeczanowski~~ Skrzeczanowski & Ostrowski,& Ostrowski, Roman & Rycyk, Antoni. (2008). Characterization of Roman & Rycyk, Antoni. (2008). Characterization of
LaserLaser Cleaning of Artworks.Cleaning of Artworks. Sensors.Sensors. 8. 10.3390/s8106507. 8. 10.3390/s8106507.
These applications can be combined to provide an These applications can be combined to provide an ~~overall~~ overal military capability, such as command military capability, such as command
and control (C2) or electronic warfare. The following discussion provides examples of DOD and control (C2) or electronic warfare. The following discussion provides examples of DOD
spectrum applications. spectrum applications.
Communications
MilitaryMilitary commanders have become accustomed to communicating with their forces nearly commanders have become accustomed to communicating with their forces nearly
instantaneously. Commanders may use wired communications (e.g., landline phones, computers) instantaneously. Commanders may use wired communications (e.g., landline phones, computers)
or wireless technologies (e.g., radio systems)—technologies that use radio frequencies (spectrum) or wireless technologies (e.g., radio systems)—technologies that use radio frequencies (spectrum)
to transmit messages over-the-air between devices. Wireless communications are often used when to transmit messages over-the-air between devices. Wireless communications are often used when
there is no physical connection between the sender and receiver. The radio frequencies use range there is no physical connection between the sender and receiver. The radio frequencies use range
from low-bandwidth options, such as transferring from low-bandwidth options, such as transferring ~~small~~ smal strings of text, to highly data-intensive strings of text, to highly data-intensive
applications, such as full motion video and video teleconferencing. The systems can be located applications, such as full motion video and video teleconferencing. The systems can be located
~~terrestrially~~terrestrial y (either with ground forces or on ships), in the air, or in space (i.e., on (either with ground forces or on ships), in the air, or in space (i.e., on ~~satellites~~satel ites). In ). In
general, communications systems use radio and microwave frequencies; however, some emerging general, communications systems use radio and microwave frequencies; however, some emerging
communications technologies use lasers—transmitting light, instead of radio waves, between communications technologies use lasers—transmitting light, instead of radio waves, between
receivers.20 Radios use different frequencies depending on the required range and amount of data receivers.20 Radios use different frequencies depending on the required range and amount of data
they are required to transmit. Ground-based radios are they are required to transmit. Ground-based radios are ~~typically~~typical y used at short ranges, limited by used at short ranges, limited by
line of sight, that span no more than 50 miles. In general, militariesline of sight, that span no more than 50 miles. In general, militaries ~~use satellites~~ use satel ites to communicate to communicate
over longer distances. over longer distances.
Terrestrial Radios
For more than a century, the U.S. military has used ground-based (terrestrial) radios to For more than a century, the U.S. military has used ground-based (terrestrial) radios to
communicate. In their infancy during World War I and World War II, these radios were used to communicate. In their infancy during World War I and World War II, these radios were used to
transmit voice communications to coordinate forces. Radio systems have since evolved to use transmit voice communications to coordinate forces. Radio systems have since evolved to use
new frequency bands to transmit larger amounts of data. Systems like the Joint Tactical Radio new frequency bands to transmit larger amounts of data. Systems like the Joint Tactical Radio

20 Stephen Carlson, “Marines conduct field test of laser-based20 Stephen Carlson, “Marines conduct field test of laser-based communications system,” communications system,” UPI, August, August 27, 2018, 27, 2018,
https://www.upi.com/Defense-News/2018/08/27/Marines-conducthttps://www.upi.com/Defense-News/2018/08/27/Marines-conduct -field-test-of-laser-based-communications-system/-field-test-of-laser-based-communications-system/
3511535389333/. 3511535389333/.
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System (JTRS) provide new electronics to modulate the radio frequencies, enabling greater data System (JTRS) provide new electronics to modulate the radio frequencies, enabling greater data
transmission and encryption for security. Many of these terrestrial radios are limited to line-of-transmission and encryption for security. Many of these terrestrial radios are limited to line-of-
sight range due to the curvature of the earth. Some, like the PRC-117 Multiband Manpack Radio, sight range due to the curvature of the earth. Some, like the PRC-117 Multiband Manpack Radio,
use multiple frequency bands to transmit data—this radio system uses frequencies from 30 MHz use multiple frequency bands to transmit data—this radio system uses frequencies from 30 MHz
– 2000 MHz.21 – 2000 MHz.21
For several decades, the military has mostly used For several decades, the military has mostly used ~~satellites~~satel ites to provide beyond-line-of-sight to provide beyond-line-of-sight
(BLOS) radio transmissions—signals traveling over the horizon, (BLOS) radio transmissions—signals traveling over the horizon, ~~typically~~typical y defined as extending defined as extending
no more than 50 miles. However, a few terrestrial-based systems can provide BLOS capabilities. no more than 50 miles. However, a few terrestrial-based systems can provide BLOS capabilities.
An example is the AN/TRC-170 Tropospheric Scatter Microwave Radio Terminal (An example is the AN/TRC-170 Tropospheric Scatter Microwave Radio Terminal (~~see~~see Figure
4)..22 This radio uses microwaves to bounce signals off the troposphere, providing a BLOS 22 This radio uses microwaves to bounce signals off the troposphere, providing a BLOS
capability for communications with ground forces at ranges of up to 100 nautical miles capability for communications with ground forces at ranges of up to 100 nautical miles
(approximately 115 standard miles), depending on weather conditions. (approximately 115 standard miles), depending on weather conditions.
Figure 4. AN/TRC-170 Tropospheric Scatter Microwave Radio Terminal

Source: https://www.marines.mil/News/https://www.marines.mil/News/~~News~~N ews-Display/Article/1169154/the-antrc-170-continues-to-stayreliable--Display/Article/1169154/the-antrc-170-continues-to-stayreliable-
for-the-corps/. for-the-corps/.
Notes: Photo by Lance Cpl. Cody Lemons. Photo by Lance Cpl. Cody Lemons.
Satellite Communications
Long-distance Long-distance ~~satellite~~satel ite communications range from data feeds for unmanned aircraft systems communications range from data feeds for unmanned aircraft systems
(also known as drones) to hardened signals for nuclear command, control, and communications.23 (also known as drones) to hardened signals for nuclear command, control, and communications.23
~~Satellite communications generally~~ Satel ite communications general y use multiple frequency bands to transmit data more quickly. use multiple frequency bands to transmit data more quickly.
While While ~~satellite~~satel ite communications enables long–distance transmissions, it introduces latency (or communications enables long–distance transmissions, it introduces latency (or
time delay) because the transmissions must travel (at the speed of light) up and down to the time delay) because the transmissions must travel (at the speed of light) up and down to the
~~satellite~~satel ite in orbit.24 Most communications in orbit.24 Most communications ~~satellites~~satel ites operate in geosynchronous orbit (GEO), which operate in geosynchronous orbit (GEO), which

21 L3Harris, “L3Harris Falcon III® AN/PRC-117G(V)1(C)21 L3Harris, “L3Harris Falcon III® AN/PRC-117G(V)1(C) ~~Multiband Networking~~ Multiband Net working Manpack Radio,” press release, Manpack Radio,” press release,
2020, https://www.harris.com/solution/harris-falcon-iii-an-prc-117gv1c-multiband-networking-manpack-radio. 2020, https://www.harris.com/solution/harris-falcon-iii-an-prc-117gv1c-multiband-networking-manpack-radio.
22 U.S. 22 U.S. Marine Corps, “Marine Corps, “~~The AN/TRC~~T he AN/T RC-170 Continues to Stay Reliable-170 Continues to Stay Reliable for the Corps,” press release, May 2, 2017, for the Corps,” press release, May 2, 2017,
https://www.marines.mil/News/News-Display/Article/1169154/the-antrc-170-continues-to-stayreliable-for-the-corps/. https://www.marines.mil/News/News-Display/Article/1169154/the-antrc-170-continues-to-stayreliable-for-the-corps/.
~~23 These~~23 T hese radio signals radio signals are designedare designed to operate during a nuclear event, when most other electronic transmissions are to operate during a nuclear event, when most other electronic transmissions are
disrupted. disrupted.
24 While there is a time delay when “drone” operators in the United States fly large unmanned aircraft in other parts of 24 While there is a time delay when “drone” operators in the United States fly large unmanned aircraft in other parts of
the world, this isthe world, this is augmented by automation and local groundaugmented by automation and local ground control stations for critical phases of flight (i.e., takeoff control stations for critical phases of flight (i.e., takeoff
landing, and taxiing) to reducelanding, and taxiing) to reduce the effect of lag. Nuclearthe effect of lag. Nuclear command and control uses multiple methods of command and control uses multiple methods of
communications—not just satellites—to issue orders to nuclear forces. communications—not just satellites—to issue orders to nuclear forces. ~~This includes~~ T his includes the E-4B National Airborne the E-4B National Airborne
Operations Center and the E-6 Operations Center and the E-6 ~~Take~~T ake Charge and Move Out systems. Charge and Move Out systems.
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is approximately 22,000 miles from the Earth’s surface. This is approximately 22,000 miles from the Earth’s surface. This ~~allows for satellite~~al ows for satel ite terminals to terminals to
remain in position, rather than having to track a remain in position, rather than having to track a ~~satellite~~satel ite in either low or middle earth orbits. in either low or middle earth orbits.
The U.S. military operates several global The U.S. military operates several global ~~satellite communication constellations~~satel ite communication constel ations including including
 Advanced Extremely High Frequency (AEHF),25  Advanced Extremely High Frequency (AEHF),25
 Wideband Global  Wideband Global ~~Satellite~~ Satel ite Communications (WGS),26 and Communications (WGS),26 and
 Mobile User Objective System (MUOS).27  Mobile User Objective System (MUOS).27
In addition to its own In addition to its own ~~satellites~~satel ites, the DOD uses commercial , the DOD uses commercial ~~satellites~~satel ites for communications. This is for communications. This is
due, in part, to the limited bandwidth available on DOD-operated due, in part, to the limited bandwidth available on DOD-operated ~~satellites~~satel ites (i.e., the number of (i.e., the number of
~~satellites~~satel ites on orbit, the amount of data each on orbit, the amount of data each ~~satellite~~satel ite is able to transmit, as is able to transmit, as ~~well~~ wel as some limitations as some limitations
of coverage). Examples of of coverage). Examples of ~~satellite~~satel ite communications companies that contract with the DOD communications companies that contract with the DOD
include Inmarsat, Viasat, Iridium, and Intelsat.28 include Inmarsat, Viasat, Iridium, and Intelsat.28
Situational Awareness
Another defense application of the electromagnetic spectrum is the use of radio waves, Another defense application of the electromagnetic spectrum is the use of radio waves,
microwaves, and infrared radiation to develop a picture of the battle space by determining the microwaves, and infrared radiation to develop a picture of the battle space by determining the
location of friendly and enemy forces. This is done through various technologies, as described location of friendly and enemy forces. This is done through various technologies, as described
below. below.
Radar and LIDAR
The most common situational awareness application is radar; however, recently light detection The most common situational awareness application is radar; however, recently light detection
and ranging (LIDAR) systems are also used. Both technologies send out an electromagnetic and ranging (LIDAR) systems are also used. Both technologies send out an electromagnetic
signal and sense the portion that is reflected back to determine an object’s distance, speed, and signal and sense the portion that is reflected back to determine an object’s distance, speed, and
sometimes altitude. Radars operate on different radio and microwave frequencies, depending on sometimes altitude. Radars operate on different radio and microwave frequencies, depending on
their purpose. Lower-band frequency radars provide a longer range picture of the battle space, but their purpose. Lower-band frequency radars provide a longer range picture of the battle space, but
because of clutter (undesired signals returned to the radar) they are not able to provide target-because of clutter (undesired signals returned to the radar) they are not able to provide target-
quality pictures. These systems are used for long-range quality pictures. These systems are used for long-range ~~surveillance~~surveil ance, particularly for identifying , particularly for identifying
ships and aircraft. Higher-band frequencies provide target-quality pictures, but lack the same ships and aircraft. Higher-band frequencies provide target-quality pictures, but lack the same
effective range. Radar and LIDAR systems are commonly associated with air defense, military effective range. Radar and LIDAR systems are commonly associated with air defense, military
aviation, aviation, ~~artillery~~artil ery, and space systems. While radar has become ubiquitous in military formations, , and space systems. While radar has become ubiquitous in military formations,
LIDAR technologies are LIDAR technologies are ~~still~~ stil being developed. being developed.
Passive Radar
Another technology that the U.S. and its competitors are developing is passive radar. Passive Another technology that the U.S. and its competitors are developing is passive radar. Passive
radars do not emit radio signals; instead, they listen to radio signals emitted from the target. Some radars do not emit radio signals; instead, they listen to radio signals emitted from the target. Some

25 For more information, see Air Force Space25 For more information, see Air Force Space Command, “Advanced Extremely High Frequency System,” fact sheet, Command, “Advanced Extremely High Frequency System,” fact sheet,
March 22, 2017, https://www.afspc.af.mil/About-Us/Fact-Sheets/Display/Article/249024/advanced-extremely-high-March 22, 2017, https://www.afspc.af.mil/About-Us/Fact-Sheets/Display/Article/249024/advanced-extremely-high-
frequency-system/. frequency-system/.
26 For more information, see U.S. Air Force, “Wideband Global26 For more information, see U.S. Air Force, “Wideband Global ~~SATCOM~~ SAT COM Satellite,” fact sheet, November 15, 2015, Satellite,” fact sheet, November 15, 2015,
https://www.af.mil/Abouthttps://www.af.mil/About -Us/Fact-Us/Fact -Sheets/Display/Article/104512/wideband-global-satcom-satellite/. -Sheets/Display/Article/104512/wideband-global-satcom-satellite/.
27 For more information, see Space and Naval Warfare Systems Command, “Mobile User Objective System (MUOS),” 27 For more information, see Space and Naval Warfare Systems Command, “Mobile User Objective System (MUOS),”
fact sheet, December 2011, https://www.secnav.navy.mil/rda/Documents/muos_overview_for_asn_rda_12-27-11-s.pdf. fact sheet, December 2011, https://www.secnav.navy.mil/rda/Documents/muos_overview_for_asn_rda_12-27-11-s.pdf.
28 Sandra 28 Sandra Erwin, “Satcom Conumdrum: Air Force Contemplating Right Mix of Commercial, Military Satellites,” Erwin, “Satcom Conumdrum: Air Force Contemplating Right Mix of Commercial, Military Satellites,”
SpaceNews, May 6, 2019, https://spacenews.com/satcom-conumdrum-air-force-contemplating-right, May 6, 2019, https://spacenews.com/satcom-conumdrum-air-force-contemplating-right -mix-of--mix-of-
commercial-military-satellites/. commercial-military-satellites/.
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analysts argue that passive radars have the potential to detect low-observable aircraft such as the analysts argue that passive radars have the potential to detect low-observable aircraft such as the
B-2 bomber and the F-35 fighter jet that are optimized for low radar cross section—the amount of B-2 bomber and the F-35 fighter jet that are optimized for low radar cross section—the amount of
measurable radar signal reflected back to its source—at certain frequencies and flight profiles measurable radar signal reflected back to its source—at certain frequencies and flight profiles
(e.g., head on or the side).29 Furthermore, because passive radars do not emit a signal, it is (e.g., head on or the side).29 Furthermore, because passive radars do not emit a signal, it is
difficult to detect them using traditional methods (i.e., signals difficult to detect them using traditional methods (i.e., signals ~~intelligence~~intel igence). Other analysts note ). Other analysts note
that, while passive radars may aid in the detection of stealth systems, they do not necessarily that, while passive radars may aid in the detection of stealth systems, they do not necessarily
provide the information needed to target and engage the systems and are therefore most useful as provide the information needed to target and engage the systems and are therefore most useful as
cues for other sensors.30 Advances in microelectronics cues for other sensors.30 Advances in microelectronics ~~allow~~al ow passive radar technology to detect passive radar technology to detect
different frequencies, such as different frequencies, such as ~~cellular~~cel ular signals, that are signals, that are ~~traditionally~~ traditional y not captured, enabling the not captured, enabling the
potential detection of a wider range of aircraft. At the 2018 Berlin Airshow, a German radar potential detection of a wider range of aircraft. At the 2018 Berlin Airshow, a German radar
company tested a newly developed passive radar to identify and track an F-35 using company tested a newly developed passive radar to identify and track an F-35 using ~~cellular~~
cel ular frequencies among other techniques.31 China and Russia have funded research and development frequencies among other techniques.31 China and Russia have funded research and development
efforts to further develop these technologies.32 The DOD has funded research for this technology efforts to further develop these technologies.32 The DOD has funded research for this technology
through the Defense Advanced Research Projects Agency (DARPA).33 through the Defense Advanced Research Projects Agency (DARPA).33
Signals Intelligence
Signals Signals ~~intelligence~~ intel igence (SIGINT) systems primarily detect and collect spectrum emissions. These (SIGINT) systems primarily detect and collect spectrum emissions. These
passive systems—that is, they do not emit their own signal—can listen to radio and radar passive systems—that is, they do not emit their own signal—can listen to radio and radar
frequencies and observe heat signatures of personnel, missiles, aircraft, frequencies and observe heat signatures of personnel, missiles, aircraft, ~~artillery~~artil ery, and vehicles. , and vehicles.
One subset of SIGINT is collecting communications signals to analyze how militaries One subset of SIGINT is collecting communications signals to analyze how militaries
communicate—such as what time radios transmit, from what location, and specific radio communicate—such as what time radios transmit, from what location, and specific radio
frequencies—as frequencies—as ~~well~~ wel as the data transmitted. A second subset of SIGINT is electronic as the data transmitted. A second subset of SIGINT is electronic
~~intelligence. This intelligence~~ intel igence. This intel igence discipline analyzes frequencies, patterns, operating procedures— discipline analyzes frequencies, patterns, operating procedures—
among other information—of any other system that utilizes the spectrum. This includes radars, among other information—of any other system that utilizes the spectrum. This includes radars,
~~satellite~~ satel ite systems, and signal jammers, among other systems. systems, and signal jammers, among other systems.
Infrared Sensors
Hot objects emit radiation in the infrared segment of the spectrum. The higher their temperature Hot objects emit radiation in the infrared segment of the spectrum. The higher their temperature
relative to their surrounding environment, the easier they are to detect using infrared sensors. The relative to their surrounding environment, the easier they are to detect using infrared sensors. The
U.S. military has long used infrared signatures to track enemy aircraft and ground vehicles and to U.S. military has long used infrared signatures to track enemy aircraft and ground vehicles and to
guide missiles onto targets. The AIM-9X air-to-air and AGM-114 guide missiles onto targets. The AIM-9X air-to-air and AGM-114 ~~Hellfire~~ Hel fire air-to-ground missiles, air-to-ground missiles,

29 Dimitrios Oikonomou, Panagiotis Nomikos, and George29 Dimitrios Oikonomou, Panagiotis Nomikos, and George Limnaios, et al., “Passive RadarsLimnaios, et al., “Passive Radars and their use on the and their use on the
Modern Battlefield,” Modern Battlefield,” Journal of Computations & Modelling, vol. 9, no. 2 (2019), pp. 37-61. , vol. 9, no. 2 (2019), pp. 37-61.
30 30 ~~These~~T hese analysts argue that passive radars typically use lower analysts argue that passive radars typically use lower frequencies whichfrequencies which do not provide a sufficient position to do not provide a sufficient position to
target a munition. target a munition. ~~Typical~~T ypical air defense radars air defense radars ~~use~~ use higher bandhigher band frequencies to provide quality targeting data. Furthermore, frequencies to provide quality targeting data. Furthermore,
the geometry to detect aircraft with passive radar systems can be extremely difficult, particularly if the source of the the geometry to detect aircraft with passive radar systems can be extremely difficult, particularly if the source of the
radio energy isradio energy is not known. not known. ~~Tyler~~T yler Rogoway, “No, Passive Radar Rogoway, “No, Passive Radar Isn't Going to Make Isn't Going to Make ~~Stealth Technology~~St ealth T echnology Obsolete Obsolete
Anytime Soon,” Anytime Soon,” The Drive, September 30, 2019, https://www.thedrive.com/the-war-zone/30100/no-passive-radar-isnt-, September 30, 2019, https://www.thedrive.com/the-war-zone/30100/no-passive-radar-isnt-
stealth-ending-magic-people. stealth-ending-magic-people.
31 Ibid. 31 Ibid. ~~See~~ See also Sebastian Sprenger,also Sebastian Sprenger, “Stealthy No More? A German Radar“Stealthy No More? A German Radar Vendor SaysVendor Says ~~It Tracked~~ It T racked the F-35 Jet in the F-35 Jet in
2018—from a Pony Farm,” 2018—from a Pony Farm,” C4ISRNet, September 29, 2019, https://www.c4isrnet.com/intel-geoint/sensors/2019/09/30/, September 29, 2019, https://www.c4isrnet.com/intel-geoint/sensors/2019/09/30/
stealthy-no-more-a-german-radar-vendor-says-it-tracked-the-f-35-jet-in-2018-from-a-pony-farm/. stealthy-no-more-a-german-radar-vendor-says-it-tracked-the-f-35-jet-in-2018-from-a-pony-farm/.
32 Gökhan Soysal32 Gökhan Soysal and E.F.E. Murat, “and E.F.E. Murat, “~~UMTS~~UMT S passive radar implementation with two stage tracking algorithm,” passive radar implementation with two stage tracking algorithm,”
Communications Faculty of SciencesCommunications Faculty of Sciences University of Ankara Series, 2016, pp. 29University of Ankara Series, 2016, pp. 29 -53, https://dergipark.org.tr/en/-53, https://dergipark.org.tr/en/
download/article-file/778904. download/article-file/778904.
33 J.R. Wilson, “New frontiers in passive radar and sonar,” 33 J.R. Wilson, “New frontiers in passive radar and sonar,” Military & Aerospace Electronics, February, February 8, 2016, 8, 2016,
https://www.militaryaerospace.com/communications/article/16709052/new-frontiers-in-passive-radar-and-sonar. For https://www.militaryaerospace.com/communications/article/16709052/new-frontiers-in-passive-radar-and-sonar. For
more information on DARPA, see CRSmore information on DARPA, see CRS Report R45088, Report R45088, Defense Advanced Research Projects Agency: Overview and
Issues for Congress, by Marcy E. Gallo. , by Marcy E. Gallo.
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for example, use infrared guidance.34 Aircraft use Infrared Search and Track (IRST) pods to for example, use infrared guidance.34 Aircraft use Infrared Search and Track (IRST) pods to
identify enemy aircraft, particularly as advances in aircraft design embrace low radar cross-identify enemy aircraft, particularly as advances in aircraft design embrace low radar cross-
sections to make radar detection more difficult. The Navy is currently funding development of an sections to make radar detection more difficult. The Navy is currently funding development of an
IRST pod for the F-18E/F Super Hornet, and the Air Force has been procuring IRST capabilities IRST pod for the F-18E/F Super Hornet, and the Air Force has been procuring IRST capabilities
for the F-15C Eagle.35 Several space systems use infrared technologies to detect missile launches. for the F-15C Eagle.35 Several space systems use infrared technologies to detect missile launches.
The Space-Based Infrared The Space-Based Infrared ~~Surveillance (SBIRS) constellation uses six satellites in~~
Surveil ance (SBIRS) constel ation uses six satel ites in geosynchronous orbit, as geosynchronous orbit, as ~~well~~ wel as additional as additional ~~satellites in highly elliptical orbits (see~~satel ites in highly el iptical orbits (see Figure 5) to to
provide an early warning capability for missile launches.36 The Space Force is developing a provide an early warning capability for missile launches.36 The Space Force is developing a
follow-on follow-on ~~constellation~~constel ation for SBIRS. The Space Development Agency is developing a hypersonic for SBIRS. The Space Development Agency is developing a hypersonic
missile detection missile detection ~~constellation~~constel ation in low-earth orbit that would use infrared technologies similar to in low-earth orbit that would use infrared technologies similar to
SBIRS.37 SBIRS.37
Figure 5. The Space-Based Infrared Surveillance (SBIRS) Constellation

Source: https://spacenews.com/air-force-tests-ground-station-for-ful -missile-warning-constel ation/. https://spacenews.com/air-force-tests-ground-station-for-ful -missile-warning-constel ation/.
Electronic Warfare
Electronic warfare (EW) is the use of the electromagnetic spectrum to gain and maintain military Electronic warfare (EW) is the use of the electromagnetic spectrum to gain and maintain military
control of it.38 SIGINT capabilities control of it.38 SIGINT capabilities ~~allow~~al ow military forces to understand where adversary forces are military forces to understand where adversary forces are
located as located as ~~well~~ wel as what frequencies they use for communications and radars. This as what frequencies they use for communications and radars. This ~~intelligence,~~

~~34 U.S.~~ intel igence, 34 U.S. Air Force, “AIM-9 Sidewinder,”Air Force, “AIM-9 Sidewinder,” press release, December 18, 2004, https://www.af.mil/About-Us/Fact-Sheets/press release, December 18, 2004, https://www.af.mil/About-Us/Fact-Sheets/
Display/Article/104557/aim-9-sidewinder/. Display/Article/104557/aim-9-sidewinder/.
35 U.S. 35 U.S. Navy FY2021 Aircraft Procurement Line Item 0515 Infrared Search and Navy FY2021 Aircraft Procurement Line Item 0515 Infrared Search and ~~Track~~T rack (IRST (IRST ), at https://apps.dtic.mil/), at https://apps.dtic.mil/
procurement/Y2021/Navy/stamped/U_P40_0515_BSA-1_BA-5_APP-1506N_PB_2021.pdf, and U.S. Air Force procurement/Y2021/Navy/stamped/U_P40_0515_BSA-1_BA-5_APP-1506N_PB_2021.pdf, and U.S. Air Force
FY2021 Aircraft Procurement Line Item F01500 F-15, at https://apps.dtic.mil/procurement/Y2021/AirForce/stamped/FY2021 Aircraft Procurement Line Item F01500 F-15, at https://apps.dtic.mil/procurement/Y2021/AirForce/stamped/
U_P40_F01500_BSA-2_BA-5_APP-3010F_PB_2021.pdf. U_P40_F01500_BSA-2_BA-5_APP-3010F_PB_2021.pdf.
36 Lockheed Martin, “Space Based 36 Lockheed Martin, “Space Based Infrared SurveillanceInfrared Surveillance SBIRS,”SBIRS,” press release, 2020, at press release, 2020, at
https://www.lockheedmartin.com/en-us/products/sbirs.html. https://www.lockheedmartin.com/en-us/products/sbirs.html.
37 Sandra 37 Sandra Erwin, “Space Development Agency to Deploy Hypersonic Missile Defense Satellites by 2022,” Erwin, “Space Development Agency to Deploy Hypersonic Missile Defense Satellites by 2022,” Space News, ,
June 7, 2020, at https://spacenews.com/space-development-agency-to-deploy-hypersonic-missile-defense-satellites-by-June 7, 2020, at https://spacenews.com/space-development-agency-to-deploy-hypersonic-missile-defense-satellites-by-
2022/. 2022/.
38 See38 See ~~CRS~~ CRS In FocusIn Focus IF11118, IF11118, Defense Primer: Electronic Warfare,, by John R. Hoehn. by John R. Hoehn.
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which the military which the military ~~calls~~cal s electronic support, is then used to develop an operational plan to jam (i.e., electronic support, is then used to develop an operational plan to jam (i.e.,
attack an adversary’s use of the spectrum) radio frequencies. Testing SIGINT capabilities on their attack an adversary’s use of the spectrum) radio frequencies. Testing SIGINT capabilities on their
own forces, militaries can develop techniques to protect themselves from attacks. own forces, militaries can develop techniques to protect themselves from attacks.
Electronic warfare affects Electronic warfare affects ~~all~~ al military domains—land, air, sea, space, and cyberspace—and each military domains—land, air, sea, space, and cyberspace—and each
of the military services has its own EW capabilities and programs. EW capabilities are of the military services has its own EW capabilities and programs. EW capabilities are
~~traditionally~~ traditional y divided into two distinct categories: terrestrial and airborne. Because each kind of divided into two distinct categories: terrestrial and airborne. Because each kind of
EW has its respective advantages and disadvantages, multiple capabilities may be required to EW has its respective advantages and disadvantages, multiple capabilities may be required to
provide a desired effect. Terrestrial EW sensors and jammers—which can be located on land or provide a desired effect. Terrestrial EW sensors and jammers—which can be located on land or
on ships at sea—are limited by the amount of power available; these capabilities are also limited on ships at sea—are limited by the amount of power available; these capabilities are also limited
due to variance in the terrain in which they operate. Ground EW capabilities are used to intercept due to variance in the terrain in which they operate. Ground EW capabilities are used to intercept
and to jam radios and and to jam radios and ~~artillery~~artil ery radars. Recent uses include jamming improvised explosive devices radars. Recent uses include jamming improvised explosive devices
in Iraq and Afghanistan.39 Airborne EW is used to intercept, decrypt, and disrupt communications, in Iraq and Afghanistan.39 Airborne EW is used to intercept, decrypt, and disrupt communications,
radars, and other C2 systems over a large area. Examples of airborne EW aircraft include the E-2 radars, and other C2 systems over a large area. Examples of airborne EW aircraft include the E-2
Hawkeye, the EA-18G Growler, and the EC-130H Compass Hawkeye, the EA-18G Growler, and the EC-130H Compass ~~Call~~Cal .40 .40
Spectrum Operations41
Numerous military operations use the spectrum, including command and control (C2), signature Numerous military operations use the spectrum, including command and control (C2), signature
management, and navigation warfare. Overviews of these operations are discussed below. management, and navigation warfare. Overviews of these operations are discussed below.
Command and Control
One type of spectrum operation is Command and Control. C2 uses One type of spectrum operation is Command and Control. C2 uses ~~all~~ al of the above applications to of the above applications to
develop a common operating picture (location of friendly and enemy forces) and communicate develop a common operating picture (location of friendly and enemy forces) and communicate
the commander’s orders. Command and control is resourced according to a unit’s size and the commander’s orders. Command and control is resourced according to a unit’s size and
mission focus, from a few radios and computers for platoon- and company-level operations to mission focus, from a few radios and computers for platoon- and company-level operations to
specialized specialized ~~satellites~~satel ites and aircraft for joint operations such as nuclear C2. Command and control and aircraft for joint operations such as nuclear C2. Command and control
aircraft, such as the E-8C Joint STARS, use communications systems and synthetic aperture aircraft, such as the E-8C Joint STARS, use communications systems and synthetic aperture
radars to develop a comprehensive picture of the battlespace to direct ground forces to their most radars to develop a comprehensive picture of the battlespace to direct ground forces to their most
effective positions for countering enemy forces.42 effective positions for countering enemy forces.42
Signature Management
Low observable weapons systems manipulate the spectrum to reduce their electromagnetic Low observable weapons systems manipulate the spectrum to reduce their electromagnetic
signature, such as radar returns,43 radio emissions, and even heat. This signature management can signature, such as radar returns,43 radio emissions, and even heat. This signature management can
take many forms; for example, reducing a radar signature through physical or other means, take many forms; for example, reducing a radar signature through physical or other means,
creating narrow radio beams to reduce the probability of detection or intercept, and reducing creating narrow radio beams to reduce the probability of detection or intercept, and reducing
spectrum emissions. These design approaches can be used in ships (e.g., Zumwalt-class spectrum emissions. These design approaches can be used in ships (e.g., Zumwalt-class

39 For more information on ground electronic warfare systems see CRS39 For more information on ground electronic warfare systems see CRS Report R45919, Report R45919, Ground Electronic Warfare:
Background and Issues for Congress, by John R. Hoehn. , by John R. Hoehn.
40 For more information about these aircraft systems see CRS 40 For more information about these aircraft systems see CRS Report R44572, Report R44572, U.S. Airborne Electronic Attack
~~Programs~~Program s: Background and Issues for Congress, by John R. Hoehn. , by John R. Hoehn.
~~41 This~~41 T his section was section was written by John R.written by John R. Hoehn. Hoehn.
42 U.S.42 U.S. Air Force, Air Force, E-8C Joint STARS, Washington, DC, September 23, 2015, https://www.af.mil/About-Us/Fact-Sheets/, Washington, DC, September 23, 2015, https://www.af.mil/About-Us/Fact-Sheets/
Display/Article/104507/e-8c-joint-stars/. Display/Article/104507/e-8c-joint-stars/.
43 Radar works 43 Radar works ~~by emitting~~ by emitt ing a radio signal a radio signal and then listening for the signal to return. Low observableand then listening for the signal to return. Low observable technologies use technologies use
different materials (known as radar absorbingdifferent materials (known as radar absorbing material) and different shapes (typically reducing the number of 90° or material) and different shapes (typically reducing the number of 90° or
right angles) to reduceright angles) to reduce or prevent the radio signals from returning to their original source. or prevent the radio signals from returning to their original source.
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destroyer), aircraft (e.g., the B-2 Spirit and the F-35 Lightning II), and radar systems (e.g., the destroyer), aircraft (e.g., the B-2 Spirit and the F-35 Lightning II), and radar systems (e.g., the
AN/APG-81 actively AN/APG-81 actively ~~electronically~~electronical y scanned array radar).44 These systems look to reduce their scanned array radar).44 These systems look to reduce their
signature in the microwave and infrared parts of the spectrum. signature in the microwave and infrared parts of the spectrum.
Communications systems are also focused on reducing their signature. Using beam-forming, Communications systems are also focused on reducing their signature. Using beam-forming,
reduced power, and other techniques, these systems are designed to be low probability of reduced power, and other techniques, these systems are designed to be low probability of
intercept/low probability of detection (LPI/LPD). The intent is to make it more difficult for intercept/low probability of detection (LPI/LPD). The intent is to make it more difficult for
potential adversaries to use their SIGINT capabilities to find U.S. forces, and potential adversaries to use their SIGINT capabilities to find U.S. forces, and ~~potentially~~potential y target target
them with long-range munitions. them with long-range munitions.
Navigation Warfare
According to DOD, navigation warfare (NAVWAR) is “deliberate offensive and defensive actions According to DOD, navigation warfare (NAVWAR) is “deliberate offensive and defensive actions
to assure friendly use and prevent adversary use of [precision, navigation, and timing] PNT to assure friendly use and prevent adversary use of [precision, navigation, and timing] PNT
information through coordinated employment of space, cyberspace, and electronic warfare (EW) information through coordinated employment of space, cyberspace, and electronic warfare (EW)
capabilities. NAVWARcapabilities. NAVWAR is further enabled by supporting activities such as ISR and EMS is further enabled by supporting activities such as ISR and EMS
management.”45 The Global Positioning System (GPS) performs navigation warfare for the U.S. management.”45 The Global Positioning System (GPS) performs navigation warfare for the U.S.
military by providing precision, navigation, and timing (semilitary by providing precision, navigation, and timing (see Figure 6). Competing PNT systems . Competing PNT systems
have been developed by other nations, including Russia (GLONASS), China (Beidou), and the have been developed by other nations, including Russia (GLONASS), China (Beidou), and the
European Union (Galileo).46 European Union (Galileo).46
Figure 6. The Global Positioning System (GPS) Constellation

Source: https://www.gps.gov/multimedia/images/constel ation.jpg. https://www.gps.gov/multimedia/images/constel ation.jpg.

44 For more information on select low observable44 For more information on select low observable aircraft, see CRSaircraft, see CRS Report R44463, Report R44463, Air Force B-21 Raider Long-Range
Strike ~~Bomber~~Bom ber, by Jeremiah Gertler, and CRS, by Jeremiah Gertler, and CRS Report RL30563, Report RL30563, F-35 Joint Strike Fighter (JSF) Program , by Jeremiah , by Jeremiah
Gertler. For more information on the ZumwaltGertler. For more information on the Zumwalt -class destroyer, see CRS-class destroyer, see CRS Report RL32109, Report RL32109, Navy DDG-51 and DDG-
1000 Destroyer ~~Programs~~Program s: Background and Issues for Congress,, by Ronald O'Rourke. by Ronald O'Rourke.
45 Department of Defense, 45 Department of Defense, Space Operations, JP 3-14, Washington, DC, April 10, 2018, pp. II-3, https://www.jcs.mil/, JP 3-14, Washington, DC, April 10, 2018, pp. II-3, https://www.jcs.mil/
Portals/36/Documents/Doctrine/pubs/jp3_14.pdf. Portals/36/Documents/Doctrine/pubs/jp3_14.pdf.
46 U.S. 46 U.S. ~~GPS~~ GPS Office, “Other Global Navigation Satellite Systems (GNSS),”Office, “Other Global Navigation Satellite Systems (GNSS),” press release, January 30, 2020, at press release, January 30, 2020, at
https://www.gps.gov/systems/gnss/. https://www.gps.gov/systems/gnss/.
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Command and Control (C2)
C2 systems are the communications, people, and procedures that enable commanders to direct C2 systems are the communications, people, and procedures that enable commanders to direct
forces. DOD states that communications systems are critical in providing timely information to forces. DOD states that communications systems are critical in providing timely information to
enable decisionmaking.47 According to DOD, these communications need to be interoperable enable decisionmaking.47 According to DOD, these communications need to be interoperable
(interoperability between communications systems revolves around the protocols such as (interoperability between communications systems revolves around the protocols such as
frequency hopping and encryption, as frequency hopping and encryption, as ~~well~~ wel as the frequencies uses) to facilitate information as the frequencies uses) to facilitate information
sharing, agile to adjust to the operating environment, and trusted to ensure the information in the sharing, agile to adjust to the operating environment, and trusted to ensure the information in the
system is accurate. An important aspect of C2 systems is the ability to network and share system is accurate. An important aspect of C2 systems is the ability to network and share
information in a timely fashion to enable commanders and their staff to make decisions. Thus C2 information in a timely fashion to enable commanders and their staff to make decisions. Thus C2
systems collect information from systems collect information from ~~intelligence~~intel igence systems and build a picture of the operating systems and build a picture of the operating
environment for the commander and their staff to make effective decisions (some analysts environment for the commander and their staff to make effective decisions (some analysts
combine C2 with computers, communications, combine C2 with computers, communications, ~~intelligence, surveillance~~intel igence, surveil ance, and reconnaissance , and reconnaissance
systems [C4ISR] to talk about the entire system enabling decisionmaking). To create these systems [C4ISR] to talk about the entire system enabling decisionmaking). To create these
networks, DOD utilizes computers to manage and process data and communications equipment networks, DOD utilizes computers to manage and process data and communications equipment
so that commanders can act upon the data transmitted to them. so that commanders can act upon the data transmitted to them.
Emerging Military Applications of the Spectrum48
The following section discusses emerging technologies and concepts that could affect the The following section discusses emerging technologies and concepts that could affect the
military’s use of the spectrum. military’s use of the spectrum.
Fifth Generation (5G) Communications49
The fifth generation (5G) of mobile technologies The fifth generation (5G) of mobile technologies ~~will~~ wil increase the speed of data transfer and increase the speed of data transfer and
improve bandwidth over existing fourth generation (4G) technologies, in turn improve bandwidth over existing fourth generation (4G) technologies, in turn ~~potentially~~potential y enabling enabling
new military and commercial applications. 5G technologies plan to use three segments of the new military and commercial applications. 5G technologies plan to use three segments of the
electromagnetic spectrum: high band (also electromagnetic spectrum: high band (also ~~called millimeter~~ cal ed mil imeter wave, or MMW), which operates wave, or MMW), which operates
between around 24 and 300 gigahertz (GHz); mid band, which operates between 1 GHz and 6 between around 24 and 300 gigahertz (GHz); mid band, which operates between 1 GHz and 6
GHz; and low band, which operates below 1 GHz. Mid band and low band are often collectively GHz; and low band, which operates below 1 GHz. Mid band and low band are often collectively
referred to as sub-6.50 Each band offers different capabilities. High-band spectrum offers ultra-fast referred to as sub-6.50 Each band offers different capabilities. High-band spectrum offers ultra-fast
services to high-density areas but is limited in range and more vulnerable to disruption. Mid-band services to high-density areas but is limited in range and more vulnerable to disruption. Mid-band
spectrum offers improved capacity and coverage, faster service, and new features (like edge spectrum offers improved capacity and coverage, faster service, and new features (like edge
computing) compared with existing 4G technologies. Low-band spectrum offers the widespread computing) compared with existing 4G technologies. Low-band spectrum offers the widespread
coverage needed for many internet-of-things applications. coverage needed for many internet-of-things applications.
5G technologies could have a number of potential military applications, particularly for 5G technologies could have a number of potential military applications, particularly for
autonomous vehicles, C2, logistics, maintenance, augmented and virtual reality, and autonomous vehicles, C2, logistics, maintenance, augmented and virtual reality, and ~~intelligence,~~
~~surveillance~~intel igence, surveil ance, and reconnaissance (ISR) systems—, and reconnaissance (ISR) systems—~~all~~ al of which would benefit from improved data of which would benefit from improved data

47 Department of Defense, 47 Department of Defense, Joint Communications System , JP 6-0, Washington, DC, June 10, 2015, Incorporating , JP 6-0, Washington, DC, June 10, 2015, Incorporating
Change 1, October 4, 2019, p. vii, https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp6_0ch1.pdf?ver=2019-Change 1, October 4, 2019, p. vii, https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp6_0ch1.pdf?ver=2019-
10-15-172254-827. 10-15-172254-827.
~~48 This~~48 T his section was section was written by John R.written by John R. Hoehn and Kelley M. Sayler. Hoehn and Kelley M. Sayler.
49 49 ~~This~~T his section is derived from CRS section is derived from CRS In FocusIn Focus IF11251, IF11251, National Security Implications of Fifth Generation (5G) Mobile
Technologies, by John R. Hoehn and Kelley M. Sayler., by John R. Hoehn and Kelley M. Sayler. For more information on 5G, see CRSFor more information on 5G, see CRS Report R45485, Report R45485, Fifth-
Generation (5G) ~~Telecommunications~~Telecom m unications Technologies: Issues for Congress, by Jill, by Jill C. GallagherC. Gallagher and Michael E. DeVine.and Michael E. DeVine.
50 For more information on 5G spectrum allocation, see CRS 50 For more information on 5G spectrum allocation, see CRS Report R45485, Report R45485, Fifth-Generation (5G)
~~Telecommunications~~Telecom m unications Technologies: Issues for Congress, by Jill C., by Jill C. ~~Gallagher~~ Gallagher and Michael E. DeVine.and Michael E. DeVine.
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rates and lower latency (i.e., less time delay).51 Autonomous military vehicles, like their rates and lower latency (i.e., less time delay).51 Autonomous military vehicles, like their
commercial counterparts, could commercial counterparts, could ~~potentially~~potential y circumvent on-board data processing limitations by circumvent on-board data processing limitations by
storing large databases (e.g., maps) in the cloud. 5G technologies could also be incorporated into storing large databases (e.g., maps) in the cloud. 5G technologies could also be incorporated into
ISR systems, which increasingly demand high-bandwidths to process, exploit, and disseminate ISR systems, which increasingly demand high-bandwidths to process, exploit, and disseminate
information from a growing number of battlespace sensors. Similarly, 5G could reduce latency in information from a growing number of battlespace sensors. Similarly, 5G could reduce latency in
other data-intensive activities, such as logistics and maintenance, and could other data-intensive activities, such as logistics and maintenance, and could ~~additionally~~additional y enable enable
augmented or virtual reality environments that could enhance training.52 augmented or virtual reality environments that could enhance training.52 ~~Finally~~Final y, C2 systems , C2 systems
could benefit from the high speed, low latency capability of 5G.53could benefit from the high speed, low latency capability of 5G.53
DOD has expressed interest in developing 5G networks and technologies. DOD is in the initial DOD has expressed interest in developing 5G networks and technologies. DOD is in the initial
stages of testing and experimentation for 5G applications. It has selected 12 military stages of testing and experimentation for 5G applications. It has selected 12 military ~~installations~~
instal ations as test beds for various applications and aspects of the technology: as test beds for various applications and aspects of the technology:
 Marine Corps Logistics Base Albany, GA (smart warehouses);  Marine Corps Logistics Base Albany, GA (smart warehouses);
 Naval Base San Diego, CA (for smart warehouses);  Naval Base San Diego, CA (for smart warehouses);
  ~~Hill~~ Hil Air Force Base, UT (spectrum sharing between 5G and airborne radar); Air Force Base, UT (spectrum sharing between 5G and airborne radar);
 Joint Base Lewis-McChord, WA (augmented and virtual reality);  Joint Base Lewis-McChord, WA (augmented and virtual reality);
  ~~Nellis~~Nel is Air Force Base, NV (survivable command and control and network Air Force Base, NV (survivable command and control and network
enhancement); enhancement);
 Naval Base Norfolk, VA (ship-wide and pier connectivity);  Naval Base Norfolk, VA (ship-wide and pier connectivity);
 Joint Base Pearl Harbor-Hickam, HI (enhancing aircraft mission readiness);  Joint Base Pearl Harbor-Hickam, HI (enhancing aircraft mission readiness);
 Joint Base San Antonio, TX (augmented reality support of maintenance and  Joint Base San Antonio, TX (augmented reality support of maintenance and
training and evaluating DOD’s 5G core security experimentation network); training and evaluating DOD’s 5G core security experimentation network);
 Tinker Air Force Base, OK (spectrum sharing between military communications  Tinker Air Force Base, OK (spectrum sharing between military communications
and 5G); and 5G);
 Camp Pendleton, CA (connectivity for forward operating bases and tactical  Camp Pendleton, CA (connectivity for forward operating bases and tactical
operations centers); operations centers);
 Ft. Hood, TX (connectivity for forward operating bases and tactical operations  Ft. Hood, TX (connectivity for forward operating bases and tactical operations
centers); and centers); and
 Ft. Irwin National Training Center, CA (for connectivity for forward operating  Ft. Irwin National Training Center, CA (for connectivity for forward operating
bases and tactical operations centers).54 bases and tactical operations centers).54
On September 18, 2020, DOD released a Request for Information seeking input on best methods On September 18, 2020, DOD released a Request for Information seeking input on best methods
for sharing spectrum between military and civilian users, input on DOD ownership and operation for sharing spectrum between military and civilian users, input on DOD ownership and operation
of 5G networks for domestic operations, and other issues related to the of 5G networks for domestic operations, and other issues related to the ~~allocation~~al ocation and shared use and shared use

~~51 The~~ 51 T he U.S. military currently uses satellites for the preponderance of its U.S. military currently uses satellites for the preponderance of its ~~long~~lo ng-distance communications; however, -distance communications; however,
satellite communications can significantly increase latency due to the amount of distance a signal needssatellite communications can significantly increase latency due to the amount of distance a signal needs to travel, to travel,
causingcausing ~~delays~~ delays in the execution of military operations. in the execution of military operations.
52 Justin Doubleday, 52 Justin Doubleday, “DOD Releases“DOD Releases ~~Second Tranche~~ Second T ranche of Draft 5G Proposal Requests,” of Draft 5G Proposal Requests,” Inside Defense, December 9, , December 9,
2019, https://insidedefense.com/insider/dod-releases-second-tranche-draft2019, https://insidedefense.com/insider/dod-releases-second-tranche-draft -5g-proposal-requests. -5g-proposal-requests.
53 Defense Innovation Board, 53 Defense Innovation Board, The 5G Ecosystem: Risks and Opportunities for DOD, April 2019, , April 2019,
https://media.defense.gov/2019/Apr/03/2002109302/-1/-1/0/https://media.defense.gov/2019/Apr/03/2002109302/-1/-1/0/~~DIB_5G_STUDY_04~~DIB_5G_ST UDY_04.03.19.PDF. .03.19.PDF.
54 Justin Doubleday, 54 Justin Doubleday, “DOD Releases“DOD Releases ~~Second Tranche~~ Second T ranche of Draft 5G Proposal Requests,” of Draft 5G Proposal Requests,” Inside Defense, December 9, , December 9,
2019, https://insidedefense.com/insider/dod-releases-second-tranche-draft2019, https://insidedefense.com/insider/dod-releases-second-tranche-draft -5g-proposal-requests; and Department of -5g-proposal-requests; and Department of
Defense, “DOD Names Seven Installations as SitesDefense, “DOD Names Seven Installations as Sites for Secondfor Second Round of 5G Round of 5G ~~Technology Testing~~T echnology T esting, Experimentation,” , Experimentation,”
press release, June 3, 2020, https://www.defense.gov/Newsroom/Releases/Release/Article/2206761/dod-names-seven-press release, June 3, 2020, https://www.defense.gov/Newsroom/Releases/Release/Article/2206761/dod-names-seven-
installations-as-sites-for-second-round-of-5g-technology-testin/. installations-as-sites-for-second-round-of-5g-technology-testin/.
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of DOD spectrum.55 The intent, DOD says, is to “ensure the greatest effective and efficient use of of DOD spectrum.55 The intent, DOD says, is to “ensure the greatest effective and efficient use of
the Department of Defense’s spectrum for training, readiness, and lethality.”56 DOD requested the Department of Defense’s spectrum for training, readiness, and lethality.”56 DOD requested
$1.5 $1.5 ~~billion~~ bil ion for microelectronics/5G in FY2021, but it did not provide a further breakdown in for microelectronics/5G in FY2021, but it did not provide a further breakdown in
funding between microelectronics and 5G.57funding between microelectronics and 5G.57
Use and Applications of Artificial Intelligence (AI)58
DOD is researching cognitive electronic warfare systems that use artificial DOD is researching cognitive electronic warfare systems that use artificial ~~intelligence~~intel igence to identify to identify
novel electronic emissions, determine whether the emission originates from a hostile source, and novel electronic emissions, determine whether the emission originates from a hostile source, and
develop an effective jamming signal. According to former DOD electronic warfare official develop an effective jamming signal. According to former DOD electronic warfare official
~~William~~ Wil iam Conley, “a future battlespace Conley, “a future battlespace ~~will~~ wil contain threat signals not previously observed, [so] it contain threat signals not previously observed, [so] it
~~will~~ wil be essential for many platforms to be executing real time decision algorithms.”59 DOD is also be essential for many platforms to be executing real time decision algorithms.”59 DOD is also
researching options for using advances in computing power to improve electronic deception, or researching options for using advances in computing power to improve electronic deception, or
“spoofing,” capabilities. For example, Digital Radio Frequency Memory could be used to “spoofing,” capabilities. For example, Digital Radio Frequency Memory could be used to
generate false radar returns that complicate adversary targeting.60 generate false radar returns that complicate adversary targeting.60
Similarly, DOD is exploring AI-enabled dynamic spectrum sharing. Because spectrum is Similarly, DOD is exploring AI-enabled dynamic spectrum sharing. Because spectrum is
currently currently ~~allocated~~al ocated in set segments, in set segments, ~~allocation~~al ocation cannot be responsive to changes in the volume of cannot be responsive to changes in the volume of
traffic across segments (i.e., some segments may be overwhelmed while others are underutilized), traffic across segments (i.e., some segments may be overwhelmed while others are underutilized),
leading to inefficiencies. DARPA has sponsored the Spectrum Collaboration leading to inefficiencies. DARPA has sponsored the Spectrum Collaboration ~~Challenge~~Chal enge (SC2), (SC2),
which “aims to ensure that the which “aims to ensure that the ~~exponentially~~exponential y growing number of military and civilian growing number of military and civilian wireless wireless
devices devices ~~will~~ wil have full access to the increasingly crowded electromagnetic spectrum.”61 Teams have full access to the increasingly crowded electromagnetic spectrum.”61 Teams
competing in SC2—the final competition was held in October 2019—leveraged AI and machine competing in SC2—the final competition was held in October 2019—leveraged AI and machine
learning algorithms to develop options for dynamic spectrum sharing, in which radios learning algorithms to develop options for dynamic spectrum sharing, in which radios
autonomously coordinate to optimize spectrum use. autonomously coordinate to optimize spectrum use.
Directed-Energy (DE) Technologies
A number of directed energy technologies, including laser communications and directed-energy A number of directed energy technologies, including laser communications and directed-energy
weapons, make use of the electromagnetic spectrum.62weapons, make use of the electromagnetic spectrum.62
Laser Communications
DOD is testing systems that use focused infrared energy to transmit data—a concept known as DOD is testing systems that use focused infrared energy to transmit data—a concept known as
laser communications. For example, Free Space Optics (FSO) “is an optical communication laser communications. For example, Free Space Optics (FSO) “is an optical communication

55 DOD, Request55 DOD, Request for Information, for Information, Defense Spectrum Sharing Request for Information, Published September 18, 2020, , Published September 18, 2020,
https://beta.sam.gov/opp/4851a65e2b2d4d73865a0e9865b0c28a/view?keywords=spectrum&sort=-modifiedDate&https://beta.sam.gov/opp/4851a65e2b2d4d73865a0e9865b0c28a/view?keywords=spectrum&sort=-modifiedDate&
index=&is_active=true&page=1. index=&is_active=true&page=1.
56 Ibid. 56 Ibid.
57 DOD 57 DOD FY2021 Defense Budget Overview: ~~Irreversible~~ Irreversible Implementation of the National Defense Strategy, Washington, , Washington,
DC, May 13, 2020, pp. 1-8, https://comptroller.defense.gov/Portals/45/Documents/defbudget/fy2021/DC, May 13, 2020, pp. 1-8, https://comptroller.defense.gov/Portals/45/Documents/defbudget/fy2021/
fy2021_Budget_Request_Overview_Book.pdf. fy2021_Budget_Request_Overview_Book.pdf.
58 For a general discussion 58 For a general discussion of military applications of artificial intelligence, see CRSof military applications of artificial intelligence, see CRS Report R45178, Report R45178, Artificial
Intelligence and National Security, by Kelley M. Sayler. , by Kelley M. Sayler.
59 “EW, Cyber Require 59 “EW, Cyber Require Next ~~Next~~-Gen Hardware:-Gen Hardware: Conley,” Conley,” Breaking Defense, September 27, 2019, , September 27, 2019,
https://breakingdefense.com/2019/09/ew-cyber-require-nexthttps://breakingdefense.com/2019/09/ew-cyber-require-next -gen-hardware-conley/. -gen-hardware-conley/.
60 Ibid. 60 Ibid.
61 DARPA, “61 DARPA, “ Spectrum Collaboration Challenge (SC2),” https://www.darpa.mil/program/spectrum-collaboration-Spectrum Collaboration Challenge (SC2),” https://www.darpa.mil/program/spectrum-collaboration-
challenge. challenge.
62 Other directed energy technologies include laser range finders, target designators, and remote sensors. 62 Other directed energy technologies include laser range finders, target designators, and remote sensors.
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system that transfers data on a highly secured and nearly undetectable infrared laser, separate system that transfers data on a highly secured and nearly undetectable infrared laser, separate
from the radio frequency spectrum…. This from the radio frequency spectrum…. This ~~allows~~al ows more users on a single network and larger files, more users on a single network and larger files,
imagery and information to be transmitted.”63 The Marine Corps requested procurement funding imagery and information to be transmitted.”63 The Marine Corps requested procurement funding
in FY2019 and FY2020; however, it does not appear have requested funds in FY2021. It is in FY2019 and FY2020; however, it does not appear have requested funds in FY2021. It is
unclear how many FSO systems the Marine Corps procured (seunclear how many FSO systems the Marine Corps procured (see Figure 7).
Figure 7. U.S. Marine Corps Free Space Optics Communications System

Source: https://www.upi.com/Defense-News/2018/08/27/Marines-conduct-field-test-of-laser-based-https://www.upi.com/Defense-News/2018/08/27/Marines-conduct-field-test-of-laser-based-
communications-system/3511535389333/. communications-system/3511535389333/.
Notes: The picture caption reads: “U.S. Marines test the Free The picture caption reads: “U.S. Marines test the Free Space Optics laserSpace Optics laser communications systemcommunications system earlier earlier
this month at Camp Hansen in Okinawa, Japan. Photo by Sgt. Timothy Valero/U.S.this month at Camp Hansen in Okinawa, Japan. Photo by Sgt. Timothy Valero/U.S. Marine Corps.” Marine Corps.”
Directed-Energy Weapons64
DOD defines directed-energy (DE) weapons as those using concentrated electromagnetic energy, DOD defines directed-energy (DE) weapons as those using concentrated electromagnetic energy,
rather than kinetic energy, to “incapacitate, damage, disable, or destroy enemy equipment, rather than kinetic energy, to “incapacitate, damage, disable, or destroy enemy equipment,
facilities, and/or personnel.”65 DE weapons could be used by ground forces in counter rocket,66 facilities, and/or personnel.”65 DE weapons could be used by ground forces in counter rocket,66
~~artillery~~artil ery, and mortar (C-RAM), counter-unmanned aircraft systems (C-UAS), or short-range air , and mortar (C-RAM), counter-unmanned aircraft systems (C-UAS), or short-range air
defense (SHORAD) missions.67 They could offer low costs per shot and—assuming access to a defense (SHORAD) missions.67 They could offer low costs per shot and—assuming access to a
sufficient power supply—nearly limitless magazines that, in contrast to existing conventional sufficient power supply—nearly limitless magazines that, in contrast to existing conventional
systems, could enable an efficient and effective means of defending against missile salvos or systems, could enable an efficient and effective means of defending against missile salvos or
swarms of unmanned systems.68 swarms of unmanned systems.68 ~~Theoretically~~Theoretical y, DE weapons could also provide options for boost-, DE weapons could also provide options for boost-

63 Department of Defense, “Okinawa Marines 63 Department of Defense, “Okinawa Marines ~~Test~~T est Future of Wireless Communications,” Future of Wireless Communications,” ~~press~~p ress release, August release, August 24, 24,
2018, at https://www.defense.gov/Explore/News/Article/Article/1611671/okinawa-marines-test-future-of-wireless-2018, at https://www.defense.gov/Explore/News/Article/Article/1611671/okinawa-marines-test-future-of-wireless-
communications/. communications/.
64 64 ~~This~~T his section is derived from CRS section is derived from CRS Report R46458, Report R46458, Emerging Military Technologies: Background and Issues for
Congress, by Kelley M. Sayler. , by Kelley M. Sayler.
65 Joint Chiefs of Staff, Electronic Warfare, Joint Publication 3-13.1, February 8, 2012, pp. 1-16. 65 Joint Chiefs of Staff, Electronic Warfare, Joint Publication 3-13.1, February 8, 2012, pp. 1-16.
66 For example, see CRS66 For example, see CRS Report R45098, Report R45098, U.S. Army Weapons-Related Directed Energy (DE) Programs: Background
and Potential Issues for Congress, by Andrew, by Andrew Feickert ~~Feickert~~. .
67 For more information about the role of DE weapons in C-UAS 67 For more information about the role of DE weapons in C-UAS missions, see CRSmissions, see CRS In Focus IF11426, In Focus IF11426, Department of
Defense Counter-~~Unmanned Aircraft Systems~~Unm anned Aircraft System s, by John R. Hoehn and Kelley M. Sayler. , by John R. Hoehn and Kelley M. Sayler.
68 Although research has been conducted on chemically fueled lasers, 68 Although research has been conducted on chemically fueled lasers, most countries are now pursuingmost countries are now pursuing ~~solid~~ solid state state
lasers, whichlasers, which are fueledare fueled by electrical power. As a result, the cost per shot is equivalent to the cost of the by electrical power. As a result, the cost per shot is equivalent to the cost of the ~~electrical~~electrica l
power requiredpower required to fire the shot. Some analysts have noted that the cost per shot could thus be betweento fire the shot. Some analysts have noted that the cost per shot could thus be between $1 and $20. See $1 and $20. See
Ariel Robinson, “Ariel Robinson, “ Directed Energy Weapons: Will Directed Energy Weapons: Will ~~They~~T hey Ever Be Ready?,” Ever Be Ready?,” National Defense, July 1, 2015, at , July 1, 2015, at
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phase missile intercept, given their speed-of-light travel time; however, as in the case of phase missile intercept, given their speed-of-light travel time; however, as in the case of
hypersonic missile defense, experts disagree on the affordability, technological feasibility, and hypersonic missile defense, experts disagree on the affordability, technological feasibility, and
utility of this application.69 utility of this application.69
High-powered microwave weapons, a subset of DE weapons, could be used as a nonkinetic High-powered microwave weapons, a subset of DE weapons, could be used as a nonkinetic
means of disabling electronics, communications systems, and improvised explosive devices, or as means of disabling electronics, communications systems, and improvised explosive devices, or as
a nonlethal “heat ray” system for crowd control. a nonlethal “heat ray” system for crowd control.
Although the United States has been researching directed energy since the 1960s, some experts Although the United States has been researching directed energy since the 1960s, some experts
have observed that “actual directed-energy programs … have frequently have observed that “actual directed-energy programs … have frequently ~~fallen~~fal en short of short of
expectations,” with DOD investing expectations,” with DOD investing ~~billions~~bil ions of dollars in programs that were ultimately of dollars in programs that were ultimately
~~cancelled~~cancel ed.70 Others contend that developments in commercial lasers could be leveraged for .70 Others contend that developments in commercial lasers could be leveraged for
military applications.71 Directed-energy weapons programs, however, continue to raise questions military applications.71 Directed-energy weapons programs, however, continue to raise questions
about their technological maturity, including questions about their abilityabout their technological maturity, including questions about their ability to improve beam quality to improve beam quality
and control to militarilyand control to militarily useful levels and their ability to meet power, cooling, and size useful levels and their ability to meet power, cooling, and size
requirements so that the weapons could be integrated into current platforms.72requirements so that the weapons could be integrated into current platforms.72
The U.S. Navy fielded the first operational U.S. DE weapon,73 the Laser Weapon System The U.S. Navy fielded the first operational U.S. DE weapon,73 the Laser Weapon System
(LaWS), in 2014 aboard the USS (LaWS), in 2014 aboard the USS Ponce. LaWS was a 30-kilowatt (-kW) laser prototype that . LaWS was a 30-kilowatt (-kW) laser prototype that
“was capable of blinding enemy forces as a warning, shooting down drones, disabling boats, or “was capable of blinding enemy forces as a warning, shooting down drones, disabling boats, or
damaging helicopters.”74 The Navy plans to deploy its 60-kW laser, HELIOS, aboard the USS damaging helicopters.”74 The Navy plans to deploy its 60-kW laser, HELIOS, aboard the USS
Preble in 2021, while the Army plans to field its first “combat relevant” laser—the 50-kW in 2021, while the Army plans to field its first “combat relevant” laser—the 50-kW
Directed Energy Mobile Short-Range Air Defense System—on Stryker fighting vehicles in Directed Energy Mobile Short-Range Air Defense System—on Stryker fighting vehicles in
FY2022.75 Similarly, the Air Force is currently conducting field assessments of several counter-FY2022.75 Similarly, the Air Force is currently conducting field assessments of several counter-
UAS DE systems, including both laser and high-powered microwave systems.76 UAS DE systems, including both laser and high-powered microwave systems.76
The Army, Navy, Air Force, and DARPA each have additional The Army, Navy, Air Force, and DARPA each have additional DE development programs DE development programs
underway, with the Pentagon requesting $235 underway, with the Pentagon requesting $235 ~~million~~mil ion for directed-energy weapons and directed- for directed-energy weapons and directed-

https://www.nationaldefensemagazine.org/articles/2015/7/1/2015july-directed-energy-weapons-will-they-ever-be-https://www.nationaldefensemagazine.org/articles/2015/7/1/2015july-directed-energy-weapons-will-they-ever-be-
ready. ready.
69 See, 69 See, for example, James N. Miller and Frank A. Rose, “for example, James N. Miller and Frank A. Rose, “ Bad Idea:Bad Idea: Space-BasedSpace-Based Interceptors and Space-Based Interceptors and Space-Based
Directed Energy Systems,” Center for Strategic andDirected Energy Systems,” Center for Strategic and International Studies, December 13, 2018, at International Studies, December 13, 2018, at
https://defense360.csis.org/bad-idea-space-based-interceptors-and-space-based-directed-energy-systems/; and Justin https://defense360.csis.org/bad-idea-space-based-interceptors-and-space-based-directed-energy-systems/; and Justin
Doubleday,Doubleday, “ “Pentagon punts MDA‘s laser ambitions, shifts fundingPentagon punts MDA‘s laser ambitions, shifts funding toward OSD-ledtoward OSD-led ‘laser scaling,’” ‘laser scaling,’” Inside Defense, ,
February 19, 2020, at https://insidedefense.com/daily-news/pentagon-punts-mdas-laser-ambitions-shifts-funding-February 19, 2020, at https://insidedefense.com/daily-news/pentagon-punts-mdas-laser-ambitions-shifts-funding-
toward-osd-led-laser-scaling.toward-osd-led-laser-scaling.
70 Paul Scharre, Preface to “Directed-Energy Weapons: Promise and Prospects,” Center for a New American Security, 70 Paul Scharre, Preface to “Directed-Energy Weapons: Promise and Prospects,” Center for a New American Security,
April 2015, p. 4. April 2015, p. 4.
71 See 71 See Ariel Robinson, “Directed Energy Weapons.”Ariel Robinson, “Directed Energy Weapons.”
72 Ibid. 72 Ibid.
73 For more information see, CRS73 For more information see, CRS Report R44175, Report R44175, Navy Lasers, Railgun, and Gun-Launched Guided Projectile:
Background and Issues for Congress, by Ronald O'Rourke. , by Ronald O'Rourke.
74 Kyle Mizokami, “ 74 Kyle Mizokami, “~~The~~ T he U.S. Army Plans U.S. Army Plans ToT o Field the Most Powerful Laser Weapon Yet,” Field the Most Powerful Laser Weapon Yet,” Popular Mechanics, ,
AugustAugust 7, 2019. 7, 2019.
75 Lockheed Martin, “75 Lockheed Martin, “ Lockheed Martin’s HELIOS Laser Weapon System Lockheed Martin’s HELIOS Laser Weapon System ~~Takes Step Toward Ship Integration~~T akes Step T oward Ship Integration ,” March ,” March
11, 2020, at https://news.lockheedmartin.com/2020-03-11-Lockheed-Martins-HELIOS-Laser-Weapon-System-Takes-11, 2020, at https://news.lockheedmartin.com/2020-03-11-Lockheed-Martins-HELIOS-Laser-Weapon-System-Takes-
Step-Step-~~Toward~~T oward-Ship-Integration; and Office of the Under Secretary of Defense (Comptroller)/Chief Financial -Ship-Integration; and Office of the Under Secretary of Defense (Comptroller)/Chief Financial ~~Officer~~Offic er, ,
“Defense Budget“Defense Budget Overview: United States Department of Defense Fiscal Year 2021 BudgetOverview: United States Department of Defense Fiscal Year 2021 Budget Request,”Request,” February 2020, February 2020,
at https://comptroller.defense.gov/Portals/45/Documents/defbudget/fy2021/at https://comptroller.defense.gov/Portals/45/Documents/defbudget/fy2021/
fy2021_Budget_Request_Overview_Book.pdf. fy2021_Budget_Request_Overview_Book.pdf.
76 Kyle Mizokami, “ 76 Kyle Mizokami, “~~The~~ T he Air Force Mobilizes Air Force Mobilizes Its Laser and Microwave Weapons Abroad,” Its Laser and Microwave Weapons Abroad,” Popular Mechanics, April 9, , April 9,
2020, at https://www.popularmechanics.com/military/weapons/a32083799/laser-microwave-weapons/. 2020, at https://www.popularmechanics.com/military/weapons/a32083799/laser-microwave-weapons/.
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energy defensive capabilities energy defensive capabilities in FY2020; the FY2021 budget overview does not provide the in FY2020; the FY2021 budget overview does not provide the
topline funding request for DE weapons.77 These programs are intended to scale up power levels topline funding request for DE weapons.77 These programs are intended to scale up power levels
from around 150 kW, as is currently feasible, to around 300 kW, a level at which cruise missiles from around 150 kW, as is currently feasible, to around 300 kW, a level at which cruise missiles
could potential y ~~could potentially~~ be intercepted, by FY2022 and to around 500 kW by FY2024.78be intercepted, by FY2022 and to around 500 kW by FY2024.78
Counter-Unmanned Aircraft Systems (C-UAS)79
Unmanned aircraft systems (UAS), commonly Unmanned aircraft systems (UAS), commonly ~~called~~cal ed drones, have proliferated rapidly and are drones, have proliferated rapidly and are
availableavailable to nation states and to non-state actors and individuals. These systems could provide to nation states and to non-state actors and individuals. These systems could provide
U.S. adversaries with a low-cost means of conducting U.S. adversaries with a low-cost means of conducting ~~intelligence, surveillance~~intel igence, surveil ance, and , and
reconnaissance missions against—or attacking—U.S. forces. Furthermore, many reconnaissance missions against—or attacking—U.S. forces. Furthermore, many ~~smaller~~smal er UASs UASs
cannot be detected by traditional air defense systems due to their size, construction material, and cannot be detected by traditional air defense systems due to their size, construction material, and
flight altitude. flight altitude.
C-UAS can employ a number of methods to detect the presence of hostile or unauthorized UAS. C-UAS can employ a number of methods to detect the presence of hostile or unauthorized UAS.
The first is using electro-optical, infrared, or acoustic sensors to detect a target by its visual, heat, The first is using electro-optical, infrared, or acoustic sensors to detect a target by its visual, heat,
or sound signatures, respectively. A second method is to use radar systems. However, these or sound signatures, respectively. A second method is to use radar systems. However, these
methods are not always capable of detecting methods are not always capable of detecting ~~small~~ smal UAS due to the limitedUAS due to the limited signatures and size of signatures and size of
such UAS. A third method is identifying the wireless signals used to control the UAS, commonly such UAS. A third method is identifying the wireless signals used to control the UAS, commonly
using radio frequency sensors. These methods can be—and often are—combined to provide a using radio frequency sensors. These methods can be—and often are—combined to provide a
more effective, layered detection capability. more effective, layered detection capability.
Once detected, the UAS may be engaged or disabled. Electronic warfare “jamming” can interfere Once detected, the UAS may be engaged or disabled. Electronic warfare “jamming” can interfere
with a UAS’s communications link to its operator. Jamming devices can be as light as 5 to 10 with a UAS’s communications link to its operator. Jamming devices can be as light as 5 to 10
pounds and therefore man-portable, or as heavy as several hundred pounds and in fixed locations pounds and therefore man-portable, or as heavy as several hundred pounds and in fixed locations
or mounted on vehicles. In addition, UAS can be neutralized or destroyed using guns, nets, or mounted on vehicles. In addition, UAS can be neutralized or destroyed using guns, nets,
directed energy, traditional air defense systems, or even trained animals such as eagles. DOD is directed energy, traditional air defense systems, or even trained animals such as eagles. DOD is
developing and procuring a number of different C-UAS technologies to try to ensure a robust developing and procuring a number of different C-UAS technologies to try to ensure a robust
defensive capability. defensive capability.
In December 2019, DOD streamlined its various counter- In December 2019, DOD streamlined its various counter-~~small~~ smal UAS (C-sUAS) programs, naming UAS (C-sUAS) programs, naming
the Army as the executive agent tasked with overseeing the Army as the executive agent tasked with overseeing ~~all~~ al DOD C-sUAS development efforts. DOD C-sUAS development efforts.
On January 6, 2020, the Secretary of Defense approved the implementation plan of the new On January 6, 2020, the Secretary of Defense approved the implementation plan of the new
office, known as the Joint C-sUAS Office (JCO). Working in consultation with the combatant office, known as the Joint C-sUAS Office (JCO). Working in consultation with the combatant
commands and the Office of the Under Secretary of Defense for Acquisition and Sustainment, commands and the Office of the Under Secretary of Defense for Acquisition and Sustainment,
JCO assessed over 40 fielded C-sUAS systems. On June 25, 2020, Maj. Gen. Sean Gainey, JCO assessed over 40 fielded C-sUAS systems. On June 25, 2020, Maj. Gen. Sean Gainey,
director of the JCO, announced that seven C-sUAS defensive systems and one standardized director of the JCO, announced that seven C-sUAS defensive systems and one standardized
command and control system are to be further developed. According to media reports, during its command and control system are to be further developed. According to media reports, during its

77 Office of the Under Secretary of Defense (Comptroller)/Chief Financial Officer, Defense Budget77 Office of the Under Secretary of Defense (Comptroller)/Chief Financial Officer, Defense Budget Overview:Overview: United United
States Department of Defense Fiscal Year 2020 Budget Request,States Department of Defense Fiscal Year 2020 Budget Request, March 2019, p. 9. March 2019, p. 9.
78 Despite a lack of consensus regarding78 Despite a lack of consensus regarding the precise power level needed to neutralize different target sets, it is generally the precise power level needed to neutralize different target sets, it is generally
believedbelieved that a laser of around 100 kW could engagethat a laser of around 100 kW could engage UAVs,UAVs, small boats, rockets, artillery, and mortar, whereas a laser small boats, rockets, artillery, and mortar, whereas a laser
of around 300 kW laser couldof around 300 kW laser could additionally engageadditionally engage ~~cruise missiles~~ cruise missiles flying in certain profiles (i.e., flying across—rather flying in certain profiles (i.e., flying across—rather
than atthan at —the laser). See, for example, CRS—the laser). See, for example, CRS Report R41526, Report R41526, Navy Shipboard Lasers for Surface, Air, and Missile
Defense: Background and Issues for Congress, by Ronald O'Rourke, and Sydney, by Ronald O'Rourke, and Sydney J. FreedbergJ. Freedberg Jr., “Jr., “ Lasers to Kill Lasers to Kill
CruiseCruise ~~Missiles~~ Missiles Sought by Navy, Air Force, Army,” Sought by Navy, Air Force, Army,” Breaking Defense, October 29, 2019. For information about , October 29, 2019. For information about
DOD’s Laser ScalingDOD’s Laser Scaling Plan, see Jason Sherman, “Plan, see Jason Sherman, “ New Laser ScalingNew Laser Scaling Plan sets directed-energy efforts, FY-19 Plan sets directed-energy efforts, FY-19
contracts,” contracts,” Inside Defense, April 17, 2019, at https://insidedefense.com/daily-news/new-laser-scaling-plan-sets-, April 17, 2019, at https://insidedefense.com/daily-news/new-laser-scaling-plan-sets-
directed-energy-efforts-fy-19-contracts. directed-energy-efforts-fy-19-contracts.
79 79 ~~This~~T his section is derived from CRS section is derived from CRS In FocusIn Focus IF11426, IF11426, Department of Defense Counter-Unmanned Aircraft Systems, by , by
John R. Hoehn and Kelley M. Sayler. John R. Hoehn and Kelley M. Sayler.
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first year of operation, the office is to first year of operation, the office is to ~~additionally~~ additional y produce a DOD Directive on C-sUAS, a threat produce a DOD Directive on C-sUAS, a threat
assessment of C-sUAS capabilities, a DOD C-sUAS strategy, and a Joint Capability Development assessment of C-sUAS capabilities, a DOD C-sUAS strategy, and a Joint Capability Development
Document outlining operational requirements for future systems.80 Document outlining operational requirements for future systems.80
Emerging Concepts81
DOD is developing a series of concepts, many of which are enabled by AI, to improve multi-DOD is developing a series of concepts, many of which are enabled by AI, to improve multi-
domain command and control (C2) and execute the National Defense Strategy. For example, domain command and control (C2) and execute the National Defense Strategy. For example,
DOD is developing a concept, Joint DOD is developing a concept, Joint ~~All~~ Al Domain Command and Control (JADC2), to direct forces Domain Command and Control (JADC2), to direct forces
across multiple domains (air, space, cyber, land, sea).82 According to defense officials, across multiple domains (air, space, cyber, land, sea).82 According to defense officials,
commanders currently execute C2 by exchanging data through manpower-intensive processes commanders currently execute C2 by exchanging data through manpower-intensive processes
that that ~~typically~~typical y focus on a single domain. This reduces a commander’s situational awareness, speed focus on a single domain. This reduces a commander’s situational awareness, speed
of decisionmaking, and abilityof decisionmaking, and ability to rapidly and continuously integrate capabilities across domains. to rapidly and continuously integrate capabilities across domains.
These processes are not automated and These processes are not automated and ~~typically~~typical y provide single domain awareness.83 In contrast, provide single domain awareness.83 In contrast,
JADC2 is to enhance information-sharing across domains through “a combination of new JADC2 is to enhance information-sharing across domains through “a combination of new
technology, processes and new organizations.”84technology, processes and new organizations.”84
Figure 8. Visualization of JADC2 Vision

Source: https://www.monch.com/mpg/news/ew-c4i-channel/7334-saic-and-usaf-partner-for-jadc2.html. https://www.monch.com/mpg/news/ew-c4i-channel/7334-saic-and-usaf-partner-for-jadc2.html.

~~80 Theresa~~ 80 T heresa Hitchens, “DoD Winnowing Efforts Hitchens, “DoD Winnowing Efforts ToT o Counter Small Drones,” Counter Small Drones,” Breaking Defense, March 5, 2020, at, March 5, 2020, at
https://breakingdefense.com/2020/03/dod-winnowing-efforts-to-counter-small-drones/. https://breakingdefense.com/2020/03/dod-winnowing-efforts-to-counter-small-drones/.
81 81 ~~This~~T his section was section was written by John R.written by John R. Hoehn, Kelley M. Sayler, and NishawnHoehn, Kelley M. Sayler, and Nishawn S. S. Smagh. Smagh.
82 For more information about JADC2, see CRS82 For more information about JADC2, see CRS In Focus IF11493, In Focus IF11493, Joint All-Domain Command and Control (JADC2), ,
by John R. Hoehn. by John R. Hoehn.
83 For example, the Air Force fields83 For example, the Air Force fields the Air Operations Center which provides command and control of air and space the Air Operations Center which provides command and control of air and space
operations for a single combatant command. Similarly the Navy usesoperations for a single combatant command. Similarly the Navy uses the Maritime Operations Center to command the Maritime Operations Center to command
naval forces in a specific area of operation. For the Air Operations Center to share information (and potentially tasking naval forces in a specific area of operation. For the Air Operations Center to share information (and potentially tasking
instructions) with the Maritime Operations Center requires manual processes. Similarly these command and control instructions) with the Maritime Operations Center requires manual processes. Similarly these command and control
structures are geographically focused, and do not provide insights into potential adversary operations in other structures are geographically focused, and do not provide insights into potential adversary operations in other
geographic regions. geographic regions.
84 Jay Koester, “ 84 Jay Koester, “ JADC2 ‘Experiment 2’ provides looking glass into future experimentation,” JADC2 ‘Experiment 2’ provides looking glass into future experimentation,” U.S. Army, April 23, , April 23,
2020, at https://www.army.mil/article/234900/2020, at https://www.army.mil/article/234900/
jadc2_experiment_2_provides_looking_glass_into_future_experimentationjadc2_experiment_2_provides_looking_glass_into_future_experimentation . .
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DOD uses ride-sharing service Uber as an analogy to describe its desired end state for JADC2. DOD uses ride-sharing service Uber as an analogy to describe its desired end state for JADC2.
Uber combines two different apps—one for riders and a second for drivers. 85 Using the Uber combines two different apps—one for riders and a second for drivers. 85 Using the
respective users’ position, the Uber algorithm determines the optimal match based on distance, respective users’ position, the Uber algorithm determines the optimal match based on distance,
travel time, and passengers (among other variables). The application then seamlessly provides travel time, and passengers (among other variables). The application then seamlessly provides
directions for the driver to follow, delivering the passenger to their destination. Uber relies on directions for the driver to follow, delivering the passenger to their destination. Uber relies on
~~cellular~~cel ular and Wi-Fi networks to transmit data to match riders and provide driving instructions. The and Wi-Fi networks to transmit data to match riders and provide driving instructions. The
military equivalent might be using military equivalent might be using ~~all available intelligence~~ al available intel igence sensors—particularly space, air and sensors—particularly space, air and
maritime-based sensors—to detect adversary targets. Artificial maritime-based sensors—to detect adversary targets. Artificial ~~intelligence~~intel igence algorithms would then algorithms would then
identify where different missiles, aircraft, and identify where different missiles, aircraft, and ~~artillery~~artil ery units are to determine the best to assign to units are to determine the best to assign to
an emerging target. an emerging target. ~~Finally~~Final y, using the optimal communications method the algorithms would then , using the optimal communications method the algorithms would then
direct the appropriate munition onto the target. The Air Force has been designated as the direct the appropriate munition onto the target. The Air Force has been designated as the
executive agent charged with overseeing the services’ first-year JADC2 activities.86 JADC2 is executive agent charged with overseeing the services’ first-year JADC2 activities.86 JADC2 is
intended to reach full operational capability by 2035.87intended to reach full operational capability by 2035.87
Similarly, DARPA has researched a concept Similarly, DARPA has researched a concept ~~called~~cal ed “Mosaic Warfare,” intended to leverage AI to “Mosaic Warfare,” intended to leverage AI to
network systems and sensors, prioritize incoming sensor data, and autonomously determine the network systems and sensors, prioritize incoming sensor data, and autonomously determine the
optimal composition of forces. Such concepts could provide a comprehensive common operating optimal composition of forces. Such concepts could provide a comprehensive common operating
picture, coordinate operations across warfare domains, and picture, coordinate operations across warfare domains, and ~~challenge~~chal enge adversaries’ targeting adversaries’ targeting
calculations. These concepts calculations. These concepts ~~additionally~~additional y propose limiting the amount of and/or disguising propose limiting the amount of and/or disguising
electronic emissions in the spectrum to further complicate adversaries’ ability to target U.S. electronic emissions in the spectrum to further complicate adversaries’ ability to target U.S.
forces.forces.
~~Potential Spectrum Issues for Congress88~~
~~As Congress considers several policy implications of the use of the spectrum, several potential~~
~~issues emerge. These issues can be categorized broadly as technical issues, organizational issues,~~
~~and issues related to commercial use of the spectrum.~~
~~Technical Challenges~~
~~This section discusses several potential technical issues associated with the spectrum. These~~
~~include communications system interoperability, adversary technological development, and~~
~~spectrum sharing technologies to enable commercial applications.~~
~~Communications System Interoperability~~
~~One challenge the DOD is confronted with is system interoperability both between individual~~
~~weapons systems as well as between each of the military services. This issue has been~~
~~documented with the F-22 and F-35 fighter aircraft developing incompatible data link protocols—~~
~~the F-22 uses the intra-flight data link (IFDL) and the F-35 uses the multifunction advanced data~~

~~85 Gen David Goldfein and Gen John Raymond, “America’s future battle network is key to multidomain defense,”~~
~~Defense News~~, DOD Spectrum Strategies and Policies88 DOD has recently changed its strategy and organizational structure for and focus on spectrum operations. First, in May 2020, the Joint Staff released Joint Publication (JP) 3-85, which documents DOD’s doctrine for Joint Electromagnetic Spectrum Operations.89 This document states that the electromagnetic spectrum “is a maneuver space essential for facilitating control within the operational environment (OE) and impacts al portions of the OE and military operations.”90 JP 3-85 also changed how DOD trains and organizes for EMSO by combining electronic warfare and spectrum management operations into a single function. Previously, spectrum management and electronic warfare were two separate disciplines run by different organizations within each military command.91 JP 3-85 notes that, while signals intel igence supports EMSO, it remains an intel igence discipline tasked by the intel igence directorate. 85 Gen David Goldfein and Gen John Raymond, “America’s future battle network is key to multidomain defense,” Defense News, February 27, 2020, at https://www.defensenews.com/opinion/commentary/2020/02/27/americas-future-February 27, 2020, at https://www.defensenews.com/opinion/commentary/2020/02/27/americas-future-
battle-network-is-key-to-multidomain-defense/. battle-network-is-key-to-multidomain-defense/.
~~86 The~~86 T he services have a number of related programs that are designed services have a number of related programs that are designed to demonstrate the capabilities needed to execute to demonstrate the capabilities needed to execute
JADC2, includingJADC2, including the Army’s Project Convergence and the Air Force’s Advancedthe Army’s Project Convergence and the Air Force’s Advanced Battle Management System. Jay Battle Management System. Jay
Koester, “Koester, “ JADC2 ‘Experiment 2’ provides looking glass into future experimentationJADC2 ‘Experiment 2’ provides looking glass into future experimentation ,” ,” U.S. Army, April 23, 2020, at , April 23, 2020, at
https://www.army.mil/article/234900/jadc2_experiment_2_provides_looking_glass_into_future_experimentation. https://www.army.mil/article/234900/jadc2_experiment_2_provides_looking_glass_into_future_experimentation.
87 Ibid. 87 Ibid.
88 88 ~~This~~T his section was section was written by John R. Hoehn. 89 Department of Defense, Joint Electromagnetic Spectrum Operations, JP 3-85, Washington, DC, May 22, 2020, https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp3_85.pdf?ver=2020-04-09-140128-347. 90 Ibid., p. I-1. 91 T raditionally electronic warfare was managed by the operations directorate, while spectrum management was delegated to the communications directorate—this is akin to the Chief Operations Officer and Chief Information Officer in the commercial sector controlling different aspects and viewpoints of the spectrum environment. JP 3 -85 Congressional Research Service 20 Overview of Department of Defense Use of the Electromagnetic Spectrum Then, in September 2020, DOD released a new electromagnetic spectrum enterprise directive to set policy and assign bureaucratic responsibilities for EMSO.92 This directive identifies the DOD Chief Information Officer (CIO) as the primary staff assistant for spectrum management policy, and the Undersecretary of Defense for Acquisition and Sustainment as the lead organization for electronic warfare programs.93 The Undersecretary of Defense for Research and Engineering is designated as the primary organization responsible for developing spectrum management and electronic warfare technologies. In October 2020, DOD released the Electromagnetic Spectrum Superiority Strategy.94 The strategy outlines DOD’s intent to “develop superior EMS capabilities; evolve to an agile, fully integrated EMS infrastructure; pursue total force EMS readiness; secure enduring partnerships for EMS advantage; and establish effective EMS governance to support strategic and operational objectives.”95 This strategy combines the DOD’s electromagnetic spectrum strategy from 2013 and the electronic warfare strategy from 2017. The 2013 strategy identified the commercial sector’s increasing demand for spectrum, which DOD cal s “congestion.”96 The 2017 strategy identified how potential adversaries are developing systems to chal enge U.S. dominance of the spectrum, which DOD terms “contested.”97 The new 2020 strategy combines these two approaches into a single document and outlines how DOD plans to meet commercial demand for spectrum, while being able to support operations in a contested environment. In addition, DOD is developing a roadmap and implementation plan to achieve the strategy’s vision and goals. From an operational perspective, U.S. Strategic Command traditional y has been delegated responsibility for the spectrum. The FY2021 National Defense Authorization Act (NDAA) directed that “the Secretary of Defense shal transfer to an appropriate entity w ithin the Department of Defense al the responsibilities and functions of the Commander of the United States Strategic Command that are germane to electromagnetic spectrum operations” within two years.98 DOD has designated the Vice Chairman of the Joint Chiefs of Staff as the designated official.99 delegates the whole EMSO enterprise to the operations directorate. 92 Department of Defense, DOD Directive 3610.01: Electromagnetic Spectrum Enterprise Policy, September 4, 2020, https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodd/361001p.pdf?ver=2020 -09-04-112353-317. 93 Ibid., pp. 5-6. 94 Department of Defense, Electromagnetic Spectrum Superiority Strategy, October 29, 2020, https://media.defense.gov/2020/Oct/29/2002525927/-1/-1/0/ELECT ROMAGNET IC_SPECT RUM_SUPERIORIT Y_ST RAT EGY.PDF. 95 Ibid., p. i. 96 Department of Defense, Electromagnetic Spectrum Strategy, September 11, 2013, https://archive.defense.gov/news/dodspectrumstrategy.pdf. 97 Department of Defense, Electronic Warfare Strategy, 2017. 98 P.L. 116-283 §152. 99 Department of Defense, “Electromagnetic Spectrum Operations Cross Functional T eam Leaders,” press release, https://emso.defense.gov/About -Us/Leadership/, accessed March 8, 2020, and T heresa Hitchens, “ ‘Spectrum Superiority’ Key T o All Domain Operations: Gen. Hyten,” Breaking Defense, January 7, 2021, https://breakingdefense.com/2021/01/spectrum-superiority-key-to-all-domain-operations-gen-hyten/. Congressional Research Service 21 Overview of Department of Defense Use of the Electromagnetic Spectrum Potential Spectrum Issues for Congress100 As Congress considers several policy implications of the use of the spectrum, several potential issues emerge. These issues can be categorized broadly as technical issues, organizational issues, and issues related to commercial use of the spectrum. Technical Challenges This section discusses several potential technical issues associated with the spectrum. These include communications system interoperability, adversary technological development, and spectrum sharing technologies to enable commercial applications. Communications System Interoperability One chal enge the DOD is confronted with is system interoperability both between individual weapons systems as wel as between each of the military services. This issue has been documented with the F-22 and F-35 fighter aircraft developing incompatible data link protocols—the F-22 uses the intra-flight data link (IFDL) and the F-35 uses the multifunction advanced data~~written by John R. Hoehn and Jill C. Gallagher.~~
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link (MADL)—preventing these two Air Force fighter jets from sharing information with each link (MADL)—preventing these two Air Force fighter jets from sharing information with each
other.other.89101 Each service develops its command, control, and communications systems to meet their Each service develops its command, control, and communications systems to meet their
individualindividual needs. For instance, the Navy uses the AEGIS needs. For instance, the Navy uses the AEGIS ~~ballistic~~bal istic missile defense system—which missile defense system—which
is is ~~installed~~instal ed on guided missile cruisers and destroyers—which is currently unable to transmit radar on guided missile cruisers and destroyers—which is currently unable to transmit radar
data to the Army’s Integrated Battle Command System (IBCS) which performs a similar function. data to the Army’s Integrated Battle Command System (IBCS) which performs a similar function.
As mentioned, 5G encompasses low-band, mid-band, and high-band spectrum. DOD uses As mentioned, 5G encompasses low-band, mid-band, and high-band spectrum. DOD uses ~~all~~
al three bands for its operations. While the bulk of its holdings are in the lowthree bands for its operations. While the bulk of its holdings are in the low -band and mid-band -band and mid-band
spectrum, DOD also uses high-band (including spectrum, DOD also uses high-band (including ~~millimeter~~mil imeter wave or MMW) frequencies for high- wave or MMW) frequencies for high-
profile military applications such as Advanced Extremely High Frequency profile military applications such as Advanced Extremely High Frequency ~~satellites~~satel ites that provide that provide
assured global communications for U.S. forces. Coordinating investments across four branches of assured global communications for U.S. forces. Coordinating investments across four branches of
government, three bands of spectrum, and across multiple geographies is a government, three bands of spectrum, and across multiple geographies is a ~~challenge~~chal enge. .
The Defense Innovation Board and FCC Commissioner Rosenworcel have suggested that DOD The Defense Innovation Board and FCC Commissioner Rosenworcel have suggested that DOD
should focus on sub-6 GHz deployments; they argue that the rest of the world, including China, is should focus on sub-6 GHz deployments; they argue that the rest of the world, including China, is
deploying 5G for military use in the low-band and mid-band first, and that the U.S. should do the deploying 5G for military use in the low-band and mid-band first, and that the U.S. should do the
same so as to (a) not same so as to (a) not ~~fall~~ fal behind other countries in sub-6 GHz deployments, and (b) ensure U.S. behind other countries in sub-6 GHz deployments, and (b) ensure U.S.
forces may be able to operate and interoperate with those countries when abroad. forces may be able to operate and interoperate with those countries when abroad.
Industry observers assert that the significant innovations Industry observers assert that the significant innovations ~~will~~ wil come in the MMW spectrum, come in the MMW spectrum,
including high-speed, low latency applications, providing the U.S. a competitive edge in the including high-speed, low latency applications, providing the U.S. a competitive edge in the
global defense market and on the battlefield. global defense market and on the battlefield. ~~Still~~ Stil others assert that investments across others assert that investments across ~~all~~ al three three
bands bands ~~will~~ wil benefit DOD as 5G offers greater capacity, speeds, functionality, customization, and benefit DOD as 5G offers greater capacity, speeds, functionality, customization, and
security. In deciding DOD appropriations, Congress may consider where and how federal funds security. In deciding DOD appropriations, Congress may consider where and how federal funds
for 5G should be invested. 100 T his section was written by John R. Hoehn and Jill C. Gallagher. 101 Brian W. Everstine, “T he F-22 and the F-35 Are Struggling to T alk to Each Other … And to the Rest of USAF,” Air Force Magazine, January 29, 2018, at https://www.airforcemag.com/article/the-f-22-and-the-f-35-are-struggling-to-talk-to-each-other-and-to-the-rest-of-usaf/. Congressional Research Service 22 Overview of Department of Defense Use of the Electromagnetic Spectrum ~~for 5G should be invested.~~
Adversary Spectrum Interference Developments
Another potential issue for Congress is balancing spectrum needs of commercial users and Another potential issue for Congress is balancing spectrum needs of commercial users and
consumers, and at the same time ensuring DOD has the spectrum it needs to keep pace with consumers, and at the same time ensuring DOD has the spectrum it needs to keep pace with
adversaries. The DOD states “[s]ince modern military operations are adversaries. The DOD states “[s]ince modern military operations are ~~critically~~critical y dependent on the dependent on the
EMS, a key goal of our adversaries and enemies is to deny our ability to use it successfully.”EMS, a key goal of our adversaries and enemies is to deny our ability to use it successfully.”90
102 After observing how the U.S. military operates, potential adversaries like Russia and China have After observing how the U.S. military operates, potential adversaries like Russia and China have
identified the U.S. military’ reliance on the spectrum as a potential vulnerability. As a result, these identified the U.S. military’ reliance on the spectrum as a potential vulnerability. As a result, these
potential adversaries have focused on potential adversaries have focused on ~~challenging~~chal enging the U.S. military’s network and EW the U.S. military’s network and EW
capabilities—these systems are part of an capabilities—these systems are part of an ~~overall approach called~~overal approach cal ed anti-access/area denial anti-access/area denial
(A2/AD) which are intended to (A2/AD) which are intended to ~~challenge~~chal enge the ability of the military from entering a contested area the ability of the military from entering a contested area
like the Balticlike the Baltic states or the South China Sea.states or the South China Sea.91103 The FY2019 National Defense Authorization Act The FY2019 National Defense Authorization Act
(NDAA) required DOD to contract an independent assessment of EW capabilities, with a report (NDAA) required DOD to contract an independent assessment of EW capabilities, with a report
due October 1, 2019.due October 1, 2019.92104 The Center for Strategic and Budgetary Assessments ultimately The Center for Strategic and Budgetary Assessments ultimately performed performed
~~this assessment, providing an overview of adversary capabilities and doctrines.93~~

~~89 Brian W. Everstine, “The F-22 and the F-35 Are Struggling to Talk to Each Other … And to the Rest of USAF,”~~ ~~Air~~
~~Force Magazine, January 29, 2018, at https://www.airforcemag.com/article/the-f-22-and-the-f-35-are-struggling-to-~~
~~talk-to-each-other-and-to-the-rest-of-usaf/.~~
~~90 Department of Defense, Joint Electromagnetic Spectrum Operations, JP 3-85, Washington, DC, March 22, 2020, p.~~
~~I-3, https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp3_85.pdf?ver=2020-04-09-140128-347.~~
~~91 For more information on adversary electronic warfare capabilities see CRS Report R45919,~~ ~~Ground Electronic~~
~~Warfare: Background and Issues for Congress, by John R. Hoehn.~~
~~92 P.L. 115-232 §255.~~
93 Bryan Clark, Whitney M. McNamara, and Timothy A. Walton, Winning the Invisible War: Gaining an Enduring
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this assessment, providing an overview of adversary capabilities and doctrines.105
For more than a decade, the Russian military has focused on modernizing its forces, with a For more than a decade, the Russian military has focused on modernizing its forces, with a
particular emphasis on command, control, communications, and computers (C4) and ISR particular emphasis on command, control, communications, and computers (C4) and ISR
systems, of which EW plays an important part. According to military analyst Robert McDermott, systems, of which EW plays an important part. According to military analyst Robert McDermott,
the Russian military views electronic warfare as a “type of armed struggle using electronic means the Russian military views electronic warfare as a “type of armed struggle using electronic means
against enemy C4ISR to ‘change the quality of information,’ or using electronic means against against enemy C4ISR to ‘change the quality of information,’ or using electronic means against
various assets to change the condition of the operational environment.”various assets to change the condition of the operational environment.”94106 McDermott describes a McDermott describes a
close relationship between Russian signals close relationship between Russian signals ~~intelligence~~intel igence forces and EW forces, where several EW forces and EW forces, where several EW
units perform SIGINT functions. The Russian military’s emphasis on EW may create problems units perform SIGINT functions. The Russian military’s emphasis on EW may create problems
for U.S. military forces if the Russians are able to deny significant portions of the EMS. for U.S. military forces if the Russians are able to deny significant portions of the EMS.
Most of the focus on Chinese EW operations has been on the air, maritime, and space domains. Most of the focus on Chinese EW operations has been on the air, maritime, and space domains.
According to According to Jane’s Defence Weekly, China has invested substantial resources into science and , China has invested substantial resources into science and
technology initiatives focused on improving its network and electronic warfare technology initiatives focused on improving its network and electronic warfare
capabilities.capabilities.95107 These investments include ground-based sensors and jammers, space-based These investments include ground-based sensors and jammers, space-based
~~intelligence~~ intel igence assets, and a number of airborne jammers.assets, and a number of airborne jammers.96108 China is also investing in unmanned China is also investing in unmanned
systems that could systems that could ~~potentially~~potential y swarm to provide desired effects, including SIGINT interceptions swarm to provide desired effects, including SIGINT interceptions
and electronic attack.and electronic attack.97109 China has also focused on developing advanced jammers and anti- 102 Department of Defense, Joint Electromagnetic Spectrum Operations, JP 3-85, Washington, DC, March 22, 2020, p. I-3, https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp3_85.pdf?ver=2020-04-09-140128-347. 103 For more information on adversary electronic warfare capabilities see CRS Report R45919, Ground Electronic Warfare: Background and Issues for Congress, by John R. Hoehn. 104 P.L. 115-232 §255. 105 Bryan Clark, Whitney M. McNamara, and T imothy A. Walton, Winning the Invisible War: Gaining an Enduring U.S. Advantage in the Electrom agnetic Spectrum , Center for Strategic and Budgetary ~~China has also focused on developing advanced jammers and anti-satellite~~
~~technologies to deny U.S. forces access to satellites.98 For example, in 2007, China demonstrated~~
~~its ability to launch an anti-satellite weapon to destroy an old weather satellite in low earth orbit.~~
~~According to the 2020 Annual Report on China Military Power, the DOD reported that “the PRC~~
~~is developing electronic warfare capabilities such as satellite jammers; offensive cyber~~
~~capabilities; and directed-energy weapons.”99~~
~~A challenge for DOD has been in keeping pace with rapidly evolving technologies and~~
~~coordinating information on adversaries’ technologies and capabilities across DOD~~
~~components.100 In December 2018, the Government Accountability Office (GAO) issued a report~~
~~stating that adversaries are developing electronic attack weapons to target U.S. systems with~~
~~sensitive electronic components, such as military sensors, communication, navigation, and~~
~~information systems.101 The Senate Armed Services Committee, citing the report, stated, “These~~

~~U.S. Advantage in the Electromagnetic Spectrum, Center for Strategic and Budgetary~~ Assessments, Washington, DC, Assessments, Washington, DC,
November 20, 2019, https://csbaonline.org/research/publications/winning-the-invisible-war-gaining-an-enduring-u.s-November 20, 2019, https://csbaonline.org/research/publications/winning-the-invisible-war-gaining-an-enduring-u.s-
advantage-in-the-electromagnetic-spectrum. advantage-in-the-electromagnetic-spectrum.
94106 Robert N. McDermott, Russia’s Electronic Warfare Capabilities to 2025, p. 3, International Centre for Defence and Robert N. McDermott, Russia’s Electronic Warfare Capabilities to 2025, p. 3, International Centre for Defence and
Security, September 2017. See Department of Defense, Defense Intelligence Agency,Security, September 2017. See Department of Defense, Defense Intelligence Agency, ~~Russia~~ Russia Military Power, Building Military Power, Building
a Military to Support Great Power Aspirations, 2017, p. 42.a Military to Support Great Power Aspirations, 2017, p. 42.
~~95 Tate~~ 107 T ate Nurkin, Kelly Bedard, Nurkin, Kelly Bedard, James Clad,James Clad, et al., China’s Advancedet al., China’s Advanced Weapons Systems, IHSWeapons Systems, IHS Jane's, May 12, 2018, p. Jane's, May 12, 2018, p.
11, https://www.uscc.gov/sites/default/files/Research/11, https://www.uscc.gov/sites/default/files/Research/
Jane%27s%20by%20IHS%20Markit_China%Jane%27s%20by%20IHS%20Markit_China%~~27s~~2 7s%20Advanced%20Weapons%20Systems.pdf. %20Advanced%20Weapons%20Systems.pdf.
96108 Elsa Kania, China’s Strategic Situational Awareness Elsa Kania, China’s Strategic Situational Awareness Capabilities, Center for Strategic and International Studies, Capabilities, Center for Strategic and International Studies,
Washington, DC, JulyWashington, DC, July 29, 2019, https://ontheradar.csis.org/issue-briefs/china-situational-awareness/. 29, 2019, https://ontheradar.csis.org/issue-briefs/china-situational-awareness/.
~~97 Tate~~109 T ate Nurkin, Kelly Bedard, Nurkin, Kelly Bedard, James Clad,James Clad, et al., China’s Advancedet al., China’s Advanced Weapons Systems, IHSWeapons Systems, IHS Jane's, May 12, 2018, p. Congressional Research Service 23 Overview of Department of Defense Use of the Electromagnetic Spectrum satel ite technologies to deny U.S. forces access to satel ites.110 For example, in 2007, China demonstrated its ability to launch an anti-satel ite weapon to destroy an old weather satel ite in low earth orbit. According to the 2020 Annual Report on China Military Power, the DOD reported that “the PRC is developing electronic warfare capabilities such as satel ite jammers; offensive cyber capabilities; and directed-energy weapons.”111 A chal enge for DOD has been in keeping pace with rapidly evolving technologies and coordinating information on adversaries’ technologies and capabilities across DOD components.112 In December 2018, the Government Accountability Office (GAO) issued a report stating that adversaries are developing electronic attack weapons to target U.S. systems with sensitive electronic components, such as military sensors, communication, navigation, and information systems.113 The Senate Armed Services Committee, citing the report, stated, “These ~~Jane's, May 12, 2018, p.~~
~~41, https://www.uscc.gov/sites/default/files/Research/~~
~~Jane%27s%20by%20IHS%20Markit_China%27s%20Advanced%20Weapons%20Systems.pdf.~~
~~98 Department of Defense, Defense Intelligence Agency, China Military Power: Modernizing a Force to Fight and Win,~~
~~2019, p. 42.~~
~~99 Department of Defense, Military and Security Developments Involving the People’s Republic of China 2020,~~
~~Washington, DC, September 2020, p. 65, https://media.defense.gov/2020/Sep/01/2002488689/-1/-1/1/2020-DOD-~~
~~CHINA-MILITARY-POWER-REPORT-FINAL.PDF.~~
~~100 Sydney J. Freedberg, Jr., “Who’ll Fix EW? Task Force Gropes for Answers,” Breaking Defense, December 18,~~
~~2019, https://breakingdefense.com/2019/12/wholl-fix-ew-task-force-gropes-for-answers/.~~
101 U.S. Government Accountability Office, National Security: Long-Range Emerging Threats Facing the United States
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weapons are intended to degrade U.S. capabilities and could restrict situational awareness or may weapons are intended to degrade U.S. capabilities and could restrict situational awareness or may
affect military operations. The committee is concerned about the extent to which [DOD] is affect military operations. The committee is concerned about the extent to which [DOD] is
planning and preparing to defend itself and operate in an environment where peer and near-peer planning and preparing to defend itself and operate in an environment where peer and near-peer
adversaries could use existing and emerging capabilities that degrade use of the electromagnetic adversaries could use existing and emerging capabilities that degrade use of the electromagnetic
spectrum.”spectrum.”~~102~~114
Spectrum Sharing
In the past, repurposing efforts have focused on In the past, repurposing efforts have focused on ~~reallocating~~real ocating spectrum from federal to nonfederal spectrum from federal to nonfederal
use. As spectrum-sharing technologies emerged, Congress encouraged not only the use. As spectrum-sharing technologies emerged, Congress encouraged not only the ~~reallocation of~~
real ocation of spectrum from federal to nonfederal entities, but also sharing between federal and commercial spectrum from federal to nonfederal entities, but also sharing between federal and commercial
users. For example, the Middle Class Tax Relief and Job Creation Act of 2012 users. For example, the Middle Class Tax Relief and Job Creation Act of 2012 ~~allowed~~al owed federal federal
agencies to receive payments for costs incurred when they are asked to relocate due to a spectrum agencies to receive payments for costs incurred when they are asked to relocate due to a spectrum
auction or when they agree to share use of their spectrum.auction or when they agree to share use of their spectrum.~~103~~115 The Spectrum Pipeline Act of 2015 The Spectrum Pipeline Act of 2015
appropriated funds for federal agencies to engage in planning and to conduct studies and analyses appropriated funds for federal agencies to engage in planning and to conduct studies and analyses
to examine the potential for spectrum to examine the potential for spectrum ~~reallocation~~real ocation or sharing. or sharing.~~104~~116
DOD has participated in several spectrum-sharing initiatives, some of which have resulted in the DOD has participated in several spectrum-sharing initiatives, some of which have resulted in the
~~reallocation~~real ocation or shared use of spectrum. or shared use of spectrum.~~105~~117 For example, DOD, the Department of Homeland For example, DOD, the Department of Homeland
Security (DHS), the Federal Aviation Administration (FAA), and the National Oceanic and 41, https://www.uscc.gov/sites/default/files/Research/Jane%27s%20by%20IHS%20Markit_China%27s%20Advanced%20Weapons%20Systems.pdf. 110 Department of Defense, Defense Intelligence Agency, China Military Power: Modernizing a Force to Fight and Win, 2019, p. 42. 111 Department of Defense, Military and Security Developments Involving the People’s Republic of China 2020 , Washington, DC, September 2020, p. 65, https://media.defense.gov/2020/Sep/01/2002488689/-1/-1/1/2020-DOD-CHINA-MILIT ARY-POWER-REPORT -FINAL.PDF. 112 Sydney J. Freedberg, Jr., “Who’ll Fix EW? T ask Force Gropes for Answers,” Breaking Defense, December 18, 2019, https://breakingdefense.com/2019/12/wholl-fix-ew-task-force-gropes-for-answers/. 113 U.S. Government Accountability Office, National Security: Long-Range Emerging Threats Facing the United States As Identified by Federal Agencies, GAO-19-204SP, December 2018, p. 4, https://www.gao.gov/assets/700/695981.pdf. 114 U.S. Congress, House Committee on Armed Services, Report of the Committee on Armed Services on H.R. 2500 together with Additional and Dissenting Views, H.Rept. 116-120, 116th Cong., 1st sess., June 19, 2019, 36-763 (Washington: GPO, 2019), p. 69, https://www.govinfo.gov/content/pkg/CRPT -116hrpt120/html/CRPT-116hrpt120.htm. 115 P.L. 112-96, T itle VI, Subtitle G—Federal Spectrum Relocation, Section 6701 (a)(1)(B). 116 P.L. 114-74, T itle X—Spectrum Pipeline, Section 1005 (a). 117 Mark Rockwell, “DOD looks to share more spectrum,” Defense Systems, March 1, 2018, https://defensesystems.com/articles/2018/03/01/ntia-dod-spectrum-5g.aspx. Congressional Research Service 24 Overview of Department of Defense Use of the Electromagnetic Spectrum Atmospheric Administration (NOAA) have studied the potential to combine surveil ance, air safety, and weather radar applications into a single, spectrum-conserving “system of systems” by 2024. This system would al ow the agencies to vacate 30 MHz of spectrum in the 1300–1350 band, thus making it available for real ocation for shared federal and nonfederal use. Additional y, DOD plans to conduct a comprehensive engineering study to determine the potential for introducing advanced wireless services in this band without harming critical government operations.118 Agencies began studying the real ocation and sharing potential of the spectrum in 2017, and are stil actively studying potential use of the band. The studies are expected to inform future repurposing decisions.119 On August 10, 2020, the White House and DOD announced that a 100 MHz block of contiguous mid-band spectrum in the 3450-3550 MHz band wil be made available for commercial use (e.g., 5G), and is expected to be auctioned in 2021. DOD leveraged technical work performed by the NTIA to “devise a spectrum sharing framework that supports industry’s need for additional mid-band spectrum while protecting critical national security requirements.”120 At its September 30, 2020 meeting, the FCC adopted a Further Notice of Proposed Rulemaking (FNPRM) al ocating the 3.45-3.55 GHz spectrum band for flexible-use service. It seeks comment on an appropriate regime to coordinate nonfederal and federal use and proposes a band plan, as wel as technical, licensing, and competitive bidding rules for the band, signaling that the FCC is moving forward on the 2021 auction date.121 In addition, new technologies that would enable dynamic spectrum sharing—automated sharing between federal and nonfederal users—are under development.122 For example, in September 2019, the FCC approved a spectrum sharing arrangement between commercial and federal users in the 3550-3700 MHz band (also known as Citizens Broadband Radio Service or CBRS), whereby commercial users (licensed and unlicensed) wil share spectrum with incumbent DOD users. DOD wil have priority access when needed while stil al owing for licensed and unlicensed use. In December 2019, DOD issued a special notice seeking input from industry on 5G technology development, including dynamic spectrum sharing technologies.123 DOD and the Department of the Air Force sought input on effective methodologies (hardware, software, and systems) for sharing or coexistence between airborne radar systems and 5G cel ular systems in shared (completely or partial y overlapping) spectral bands. The intent is to evaluate the impact of the 5G network on airborne radar systems and the radar systems’ impact on the 5G network, 118 Office of Science and T echnology Policy, Emerging Technologies and Their Expected Impact on Non -Federal Spectrum Dem and, May 2019, https://www.whitehouse.gov/wp-content/uploads/2019/05/Emerging-T echnologies-and-Impact-on-Non-Federal-Spectrum-Demand-Report-May-2019.pdf. 119 U.S. Department of Commerce, Annual Report on the Status of Spectrum Repurposing, August 2019, https://www.ntia.doc.gov/files/ntia/publications/spectrum_repurposing_report_august_2019.pdf. 120 U.S. Department of Defense, “White House and DOD Announce Additional Mid-Band Spectrum Available for 5G by the end of the Summer,” press release, August 10, 2020, https://www.defense.gov/Newsroom/Releases/Release/Article/2307275/white-house-and-dod-announce-additional-mid-band-spectrum-available-for-5g-by-t/. 121 FCC, “FCC Moves to Free Up 100 Megahertz of Critical Mid-Band Spectrum in the 3.45-3.55 GHz Band for 5G,” press release, September 30, 2020, https://docs.fcc.gov/public/attachments/DOC-367236A1.pdf. 122 T he CBRS spectrum sharing arrangement is being used to model for other spectrum sharing arrangements. National T elecommunications and Information Agency, “Spectrum Sharing Model Gaining Ground,” press release, May 1, 2019, https://www.ntia.doc.gov/blog/2019/spectrum-sharing-model-gaining-ground. 123 U.S. Department of Defense, “DOD Issues Special Notice Seeking Input From Industry on 5G T echnology Development,” press release, December 2, 2019, https://www.defense.gov/Newsroom/Releases/Release/Article/2029707/dod-issues-special-notice-seeking-input -from-industry-on-5g-technology-developm/. Congressional Research Service 25 Overview of Department of Defense Use of the Electromagnetic Spectrum employing both active and passive techniques to enable sharing or coexistence. In September 2020, DOD issued a request for information seeking new methods to facilitate spectrum sharing between military and civilian users, and to identify issues of concern related to sharing spectrum for DOD.124 While policymakers and users are both interested in spectrum sharing, and see it as a way of extending spectrum access for new users, the policies, approaches, technologies, and applications are stil emerging and may face chal enges. Introducing new users into spectrum bands creates a potential for interference with military capabilities; detecting and mitigating interference is a chal enge. Prioritization of use is another chal enge, as is policy control and coordination with secondary users.125 Further, to maximize use of shared spectrum, users may need to know when spectrum is being used and when it is available which may present chal enges for DOD, as it may not want to share that information publicly. On the one hand, industry stakeholders say that military and other federal users have more spectrum than they need and that holding large swathes of spectrum for future use inhibits innovations and restricts economic advancement.126 On the other hand, some defense advocates say that as commercial use of spectrum is increasing, so is military use. These observers note that agencies holding large swathes of spectrum see only risks in relinquishing spectrum; they note, “no military planner would want to be known as the person who gave back spectrum subsequently needed.”127 The chal enge for Congress is in encouraging policies that enable the most efficient use of spectrum, while stil protecting and prioritizing DOD mission critical functions. DOD Spectrum Organizational Issues Over the past several years, Congress has expressed interest in the DOD’s organization of spectrum-related issues. The EW Executive Committee—led by the Deputy Secretary of Defense—is tasked with synchronizing and integrating EW across DOD components by sharing tactics, techniques, procedures, intel igence, and technologies. The EW EXCOM is responsible for establishing DOD EW policy.128 The FY2019 NDAA mandated the creation of an EW Cross Functional Team to develop an electronic warfare strategy, including assessments of vulnerabilities and capability gaps,129 leading to an acquisition plan. The most recent DOD EW strategy was released in 2017. The NDAA for FY2019 (P.L. 115-232, Section 1053) directed DOD to establish a cross- functional team to oversee the implementation of an integrated spectrum strategy. The intent is to 124 DOD, Request for Information, Defense Spectrum Sharing Request for Information, Published September 18, 2020, https://beta.sam.gov/opp/4851a65e2b2d4d73865a0e9865b0c28a/view?keywords=spectrum&sort=-modifiedDate&index=&is_active=true&page=1. 125 Frank Rayal, “Challenges & Impediments to Implementing Spectrum Sharing,” Frank Rayal (blog), September 24, 2012, “https://frankrayal.com/2012/09/24/challenges-impediments-to-implementing-spectrum-sharing/. 126 CT IA, “Benefits from Clearing Federal Spectrum Helps Government Agencies Modernize Operations, New CT IA Paper Finds,” press release, August 11, 2020, https://www.ctia.org/news/release-benefits-from-clearing-federal-spectrum-helps-government-agencies-modernize-operations-new-ctia-paper-finds. 127 Roslyn Layton, “GPS Interference Fears Are T oday’s Y2K, Says Former UK Spectrum Director,” Forbes, May 8, 2020, https://www.forbes.com/sites/roslynlayton/2020/05/08/gps-interference-fears-are-todays-y2k-says-former-uk-spectrum-director/#79d799e17329. 128 10 U.S.C. §113. 129 P.L. 115-232 §918. Congressional Research Service 26 Overview of Department of Defense Use of the Electromagnetic Spectrum meld two existing strategies, DOD’s 2013 electromagnetic spectrum strategy developed by the chief information office (CIO) and the department’s electronic warfare strategy, into a single policy: 130 the Electromagnetic Spectrum Superiority Strategy.131 In April 2019, DOD stood up the Electromagnetic Spectrum Operations (EMSO) Cross Functional Team, comprised of senior members from each branch, the Joint Staff, U.S. Command, Cyber Command, and other offices. This organization has been active in updating DOD spectrum policy and strategy. In May 2020, the Joint Staff released new doctrine on Joint Electromagnetic Military Operations, elevating the spectrum to a maneuver space.132 On September 4, 2020, DOD issued DOD Directive 3610.01, ~~Security (DHS), the Federal Aviation Administration (FAA), and the National Oceanic and~~
~~Atmospheric Administration (NOAA) have studied the potential to combine surveillance, air~~
~~safety, and weather radar applications into a single, spectrum-conserving “system of systems” by~~
~~2024. This system would allow the agencies to vacate 30 MHz of spectrum in the 1300–1350~~
~~band, thus making it available for reallocation for shared federal and nonfederal use. Additionally,~~
~~DOD plans to conduct a comprehensive engineering study to determine the potential for~~
~~introducing advanced wireless services in this band without harming critical government~~
~~operations.106 Agencies began studying the reallocation and sharing potential of the spectrum in~~
~~2017, and are still actively studying potential use of the band. The studies are expected to inform~~
~~future repurposing decisions.107~~
~~On August 10, 2020, the White House and DOD announced that a 100 MHz block of contiguous~~
~~mid-band spectrum in the 3450-3550 MHz band will be made available for commercial use (e.g.,~~
~~5G), and is expected to be auctioned in 2021. DOD leveraged technical work performed by the~~
~~NTIA to “devise a spectrum sharing framework that supports industry’s need for additional mid-~~
~~band spectrum while protecting critical national security requirements.”108 At its September 30,~~

As Identified by Federal Agencies, GAO-19-204SP, December 2018, p. 4, https://www.gao.gov/assets/700/695981.pdf.
~~102 U.S. Congress, House Committee on Armed Services,~~ ~~Report of the Committee on Armed Services on H.R. 2500~~
~~together with Additional and Dissenting Views, H.Rept. 116-120, 116th Cong., 1st sess., June 19, 2019, 36-763~~
~~(Washington: GPO, 2019), p. 69, https://www.govinfo.gov/content/pkg/CRPT-116hrpt120/html/CRPT-~~
~~116hrpt120.htm.~~
~~103 P.L. 112-96, Title VI, Subtitle G—Federal Spectrum Relocation, Section 6701 (a)(1)(B).~~
~~104 P.L. 114-74, Title X—Spectrum Pipeline, Section 1005 (a).~~
~~105 Mark Rockwell, “DOD looks to share more spectrum,” Defense Systems, March 1, 2018,~~
~~https://defensesystems.com/articles/2018/03/01/ntia-dod-spectrum-5g.aspx.~~
~~106 Office of Science and Technology Policy,~~ ~~Emerging Technologies and Their Expected Impact on Non-Federal~~
~~Spectrum Demand, May 2019, https://www.whitehouse.gov/wp-content/uploads/2019/05/Emerging-Technologies-and-~~
~~Impact-on-Non-Federal-Spectrum-Demand-Report-May-2019.pdf.~~
~~107 U.S. Department of Commerce, Annual Report on the Status of Spectrum Repurposing, August 2019,~~
~~https://www.ntia.doc.gov/files/ntia/publications/spectrum_repurposing_report_august_2019.pdf.~~
~~108 U.S. Department of Defense, “White House and DOD Announce Additional Mid-Band Spectrum Available for 5G~~
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~~Overview of Department of Defense Use of the Electromagnetic Spectrum~~

~~2020 meeting, the FCC adopted a Further Notice of Proposed Rulemaking (FNPRM) allocating~~
~~the 3.45-3.55 GHz spectrum band for flexible-use service. It seeks comment on an appropriate~~
~~regime to coordinate nonfederal and federal use and proposes a band plan, as well as technical,~~
~~licensing, and competitive bidding rules for the band, signaling that the FCC is moving forward~~
~~on the 2021 auction date.109~~
~~In addition, new technologies that would enable dynamic spectrum sharing—automated sharing~~
~~between federal and nonfederal users—are under development.110 For example, in September~~
~~2019, the FCC approved a spectrum sharing arrangement between commercial and federal users~~
~~in the 3550-3700 MHz band (also known as Citizens Broadband Radio Service or CBRS),~~
~~whereby commercial users (licensed and unlicensed) will share spectrum with incumbent DOD~~
~~users. DOD will have priority access when needed while still allowing for licensed and~~
~~unlicensed use.~~
~~In December 2019, DOD issued a special notice seeking input from industry on 5G technology~~
~~development, including dynamic spectrum sharing technologies.111 DOD and the Department of~~
~~the Air Force sought input on effective methodologies (hardware, software, and systems) for~~
~~sharing or coexistence between airborne radar systems and 5G cellular systems in shared~~
~~(completely or partially overlapping) spectral bands. The intent is to evaluate the impact of the~~
~~5G network on airborne radar systems and the radar systems’ impact on the 5G network,~~
~~employing both active and passive techniques to enable sharing or coexistence. In September~~
~~2020, DOD issued a request for information seeking new methods to facilitate spectrum sharing~~
~~between military and civilian users, and to identify issues of concern related to sharing spectrum~~
~~for DOD.112~~
~~While policymakers and users are both interested in spectrum sharing, and see it as a way of~~
~~extending spectrum access for new users, the policies, approaches, technologies, and applications~~
~~are still emerging and may face challenges. Introducing new users into spectrum bands creates a~~
~~potential for interference with military capabilities; detecting and mitigating interference is a~~
~~challenge. Prioritization of use is another challenge, as is policy control and coordination with~~
~~secondary users.113 Further, to maximize use of shared spectrum, users may need to know when~~
~~spectrum is being used and when it is available which may present challenges for DOD, as it may~~
~~not want to share that information publicly.~~
~~On the one hand, industry stakeholders say that military and other federal users have more~~
~~spectrum than they need and that holding large swathes of spectrum for future use inhibits~~

~~by the end of the Summer,” press release, August 10, 2020, https://www.defense.gov/Newsroom/Releases/Release/~~
~~Article/2307275/white-house-and-dod-announce-additional-mid-band-spectrum-available-for-5g-by-t/.~~
~~109 FCC, “FCC Moves to Free Up 100 Megahertz of Critical Mid-Band Spectrum in the 3.45-3.55 GHz Band for 5G,”~~
~~press release, September 30, 2020, https://docs.fcc.gov/public/attachments/DOC-367236A1.pdf.~~
~~110 The CBRS spectrum sharing arrangement is being used to model for other spectrum sharing arrangements. National~~
~~Telecommunications and Information Agency, “Spectrum Sharing Model Gaining Ground,” press release, May 1,~~
~~2019, https://www.ntia.doc.gov/blog/2019/spectrum-sharing-model-gaining-ground.~~
~~111 U.S. Department of Defense, “DOD Issues Special Notice Seeking Input From Industry on 5G Technology~~
~~Development,” press release, December 2, 2019, https://www.defense.gov/Newsroom/Releases/Release/Article/~~
~~2029707/dod-issues-special-notice-seeking-input-from-industry-on-5g-technology-developm/.~~
~~112 DOD, Request for Information, Defense Spectrum Sharing Request for Information, Published September 18, 2020,~~
~~https://beta.sam.gov/opp/4851a65e2b2d4d73865a0e9865b0c28a/view?keywords=spectrum&sort=-modifiedDate&~~
~~index=&is_active=true&page=1.~~
~~113 Frank Rayal, “Challenges & Impediments to Implementing Spectrum Sharing,” Frank Rayal (blog), September 24,~~
~~2012, “https://frankrayal.com/2012/09/24/challenges-impediments-to-implementing-spectrum-sharing/.~~
~~Congressional Research Service~~

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~~Overview of Department of Defense Use of the Electromagnetic Spectrum~~

~~innovations and restricts economic advancement.114 On the other hand, some defense advocates~~
~~say that as commercial use of spectrum is increasing, so is military use. These observers note that~~
~~agencies holding large swathes of spectrum see only risks in relinquishing spectrum; they note,~~
~~“no military planner would want to be known as the person who gave back spectrum~~
~~subsequently needed.”115 The challenge for Congress is in encouraging policies that enable the~~
~~most efficient use of spectrum, while still protecting and prioritizing DOD mission critical~~
~~functions.~~
~~DOD Spectrum Organizational Issues~~
~~Over the past several years, Congress has expressed interest in the DOD’s organization of~~
~~spectrum-related issues. The EW Executive Committee—led by the Deputy Secretary of~~
~~Defense—is tasked with synchronizing and integrating EW across DOD components by sharing~~
~~tactics, techniques, procedures, intelligence, and technologies. The EW EXCOM is responsible~~
~~for establishing DOD EW policy.116 The FY2019 NDAA mandated the creation of an EW Cross~~
~~Functional Team to develop an electronic warfare strategy, including assessments of~~
~~vulnerabilities and capability gaps,117 leading to an acquisition plan. The most recent DOD EW~~
~~strategy was released in 2017.~~
~~The NDAA for FY2019 (P.L. 115-232, Section 1053) directed DOD to establish a cross-~~
~~functional team to oversee the implementation of an integrated spectrum strategy. The intent is to~~
~~meld two existing strategies, DOD’s 2013 electromagnetic spectrum strategy developed by the~~
~~chief information office (CIO) and the department’s electronic warfare strategy, into a single~~
~~policy: 118 the Electromagnetic Spectrum Superiority Strategy.119 In April 2019, DOD stood up the~~
~~Electromagnetic Spectrum Operations (EMSO) Cross Functional Team, comprised of senior~~
~~members from each branch, the Joint Staff, U.S. Command, Cyber Command, and other offices.~~
~~This organization has been active in updating DOD spectrum policy and strategy. In May 2020,~~
~~the Joint Staff released new doctrine on Joint Electromagnetic Military Operations, elevating the~~
~~spectrum to a maneuver space.120 On September 4, 2020, DOD issued DOD Directive 3610.01,~~
~~Electromagnetic Spectrum Enterprise Policy, which sets DOD policy and roles and~~
~~responsibilities for integrated DOD electromagnetic spectrum operations.121 On October 29, 2020,~~
~~the EMS Operations Cross Functional Team released the DOD Spectrum Superiority Strategy.122~~

~~114 CTIA, “Benefits from Clearing Federal Spectrum Helps Government Agencies Modernize Operations, New CTIA~~
~~Paper Finds,” press release, August 11, 2020, https://www.ctia.org/news/release-benefits-from-clearing-federal-~~
~~spectrum-helps-government-agencies-modernize-operations-new-ctia-paper-finds.~~
~~115 Roslyn Layton, “GPS Interference Fears Are Today’s Y2K, Says Former UK Spectrum Director,” Forbes, May 8,~~
~~2020, https://www.forbes.com/sites/roslynlayton/2020/05/08/gps-interference-fears-are-todays-y2k-says-former-uk-~~
~~spectrum-director/#79d799e17329.~~
~~116 10 U.S.C. §113.~~
~~117 P.L. 115-232 §918.~~
~~118 The EMSO CFT is in the process of developing a new EMS strategy and anticipates releasing the strategy by the~~
~~end of 2020. Department of Defense, Electromagnetic Spectrum Strategy, September 11, 2013,~~
~~https://dodcio.defense.gov/Portals/0/Documents/Spectrum/ESS.pdf.~~
~~119 Lauren C. Williams, “DOD Preps New Electromagnetic Spectrum Strategy,” Defense Systems, December 23, 2019,~~
~~https://defensesystems.com/articles/2019/12/23/dod-spectrum-warfare-williams.aspx.~~
~~120 While a maneuver space is not considered a domain, this implies~~
~~121 Department of Defense,~~ ~~DOD Directive 3610.01:~~ Electromagnetic Spectrum Enterprise Policy~~, September 4, 2020,~~
~~https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodd/361001p.pdf?ver=2020-09-04-112353-317.~~
~~122 Department of Defense, Electromagnetic Spectrum Superiority Strategy, October 29, 2020,~~
~~https://media.defense.gov/2020/Oct/29/2002525927/-1/-~~
~~Congressional Research Service~~

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~~Overview of Department of Defense Use of the Electromagnetic~~, which sets DOD policy and roles and responsibilities for integrated DOD electromagnetic spectrum operations.133 On October 29, 2020, the EMS Operations Cross Functional Team released the DOD Spectrum Superiority Strategy.134 ~~Spectrum~~

This strategy recognizes the importance of spectrum in support of military operations, and This strategy recognizes the importance of spectrum in support of military operations, and
combines two traditional separate disciplines—electronic warfare and spectrum management—to combines two traditional separate disciplines—electronic warfare and spectrum management—to
take a holistic view of the DOD spectrum enterprise. take a holistic view of the DOD spectrum enterprise. ~~Finally~~Final y, the FY2021 NDAA transfers , the FY2021 NDAA transfers
responsibility for electronic warfare from Strategic Command to the Vice Chairman of the Joint responsibility for electronic warfare from Strategic Command to the Vice Chairman of the Joint
Chiefs of Staff.Chiefs of Staff.~~123~~
135 Commercial Demand for Federal Spectrum
As the nation continues to experience significant growth in commercial wireless services (e.g., As the nation continues to experience significant growth in commercial wireless services (e.g.,
mobile phones, mobile applications, video streaming, Wi-Fi), demand for spectrum has increased. mobile phones, mobile applications, video streaming, Wi-Fi), demand for spectrum has increased.
To meet current commercial and consumer demands, the U.S. government has identified To meet current commercial and consumer demands, the U.S. government has identified
spectrum that is optimal for wireless communication use. Sometimes the spectrum targeted for spectrum that is optimal for wireless communication use. Sometimes the spectrum targeted for
wireless services is in use by other commercial users (e.g., radio and television broadcasters, wireless services is in use by other commercial users (e.g., radio and television broadcasters,
~~satellite~~satel ite communication providers). Sometimes the spectrum targeted is in use by federal communication providers). Sometimes the spectrum targeted is in use by federal
agencies. Since DOD holds spectrum across multiple bands, it has been affected by effort to agencies. Since DOD holds spectrum across multiple bands, it has been affected by effort to
~~reallocate~~ real ocate spectrum for commercial wireless use. spectrum for commercial wireless use.
The growth in commercial wireless services has produced new revenues and new jobs for the The growth in commercial wireless services has produced new revenues and new jobs for the
United States.United States.~~124~~136 Hence the Hence the ~~challenge~~chal enge for Congress is in balancing the for Congress is in balancing the ~~allocation~~al ocation of spectrum for of spectrum for
commercial and consumer wireless services while protecting federal agency use of spectrum that commercial and consumer wireless services while protecting federal agency use of spectrum that
support mission-critical functions. This balance was recently demonstrated with the FCC’s support mission-critical functions. This balance was recently demonstrated with the FCC’s
Auction 107 for C-Band spectrum, which garnered approximately $81 Auction 107 for C-Band spectrum, which garnered approximately $81 ~~billion~~bil ion from bidders. from bidders.~~125~~137 130 T he EMSO CFT is in the process of developing a new EMS strategy and anticipates releasing the strategy by the end of 2020. Department of Defense, Electrom agnetic Spectrum Strategy, September 11, 2013, https://dodcio.defense.gov/Portals/0/Documents/Spectrum/ESS.pdf. 131 Lauren C. Williams, “DOD Preps New Electromagnetic Spectrum Strategy,” Defense Systems, December 23, 2019, https://defensesystems.com/articles/2019/12/23/dod-spectrum-warfare-williams.aspx. 132 While a maneuver space is not considered a domain, this implies 133 Department of Defense, DOD Directive 3610.01: Electromagnetic Spectrum Enterprise Policy, September 4, 2020, https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodd/361001p.pdf?ver=2020-09-04-112353-317. 134 Department of Defense, Electromagnetic Spectrum Superiority Strategy, October 29, 2020, https://media.defense.gov/2020/Oct/29/2002525927/-1/-1/0/ELECT ROMAGNET IC_SPECT RUM_SUPERIORIT Y_ST RAT EGY.PDF. 135 P.L. 116-283 §152 T ransfer of Responsibilities and Functions Relating to Electromagnetic Spectrum Operations. 136 Recon Analytics, LLC, “How America’s 4G Leadership Propelled the U.S. Economy,” April 16, 2018, https://api.ctia.org/wp-content/uploads/2018/04/Recon-Analytics_How-Americas-4G-Leadership-Propelled-US-Economy_2018.pdf. 137 Federal Communications Commission, “Auction 107 - 3.7 GHz,” press release, January 15, 2021, Congressional Research Service 27 Overview of Department of Defense Use of the Electromagnetic Spectrum
Federal agencies hold various segments of spectrum that commercial entities may be able to use Federal agencies hold various segments of spectrum that commercial entities may be able to use
for wireless services. Since DOD is the largest holder of federal frequencies, policies to for wireless services. Since DOD is the largest holder of federal frequencies, policies to ~~reallocate~~real ocate
spectrum for commercial use often affect DOD. As Congress considers policies to spectrum for commercial use often affect DOD. As Congress considers policies to ~~allocate~~al ocate
additional spectrum for commercial use, it may consider increasing demands for spectrum, the additional spectrum for commercial use, it may consider increasing demands for spectrum, the
impact on DOD systems and uses, unintended frequency interference, the interagency process for impact on DOD systems and uses, unintended frequency interference, the interagency process for
~~allocating~~ al ocating spectrum, and DOD’s ability to anticipate future spectrum needs. spectrum, and DOD’s ability to anticipate future spectrum needs.
Increasing Demand for Spectrum
As more people are using more data on more devices and as new technologies emerge (5G), As more people are using more data on more devices and as new technologies emerge (5G),
demand for mobile data (e.g., video) is increasing. Cisco, the U.S.-based network equipment demand for mobile data (e.g., video) is increasing. Cisco, the U.S.-based network equipment
maker, reported that in 2018, “global mobile data traffic amounted to 19.01 exabytes per maker, reported that in 2018, “global mobile data traffic amounted to 19.01 exabytes per
month;month;~~126~~138 by 2022, mobile data traffic is expected to reach 77.5 exabytes per month by 2022, mobile data traffic is expected to reach 77.5 exabytes per month
worldwide,”worldwide,”~~127~~139 which which ~~will~~ wil increase demand for additional spectrum. increase demand for additional spectrum.
To accommodate new technologies, more users, and more data-intensive applications (e.g., video To accommodate new technologies, more users, and more data-intensive applications (e.g., video
streaming, gaming), global telecommunications providers and equipment makers around the ~~streaming, gaming), global telecommunications providers and equipment makers around the~~

~~1/0/ELECTROMAGNETIC_SPECTRUM_SUPERIORITY_STRATEGY.PDF.~~
~~123 P.L. 116-283 §152 Transfer of Responsibilities and Functions Relating to Electromagnetic Spectrum Operations.~~
~~124 Recon Analytics, LLC, “How America’s 4G Leadership Propelled the U.S. Economy,” April 16, 2018,~~
~~https://api.ctia.org/wp-content/uploads/2018/04/Recon-Analytics_How-Americas-4G-Leadership-Propelled-US-~~
~~Economy_2018.pdf.~~
~~125 Federal Communications Commission, “Auction 107 - 3.7 GHz,” press release, January 15, 2021,~~
~~https://auctiondata.fcc.gov/public/projects/auction107.~~
~~126 An average person uses about 2-3 gigabytes per month. Collectively in 2018, consumers used about 19 billion~~
~~gigabytes per month. In 2022, consumers are expected to use 77.5 billion gigabytes per month.~~
~~127 https://www.statista.com/statistics/271405/global-mobile-data-traffic-forecast/~~
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~~Overview of Department of Defense Use of the Electromagnetic Spectrum~~

world developed 5G wireless networks and technologies. 5G technologies promise increased world developed 5G wireless networks and technologies. 5G technologies promise increased
speeds, improved connectivity, and reduced latency (i.e., lag time when sending commands from speeds, improved connectivity, and reduced latency (i.e., lag time when sending commands from
your device). However, for 5G, providers need large swathes of spectrum (100 MHz blocks) in your device). However, for 5G, providers need large swathes of spectrum (100 MHz blocks) in
the low-band (below 1 GHz), mid-band (1-6 GHz), and high-band (above 6 GHz) radio spectrum. the low-band (below 1 GHz), mid-band (1-6 GHz), and high-band (above 6 GHz) radio spectrum.
Providers expect that the 5G solution—additional spectrum and new 5G technologies—Providers expect that the 5G solution—additional spectrum and new 5G technologies—~~will~~ wil help help
to meet increasing demands for mobile data, support advanced 5G services to businesses, and to meet increasing demands for mobile data, support advanced 5G services to businesses, and
yield new 5G applications, including new military applications.yield new 5G applications, including new military applications.~~128~~
140 However, the spectrum is already crowded with users, including federal agency users. DOD is However, the spectrum is already crowded with users, including federal agency users. DOD is
~~allocated~~al ocated about 40% of about 40% of ~~federally~~federal y-assigned spectrum,-assigned spectrum,~~129~~141 including significant frequency bands in including significant frequency bands in
the 1-6GHz range—prime spectrum for mobile telecommunication technologies. Some the 1-6GHz range—prime spectrum for mobile telecommunication technologies. Some
stakeholders and policymakers have stakeholders and policymakers have ~~called~~cal ed for the for the ~~reallocation~~real ocation of federal agency spectrum for of federal agency spectrum for
commercial use, or incentives for some federal agencies to relinquish or share spectrum for 5G commercial use, or incentives for some federal agencies to relinquish or share spectrum for 5G
use.use.~~130~~142 DOD asserts that its spectrum supports military operations, and the research and DOD asserts that its spectrum supports military operations, and the research and
development of advanced technologies, thus should remain with DOD. development of advanced technologies, thus should remain with DOD.
Starting in 1993, the Omnibus Budget Reconciliation Act (OBRA), Starting in 1993, the Omnibus Budget Reconciliation Act (OBRA),~~131~~143 required the Secretary of required the Secretary of
Commerce to identify at least 200 MHz of spectrum used by the federal government for Commerce to identify at least 200 MHz of spectrum used by the federal government for
~~reallocation~~real ocation to new spectrum-based technologies (i.e., commercial use). Year after year, the U.S. to new spectrum-based technologies (i.e., commercial use). Year after year, the U.S.
government has continued to government has continued to ~~reallocate~~real ocate spectrum from federal to commercial wireless use. In its spectrum from federal to commercial wireless use. In its
first Annual Report on the Status of Spectrum Repurposing (2019), NTIA notes, “[t]o date, most first Annual Report on the Status of Spectrum Repurposing (2019), NTIA notes, “[t]o date, most
repurposing activities and the statutory mandates for repurposing focus on accommodating non-repurposing activities and the statutory mandates for repurposing focus on accommodating non-
federal uses and have not directed the repurposing of spectrum to new federal uses; they also federal uses and have not directed the repurposing of spectrum to new federal uses; they also
https://auctiondata.fcc.gov/public/projects/auction107. 138 An average person uses about 2-3 gigabytes per month. Collectively in 2018, consumers used about 19 billion gigabytes per month. In 2022, consumers are expected to use 77.5 billion gigabytes per month. 139 https://www.statista.com/statistics/271405/global-mobile-data-traffic-forecast/ 140 CRS In Focus IF11251, National Security Implications of Fifth Generation (5G) Mobile Technologies, by John R. Hoehn and Kelley M. Sayler. 141 U.S. Government Accountability Office, NT IA Planning and Processes Need Strengthening to Promote the Efficient Use of Spectrum by Federal Agencies, GAO-11-352, April 2011, p. 21, https://www.gao.gov/assets/320/318264.pdf. 142 https://www.politico.com/news/agenda/2020/02/22/pentagon-airwaves-midband-106240. 143 P.L. 103-66. Congressional Research Service 28 Overview of Department of Defense Use of the Electromagnetic Spectrum prioritize exclusive non-federal use over sharing.”144~~prioritize exclusive non-federal use over sharing.”132~~ Congress may require the Congress may require the ~~reallocation~~real ocation of of
specific spectrum bands, specific spectrum bands, ~~call~~ cal for the identification of certain amounts of spectrum (e.g., 255 MHz for the identification of certain amounts of spectrum (e.g., 255 MHz
below 6 GHz), or below 6 GHz), or ~~call~~ cal for testing and studies to identify appropriate spectrum for commercial for testing and studies to identify appropriate spectrum for commercial
use.use.~~133~~145 Since DOD holds about 40% of the Since DOD holds about 40% of the ~~federally~~federal y-held spectrum,-held spectrum,~~134~~146 it can be affected by these it can be affected by these
policies.policies.~~135~~147
Congress has tried to assess and address the impact of federal spectrum policies on agencies. For Congress has tried to assess and address the impact of federal spectrum policies on agencies. For
example, in 2004 Congress established a program to help cover the costs that federal agencies example, in 2004 Congress established a program to help cover the costs that federal agencies
incur when spectrum is incur when spectrum is ~~reallocated~~real ocated. Congress enacted the Commercial Spectrum Enhancement . Congress enacted the Commercial Spectrum Enhancement
Act (CSEA),Act (CSEA),~~136~~148 which created the Spectrum Relocation Fund (SRF). The SRF used revenues from which created the Spectrum Relocation Fund (SRF). The SRF used revenues from
spectrum auctions to provide funding to defray the costs of relocating federal users to new bands. spectrum auctions to provide funding to defray the costs of relocating federal users to new bands.
However, as wireless technology use increased, and demand for mobile data continued to rise, the However, as wireless technology use increased, and demand for mobile data continued to rise, the
U.S. government continued to examine and U.S. government continued to examine and ~~reallocate~~real ocate spectrum to meet emerging demands. Some have argued that a piecemeal approach to spectrum planning is ineffective.149 They say it does not provide companies or affected federal agencies with enough time or information to plan future investments. Advocates assert that a long-term spectrum plan or pipeline wil al ow ~~spectrum to meet emerging demands. Some~~

~~128 CRS In Focus IF11251, National Security Implications of Fifth Generation (5G) Mobile Technologies, by John R.~~
~~Hoehn and Kelley M. Sayler.~~
~~129 U.S. Government Accountability Office, NTIA Planning and Processes Need Strengthening to Promote the Efficient~~
~~Use of Spectrum by Federal Agencies, GAO-11-352, April 2011, p. 21, https://www.gao.gov/assets/320/318264.pdf.~~
~~130 https://www.politico.com/news/agenda/2020/02/22/pentagon-airwaves-midband-106240.~~
~~131 P.L. 103-66.~~
~~132 Ibid.~~
~~133 U.S. Department of Commerce, Annual Report on the Status of Spectrum Repurposing, August 2019,~~
~~https://www.ntia.doc.gov/files/ntia/publications/spectrum_repurposing_report_august_2019.pdf.~~
134 U.S. Government Accountability Office, NTIA Planning and Processes Need Strengthening to Promote the Efficient
Use of Spectrum by Federal Agencies, GAO-11-352, April 2011, p. 21, https://www.gao.gov/assets/320/318264.pdf.
~~135 George Leopold, “DOD returns fire on spectrum relocation,” EE|Times, August 30, 2001, https://www.eetimes.com/~~
~~dod-returns-fire-on-spectrum-relocation/#.~~
~~136 Title II of P.L. 108-494.~~
~~Congressional Research Service~~

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~~link to page 38~~ ~~Overview of Department of Defense Use of the Electromagnetic Spectrum~~

~~have argued that a piecemeal approach to spectrum planning is ineffective.137 They say it does not~~
~~provide companies or affected federal agencies with enough time or information to plan future~~
~~investments. Advocates assert that a long-term spectrum plan or pipeline will allow~~ industry to industry to
plan future investments and agencies to plan future improvements, reduce the time it takes to plan future investments and agencies to plan future improvements, reduce the time it takes to
bring spectrum to market, and perhaps assist in resolving ongoing spectrum disputes.bring spectrum to market, and perhaps assist in resolving ongoing spectrum disputes.~~138~~150 In 2018, In 2018,
two spectrum planning initiatives were launched. two spectrum planning initiatives were launched.
The FCC developed the 5G FAST Plan, which identified spectrum for 5G use, and streamlined The FCC developed the 5G FAST Plan, which identified spectrum for 5G use, and streamlined
regulations to speed 5G deployment.regulations to speed 5G deployment.~~139~~151 This plan provides insight into FCC actions (e.g., future This plan provides insight into FCC actions (e.g., future
~~reallocations~~real ocations, auctions); however, the GAO found that the plan was not developed with outside , auctions); however, the GAO found that the plan was not developed with outside
entities, including the NTIA or other relevant stakeholders, including carriers.entities, including the NTIA or other relevant stakeholders, including carriers.~~140~~152 In 2018, the In 2018, the
President directed the NTIA to develop a National Spectrum Strategy to set forth a “balanced, President directed the NTIA to develop a National Spectrum Strategy to set forth a “balanced,
forward-looking, flexible, and sustainable approach to spectrum management.”forward-looking, flexible, and sustainable approach to spectrum management.”~~141~~153 Federal agencies were directed to review current frequency assignments and spectrum usage to identify 144 Ibid. 145 U.S. Department of Commerce, Annual Report on the Status of Spectrum Repurposing, August 2019, https://www.ntia.doc.gov/files/ntia/publications/spectrum_repurposing_report_august_2019.pdf. 146 U.S. Government Accountability Office, NTIA Planning and Processes Need Strengthening to Promote the Efficient Use of Spectrum by Federal Agencies, GAO-11-352, April 2011, p. 21, https://www.gao.gov/assets/320/318264.pdf. 147 George Leopold, “ DOD returns fire on spectrum relocation,” EE|Times, August 30, 2001, https://www.eetimes.com/dod-returns-fire-on-spectrum-relocation/#. 148 T itle II of P.L. 108-494. 149 U.S. House of Representatives, Committee on Energy and Commerce, Subcommittee on Communications and T echnology, hearings, “ Our Wireless Future: Building A Comprehensive Approach to Spectrum Policy ,” 116th Cong., 1st sess., July ~~Federal~~
~~agencies were directed to review current frequency assignments and spectrum usage to identify~~
~~spectrum that could be reallocated or shared with commercial uses. NTIA held a Spectrum Policy~~
~~Symposium in August 2019 to seek public comment on the plan. DOD speakers noted that, with~~
~~new technologies and cooperation with commercial users, DOD is exploring opportunities to~~
~~share spectrum.142 NTIA has reported that the National Spectrum Strategy is under development.~~
~~Congress may be interested in encouraging coordination between the agencies to balance the~~
~~needs of commercial 5G providers and users and the mission critical needs of DOD. On the one~~
~~hand, reallocating spectrum from DOD may help to speed deployment of 5G networks, spur the~~
~~development of 5G use cases, and strengthen the U.S. position in the global 5G market. On the~~
~~other hand, DOD provides critical national defense functions; taking spectrum from DOD could~~
~~affect military operations and result in the permanent loss of spectrum for DOD uses, including~~
~~critical defense operations and future capabilities.~~
~~Unintended Commercial Frequency Interference143~~
~~As new users, technologies, and services are introduced to the spectrum, the potential for~~
~~interference may increase.144 Interference occurs when unwanted radio frequency signals disrupt~~

~~137 U.S. House of Representatives, Committee on Energy and Commerce, Subcommittee on Communications and~~
~~Technology, hearings, “Our Wireless Future: Building A Comprehensive Approach to Spectrum Policy,” 116th Cong.,~~
~~1st sess., July~~ 16, 2019, https://energycommerce.house.gov/committee-activity/hearings/hearing-on-our-wireless-future-16, 2019, https://energycommerce.house.gov/committee-activity/hearings/hearing-on-our-wireless-future-
building-a-comprehensive-approach-to. See testimony of Derek Khlopin, Senior Policy Advisor, building-a-comprehensive-approach-to. See testimony of Derek Khlopin, Senior Policy Advisor, ~~NTIA~~NT IA, at , at
https://energycommerce.house.gov/sites/democrats.energycommerce.house.gov/files/documents/https://energycommerce.house.gov/sites/democrats.energycommerce.house.gov/files/documents/
~~1_Testimony_Khlopin~~1_T estimony_Khlopin.pdf. See also testimony of Scott Bergmann Senior Vice.pdf. See also testimony of Scott Bergmann Senior Vice President, Regulatory Affairs President, Regulatory Affairs ~~CTIA~~CT IA, at , at
https://energycommerce.house.gov/sites/democrats.energycommerce.house.gov/files/documents/https://energycommerce.house.gov/sites/democrats.energycommerce.house.gov/files/documents/
~~2_Testimony_Bergmann.pdf.~~
~~138~~ ~~White~~ 2_T estimony_Bergmann.pdf. 150 White House 5G Summit (recorded event), September 28, 2018, https://www.youtube.com/watch?v= (recorded event), September 28, 2018, https://www.youtube.com/watch?v=~~lBbY8fvTidU.~~
~~139 FCC, “5G FAST~~ lBbY8fvT idU. 151 FCC, “5G FAST Plan,” https://www.fcc.gov/5G. Plan,” https://www.fcc.gov/5G.
~~140~~152 U.S. U.S. Government Accountability Office, Government Accountability Office, 5G Deployment: FCC Needs Comprehensive Strategic Planning to Guide
its Efforts,, GAO-20-468, June 2020, pp. 12-13, https://www.gao.gov/assets/710/707530.pdf. GAO-20-468, June 2020, pp. 12-13, https://www.gao.gov/assets/710/707530.pdf.
~~141~~153 White House, Office of the Press Secretary, “Presidential Memorandum on Developing a Sustainable White House, Office of the Press Secretary, “Presidential Memorandum on Developing a Sustainable Spectrum Spectrum
Strategy for America’s Future,” presidential memorandum, October 25, 2018, https://www.whitehouse.gov/Strategy for America’s Future,” presidential memorandum, October 25, 2018, https://www.whitehouse.gov/
presidential-actions/presidential-memorandum-developing-sustainable-spectrum-strategy-americas-future/. presidential-actions/presidential-memorandum-developing-sustainable-spectrum-strategy-americas-future/.
~~142 NTIA, NTIA Spectrum Policy Symposium Transcript, September 10, 2019, p. 12, https://www.ntia.doc.gov/files/~~
~~ntia/publications/09.10.19_npc_ntia_spectrum_policy_symposium.pdf.~~
~~143 Fore a detailed discussion of potential 5G interference with the Global Positioning System, see the Appendix.~~
~~144 Commerce Spectrum Management Advisory Committee (CSMAC), Interference and Dynamic Spectrum Access,~~
~~Interim Report, May 19, 2010, p. 13, https://www.ntia.doc.gov/files/ntia/meetings/csmac_may19_idsa_final.pdf.~~
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~~Overview of Department of Defense Use of the Electromagnetic Spectrum~~

Congressional Research Service 29 link to page 39 Overview of Department of Defense Use of the Electromagnetic Spectrum spectrum that could be real ocated or shared with commercial uses. NTIA held a Spectrum Policy Symposium in August 2019 to seek public comment on the plan. DOD speakers noted that, with new technologies and cooperation with commercial users, DOD is exploring opportunities to share spectrum.154 NTIA has reported that the National Spectrum Strategy is under development. Congress may be interested in encouraging coordination between the agencies to balance the needs of commercial 5G providers and users and the mission critical needs of DOD. On the one hand, real ocating spectrum from DOD may help to speed deployment of 5G networks, spur the development of 5G use cases, and strengthen the U.S. position in the global 5G market. On the other hand, DOD provides critical national defense functions; taking spectrum from DOD could affect military operations and result in the permanent loss of spectrum for DOD uses, including critical defense operations and future capabilities. Unintended Commercial Frequency Interference155 As new users, technologies, and services are introduced to the spectrum, the potential for interference may increase.156 Interference occurs when unwanted radio frequency signals disrupt the transmission of information in systems operating in the same band or in nearby bands. the transmission of information in systems operating in the same band or in nearby bands.
Interference is a persistent issue in spectrum management, and introducing new technologies, new Interference is a persistent issue in spectrum management, and introducing new technologies, new
users, and broadening spectrum access (e.g., through spectrum sharing or users, and broadening spectrum access (e.g., through spectrum sharing or ~~allowing~~al owing flexible use of flexible use of
spectrum) may increase the potential for harmful interference.spectrum) may increase the potential for harmful interference.~~145~~157
As the U.S. government seeks to use spectrum more flexible to support new uses, or more As the U.S. government seeks to use spectrum more flexible to support new uses, or more
cooperatively, through a shared approach, interference claims are likely to increase. For DOD, cooperatively, through a shared approach, interference claims are likely to increase. For DOD,
Congress has enacted legislation to protect DOD systems from interference. For example, Congress has enacted legislation to protect DOD systems from interference. For example,
pursuant to 10 U.S.C. §2281, Congress had authorized DOD to object “to any restriction on the pursuant to 10 U.S.C. §2281, Congress had authorized DOD to object “to any restriction on the
GPS System proposed by the head of a department or agency of the United States outside DOD GPS System proposed by the head of a department or agency of the United States outside DOD
that would adversely affect the military that would adversely affect the military potential of GPS” [emphasis added]. of GPS” [emphasis added]. ~~Additionally~~Additional y, in , in
Section 1698 of the National Defense Authorization Act for Fiscal Year 2017 (P.L. 114-328)—Section 1698 of the National Defense Authorization Act for Fiscal Year 2017 (P.L. 114-328)—
codified at Section 343 of the Communications Act—prohibits the FCC from approving codified at Section 343 of the Communications Act—prohibits the FCC from approving
commercial terrestrial operations in the bands proposed by Ligado “until 90 days after the commercial terrestrial operations in the bands proposed by Ligado “until 90 days after the
Commission resolves concerns of widespread harmful interference by such operations to covered Commission resolves concerns of widespread harmful interference by such operations to covered
GPS devices.”GPS devices.”~~146~~158 While DOD did express its concerns to the FCC on the Ligado project, the FCC While DOD did express its concerns to the FCC on the Ligado project, the FCC
asserted that the conditions it placed on Ligado (e.g., reducing power levels, creating a guard asserted that the conditions it placed on Ligado (e.g., reducing power levels, creating a guard
band, reporting base station locations) would mitigate interference concerns. band, reporting base station locations) would mitigate interference concerns.
A recent dispute with Ligado Networks, LLC has highlighted key interference issues. On April A recent dispute with Ligado Networks, LLC has highlighted key interference issues. On April
20, 2020, the FCC unanimously approved an application by Ligado Networks LLC (Ligado) to 20, 2020, the FCC unanimously approved an application by Ligado Networks LLC (Ligado) to
“deploy a low-power [9.8 decibel watts (dBW)] terrestrial nationwide network in the 1526-1536 “deploy a low-power [9.8 decibel watts (dBW)] terrestrial nationwide network in the 1526-1536
~~MHz, 1627.5-1637.5 MHz, and 1646.5-1656.5 MHz bands [of the electromagnetic spectrum]147~~
~~that will primarily support Internet of Things (IoT) services.”148~~
~~These frequency bands are traditionally used for satellite communications and position,~~
~~navigation, and timing services, such as GPS.149 DOD opposed this decision—along with the~~
~~Department of Homeland Security, Department of Transportation (DOT), Department of the~~
~~Interior, Department of Justice, the Federal Aviation Administration (FAA), and others.150 That~~
~~opposition was related to concerns that Ligado’s proposed terrestrial network could interfere with~~
~~signals from satellites to terrestrial GPS receivers and enabled devices.151 Despite federal agency~~

~~145~~ 154 NT IA, NTIA Spectrum Policy Symposium Transcript, September 10, 2019, p. 12, https://www.ntia.doc.gov/files/ntia/publications/09.10.19_npc_ntia_spectrum_policy_symposium.pdf. 155 Fore a detailed discussion of potential 5G interference with the Global Positioning System, see the Appendix. 156 Commerce Spectrum Management Advisory Committee (CSMAC), Interference and Dynamic Spectrum Access, Interim Report, May 19, 2010, p. 13, https://www.ntia.doc.gov/files/ntia/meetings/csmac_may19_idsa_final.pdf. 157 John Pahl, “Market Mechanisms for Spectrum Management: Spectrum Liberalisation and Interference John Pahl, “Market Mechanisms for Spectrum Management: Spectrum Liberalisation and Interference
Management,” Background Paper submitted to Management,” Background Paper submitted to ~~ITU~~IT U Workshop, “Shaping Workshop, “Shaping ~~Tomorrow~~T omorrow’s Network” Program, September ’s Network” Program, September
2006, https://www.scribd.com/document/60765650/Spectrum-Liberalisation-and-Interference-Management. 2006, https://www.scribd.com/document/60765650/Spectrum-Liberalisation-and-Interference-Management.
~~146 This~~158 T his provision is related to an earlier proposal from Ligado submitted to the FCC, which provision is related to an earlier proposal from Ligado submitted to the FCC, which federal agencies, including federal agencies, including
DOD, opposed. Details on the proposal, the federal agency opposition, and congressional intent is available inDOD, opposed. Details on the proposal, the federal agency opposition, and congressional intent is available in S.Rept. 116-236, pp. 75, 275. Congressional Research Service 30 Overview of Department of Defense Use of the Electromagnetic Spectrum MHz, 1627.5-1637.5 MHz, and 1646.5-1656.5 MHz bands [of the electromagnetic spectrum]159 that wil primarily support Internet of Things (IoT) services.”160 These frequency bands are traditional y used for satel ite communications and position, navigation, and timing services, such as GPS.161 DOD opposed this decision—along with the Department of Homeland Security, Department of Transportation (DOT), Department of the Interior, Department of Justice, the Federal Aviation Administration (FAA), and others.162 That opposition was related to concerns that Ligado’s proposed terrestrial network could interfere with signals from satel ites to terrestrial GPS receivers and enabled devices.163 Despite federal agency~~S.Rept.~~
~~116-236, pp. 75, 275.~~
~~147 CRS In Focus IF11155, Defense Primer: Military Use of the Electromagnetic Spectrum, by John R. Hoehn.~~
~~148 The FCC authorized Ligado to operate an Internet of Things network in the referenced frequency bands with~~
~~conditions. Federal Communications Communication Order 20-48, at https://docs.fcc.gov/public/attachments/FCC-20-~~
~~48A1.pdf.~~
~~149 Testimony of Michael Griffin, Undersecretary of Defense for Research and Engineering, Dana Deasy, DOD Chief~~
~~Information Officer, Gen John Raymond, Chief of Space Operations, and Thad Allen, Chairman of Space-Based~~
~~Precision Navigation and Timing National Advisory Board, before the U.S. Congress, Senate Armed Services~~
~~Committee, Department of Defense Spectrum Policy and the Impact of the Federal Communications Commission, 116th~~
~~Cong., 2nd sess., May 6, 2020.~~
~~150 Letter from Douglas Kinkoph, Associate Administrator Performing the Delegated Duties of the Assistant Secretary~~
~~of Communications and Information, to Hon Ajit Pai, Chairman of the Federal Communications Commission, April 10,~~
~~2020, at https://www.ntia.doc.gov/files/ntia/publications/~~
~~ntia_letter_to_fcc_chairman_re_ligado_applications_4.10.20.pdf.~~
~~151 CRS In Focus IF11558, Spectrum Interference Issues: Ligado, the L-Band, and GPS, by Jill C. Gallagher, Alyssa K.~~
~~King, and Clare Y. Cho.~~
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29

~~Overview of Department of Defense Use of the Electromagnetic Spectrum~~

opposition, the FCC unanimously approved the project, with the conditions (e.g., reducing power, opposition, the FCC unanimously approved the project, with the conditions (e.g., reducing power,
creating a guard band, reporting base station locations) that, the FCC commissioners assert, creating a guard band, reporting base station locations) that, the FCC commissioners assert,
would avoid interference between the two systems. would avoid interference between the two systems.
An issue of consideration for Congress may be in setting acceptable interference thresholds, An issue of consideration for Congress may be in setting acceptable interference thresholds,
levels of acceptable risks that are consistent with international interference standards that levels of acceptable risks that are consistent with international interference standards that ~~will~~
wil enable new technologies and protect DOD critical operations. Another area for Congress may be enable new technologies and protect DOD critical operations. Another area for Congress may be
in the resolution process, how and when federal agency concerns about interference are heard, in the resolution process, how and when federal agency concerns about interference are heard,
and how decisions may affect federal systems and operations. Congress may also consider and how decisions may affect federal systems and operations. Congress may also consider
broader issues related to wireless technologies (e.g., 5G, 6G), such as the broader issues related to wireless technologies (e.g., 5G, 6G), such as the ~~allocation~~al ocation of spectrum of spectrum
among competing users and the impact of spectrum decisions on national security. among competing users and the impact of spectrum decisions on national security.
Interagency Disputes
Congress may review the process by which the FCC and the NTIA, or other federal agencies, Congress may review the process by which the FCC and the NTIA, or other federal agencies,
resolve spectrum disputes. As noted, the FCC and NTIA operate under an MOU that requires resolve spectrum disputes. As noted, the FCC and NTIA operate under an MOU that requires
spectrum planning and coordination. The NTIA represents federal agency concerns in meetings spectrum planning and coordination. The NTIA represents federal agency concerns in meetings
with the FCC. Some observers have questioned NTIA’s ability to represent federal agency with the FCC. Some observers have questioned NTIA’s ability to represent federal agency
interests,interests,~~152~~164 while others have questioned whether federal agencies should have to work through while others have questioned whether federal agencies should have to work through
NTIA to express its concerns on FCC decisions.165 159 CRS In Focus IF11155, Defense Primer: Military Use of the Electromagnetic Spectrum , by John R. Hoehn. 160 T he FCC authorized Ligado to operate an Internet of T hings network in the referenced frequency bands with conditions. Federal Communications Communication Order 20 -48, at https://docs.fcc.gov/public/attachments/FCC-20-48A1.pdf. 161 T estimony of Michael Griffin, Undersecretary of Defense for Research and Engineering, Dana Deasy, DOD Chief Information Officer, Gen John Raymond, Chief of Space Operations, and T had Allen, Chairman o f Space-Based Precision Navigation and T iming National Advisory Board, before the U.S. Congress, Senate Armed Services Committee, Departm ent of Defense Spectrum Policy and the Im pact of the Federal Com m unications Com m ission, 116th Cong., 2nd sess., May 6, 2020. 162 Letter from Douglas Kinkoph, Associate Administrator Performing the Delegated Duties of the Assistant Secretary of Communications and Information, to Hon Ajit Pai, Chairman of the Federal Communications Commission, April 10, 2020, at https://www.ntia.doc.gov/files/ntia/publications/ntia_letter_to_fcc_chairman_re_ligado_applications_4.10.20.pdf . 163 CRS In Focus IF11558, Spectrum Interference Issues: Ligado, the L-Band, and GPS, by Jill C. Gallagher, Alyssa K. King, and Clare Y. Cho. 164 U.S. ~~NTIA to express its concerns on FCC decisions.153~~
~~As the federal government strives to make spectrum available for 5G services, several spectrum~~
~~bands used for federal agency missions (DOD and other agencies) have been targeted for~~
~~reallocation or repurposing, affecting federal agency investments and missions. This includes~~
~~DOD concerns over the L-Band, DOT concerns over the reconfiguring of the 5.9 GHz band set~~
~~aside for auto safety technologies, Department of Education concerns regarding the reallocation~~
~~of the 2.5 GHz band from educational users, and the National Oceanic and Atmospheric~~
~~Administration and the 24 GHz band used for weather forecasting.~~
~~Congress has proposed initiatives to improve spectrum management and reduce spectrum~~
~~disputes. For example, the Senate-passed version of the FY2021 NDAA (S. 4049, enrolled,~~
~~Section 1084) (c)), would direct the NTIA to evaluate a range of information technology (IT)~~
~~modernization initiatives that would improve analysis of federal government spectrum use and~~
~~management. Some in Congress have proposed updates to the MOU between the FCC and NTIA~~
~~to clarify the government’s spectrum management and reallocation process.154 Others have~~
~~suggested to Congress that a third-party, such as the White House Office of Science and~~
~~Technology Policy (OSTP) or the National Academies of Science and Engineering, serve as a~~
~~technical reviewer or as an arbiter of conflicting technical reports and interference disputes.155~~

~~152 U.S.~~ Government Accountability Office, Interdepartment Radio Advisory Committee: IRAC Representatives Government Accountability Office, Interdepartment Radio Advisory Committee: IRAC Representatives
Effectively Coordinate Federal Spectrum but Lack Seniority to Advise on Contentious Policy Issues, GAO-04-1028, Effectively Coordinate Federal Spectrum but Lack Seniority to Advise on Contentious Policy Issues, GAO-04-1028,
September 2004, pp. 3-4, https://www.gao.gov/new.items/d041028.pdf. September 2004, pp. 3-4, https://www.gao.gov/new.items/d041028.pdf.
~~153 Testimony of Thad~~165 T estimony of T had Allen, Chairman of Space-Based Allen, Chairman of Space-Based Precision Navigation and Precision Navigation and ~~Timing~~T iming National Advisory Board, National Advisory Board,
before the U.S. Congress, Senate Armed Servicesbefore the U.S. Congress, Senate Armed Services Committee, Committee, ~~Department~~Departm ent of Defense Spectrum Policy and the ~~Impact~~Im pact
of the Federal ~~Communications Commission~~Com m unications Com m ission,, 116th Cong., 2nd sess., May 6, 2020, p. 42, https://www.armed-116th Cong., 2nd sess., May 6, 2020, p. 42, https://www.armed-
services.senate.gov/imo/media/doc/20-21_05-06-2020.pdf. services.senate.gov/imo/media/doc/20-21_05-06-2020.pdf.
~~154 See discussion on MOU and arbiter for spectrum disputes during Senate hearing (video): U.S. Congress, Senate~~
~~Committee on Commerce, Science, and Transportation, The State of U.S. Spectrum Policy, 116th Cong., 2nd sess., July~~
~~23, 2020.~~
~~155 Ibid.~~
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~~Overview of Department of Defense Use of the Electromagnetic Spectrum~~

~~As spectrum is reallocated or reconfigured, some federal agencies are protesting.156~~Congressional Research Service 31 Overview of Department of Defense Use of the Electromagnetic Spectrum As the federal government strives to make spectrum available for 5G services, several spectrum bands used for federal agency missions (DOD and other agencies) have been targeted for real ocation or repurposing, affecting federal agency investments and missions. This includes DOD concerns over the L-Band, DOT concerns over the reconfiguring of the 5.9 GHz band set aside for auto safety technologies, Department of Education concerns regarding the real ocation of the 2.5 GHz band from educational users, and the National Oceanic and Atmospheric Administration and the 24 GHz band used for weather forecasting. Congress has proposed initiatives to improve spectrum management and reduce spectrum disputes. For example, the Senate-passed version of the FY2021 NDAA (S. 4049, enrolled, Section 1084) (c)), would direct the NTIA to evaluate a range of information technology (IT) modernization initiatives that would improve analysis of federal government spectrum use and management. Some in Congress have proposed updates to the MOU between the FCC and NTIA to clarify the government’s spectrum management and real ocation process.166 Others have suggested to Congress that a third-party, such as the White House Office of Science and Technology Policy (OSTP) or the National Academies of Science and Engineering, serve as a technical reviewer or as an arbiter of conflicting technical reports and interference disputes.167 As spectrum is real ocated or reconfigured, some federal agencies are protesting.168 FCC has FCC has
acknowledged that as demand for spectrum increases, and more users gain access to the spectrum, acknowledged that as demand for spectrum increases, and more users gain access to the spectrum,
disputes are likely to increase as disputes are likely to increase as ~~well~~wel . Congress may examine the interagency spectrum planning . Congress may examine the interagency spectrum planning
and dispute resolution processes to ensure that federal agency needs are heard, and that federal and dispute resolution processes to ensure that federal agency needs are heard, and that federal
agency investments are protected and that federal agency missions continue to be supported. agency investments are protected and that federal agency missions continue to be supported.
Anticipating Future Spectrum Needs
In a report to the President by the Director of the Office of Science and Technology Policy In a report to the President by the Director of the Office of Science and Technology Policy
(OSTP), the Director cites the primary use cases for 5G: (1) enhanced mobile broadband; (2) (OSTP), the Director cites the primary use cases for 5G: (1) enhanced mobile broadband; (2)
ultra-reliable and low latency communications; (3) massive machine type communications, also ultra-reliable and low latency communications; (3) massive machine type communications, also
known as massive Internet of Things (IoT); (4) fixed wireless technologies; and (5) enhanced known as massive Internet of Things (IoT); (4) fixed wireless technologies; and (5) enhanced
vehicle-to-everything (V2X). The Director notes that the identified use cases are driving research vehicle-to-everything (V2X). The Director notes that the identified use cases are driving research
and development (R&D) activities, as and development (R&D) activities, as ~~well~~ wel as the standardization activities taking place in the as the standardization activities taking place in the
international standards development groups such as the International Telecommunications Union international standards development groups such as the International Telecommunications Union
(ITU) and the Third Generation Partnership Project (3GPP). Some technology firms advocate for (ITU) and the Third Generation Partnership Project (3GPP). Some technology firms advocate for
increased investments in R&D to give the United States a competitive edge in the commercial 5G increased investments in R&D to give the United States a competitive edge in the commercial 5G
market. DOD is supporting this R&D through the development of new technologies, such as the market. DOD is supporting this R&D through the development of new technologies, such as the
dynamic spectrum sharing technologies to support the more efficient use of spectrum by 166 See discussion on MOU and arbiter for spectrum disputes during Senate hearing (video): U.S. Congress, Senate Committee on Commerce, Science, and T ransportation, The State of U.S. Spectrum Policy, 116th Cong., 2nd sess., July 23, 2020. 167 Ibid. 168 Letter from Elaine L. Chao, Secretary, U.S. Department of T ransportation~~dynamic spectrum sharing technologies to support the more efficient use of spectrum by~~
~~deploying 5G in selected bases to measure and monitor performance, and experiment with the~~
~~technologies.~~
~~The allocation of spectrum takes time, as does the buildout of a network that will operate in the~~
~~band. Often, by the time the spectrum is allocated and networks built, new technologies are~~
~~emerging. For example, future sixth generation (6G) communications technologies, along with~~
~~emerging military communications technologies. These technologies will most likely use the~~
~~spectrum differently than current systems; exactly how these systems will use the spectrum~~
~~remains unclear.157~~
~~Potential Questions for Congress158~~
~~As Congress considers its role in spectrum policy and how the DOD manages its use of the~~
~~spectrum, several potential issues and questions arise. Below are a few potential Congress may~~
~~seek additional information:~~
~~ What actions can Congress or DOD take to ensure that mission critical systems~~
~~that operate in various segments of the electromagnetic spectrum (both~~
~~domestically and abroad) are interoperable?~~

~~156 Letter from Elaine L. Chao, Secretary, U.S. Department of Transportation~~, to Federal Communications Chairman , to Federal Communications Chairman
Ajit Pai, November 20, 2019, https://www.highways.org/wp-content/uploads/2019/12/sec-chao-letter-5.9-11-20-19.pdf; Ajit Pai, November 20, 2019, https://www.highways.org/wp-content/uploads/2019/12/sec-chao-letter-5.9-11-20-19.pdf;
Letter from Jim Blew,Letter from Jim Blew, Assistant Secretary for Planning, U.S.Assistant Secretary for Planning, U.S. Department of Education, to FCC Chairman Ajit Pai, June Department of Education, to FCC Chairman Ajit Pai, June
7, 2019, https://ecfsapi.fcc.gov/file/10607076793462/190607-Education-EBSExParte.pdf; Letter from Douglas W. 7, 2019, https://ecfsapi.fcc.gov/file/10607076793462/190607-Education-EBSExParte.pdf; Letter from Douglas W.
Kinkoph, Associate Administrator, Kinkoph, Associate Administrator, ~~NTIA~~NT IA, to FCC Chairman Pai, April 10, 2020, https://www.ntia.doc.gov/files/ntia/, to FCC Chairman Pai, April 10, 2020, https://www.ntia.doc.gov/files/ntia/
publications/ntia_letter_to_fcc_chairman_re_ligado_applications_4.10.20.pdfpublications/ntia_letter_to_fcc_chairman_re_ligado_applications_4.10.20.pdf (this cover letter from (this cover letter from ~~NTIA~~NT IA was sent to was sent to
the FCC, andthe FCC, and ~~includes~~ includes letters from DOD to the Secretary of Commerce regardingletters from DOD to the Secretary of Commerce regarding concerns with recent spectrum concerns with recent spectrum
decisions, DODdecisions, DOD ~~to NTIA~~ to NT IA on spectrum concerns, and a Memorandum from the Air Force to on spectrum concerns, and a Memorandum from the Air Force to ~~NTIA~~NT IA on spectrum on spectrum
concerns, signedconcerns, signed by 12 members of this interagency spectrum working group). by 12 members of this interagency spectrum working group).
~~157 Some analysts have suggested that 6G, for instance might use spectrum in the 200-1000 GHz range, however there~~
~~are no official stands that have been identified. Future DOD use of~~Congressional Research Service 32 Overview of Department of Defense Use of the Electromagnetic Spectrum deploying 5G in selected bases to measure and monitor performance, and experiment with the technologies. The al ocation of spectrum takes time, as does the buildout of a network that wil operate in the band. Often, by the time the spectrum is al ocated and networks built, new technologies are emerging. For example, future sixth generation (6G) communications technologies, along with emerging military communications technologies. These technologies wil most likely use the spectrum differently than current systems; exactly how these systems wil use the spectrum ~~the spectrum remains unclear other than the~~
~~highlighted emerging technologies discussed earlier.~~
~~158 This section was written by John R. Hoehn, Jill C. Gallagher, and Kelley M. Sayler.~~
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~~Overview of Department of Defense Use of the Electromagnetic Spectrum~~

remains unclear.169 Potential Questions for Congress170 As Congress considers its role in spectrum policy and how the DOD manages its use of the spectrum, several potential issues and questions arise. Below are a few potential Congress may seek additional information:  What actions can Congress or DOD take to ensure that mission critical systems that operate in various segments of the electromagnetic spectrum (both domestical y and abroad) are interoperable?  What changes, if any, should the DOD make in programs or investments in order  What changes, if any, should the DOD make in programs or investments in order
to maintain a technological edge in the use of the electromagnetic spectrum over to maintain a technological edge in the use of the electromagnetic spectrum over
U.S. competitors? U.S. competitors?
 Does the U.S. government’s plan for spectrum  Does the U.S. government’s plan for spectrum ~~allocation~~al ocation sufficiently balance sufficiently balance
DOD requirements with the requirements of commercial applications? If so, DOD requirements with the requirements of commercial applications? If so,
how? how?
 What measures, if any, could accelerate spectrum repurposing, relocation, and/or  What measures, if any, could accelerate spectrum repurposing, relocation, and/or
sharing? sharing?
 Is DOD using the spectrum it has efficiently? How can DOD improve its  Is DOD using the spectrum it has efficiently? How can DOD improve its
spectrum efficiency? Is DOD adequately leveraging the spectrum to enable future spectrum efficiency? Is DOD adequately leveraging the spectrum to enable future
concepts like Multi-Domain Operations, Distributed Maritime Operations, and concepts like Multi-Domain Operations, Distributed Maritime Operations, and
JADC2? If so, how? JADC2? If so, how?
 As DOD relinquishes certain spectrum segments to commercial or shared use,  As DOD relinquishes certain spectrum segments to commercial or shared use,
how is it planning to ensure continued command and how is it planning to ensure continued command and ~~challenges~~chal enges in implementing 5G communications? 169 Some analysts have suggested that 6G, for instance might use spectrum in the 200 -1000 GHz range, however there are no official stands that have been identified. Future DOD use of the spectrum remains unclear other than the highlighted emerging technologies discussed earlier. 170 T his section was written by John R. Hoehn, Jill C. Gallagher, and Kelley M. Sayler. ~~in implementing~~
~~5G communications?~~

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Appendix. Ligado ~~Networks159~~Networks171
Concerns Regarding the FCC-Approved Ligado Network for
Mid-Band 5G Network
On AprilOn April 20, 2020, the Federal Communications Commission (FCC) unanimously approved an 20, 2020, the Federal Communications Commission (FCC) unanimously approved an
application by Ligado Networks LLC (Ligado) to “deploy a low-power [9.8 decibel watts (dBW)] application by Ligado Networks LLC (Ligado) to “deploy a low-power [9.8 decibel watts (dBW)]
terrestrial nationwide network in the 1526-1536 MHz, 1627.5-1637.5 MHz, and 1646.5-1656.5 terrestrial nationwide network in the 1526-1536 MHz, 1627.5-1637.5 MHz, and 1646.5-1656.5
MHz bands [of the electromagnetic spectrum]MHz bands [of the electromagnetic spectrum]~~160~~172 that that ~~will~~ wil primarily support Internet of Things primarily support Internet of Things
(IoT) services.”(IoT) services.”~~161~~173 These frequency bands are These frequency bands are ~~traditionally~~traditional y used for used for ~~satellite~~satel ite operations. operations.~~162~~174 The The
Department of Defense (DOD) opposed this decision, along with the Department of Homeland Department of Defense (DOD) opposed this decision, along with the Department of Homeland
Security, Department of Transportation (DOT), Department of the Interior, Department of Justice, Security, Department of Transportation (DOT), Department of the Interior, Department of Justice,
the Federal Aviation Administration (FAA), and others.the Federal Aviation Administration (FAA), and others.~~163~~175 That opposition related to concerns that That opposition related to concerns that
Ligado’s proposed network could interfere with signals from Ligado’s proposed network could interfere with signals from ~~satellites~~satel ites to Global Positioning to Global Positioning
System (GPS) receivers.System (GPS) receivers.~~164~~176 Congress may consider federal agency concerns, including DOD Congress may consider federal agency concerns, including DOD
concerns related to mission-critical systems and the FCC’s response, as it conducts oversight of concerns related to mission-critical systems and the FCC’s response, as it conducts oversight of
the FCC’s ruling. Congress may also consider broader issues related to fifth generation (5G) the FCC’s ruling. Congress may also consider broader issues related to fifth generation (5G)
mobile technologies, such as the mobile technologies, such as the ~~allocation~~al ocation of spectrum among competing users and the impact of of spectrum among competing users and the impact of
spectrum decisions on national security. spectrum decisions on national security.
DOD Concerns and Related Studies on GPS Interference
In both its formal response to the FCC’s ruling and in its May 6, 2020, testimony before the In both its formal response to the FCC’s ruling and in its May 6, 2020, testimony before the
Senate Armed Services Committee (SASC), DOD cited two primary studies that shaped its belief Senate Armed Services Committee (SASC), DOD cited two primary studies that shaped its belief
that the Ligado network “would cause unacceptable operational impacts and adversely affect the that the Ligado network “would cause unacceptable operational impacts and adversely affect the
military potential of GPS”: a 2018 DOT study and a 2016 classified study conducted by the U.S. military potential of GPS”: a 2018 DOT study and a 2016 classified study conducted by the U.S.
Air Force (USAF).Air Force (USAF).~~165~~177 The 2018 DOT study assessed the extent to which The 2018 DOT study assessed the extent to which ~~cellular~~cel ular base stations 171 T his section was written by John R. ~~base stations~~

~~159 This section was written by John R.~~ Hoehn and Kelley M. Sayler. For more information see, CRSHoehn and Kelley M. Sayler. For more information see, CRS Insight IN11400, Insight IN11400,
DOD Concerns About the FCC-Approved Ligado Network, by Kelley M. Sayler, by Kelley M. Sayler and John R. Hoehnand John R. Hoehn and CRSand CRS Insight Insight
IN11414, IN11414, The FCC-Approved Ligado Network and Potential Technical Issues for DOD Use of GPS , by John R. Hoehn, , by John R. Hoehn,
Stephen M. McCall, and Kelley M. Sayler. Stephen M. McCall, and Kelley M. Sayler.
~~160~~172 CRS CRS In FocusIn Focus IF11155, IF11155, Defense Primer: Military Use of the Electromagnetic Spectrum , by John R. Hoehn. , by John R. Hoehn.
~~161 The~~173 T he FCC authorized Ligado FCC authorized Ligado to operate an Internet of to operate an Internet of ~~Things~~T hings network in the referenced frequency bands network in the referenced frequency bands with with
conditions. Federal Communications Communication Order 20conditions. Federal Communications Communication Order 20 -48, at https://docs.fcc.gov/public/attachments/FCC-20--48, at https://docs.fcc.gov/public/attachments/FCC-20-
48A1.pdf. 48A1.pdf.
~~162 Testimony~~174 T estimony of Michael Griffin, Undersecretary of Defense for Research and Engineering, Dana Deasy, DOD Chief of Michael Griffin, Undersecretary of Defense for Research and Engineering, Dana Deasy, DOD Chief
Information Officer, Gen. John Raymond, Chief of SpaceInformation Officer, Gen. John Raymond, Chief of Space Operations, and Operations, and ~~Thad~~T had Allen, Chairman of Space-Based Allen, Chairman of Space-Based
Precision Navigation and Precision Navigation and ~~Timing~~T iming National Advisory Board, before the U.S. National Advisory Board, before the U.S. Congress, Senate Armed Services Congress, Senate Armed Services
Committee, Committee, ~~Department~~Departm ent of Defense Spectrum Policy and the ~~Impact~~Im pact of the Federal ~~Communications Commission~~Com m unications Com m ission,, 116th 116th
Cong., 2nd sess., May 6, 2020.Cong., 2nd sess., May 6, 2020.
~~163~~175 Letter from Douglas Kinkoph, Associate Administrator Performing the Delegated Duties of the Assistant Secretary Letter from Douglas Kinkoph, Associate Administrator Performing the Delegated Duties of the Assistant Secretary
of Communications and Information, to Hon. Ajit Pai, Chairman of the Federal Communications Commission, April of Communications and Information, to Hon. Ajit Pai, Chairman of the Federal Communications Commission, April
10, 2020, at https://www.ntia.doc.gov/files/ntia/publications/10, 2020, at https://www.ntia.doc.gov/files/ntia/publications/
ntia_letter_to_fcc_chairman_re_ligado_applications_4.10.20.pdf. ntia_letter_to_fcc_chairman_re_ligado_applications_4.10.20.pdf.
~~164~~176 CRS CRS In FocusIn Focus IF11558, IF11558, Spectrum Interference Issues: Ligado, the L-Band, and GPS, by Jill, by Jill C. Gallagher,C. Gallagher, Alyssa K. Alyssa K.
King, and Clare Y. Cho. King, and Clare Y. Cho.
~~165~~177 See See Department of Department of ~~Transportation~~T ransportation, , Global Positioning System (GPS) Adjacent Band Compatibility Assessment, ,
April 2018, https://www.transportation.gov/sites/dot.gov/files/docs/subdoc/186/dot-gps-adjacentApril 2018, https://www.transportation.gov/sites/dot.gov/files/docs/subdoc/186/dot-gps-adjacent -band-final--band-final-
reportapril2018.pdf, and written testimony of Dana Deasy, DOD Chief Information Officer, before the U.S. Congress, reportapril2018.pdf, and written testimony of Dana Deasy, DOD Chief Information Officer, before the U.S. Congress,
Senate Armed ServicesSenate Armed Services Committee, Committee, ~~Department~~Departm ent of Defense Spectrum Policy and the ~~Impact of~~Im pact o f the Federal
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with power levels ranging from -6 dBW to 31 dBW and with power levels ranging from -6 dBW to 31 dBW and ~~cellular~~cel ular handsets of -7 dBW would handsets of -7 dBW would
interfere with GPS. (At the time of the study, Ligado proposed a base station power level of 32 interfere with GPS. (At the time of the study, Ligado proposed a base station power level of 32
dBW.) The study concluded that base stations at the proposed Ligado frequency would have to be dBW.) The study concluded that base stations at the proposed Ligado frequency would have to be
limited to 9.8 dBW to ensure the protection of certified avionics in most scenarios. In limited to 9.8 dBW to ensure the protection of certified avionics in most scenarios. In
conversation with CRS, DOT officials asserted that the protection of other categories of GPS conversation with CRS, DOT officials asserted that the protection of other categories of GPS
equipment—including non-certified aviation, general location/navigation, high precision, timing, equipment—including non-certified aviation, general location/navigation, high precision, timing,
and space-based—could not be assured at this power level. DOD and space-based—could not be assured at this power level. DOD ~~additionally~~ additional y recommended “that recommended “that
proposals for use of bands adjacent to GPS should not be approved unless they meet the proposals for use of bands adjacent to GPS should not be approved unless they meet the
transmission power levels described in the [DOT test].”transmission power levels described in the [DOT test].”~~166~~178 Based on these recommendations, Based on these recommendations,
Ligado submitted an amended application to the FCC, reducing its proposed power levels to 9.8 Ligado submitted an amended application to the FCC, reducing its proposed power levels to 9.8
dBW.dBW.~~167~~179 Per the FCC ruling, Ligado also agreed to maintain a 23-MHz guard-band of unused Per the FCC ruling, Ligado also agreed to maintain a 23-MHz guard-band of unused
spectrum designed to separate its transmissions from GPS, thus attempting to mitigate potential spectrum designed to separate its transmissions from GPS, thus attempting to mitigate potential
interference. interference.
Details available Details available in the public domain describing the technical parameters of the 2016 classified in the public domain describing the technical parameters of the 2016 classified
USAF study are limited; however, the USAF’s formal response to the FCC ruling notes that its USAF study are limited; however, the USAF’s formal response to the FCC ruling notes that its
study,study,~~168 which specifically~~180 which specifical y tested potential interference with military GPS receivers, “supported tested potential interference with military GPS receivers, “supported
the conclusions drawn from the DOT testing ... conducted during the same month.” This may the conclusions drawn from the DOT testing ... conducted during the same month.” This may
suggest that the study may not provide evidence that a Ligado network—using the FCC-approved suggest that the study may not provide evidence that a Ligado network—using the FCC-approved
specifications from the company’s 2018 amended application—would necessarily interfere with specifications from the company’s 2018 amended application—would necessarily interfere with
GPS. Furthermore, according to FCC Chairman AjitGPS. Furthermore, according to FCC Chairman Ajit Pai,Pai,~~169~~181 DOD neither submitted nor attempted DOD neither submitted nor attempted
to submit the classified USAF study to the FCC for consideration. Nonetheless, DOD has to submit the classified USAF study to the FCC for consideration. Nonetheless, DOD has
continued to cite these studies in its public objections to the ruling. continued to cite these studies in its public objections to the ruling.
Michael Griffin, former Under Secretary of Defense for Research and Engineering (USD R&E), Michael Griffin, former Under Secretary of Defense for Research and Engineering (USD R&E),
has has ~~additionally~~ additional y asserted that any ground transmissions—regardless of power level—“would asserted that any ground transmissions—regardless of power level—“would
drown out the very weak signals that come from [GPS] drown out the very weak signals that come from [GPS] ~~satellites~~satel ites,” likening the effect of the ,” likening the effect of the
proposed Ligado network on GPS to attempting to listen to the rustling of leaves while 100 jet proposed Ligado network on GPS to attempting to listen to the rustling of leaves while 100 jet
aircraft simultaneously took off.aircraft simultaneously took off.~~170~~182
Statutory Obligations with Regard to Potential GPS Interference
DOD has noted its statutory obligation, pursuant to 10 U.S.C. §2281, to object “to any restriction DOD has noted its statutory obligation, pursuant to 10 U.S.C. §2281, to object “to any restriction
on the GPS System proposed by the head of a department or agency of the United States outside on the GPS System proposed by the head of a department or agency of the United States outside
DOD that would adversely affect the military DOD that would adversely affect the military potential of GPS” [emphasis added]. Although the of GPS” [emphasis added]. Although the

~~Communications Commission~~ Com m unications Com mission,, 116th Cong., 2nd sess., May 6, 2020, at https://www.armed-services.senate.gov/imo/116th Cong., 2nd sess., May 6, 2020, at https://www.armed-services.senate.gov/imo/
media/doc/Deasy_05-06-20.pdf. media/doc/Deasy_05-06-20.pdf.
~~166~~178 Letter from Douglas Kinkoph, Associate Administrator Performing the Delegated Duties of the Assistant Secretary Letter from Douglas Kinkoph, Associate Administrator Performing the Delegated Duties of the Assistant Secretary
of Communications and Information, to Hon. Ajit Pai, Chairman of the Federal Communications Commission, April of Communications and Information, to Hon. Ajit Pai, Chairman of the Federal Communications Commission, April
10, 2020. 10, 2020.
~~167~~179 Letter from Gerard Waldron, Counsel Letter from Gerard Waldron, Counsel to Ligado Networks LLC, to Marlene H. Dortch, Secretary to the Federal to Ligado Networks LLC, to Marlene H. Dortch, Secretary to the Federal
Communications Commission, May 31, 2018, at https://ecfsapi.fcc.gov/file/1053120688074/Communications Commission, May 31, 2018, at https://ecfsapi.fcc.gov/file/1053120688074/
Ligado%20License%20Modification%20Cover%20Letter%20and%20Amendment%20(5-31-2018).pdf. Ligado%20License%20Modification%20Cover%20Letter%20and%20Amendment%20(5-31-2018).pdf.
~~168~~180 Letter from Douglas Kinkoph, Associate Administrator Performing the Delegated Duties of the Assistant Secretary Letter from Douglas Kinkoph, Associate Administrator Performing the Delegated Duties of the Assistant Secretary
of Communications and Information, to Hon. Ajit Pai, Chairman of the Federal Communications Commission, April of Communications and Information, to Hon. Ajit Pai, Chairman of the Federal Communications Commission, April
10, 2020. 10, 2020.
~~169~~181 Letter from Hon. Ajit Pai, Chairman of the Federal Communications Commission, to Rep. Donald Bacon et al., May Letter from Hon. Ajit Pai, Chairman of the Federal Communications Commission, to Rep. Donald Bacon et al., May
26, 2020, at https://docs.fcc.gov/public/attachments/DOC-364591A2.pdf. 26, 2020, at https://docs.fcc.gov/public/attachments/DOC-364591A2.pdf.
~~170~~182 Spoken testimony of Michael Griffin, Undersecretary of Defense for Research and Engineering, before the U.S. Spoken testimony of Michael Griffin, Undersecretary of Defense for Research and Engineering, before the U.S.
Congress, Senate Armed ServicesCongress, Senate Armed Services ~~Committee,~~ ~~Department~~ Committ ee, Departm ent of Defense Spectrum Policy and the ~~Impact~~Im pact of the Federal
~~Communications Commission~~Com m unications Com mission,, 116th Cong., 2nd sess., May 6, 2020. 116th Cong., 2nd sess., May 6, 2020.
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DOT and the USAF studies do not appear to provide evidence that a Ligado network DOT and the USAF studies do not appear to provide evidence that a Ligado network would
adversely affect military GPS, neither definitively ruled out the adversely affect military GPS, neither definitively ruled out the potential for adverse effects. As a for adverse effects. As a
result, Secretary of Defense Mark Esper concluded, “Consistent with my statutory result, Secretary of Defense Mark Esper concluded, “Consistent with my statutory
responsibilities, I believe there are too many unknowns and the risks are far too great to federal responsibilities, I believe there are too many unknowns and the risks are far too great to federal
operations to operations to ~~allow~~al ow Ligado’s proposed system to proceed.” Ligado’s proposed system to proceed.”~~171~~183
DOD has DOD has ~~additionally~~ additional y noted that Section 1698 of the National Defense Authorization Act for noted that Section 1698 of the National Defense Authorization Act for
Fiscal Year 2017 (P.L. 114-328)—codified at Section 343 of the Communications Act—prevents Fiscal Year 2017 (P.L. 114-328)—codified at Section 343 of the Communications Act—prevents
the FCC from approving commercial terrestrial operations in the bands proposed by Ligado “until the FCC from approving commercial terrestrial operations in the bands proposed by Ligado “until
90 days after the Commission resolves concerns of widespread harmful interference by such 90 days after the Commission resolves concerns of widespread harmful interference by such
operations to covered GPS devices.” DOD asserts that the FCC did not resolve such concerns operations to covered GPS devices.” DOD asserts that the FCC did not resolve such concerns
prior to approving Ligado’s application; paragraph 130 of the FCC ruling provides the FCC’s prior to approving Ligado’s application; paragraph 130 of the FCC ruling provides the FCC’s
justification for its belief that the concerns were “effectively resolved.”justification for its belief that the concerns were “effectively resolved.”~~172~~184
FCC Response to Concerns About Potential GPS Interference
Several Commissioners have provided statements and written correspondence directly addressing Several Commissioners have provided statements and written correspondence directly addressing
how the FCC came to its decision. Commissioner Brendan Carr noted in a statement how the FCC came to its decision. Commissioner Brendan Carr noted in a statement
accompanying the FCC’s decision that “after a thorough and multi-year review, the FCC’s accompanying the FCC’s decision that “after a thorough and multi-year review, the FCC’s
professional staff of engineers and other experts determined that we can advance America’s 5G professional staff of engineers and other experts determined that we can advance America’s 5G
leadership while protecting GPS and other adjacent band services.”leadership while protecting GPS and other adjacent band services.”~~173~~185 Commissioners Jessica Commissioners Jessica
Rosenworcel and Geoffrey Starks termed the decision “an extremely close Rosenworcel and Geoffrey Starks termed the decision “an extremely close ~~call~~cal ,” but similarly ,” but similarly
noted in their joint statement of concurrence that, despite the concerns of DOD and others about noted in their joint statement of concurrence that, despite the concerns of DOD and others about
potential GPS interference, “in the end, we are potential GPS interference, “in the end, we are ~~compelled~~compel ed to support the expert technical analysis to support the expert technical analysis
done by the [FCC’s] engineering staff.”done by the [FCC’s] engineering staff.”~~174~~186 In a series of letters, Chairman Ajai Pai has outlined In a series of letters, Chairman Ajai Pai has outlined
the FCC’s decisionmaking process, the data the commission used to make its determination, and the FCC’s decisionmaking process, the data the commission used to make its determination, and
the FCC’s technical analysis of potential interference.the FCC’s technical analysis of potential interference.~~175~~

~~171~~187 183 Letter from Hon. Mark Esper, Secretary of Defense, to Hon. Ajit Pai, Chairman of the Federal Communications Letter from Hon. Mark Esper, Secretary of Defense, to Hon. Ajit Pai, Chairman of the Federal Communications
Commission, November 18, 2019, at https://www.ntia.doc.gov/files/ntia/publications/Commission, November 18, 2019, at https://www.ntia.doc.gov/files/ntia/publications/
ntia_letter_to_fcc_chairman_re_ligado_mss_atc_applications_dec._6_2019.pdf#page=6. ntia_letter_to_fcc_chairman_re_ligado_mss_atc_applications_dec._6_2019.pdf#page=6.
~~172~~184 Federal Communications Communication Order 20-48, at https://docs.fcc.gov/public/attachments/FCC-20- Federal Communications Communication Order 20-48, at https://docs.fcc.gov/public/attachments/FCC-20-
48A1.pdf. 48A1.pdf.
~~173~~185 Statement of Commissioner Brendan Carr, Re: LightSquared Statement of Commissioner Brendan Carr, Re: LightSquared ~~Technical~~ T echnical Working Group Report, IB Docket No. 11 Working Group Report, IB Docket No. 11 --
109; LightSquared109; LightSquared License Modification Application, IBFS Files Nos. SATLicense Modification Application, IBFS Files Nos. SAT -MOD-20120928-00160-00161, SES--MOD-20120928-00160-00161, SES-
MOD-20121001-00872, IB Docket No. 12-340; New LightSquaredMOD-20121001-00872, IB Docket No. 12-340; New LightSquared License Modification Applications, IBFS File Nos. License Modification Applications, IBFS File Nos.
SES-MOD-20151231-00981, SATSES-MOD-20151231-00981, SAT -MOD20151231-00090, SAT-MOD20151231-00090, SAT -MOD-20151231-00091, IB Docket Nos. 11-109, 12--MOD-20151231-00091, IB Docket Nos. 11-109, 12-
340; Ligado Amendment to License Modification Applications, IBFS340; Ligado Amendment to License Modification Applications, IBFS File Nos. SES-MOD-20151231- 00981, SATFile Nos. SES-MOD-20151231- 00981, SAT --
MOD-20151231-00090, SATMOD-20151231-00090, SAT -MOD-20151231-00091, IB Docket No. 11- 109, at https://docs.fcc.gov/public/-MOD-20151231-00091, IB Docket No. 11- 109, at https://docs.fcc.gov/public/
attachments/FCC-20-48A2.pdf. attachments/FCC-20-48A2.pdf.
~~174~~186 Joint Statement of Commissioners Jessica Rosenworcel Joint Statement of Commissioners Jessica Rosenworcel and Geoffrey Starks Concurring Re:and Geoffrey Starks Concurring Re: LightSquared LightSquared
~~Technical~~T echnical Working Group Report, IB Docket No. 11 Working Group Report, IB Docket No. 11 -109; LightSquared License Modification Application, IBFS Files -109; LightSquared License Modification Application, IBFS Files
Nos. SATNos. SAT -MOD-20120928-00160-00161, SES-MOD-20121001-00872, IB Docket No. 12-340; New LightSquared -MOD-20120928-00160-00161, SES-MOD-20121001-00872, IB Docket No. 12-340; New LightSquared
License Modification Applications, IBFS File Nos. SES-MOD-20151231-00981, SATLicense Modification Applications, IBFS File Nos. SES-MOD-20151231-00981, SAT -MOD20151231-00090, SAT-MOD20151231-00090, SAT --
MOD-20151231-00091, IB Docket Nos. 11-109, 12-340; Ligado Amendment to License Modification Applications, MOD-20151231-00091, IB Docket Nos. 11-109, 12-340; Ligado Amendment to License Modification Applications,
IBFSIBFS File Nos. SES-MOD-20151231- 00981, SATFile Nos. SES-MOD-20151231- 00981, SAT -MOD-20151231-00090, SAT-MOD-20151231-00090, SAT -MOD-20151231-00091, IB Docket -MOD-20151231-00091, IB Docket
No. 11- 109, at https://docs.fcc.gov/public/attachments/FCC-20-48A3.pdf. No. 11- 109, at https://docs.fcc.gov/public/attachments/FCC-20-48A3.pdf.
~~175~~187 For list of congressional correspondence, see https://www.fcc.gov/chairman-pais-letters-congress. For list of congressional correspondence, see https://www.fcc.gov/chairman-pais-letters-congress.
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Legislative Activity
The FY2021 National Defense Authorization Act (P.L. 116-283) contains five Ligado- or GPS The FY2021 National Defense Authorization Act (P.L. 116-283) contains five Ligado- or GPS
interference-related provisions: interference-related provisions:
1. Section 1611 requires DOD to develop a plan for a resilient 1. Section 1611 requires DOD to develop a plan for a resilient and survivable and survivable
positioning, navigation, and timing capability within two years. positioning, navigation, and timing capability within two years.~~176~~188 This provision This provision
would would ~~allow~~al ow DOD to reprogram resources as needed to develop the plan. DOD to reprogram resources as needed to develop the plan.
2. Section 1661 prohibits funds for retrofitting GPS devices or networks that use 2. Section 1661 prohibits funds for retrofitting GPS devices or networks that use
GPS for the purposes of “[mitigating] harmful interference from commercial GPS for the purposes of “[mitigating] harmful interference from commercial
terrestrial operations using the 1526–1536 megahertz band, the 1627.5–1637.5 terrestrial operations using the 1526–1536 megahertz band, the 1627.5–1637.5
megahertz band, or the 1646.5–1656.5 megahertz band” (i.e., the bands approved megahertz band, or the 1646.5–1656.5 megahertz band” (i.e., the bands approved
for the Ligado network).for the Ligado network).~~177~~
189 3. Section 1662 prohibits funding for contracts with entities “that [engage] in 3. Section 1662 prohibits funding for contracts with entities “that [engage] in
commercial terrestrial operations using the 1525–1559 megahertz band or the commercial terrestrial operations using the 1525–1559 megahertz band or the
1626.5–1660.5 megahertz band unless the Secretary has certified to the 1626.5–1660.5 megahertz band unless the Secretary has certified to the
congressional defense committees that such operations do not cause harmful congressional defense committees that such operations do not cause harmful
interference to a Global Positioning System device of the Department of interference to a Global Positioning System device of the Department of
Defense.”Defense.”~~178~~
190 4. Section 1663 directs the Secretary of Defense to seek an independent technical 4. Section 1663 directs the Secretary of Defense to seek an independent technical
assessment of the FCC’s Ligado authorization order (FCC 20-48) from the assessment of the FCC’s Ligado authorization order (FCC 20-48) from the
National Academy of Sciences.National Academy of Sciences.~~179~~191 This assessment is to “evaluate the potential This assessment is to “evaluate the potential
harmful interference concerns relating to Global Positioning System devices,” harmful interference concerns relating to Global Positioning System devices,”
review potential mitigation measures, and provide associated recommendations review potential mitigation measures, and provide associated recommendations
to the department. to the department.
5. Section 1664 prohibits the Secretary of Defense from obligating or expending 5. Section 1664 prohibits the Secretary of Defense from obligating or expending
funds to comply with the FCC’s Ligado authorization order until the Secretary funds to comply with the FCC’s Ligado authorization order until the Secretary
submits to the congressional defense committees an estimate of the cost submits to the congressional defense committees an estimate of the cost
associated with any potential interference-mitigation measures.associated with any potential interference-mitigation measures.~~180~~

~~176~~192 188 P.L. 116-283 §1611 Resilient and Survivable P.L. 116-283 §1611 Resilient and Survivable Positioning, Navigation, and Positioning, Navigation, and ~~Timing~~T iming Capabilities. Capabilities.
~~177~~189 P.L. 116-283 §1661 Prohibition on Availability of Funds for Certain Purposes Relating to the Global P.L. 116-283 §1661 Prohibition on Availability of Funds for Certain Purposes Relating to the Global Positioning Positioning
System. System.
~~178~~190 P.L. 116-283 §1662 Limitation on Awarding Contracts to Entities Operating Commercial P.L. 116-283 §1662 Limitation on Awarding Contracts to Entities Operating Commercial ~~Terrestrial~~T errestrial
Communication Networks that Cause Harmful Interference with the Global Positioning System. Communication Networks that Cause Harmful Interference with the Global Positioning System.
~~179~~191 P.L. 116-283 §1663 Independent P.L. 116-283 §1663 Independent ~~Technical~~T echnical Review of Federal Communications Commission Order Review of Federal Communications Commission Order 20 20-48. -48.
~~180~~192 P.L. 116-283 §1664 Estimate of Damages from Federal Communications Commission Order 20 P.L. 116-283 §1664 Estimate of Damages from Federal Communications Commission Order 20 -48. -48.
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Overview of Department of Defense Use of the Electromagnetic Spectrum

Author Information

John R. HoehnJohn R. Hoehn, Coordinator
Kelley M. Sayler Kelley M. Sayler
Analyst in Military Capabilities and Programs Analyst in Military Capabilities and Programs
Analyst in Advanced Technology and Global Analyst in Advanced Technology and Global

Security Security

Jill C. Gallagher Jill C. Gallagher

Analyst in Telecommunications Policy Analyst in Telecommunications Policy

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