5G C-Band Deployments Safely Co-exist with Aviation

It’s important for wireless spectrum to be harmonized around the world.

We must ensure wireless communications operate effectively across borders. Nations should standardize the use of radio frequencies, so mobile devices can talk to each other and the Internet. 5G Americas promotes the growth of 5G and 4G LTE networks internationally – and that means helping companies and countries align around common standards and spectrum bands.

C-Band spectrum is being used successfully in dozens of countries around the world with no impact to aviation.


Source: CTIA

5G networks use a set of radio frequencies called the “C-Band” which are important to allow mobile cellular communications devices to speak to each other and the Internet.

In the US, the C-Band refers to frequencies between 3.7 to 4.2 GHz. A July 2021 US spectrum auction of the 3.7-3.98 GHz portion of the band ended up being the biggest auction in FCC history.

In the Americas, regulatory bodies have been working to make spectrum available across all three frequency ranges, so they can support a wide variety of 5G use cases.

  • In the United States, the FCC has released spectrum aimed at enabling 5G services. The recent C-Band (3.7 GHz – 3.98 GHz) spectrum auction was the biggest auction in FCC history.
  • ISED, the Canadian regulatory body, has also been active in identifying and designating new spectrum for 5G services. ISED is currently auctioning the 3.45 – 3.65 GHz band.
  • Regarding Mexico, 5G services have not been launched yet while the regulator makes spectrum available for 5G. The 3.5 GHz band was re-farmed, giving a contiguous spectrum to the three operators (AT&T, Axtel, and Telmex).

Check out our white paper, Mid-band Spectrum & the Coexistence with Radio Altimeters, for more information.

C-Band Mid-band Spectrum: Why is it important?

The United States has lagged behind many other nations in making mid-band spectrum available for commercial uses. Globally, the availability of 5G networks is growing due to wide availability of mid-band spectrum. The US risks its wireless and technology leadership internationally without mid-band spectrum.

C-Band is a “mid-band” spectrum that offers the ability to deliver both very high data throughput, as well as wide coverage.

  • Low bands: Sub-1GHz supports wide area coverage and indoor coverage, and brings the 5G advantage across urban, suburban, rural regions.
  • Mid bands: Ranges between 1 – 6 GHz and provides balanced coverage and capacity. More spectrum must be made available in this range to accommodate the wide variety of 5G use cases.
  • High bands: mmWave ranging from 24 – 71 GHz provides high capacity and ultra-high speeds but lacks coverage and indoor penetration.

C-Band: 5G in C-Band mid-band spectrum safely coexists with radio altimeters

International 5G deployments in numerous countries have been operating without interference to radio altimeters that are used in aircrafts and helicopters, which use the nearby 4.2 – 4.4 GHz band.

In the United States, military and federal systems have operated near the altimeter band for decades without incident. The FCC identified, approved, allocated and auctioned the 3700 – 3980 MHz band for commercial wireless service without constraint under safe operating conditions on 5G deployments and parameters.

As a condition of the C-Band auction, the FCC required a 220 MHz "guard band" between the frequencies used for 5G uses and those used by radio altimeters.

Aviation studies submitted in FCC proceedings have significant shortcomings. They are overly conservative evaluating real-world conditions. A review of real-world examples of non-interference in Japan, South Korea, Europe, and with the federal systems in the United States validates 5G Americas’ position on the co-existence of mid-band spectrum and radio altimeters.

What are others saying about 5G deployments
in C-Band spectrum and the co-existence with aviation radio altimeters?

Former FCC chairs Ajit Pai, Tom Wheeler, Julius Genachowski, Michael Copps, Michael Powell and Mignon Clyburn said in a joint letter they were "concerned" about the Federal Aviation Administration’s (FAA) recent efforts to revisit the FCC’s 2020 decision to allow use of the C-Band spectrum for wireless use.

"U.S. former officials urge 'speedy' resolution of 5G wireless aviation dispute" (Reuters, 12/13/2021)

In France, the military (ANFR) tested helicopters with live 5G base stations, finding that “the emission of 5G NR base station had no impact on the operational behavior of the radio altimeter.

"FAA Aside, It’s Time to Move Forward With 5G" (Bloomberg Law, 12/22/2021)

Richard Bennett, founder of High Tech Forum and a standards engineer

America’s shift to 5G has not been done in haste: Research on its development first began about 13 years ago, in 2008. The FCC began to take steps to prepare for a transition several years ago, including performing the necessary tests to ensure that the transition would not have any negative impacts on entities using nearby spectrum.

"The FCC, FAA, And The Costly Delay Of American 5G Technology" (Forbes, 11/20/2021)

Ike Brannon, Senior Fellow, Jack Kemp Foundation

Bands up to 4.2 GHz for mobile were suggested at international spectrum conferences in 2007 and solidified in 2015. …these bands are in use in other countries without any observed interference, there is no scientific reason why interference should be a U.S.-only problem.

"FAA is at blame for last-minute C-band concerns — Webb" (FierceWireless, 12/9/2021)

William Webb, former Director at Ofcom

your letter seeks to prevent those wireless providers from delivering 5G services pursuant to the FCC’s C-Band rules and, in fact, it proposes to replace the FCC’s regulations with an undefined, new regulatory framework for C-Band operations that the Department of Transportation—not the FCC—would determine at some unspecified date in the future.

"Carr Letter: Response to Sec. Buttigieg" (1/1/2022)

Brendan Carr, FCC Commissioner

Recently, the aviation industry and the Federal Aviation Administration have suggested we should delay launching 5G in the C-Band. A delay will cause real harm. Pushing back deployment one year would subtract $50 billion in economic growth, just as our nation recovers and rebuilds from the pandemic. 

"5G vs. Air Safety: The FAA’s False Choice" (Morning Consult, 11/18/2021)

Meredith Attwell Baker, Chief Executive Officer, CTIA

Additional Resources

Check out these sources for more information:

The 5G Americas white paper explains the studies submitted by the aviation industry. These studies raise interference concerns, but as the 5G Americas white paper explains there are significant shortcomings in the studies. For instance, these studies are overly conservative in evaluating real-world conditions while ignoring the lack of interference events in Japan, South Korea, Europe, as well as with existing federal systems in the US.

On January 28, 2022, the Federal Aviation Administration (FAA) issued the following statement:

“Through continued technical collaboration, the FAA, Verizon, and AT&T have agreed on steps that will enable more aircraft to safely use key airports while also enabling more towers to deploy 5G service. The FAA appreciates the strong communication and collaborative approach with wireless companies, which have provided more precise data about the exact location of wireless transmitters and supported more thorough analysis of how 5G C-band signals interact with sensitive aircraft instruments. The FAA used this data to determine that it is possible to safely and more precisely map the size and shape of the areas around airports where 5G signals are mitigated, shrinking the areas where wireless operators are deferring their antenna activations. This will enable the wireless providers to safely turn on more towers as they deploy new 5G service in major markets across the United States. The FAA continues to work with helicopter operators and others in the aviation community to ensure they can safely operate in areas of current and planned 5G deployment.”

President Biden’s statement on discussions around delay of 5G C-Band deployment. 1/4/22. 

President Biden’s statement on the agreement to proceed with 5G deployments. 1/18/22. 

On Feb. 15, 2022, 5G Americas responded to a consultation with Innovation, Science and Economic Development Canada (ISED), a department of the Government of Canada. ISED is responsible for a number of the federal government’s functions in regulating industry and commerce, promoting science and innovation, and supporting economic development.

Canada is soliciting views on conditions for making 3650–3900 MHz (“the 3800 MHz band”) available for flexible use licenses, since this band or parts thereof has been or is being made available in other markets in the Americas.

The comments specifically address the issue of aviation radio altimeters and the use of 3800 MHz for wireless cellular communications.

Eleven wireless and technology organizations urge the US administration to take whatever steps necessary to make sure the wireless companies’ January launch plans go forward. (11/18/21).

Signatories include: CCA, CTA, CTIA, ITI, NATE, SBE Council, TechNet, TIA, USTelecom, WIA, 5GAmericas

Six former FCC Chairs sign letter express dismay over FAA’s handling of 5G C-Band spectrum deployments relating to aviation radio altimeters. (12/13/2021).

Signatories include: Ajit Pai, Tom Wheeler, Mignon Clyburn, Julius Genachowski, Michael Copps, and Michael Powell.

5G C-band service, as well as 220+ megahertz guard band separating 5G from aviation operations, “are sufficient to protect (aviation) services in the 4.2-4.4 GHZ band.” The Order also noted that the guard band “is double the guard band supported in initial comments by Boeing and (Aviation Spectrum Resources, Inc.).”

Article by former FCC Chair, Tom Wheeler. Mentions that in some studies where there was interference to radio altimeters it turned out to be other radio altimeters.

Rysavy article – Wireless analyst Peter Rysavy addresses rational decisions that are needed on C-Band. He identifies problems with aviation industry tests and writes about RTCA and AVSI not providing detailed test results associated with their report.

Rysavy Research – P.6 Figure 2: C-Band Spectrum Allocation, before auction and after auction, showing guard band.

Recon Analytics’ Roger Entner’s podcast on the C-Band delay.

This article points to Navy radar – such as the AN/SPN-43 radar, operates in mid-band frequencies at extremely high power with ground transmitters pointing at aircraft in geographical areas where U.S. planes operate. Such potential interference, however, has not been a problem in the real world.

CTIA Chief Executive Officer Meredith Attwell Baker presents her case on why FAA’s rules present a false choice.

French national Frequency Agency 5G Aviation test video demonstrating safety tests that constitute the first stage of an in-depth study aimed at “demonstrating that 5G has no impact on aircraft altimetry equipment.”

FAA is at blame for last-minute C-band concerns. Ofcom Director William Webb discusses the amount if spectrum and the inefficient use of it by aviation.

Excellent well-sourced website with comprehensive information on 5G & Aviation issues,  produced by CTIA trade association representing the wireless communications industry in the United States.

Newsweek article by Joel Thayer, President of the Digital Progress Institute: 
Federal 5G Disfunction only helps China.

Article by Richard Bennett, founder of High Tech Forum and a standards engineer, says the FAA is right to be concerned about aviation safety, but regulating the power levels and location of radio towers is far outside its realm of expertise.

Reuters – U.S. former officials urge ‘speedy’ resolution of 5G wireless aviation dispute. Six former FCC chairs urged Biden administration to quickly resolve a dispute over the planned use of 5G wireless spectrum that the aviation industry says poses an air safety risk – joint letter.

One-pager on additional international protections added by the wireless industry.

CTIA outlines numerous reasons why 5G in the C-Band successfully operates without reported interference with radio altimeters. 

Letter from Buttigieg and FAA to AT&T and Verizon. 12/31/21.

FCC Commissioner Brendan Carr letter: Response to US Secretary of Transportation Buttigieg regarding AT&T and Verizon letter to Buttigieg and FAA declining to delay C-Band deployment on 1/2/22.

AT&T and Verizon letter to Buttigieg and FAA declining to delay C-Band deployment. 1/2/22.

FAA reply thanking AT&T and Verizon for delaying deployments. 1/3/22.