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Internet of Things February 2022 Viewpoints

Technology Analyst: David Strachan-Olson

Aviation and 5G

By Guy Garrud
Garrud is a consultant with Strategic Business Insights.


Planned wide-scale rollout of C‑band 5G networks in the United States has prompted concerns about aviation safety because the networks risk interfering with radio altimeters used by passenger aircraft when making low-visibility landings. Although last-minute compromises managed to avoid disruption, future cases of interference and overlap in the EM spectrum appear inevitable.


A widespread rollout of 5G networks in the United States has raised major concerns in the aviation sector about fears that the signals could interfere with aircraft radio altimeters, which are vital tools for landing in low-visibility weather. Specifically, 5G networks in the United States use two frequency bands, part of which (C‑band) extends close to the 4.2-to-4.4‑gigahertz (GHz) range used by radio altimeters on commercial aircraft. Having two extremely close frequency bands dramatically increases the potential for interference between the radio altimeter signals and general 5G telecoms signals. By contrast, in the European Union, 5G bands stop at 3.8 GHz, leaving a wider gap in the radio spectrum between these signals and altimeter signals.

A planned widespread rollout of C‑band 5G cellular networks by AT&T and Verizon in January 2022 sparked major concerns, with the US Federal Aviation Administration (FAA) and aircraft manufacturers issuing warnings that some models of passenger aircraft would be unable to perform low-visibility landings at dozens of US airports where network operators were activating C‑band 5G towers nearby. Last-minute compromises managed to avoid large-scale disruption (although some flight cancellations still occurred) and involved a combination of the FAA's approving other means of confirming aircraft altitude and network providers' agreeing to postpone or reduce the signaling power of C‑band 5G antennas close to some airports.


The electromagnetic (EM) spectrum is vast, but the usable portion of it is actually relatively small. EM transmission generally faces a trade-off between higher-energy and thereby higher-frequency systems that can provide greater bandwidth but at the expense of shorter transmission ranges and greater vulnerability to interference than those of lower-energy systems.

Successive generations of cellular networks have gradually tended toward higher-energy and higher-bandwidth technologies, with lower-energy radio frequencies' offering lower data rates in areas with otherwise poor network coverage. However, this tendency also means that emerging 5G networks are increasingly encroaching on signal space that was previously in use for a variety of applications, including as part of telecoms companies' back-haul networks. This problem is likely to become only more severe with time as wireless-communication technologies proliferate and need to find effective ways of transmitting data without being overwhelmed by other nearby devices and networks. Advanced forms of modulation—including use of highly directional signaling networks—may be important tools for enabling next-generation telecoms networks. The airport-altimeter-interference issue also highlights the importance of joined-up thinking on the part of industry and regulators in order to avoid such last-minute compromises.

Relevant Areas to Monitor

  • Optical Networks (Li-Fi)

    Optical networks use visible light to transmit data. Li‑Fi has the potential to transform most conventional lights into data-transmission nodes. Because of the ubiquitous nature of electric illumination, using light for transmitting data also offers substantial energy-efficiency gains over using radio and microwave communication.

  • Wireless Spectrum Overlap

    5G networks, home and industrial wireless internet, and smart-home appliances and hubs all seek to communicate using the electromagnetic spectrum. Companies must either gain regulatory approval to use certain portions of the electromagnetic spectrum or make use of increasingly crowded unregulated sets of frequencies.

Impact Scale

On a scale of low, medium, or high, the anticipated level of impact for this topic is: Medium.

Impact Timing

On a scale of now, 5, 10, or 15 years, the anticipated impact timing for this topic is: 5 years.

Opportunities in the Following Industry Areas

  • Automotive/Vehicle
  • Information/Telecommunications
  • Internet of Things
  • Infrastructure/Utility
  • Transportation/Logistics

Relevant to the Following Explorer Technology Areas