Planning for 4.9 GHz Spectrum Changes (2025)

Chapter: 3 Key Findings

Previous Chapter: 2 Documentation of Research Activities
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Suggested Citation: "3 Key Findings." National Academies of Sciences, Engineering, and Medicine. 2025. Planning for 4.9 GHz Spectrum Changes. Washington, DC: The National Academies Press. doi: 10.17226/29256.

3 Key Findings

During this project, numerous initial key findings and observations were documented. Additional analysis and observations were realized based upon the FCC release of its Eighth Report and Order.

The Task 1 deliverable noted that the use of the 4.9 GHz spectrum by state DOTs, public safety entities, utilities, and government agencies was underestimated by the FCC.

The Task 2 deliverable further confirmed that there is significant interest in the band by DOTs, but this interest has been tempered by the FCC’s constant changing of its rules. It appears that there was greater interest in the band by DOTs when the FCC’s Sixth Report and Order was in effect. The Sixth Report and Order was the order that provided for a state licensing/leasing format.

From the outreach efforts, the following issues were identified:

  • Outreach participants mentioned that the lack of greater interest in the outreach effort was a result of general malaise about the band, resulting from the extended delay in finalizing rules.
  • Existing users expressed concerns regarding their ability to continue their existing operations once the new rules are in place.
  • Existing users commented about the difficulties regarding continuing existing operations. Further, some manufacturers have discontinued making equipment for the band due to uncertainties regarding the ability to continue sales of such equipment post-rulemaking.
  • Potential new users were concerned with delays in obtaining access to the band, which has resulted in alternative communications arrangements being pursued in other bands.
  • Potential new users and existing users were concerned that they may have to obtain access to the band through a nationwide commercial wireless service provider, pointing out that operations are needed in geographic areas where there often isn’t commercial wireless provider service.
  • Potential new users and existing users were concerned that obtaining service from a nationwide commercial wireless service provider may be prohibitively expensive.
  • Potential new users and existing users were concerned that obtaining service from a nationwide commercial wireless service provider may preclude certain equipment options.
  • Outreach participants seemed thoroughly knowledgeable about the existing use of the band. Thus, the only information gap is the future rules. There appeared to be unanimity in the priority being the resolution of the rule making proceeding, and finalization of the future rules.

Even though there were significantly less responses to the outreach survey, the information gathered was valuable. Further outreach at IWCE and other venues bolstered the

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Suggested Citation: "3 Key Findings." National Academies of Sciences, Engineering, and Medicine. 2025. Planning for 4.9 GHz Spectrum Changes. Washington, DC: The National Academies Press. doi: 10.17226/29256.

importance of 4.9 GHz spectrum availability and the need to continue outreach efforts and the establishment of a repository of information.

The FCC’s overturning the Sixth Report and Order created uncertainty for users, potential users, and manufacturers, dampening interest, reducing investment in the band, and creating a “wait-and-see” approach until the FCC’s proceeding is finalized.

The 4.9 GHz band had traditionally been used by a variety of public safety eligible entities for a variety of uses, including use by transportation agencies. For the most part, use is concentrated in urban areas. However, development in the band has been stymied by the lack of reasonably priced commercial off the shelf equipment that can be deployed. Further, uncertainty about further uses and eligibility in the band resulting from the FCC’s years-long proceeding has muted expansion by existing eligibles who are concerned with the possibility of stranded resources dedicated to the band. The Commission’s Eighth Report and Order provides long-anticipated direction, but Appeals of the Order have been filed with the US Court of Appeals, and therefore the proceeding remains subject to change.

In addition to state DOTs use of the 4.9 GHz spectrum, various other agencies use the spectrum for a multitude of operations.

Such operations that are supported using 4.9 GHz spectrum include but are not limited to:

  • Links for voice, data, and video.
  • Point-to-point links throughout some states, providing communications for traffic signal control, variable speed limit signs and cameras for the state’s transportation management centers.
  • Fire lookout cameras.
  • Equipment to monitor earthquake activity for early warnings.
  • Transmitting public safety video images captured from cameras installed within train cars and stations.
  • Train control purposes.
  • Airport operations.
  • Connectivity to mobile command vehicles to support Wi-Fi, phones, Internet access, etc., during events and critical incidents.
  • Bomb unit has bomb robots.
  • Public safety operations.
  • Disaster recovery and emergency support communications.
  • Create a mesh communications link between lifeguard tower units and dispatch.
  • Continuity of Operations and Continuity of Government programs.
  • Emergency call box system deployed in the underground sections subway system.
  • Point-to-point microwave connectivity.
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Suggested Citation: "3 Key Findings." National Academies of Sciences, Engineering, and Medicine. 2025. Planning for 4.9 GHz Spectrum Changes. Washington, DC: The National Academies Press. doi: 10.17226/29256.
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Suggested Citation: "3 Key Findings." National Academies of Sciences, Engineering, and Medicine. 2025. Planning for 4.9 GHz Spectrum Changes. Washington, DC: The National Academies Press. doi: 10.17226/29256.
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Next Chapter: 4 Scenarios
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