Americans increasingly rely on radio spectrum for much of their daily lives. From texting friends to car navigation these airwaves play an invisible but central role.
Much like other important resources, spectrum access is finite. Demand continues to grow. Federal spectrum policy experts recognize this – and have come up with creative new ways to allow greater spectrum access by sharing this vital resource.
One innovative approach is the Citizens Broadband Radio Service, which allows for dynamic spectrum sharing between the Department of Defense and commercial spectrum users. The DOD users have protected, prioritized use of the spectrum. When the government isn’t using the airwaves, companies and the public can gain access through a tiered licensing arrangement.
This means the DOD can use the same spectrum for its critical missions while companies can use it for 5G and high-speed Internet deployment.
This is possible through automated sense-and-avoid dynamic access. This ground-breaking framework was made possible by rules established by the Federal Communications Commission in 2015, technologies standardized and developed by industry, and certification tests executed at NTIA's research and engineering lab, the Institute for Telecommunication Sciences (ITS).
And there were a lot of questions about whether it would work.
A new report from ITS shows that it is working.
ITS worked with industry to obtain access to its proprietary data and to perform an independent, objective analysis of CBRS device deployment.
Researchers reviewed aggregated data on CBRS devices – such as cell towers – between April 1, 2021 and January 1, 2023. They found the number of devices nationwide grew by 121 percent over the 21-month analysis period – an indication that access to the spectrum is growing.
This research is in keeping with the Biden Administration's focus on evidence-based policy making.
“Innovative spectrum sharing frameworks are key to unlocking additional bandwidth for wireless connectivity across the country,” Deputy Assistant Secretary of Commerce for Communications and Information April McClain-Delaney said. “The success and growth of the CBRS band shows the promise of dynamic spectrum sharing to make more efficient use of this finite resource.”
Other key findings from the ITS report:
- About 45 percent of all active devices were deployed in counties where use of the spectrum is shared with DOD, known as Dynamic Protection Areas, or DPAs. By the end of the reporting period, there were 128,351 active devices in DPA-impacted counties with a total population of 232,348,897 residents.
- Use of the General Authorized Access (GAA) tier, which provides lower cost access to the spectrum, dominates the band. Four out of five active devices were GAA-only, which is the license tier that must accept interference from licensed and federal users.
- More than 70 percent of all active devices are deployed in rural census blocks, showing the band is playing a significant role in expanding rural wireless connectivity.
A companion study now in its initial phase will deploy sensors to measure how much spectrum CBRS emissions are actually occupying over time near DPAs. Complementary studies such as these, designed in collaboration with stakeholders to analyze spectrum utilization from multiple angles, provide objective data to inform future sharing proposals.
The goal of this ITS report was to gain insight on the growth of CBRS, and the findings show that deployments grew at a steady rate. CBRS is playing an important role in connecting rural America as well as providing a real-world example of how sharing spectrum can work for both the federal government and the private sector. This is the first of a longitudinal series of reports from ITS on the CBRS service, so we can monitor how the service develops.
NTIA would like feedback on the report from stakeholders, including observations and conclusions, how future reports may be improved, and on ways to improve the CBRS spectrum sharing framework. We are accepting comments until May 31, 2023. We will post the received comments. Please send comments to: ITSinfo@ntia.gov.