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Spectrum Technology and Research Division

BACKGROUND ON THE SPECTRUM TECHNOLOGY AND RESEARCH DIVISION

The Spectrum Technology and Research Division (STAR), launched in 2021, performs research and development on “innovative measurement methods and tools to promote novel and efficient use of spectrum through improved access, sharing, atmospheric sensing, and precision timing” (Coder 2025, p. 5). STAR work increases the availability of spectrum for commercial use without impacting the military applications. The division is split into three primary research groups: Applied Systems Metrology, Fiber Sources and Applications, and Shared Spectrum Metrology. Together, these groups help ensure that the U.S. infrastructure for communications, spanning mobile phones to GPS, operate correctly and without interferences as the public expects. Table 4-1 provides an overview of the objectives of each of these research groups. The STAR also hosts the National Advanced Spectrum and Communications Test Network (NASCTN), in coordination with the National Telecommunications and Information Administration and other members of the steering committee, which provides testing and validated data for spectrum sharing technologies. As of September 2025, the division had 25 federal employees (19 permanent and 6 term limited) and 22 associates, domestic and international guest researchers, for a total of 47 staff members.

TABLE 4-1 Overview of the Spectrum Technology and Research Division Research Groups

SOURCE: Committee generated using CTL (2025).

Each of the three subdivisions has its own unique mission and research aims. The Applied Systems Metrology group develops technical foundations for spectrum science and measurement techniques for closed-box radio frequency (RF) systems. Research aims include interference susceptibility metrology and in situ field measurements of RF systems. The Fiber Sources and Applications group develops fiber-laser frequency combs for a variety of precision measurement applications, aiming to enable global-scale, femtosecond-level synchronization and open-path dual-comb spectroscopy. The Shared Spectrum Metrology group performs research on wireless coexistence, electromagnetic compatibility, spectrum sensing and noise, and interoperability for the 5G Open Radio Access Network (O-RAN) to inform standards and regulatory policy that address RF spectrum overcrowding.

TECHNICAL PROGRAMS

STAR is contributing to the National Institute of Standards and Technology (NIST) Communications Technology Laboratory (CTL) mission in fundamental metrology as well as current and future technology applications such as spectrum sensing and sharing. STAR is conducting groundbreaking work in its optical comb time-transfer project. This research is yielding synchronization accuracies—at widely separated locations up to several tens to hundreds of kilometers—of less than a femtosecond. This is orders of magnitude better than the accuracy that can be achieved with current satellite systems such as the Global Positioning System. In addition to precise network timing for quantum communications applications, this work will also enable more accurate geodesy, with potential use in earthquake and volcano monitoring. In dual-comb spectroscopy, NIST’s Spectrum Technology and Research Division demonstrates strong atmospheric sensing measurement capabilities with 14.5 km city-scale open-path measurements and 155× compression factors (Giorgetta et al. 2024). NIST’s focus on practical field implementation and SI-traceable measurement methods represents an appropriate NMI role—establishing measurement foundations that industry and academia build upon.

Work in spectrum sensing and sharing is also of high quality. Investigations include theoretical studies as well as field testing, the latter being one of the more comprehensive measurement campaigns to date. Development of field equipment for data collection exemplifies a high-value practical outcome for NIST and for the community at large. This work will also likely drive new theoretical and numerical investigations to advance the field. Work at STAR in spectrum sensing is going beyond conventional radiometric energy detection to explore more sensitive techniques such as correlation and cyclostationary processing. It could benefit STAR and the community at large to consider additional techniques such as interferometric (two-antenna) detection, feature detection, correlation (e.g., Durbin-Watson), and matched filtering, as these techniques are superior in performance to energy detection, at the cost of some additional complexity. Collaboration with the greater remote sensing community (e.g., space and airborne sensing platforms) is beneficial, as this community has a long history of success in both weak signal detection and interference mitigation. Expanded work in this area could benefit both the remote sensing community and terrestrial (e.g., cellular) spectrum sharing and sensing systems, potentially unifying the variety of processing techniques to gain new insights that can lead to improved performance.

In the past, STAR has explored the feasibility of using drones (uncrewed aircraft systems [UASs]) for in situ characterization of antenna arrays and spectrum systems. UASs are currently used to provide unique vantage points for spectrum measurements in the NASCTN Citizens Broadband Radio Service (CBRS) Sharing Ecosystem Assessment project, and to demonstrate some free-space spectroscopy techniques in the dual-comb spectroscopy project in the Fiber Sources and Applications group. Other explorations of aerial capabilities include a possible collaboration with an external partner to develop new electromagnetic compatibility measurement techniques to qualify high-altitude balloon payloads ahead of flight, and recent work funded by National Aeronautics and Space Administration (NASA) and in collaboration with industry and universities to develop a novel noise-temperature calibration target based on a metamaterial design aimed to make a calibration target suitable for flight on a cube-sat. Developing metrology and standards for communications technologies related to drones, low-altitude aircraft, and other emerging technologies like reconfigurable intelligent surfaces is a growth area for STAR, as these are becoming a bigger part of the communications technology landscape.

Radio frequency interference (RFI) poses a critical threat to spaceborne microwave radiometry, where even minor interference can lead to costly errors and compromised weather and environment data collection. As spectrum congestion grows, unwanted signals increasingly disrupt satellite observations. NIST CTL’s advanced RF instrumentation, calibrated data collection, and interference modeling can provide essential tools to quantify and mitigate RFI, ensuring measurement integrity. RFI detection and mitigation is important with increasing spectrum use by emerging 6G nonterrestrial networks, low earth orbiting satellite constellations, and airborne platforms. With its leadership in precise radiometry, NIST is uniquely positioned to collaborate with the National Oceanic and Atmospheric Administration and NASA programs, advancing digital radiometry, onboard RFI mitigation, and small satellite calibration. This can strengthen the scientific community’s ability to safeguard Earth observation systems.

STAR has a very wide range of stakeholders and collaborators including government, industry, standards organizations, and academia, addressing a diverse portfolio. The quality of the technical programs within STAR is adequate for the division to achieve its technical objectives, but continued improvement in these programs is required for any world-class organization, including NIST. Extending the CBRS spectrum sensing to new bands—for example, 7–8 gigahertz—is a good example of future planning. As the CBRS program matures, providing new understanding of how to effectively employ spectrum sensing would be useful to more rapidly deploy spectrum sharing systems in other bands, accelerating network efficiency and supporting economic growth. This knowledge can be obtained by studying RFI in a controlled simulation or emulation environment using RF digital twins. Commercial 5G companies have built digital twins in their laboratories to study the spectrum sharing impact on U.S. Department of War (DOW) radars but they usually do not have a higher-fidelity model of DOW radars. NIST may be better placed to work with DOW to use a high-fidelity model of their radars to interact with a digital twin at their facility.

Artificial intelligence (AI)-native wireless for 6G is emerging as a key trend, integrating AI across the communication stack for smarter, more efficient systems. Digital twins are also central to this vision, yet the lack of standards and reliable datasets limits progress. CTL is uniquely positioned to lead in establishing these standards by leveraging its advanced RF instrumentation and calibrated propagation data to create benchmarks for ray-tracing and other (e.g., AI-developed) models. AI for 6G is a ripe area for new or increased inter-division collaboration. Specifically, the RFTD can contribute heavily to the 6G AI-Native Channel Modeling work in STAR. CTL and the STAR would benefit from a strategic analysis of how they can contribute to metrology, data, and standards for emerging technologies in spectrum sharing including AI-based systems as well as millimeter wave and terahertz technology, within the growing NIST AI metrology and standards efforts. By collaborating with federal, industry, and academic partners, STAR can accelerate the adoption of AI-native wireless technologies, enable standardization of digital twins for communications, and position itself as a key partner in shaping 6G research.

SCIENTIFIC EXPERTISE

The scientific expertise within STAR is of very high quality. This expertise fits the variety of technical programs via a range of researcher types, from early career scientists and engineers to midlevel staff, to senior staff of international repute. As noted, the fundamental work in time transfer with optical combs is award winning. The project was clearly explained, including techniques and goals. This project used expertise from fundamental physics, through engineering, to implementation, and illustrates the practical value that can develop from curiosity-driven research. The optical comb time transfer work has evolved over decades from fundamental research which was awarded a Nobel Prize to technology transfer for NIST, for which the research team received NIST’s 2024 Excellence in Tech Transfer award (Hall 2006 and NIST 2024).

NIST has several internal mechanisms to encourage and recognize excellent science. Within the STAR, the encouragement from managers for principal investigators to propose “seedling” projects that are high risk, high reward is great to motivate innovation and keep talented scientists and engineers interested. Such curiosity-driven research is essential to ensure the continued vitality of the scientific inquiries and engineering solutions of a national laboratory. The NIST Fellow award is an excellent way to recognize career achievement.

The STAR’s scientific and engineering expertise is well qualified to support the division’s mission. Given the broadening scope of the division’s work, additional staff will likely be required in the future; for example, as

spectrum sensing becomes more widely used, a larger suite of techniques would be investigated. This may require additional expertise (e.g., in statistical signal processing). Similarly, exploring the most effective use of digital twins and aerial drones for multiple intelligence disciplines sensing for various use cases and applications will likely require additional staff.

FACILITIES, EQUIPMENT, AND HUMAN RESOURCES

The facilities at the STAR are mostly good. The laboratories are well equipped and maintained, and field-testing facilities are well designed. Laboratory equipment is generally state of the art, but the absence of backup power for some laboratories is a problem. Some of the facilities (e.g., buildings and infrastructure) need renovation. Additional facilities may be required if STAR takes on future work from any government sponsor that requires controlled access. The division has a secure facility, but no associated secure laboratory.

Human resources are managed effectively. The early career scientists and engineers with whom the panel met were excited about their work and spoke very highly of the expertise and mentoring from senior colleagues. Technical staff, particularly primary investigators who lead projects, are highly qualified in science and engineering, but less so in technical marketing and sales. A growth opportunity for STAR is to provide greater services to DOW, which has many research needs aligned with STAR expertise. In the near-term, STAR leadership and principal investigators with good technical marketing and sales skills could engage the DOW stakeholders to leverage the opportunity to conduct dual-use research that benefits the fundamental mission of NIST and addresses DOW challenges.

EFFECTIVENESS OF DISSEMINATION OF PROGRAM OUTPUTS

Dissemination of STAR results through publications is very good. This includes journal publications, conference presentations, technical reports, standards, validated datasets, and even delivery of short courses. For example, STAR shared an extensive list of reports that it published since 2022 in connection with its NASCTN: Citizens Broadband Radio Service Sharing Ecosystem Assessment project. This activity sets a high bar for the other STAR projects that would benefit from a similar level of publication frequency and exposure. Three gaps were identified in the division’s dissemination strategy: collaboration with other government entities to share data, widely sharing and evaluating validated data, and technology transfer.

First, STAR is not collaborating efficiently with other parts of the community to share work publicly, including commercial companies, DOW, and NSF. The DOW Chief Information Officer helped charter the NIST-hosted NASCTN in 2015. Presently, DOW leans heavily on the National Spectrum Consortium (NSC) for advanced spectrum and wireless technology development. Sometimes, NSC projects seem to be better suited for CTL’s STAR. STAR would be well served by exploring more potential Pentagon-related opportunities and collaboration with the DOW Chief Information Officer or Office of the Deputy Under Secretary for Research and Engineering, which could be a source of external funding. Opportunities could include expanding its work on CBRS spectrum sharing for civilian use cases to defense use cases and learning from DOW about requirements from a defense perspective (e.g., based on real battlefield conditions) to inform future research directions. STAR can consider collaborations that would allow DOW program datasets to be made available publicly or within a U.S.-based researcher community if the dataset is International Traffic in Arms Regulations controlled. This would aid in NIST’s dissemination of validated datasets to advance work in government and industry.

Over the past decade, NSF has made substantial investments in spectrum science through program initiatives such as Spectrum Efficiency, Energy Efficiency, and Security; Spectrum and Wireless Innovation Enabled by Future Technologies—Satellite-Terrestrial Coexistence; Next Era of Wireless and Spectrum; and Verticals-enabling Intelligent Network Systems. NSF started a directorate for Technology, Innovation, and Partnership to better align its research with its stakeholder needs. STAR can better align its research portfolio in spectrum research and strategic direction with the outcomes of these parallel efforts conducted by NSC, NSF, and others. For example, NIST could take a more proactive role in engaging with the research community and leveraging the impactful results generated by these programs. Similar to how NIST utilized a risk-based approach to managing multiple-stakeholder

projects under the CBRS effort, it should utilize risk-based approaches to modify new Spectrum Research and 5G Network Slicing program plans to work around stakeholder limitations to reduce long program delays (see Recommendation 4-1). This may involve increased costs and reduction in scope but would avoid producing results that arrive too late to be impactful.

STAR’s relationship with some federal entities remains unclear. For example, the distinction between the National Telecommunications and Information Administration’s Institute for Telecommunications Sciences and NIST CTL’s STAR is understood by the staff but is not clear across the CTL online resources. The webpages of the two organizations seem to indicate that there is significant overlap in their missions. Clarifying this would benefit both organizations by enabling public and private entities to understand the differences between them, potentially streamlining the distribution of future work among them.

Second, sharing its validated data more effectively will increase STAR’s visibility and enable the wider community to test algorithm development on realistic data. NIST-validated data are essential to the spectrum sharing community because most other data collections are proprietary and do not enable fundamental research across the entire community. Currently, some STAR data are shared but are not readily and/or publicly available. Several venues and approaches could improve sharing of validated data, including through relevant Institute of Electrical and Electronics Engineers societies’ forums, or via a competition that could test and evaluate STAR’s data and algorithms. The division could, as an example, host booths with hands-on tutorials at conferences and expos that utilize and then give a dataset for researchers to use. This would provide the STAR research leaders with more opportunities to showcase their work to a large audience, attract young researchers and engineers to NIST, and share their hands-on research expertise more often with the community at large. This outreach could involve follow-up workshops at NIST as other divisions have done in the past.

Third, technology transfer is underemphasized in STAR. Greater focus on technology transfer and increased outreach to relevant companies for technology licensing would increase the visibility of STAR and could yield national economic benefits (e.g., spawning new products, start-up companies). Technology transfer can be facilitated within STAR by better defining it in the strategic planning of the division and tracking its return on investment, such as by mapping the number of the division’s Cooperative Research and Development Agreements with actual technology transitions. Internally valuing it, such as through using technology transfer metrics in project assessment, would help convey its external value in the division’s decision making with regards to continuing certain technical efforts based on their technology transition priority. STAR could also consider holding dedicated events targeted toward technology entrepreneurs and companies to showcase their research outputs, or leverage existing events, such as the National Telecommunications and Information Administration’s International Symposium of Advanced Radio Technologies, for this purpose.

FEEDBACK ON ROADMAPPING AND STRATEGY DEVELOPMENT

The benefits of technical roadmaps are well known: roadmaps align research and development efforts with organizational goals, enabling better prioritization, stakeholder alignment, and efficient resource allocation. NIST’s unique position sustained by long-term federal funding, working on very difficult or long-term technical problems, with benefits across many national and global community applications magnifies the advantages that well-strategized roadmaps would provide. Based on a recommendation from the 2022 National Academies’ review, a formal roadmapping and strategy development effort was started—which is excellent. Roadmapping exercises engaged staff and industry stakeholders to identify gaps in the divisional research spaces and outlined five goals for each research area that align with CTL’s capabilities and industry needs.

Many organizations conduct roadmapping activities every year and make it an iterative process, allowing the strategy and the technology roadmap to evolve. One-off or once every 3 or 5 year roadmap activities defeat the key purpose of a roadmapping exercise because, in such a case, the roadmap becomes stale long before the final outcome strategy from the roadmapping activity is implemented.

CTL projects require formal annual approval through a proposal that aligns with CTL’s scope, demonstrates value to NIST and CTL, and outlines milestones, impacts, and associated risks. Quad charts that address the project need and problem statement are submitted before project planning. Approved projects are planned, including

technical and funding aspects. Division chiefs review ongoing projects annually for alignment with strategic goals, budget, staffing, progress, and emerging challenges, and the quad charts are updated quarterly. Despite these extensive planning processes, the panel found it difficult to understand how the research project presentations and papers it received and reviewed fit into the overall context of STAR’s research strategy, roadmap, and mission objectives. As STAR finalizes the roadmaps it started in spring of 2025, its researchers would benefit from answering these four questions at the very beginning of each presentation or paper generated for internal and external consumption:

1. What is this project trying to do or prove?
2. Why is this project important?
3. How does this project fit into the organization’s short- and long-term research and technology strategy and roadmap?
4. What potential practical outcome or benefit accrues if this project is successful?

Customers need to understand clearly not only what the organization is doing but why and how that work fits into the overall research context and eventual desired outcome. That needs to be implicit and explicit starting at the lowest level to stay on the roadmap once it is adopted. In effect, every researcher needs to become the salesperson for his or her project, and focusing on the four questions above would help with that. Being able to address such questions would aid in prioritizing research projects. This simple approach would also improve dissemination outcomes with existing and new customers.

CONCLUSIONS AND RECOMMENDATIONS

Conclusion 4-1: The current engagement with the U.S. Department of War (DOW), National Science Foundation (NSF), and commercial stakeholders is insufficient. There is a changing focus within DOW to align even fundamental research with national security–relevant causes. Finding opportunities for dual-use research at the National Institute of Standards and Technology (NIST), engaging with DOW and NSF stakeholders more often, and aligning the internal research project investments to also contribute to DOW and NSF mission sets when applicable could advance both NIST and DOW or NSF goals.

Recommendation 4-1: The Spectrum Technology and Research Division (STAR) should collaborate more effectively with U.S. Department of War (DOW), National Science Foundation, and commercial stakeholders. More STAR-related DOW collaborations should implement a risk-based approach to manage multistakeholder programs as is done in the Citizens Broadband Radio Service program. This approach avoids producing results that arrive too late to be impactful even if it means slightly more cost and reduction in scope.

Conclusion 4-2: Radiometric (energy) detection is the standard method for spectrum sensing, but there are multiple other techniques that are superior, particularly when the signals being detected are completely known (e.g., standard waveforms). Cyclostationary detection is one example that the Spectrum Technology and Research Division is considering.

Recommendation 4-2: The Spectrum Technology and Research Division should investigate the potential use of other techniques beyond radiometric detection, e.g., interferometric (two-antenna) detection, feature detection, correlation (e.g., Durbin-Watson), and even matched filtering for spectrum sensing.

Conclusion 4-3: The panel review meeting and follow-up materials described limited projects involving drones or other low-altitude aircraft (e.g., NASA’s Advanced Air Mobility program), or involving reconfigurable intelligent surfaces, which are being intensively studied for use in 6G. This is a key focus area within the 6G network standard.

Recommendation 4-3: The Spectrum Technology and Research Division should develop projects involving drones, low-altitude aircraft, and other emerging technologies of national importance. Research and metrology in these areas should be conducted to influence 6G network architecture and the design of objective, rigorous technical evaluation of these technologies and inform gap and security vulnerability analysis.

Conclusion 4-4: The Spectrum Technology and Research Division’s tracking of technology transfer, and empowerment of the technical staff to achieve such technology transfer, seems ad hoc.

Recommendation 4-4: The Communications Technology Laboratory should better define its technology transfer strategy, track programs for return on investment, value technology transfer internally, and prioritize it as a tracked mission effectiveness measure. Implementation could involve engaging with industry to develop commercial uses cases for their technologies, undertaking one-to-one mapping with Cooperative Research and Development Agreements after the technology transfer, and making technology transfer a significant portion of program success criteria.

Conclusion 4-5: One of the objectives of the Spectrum Technology and Research Division is to provide validated data that improve spectrum sharing models and interference testing. National Institute of Standards and Technology–validated data are of high value for the spectrum sharing community because they are unbiased and nonproprietary. Sharing data can help publicize and increase visibility of the Communications Technology Laboratory’s work.

Recommendation 4-5: The Spectrum Technology and Research Division should share validated data more effectively, through venues such as Institute of Electrical and Electronics Engineers societies, perhaps in a competition, so that people can test and evaluate their algorithms.

Conclusion 4-6: The feasibility of communications digital twins is rapidly increasing because of advances in computational capabilities, and their relevance is growing with the rise of artificial intelligence (AI). As digital twins become more prominent, standardizing their design and validating their performance in AI-native wireless for 6G are emerging as critical areas of research. The broader research community would greatly benefit from the National Institute of Standards and Technology’s active involvement in shaping standards and validation frameworks for communications digital twins.

Recommendation 4-6: The Spectrum Technology and Research Division should lead the development of standardized frameworks for use of digital twins in artificial intelligence–native 6G wireless systems by leveraging the Communications Technology Laboratory (CTL)’s advanced radio frequency instrumentation and calibrated propagation data. This effort should focus on the National Institute of Standards and Technology and CTL strengths and priorities in defining interoperability standards, creating benchmark datasets, and establishing validation protocols to ensure accuracy and reproducibility.

Conclusion 4-7: The long-standing expertise of the Spectrum Technology and Research Division (STAR) in microwave radiometry and precise noise calibration makes it uniquely qualified to lead pilot projects on radio frequency interference detection and mitigation. STAR’s proven capabilities applied to spaceborne and airborne platforms can ensure high-fidelity measurements, protect mission-critical data for existing and future spaceborne microwave radiometry assets, and expand into emerging areas such as unmanned aerial vehicle sensing within 6G Non-Terrestrial Network frameworks. This will strengthen Earth observation and environmental monitoring efforts.

Recommendation 4-7: The Spectrum Technology and Research Division should employ its radiometry expertise to space research applications. A critical component of this expansion is the accurate detection

and mitigation of radio frequency interference, which is essential for preserving the integrity of passive radiometric measurements in space-based and airborne platforms. The space work could expand to the unmanned aerial vehicle domain within the 6G Non-Terrestrial Network construct.

REFERENCES