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Radio Frequency Measurement Sciences
ITS’s Radio Spectrum Measurement Sciences (RSMS) program builds on 100 years of experience in radio frequency (RF) measurements to develop, implement, and disseminate best practices for capturing accurate radio frequency measurements. The expertise and capabilities cultivated in the RSMS program support the NTIA and other federal agencies by developing and maintaining the Institute’s ability to perform critical, time-sensitive radio frequency (RF) measurements for purposes including:
- Spectrum and channel usage surveys and monitoring
- Equipment characterization and compliance
- Interference resolution and electromagnetic compatibility
- Signal coverage and quality
Spectrum surveys and spectrum monitoring measure and analyze the geographic and temporal distribution of RF signals within a spectrum band and provide empirical data to help determine which RF bands are good candidates for sharing in space or time.
Spectrum surveys span multiple frequency ranges, last for one or more months, and measure spectrum occupancy, or the percentage of time that RF spectrum is being used within a given geographic area.
Spectrum monitoring produces long-term, continuous observations of occupancy within a particular band from multiple sensors, provides real-time information about the use of a narrow range of frequencies across broad geographic areas, and enables observation of historical trends and events. If a band is unused within an area, then geographic sharing of that band is possible. If band occupancy is low, then that band is a candidate for sharing; a newcomer system could use the band when it is unoccupied by incumbent systems.
Two RF spectrum dependent systems with overlapping or near adjacent coverage may or may not interfere with each other. The analysis of whether coexistence is feasible begins with gathering the transmitter and receiver parameters of both systems. Transmitter power and receiver sensitivity, as well as information about the digital modulation, antenna characteristics, and bandwidth of both receiver and transmitter must be analyzed and understood. Electromagnetic compatibility analysis (EMC) uses all that information to establish the interference protection criteria (IPC): the engineering parameters that specify combinations of frequency and geographic separation which enable two RF systems to coexist.
NTIA's Office of Spectrum Management (OSM) and ITS’s other federal agency partners leverage RSMS expertise and capabilities to prevent and, if necessary, resolve interference problems involving federal systems. ITS’s body of knowledge is applied to troubleshooting incidents of interference between systems and existing capabilities are tailored to specific situations.
ITS work in these areas is transferred to the broader research community through reimbursable research partnerships with the National Aeronautics and Space Administration (NASA), the National Institute of Standards and Technology (NIST), National Oceanic and Atmospheric Administration (NOAA), the Federal Communications Commission (FCC), the Federal Aviation Administration (FAA), the Department of Defense (DoD), and OSM, among others.