The NIST CTL spectrum test and evaluation R&D program has three main thrusts. First, we are developing coexistence metrics and testing methods for wireless systems in shared-spectrum environments. Second, we’re developing test methods to evaluate how effective centralized spectrum-management approaches are at protecting incumbent (primary) users. This work extends to assessing the performance of secondary wireless systems as well as comparing the spectrum-utilization efficiency of alternative solutions. Third, we are applying our long experience in waveform metrology and calibration to determine how well spectrum-measurement technologies themselves measure up – and, if necessary, to improve them.
In coexistence metrics and test methods, CTL is:
- Developing metrics, test methods, procedures, and best-practices for evaluating the spectrum-sharing impacts of multiple radio access technologies, starting with coexistence analysis of radar and wireless broadband services.
- Performing coexistence analyses and developing interference protection criteria for specific technologies in Federal bands, such as with SPN-43 naval air-traffic control radar and small-cell 4G LTE wireless data in the 3.5 GHz band.
- Field-testing data of unlicensed wireless in several critical coexistence scenarios. Technologies include LTE-U (proposed to send LTE data over the same unlicensed 5 GHz frequencies as Wi-Fi), 802.11 (Wi-Fi), and distributed antenna systems, to be tested for coexistence in environments such as hospital rooms and factory floors.
In Spectrum coordination metrics and test methods, we are:
- Establishing quantitative metrics for evaluating centralized spectrum-management systems. This involves:
- Developing signal and system metrics appropriate for measuring impact on an incumbent system, including the establishment of thresholds for spectrum-sharing violations (that is, an intrusion on the incumbent by a secondary system) and application-specific metrics depending on whether the infringed-upon primary user is, say, a radar system or an emergency-communications system.
- Determining the spectrum utilization efficiency of secondary system or systems (i.e., how well they exploit available white space).
- Understanding wireless-receiver operating characteristics and the detection delay of sensing/monitoring technologies
- Once the above metrics are established, developing and refining test methods, procedures, and best-practices for measuring them.
To define measurement uncertainty in shared spectrum metrology, CTL is:
- Establishing waveform metrology and calibration of instruments used for shared-spectrum testing (channel emulators, signal generators, spectrum analyzers, software-defined radios)
- Characterizing measurement uncertainty of the identified coexistence and spectrum- coordination metrics
NIST Teams involved
Metrology for Wireless Systems Group
Shared Spectrum Metrology Group