Institute for Telecommunication Sciences
the research laboratory of the National Telecommunications and Information Administration

Institute for Telecommunication Sciences / Programs / Spectrum Monitoring

Spectrum Monitoring

“The NTIA shall design and conduct a pilot program to monitor spectrum usage in real time in selected communities throughout the country to determine whether a comprehensive monitoring program could disclose opportunities for more efficient spectrum access, including via sharing.” (The White House, Presidential Memorandum: “Expanding America’s Leadership in Wireless Communications,” June 14, 2013.)

Seemingly insatiable demand for wireless broadband access has prompted U.S. government initiatives to make more frequencies available for commercial broadband applications. Desirable radio spectrum has been mostly allocated in the U.S., leaving two basic ways to make more spectrum available: (1) open frequency bands to shared use or (2) relocate incumbent users to other bands. In both cases, the density of systems in space, frequency, and time will increase. Without adequate planning and precautions, this creates a higher probability of interference events, increased risk for incumbents and investors, and a reduction in spectrum value.

Measured spectrum occupancy is useful information for planning, engineering, and enforcing new spectrum sharing and relocation scenarios. With some standardization and the development of best practices to ensure data quality, measured spectrum data could be made available alongside license and assignment data to improve the quality and quantity of information available for planning by policy makers, spectrum managers, and investors. In the engineering phase of a transition process, real-time and historical measured spectrum data could be used to check assumptions, validate propagation and usage models, and field test dynamic coordination schemes and technologies. After a sharing or relocation authorization, open and transparent use of relevant spectrum data can play a critical role in interference resolution and enforcement in the increasingly dynamic and complex interference environment.

Long-term and continuous acquisition of spectrum data, i.e., spectrum monitoring, is currently being performed by industry, academia, and government for a variety of purposes. There has been little effort, however, to collect, extend, and curate this information for the benefit of all. The organizations acquiring spectrum data use a wide variety of data types to suit their purposes. The means of acquiring the data also varies and there is no one-size-fits-all approach. With all these disparate sources, types, and methods, there is a need for infrastructure and standardization to aggregate and achieve full collective value of the data.

A pilot project to develop spectrum monitoring capability to meet this need is one of the first research efforts undertaken under the umbrella of the CAC. Its goals are to (1) develop an infrastructure to acquire and amass spectrum monitoring data and make it available to the spectrum community in near real time via the Internet, and (2) establish best practices for the acquisition of spectrum data.

Measured Spectrum Occupancy Database (MSOD)

Toward the first of those goals, ITS and NIST CTL (Gaithersberg) are developing a distributed Measured Spectrum Occupancy Database (MSOD) architecture. The architecture will enable industry, academia, and government agencies to host MSOD instances and contribute spectrum data to the overall program. Users will be able to query MSOD via a Web service or view and download data with a browser-based data visualization application. To inform policy discussions, band occupancy statistics over long time intervals will be available in the visualization tool, as shown in the screen capture below.

DailyBandOccupancy.jpg

Near-real-time amplitude versus frequency data, displayed in the screen capture below, will also be available for spectrum coordination and enforcement purposes.

LiveStream.jpg

RF Sensor Development and Deployment

Toward the second goal, we are pursuing RF sensor development and deployment. Sensor hardware and software are being designed to detect well-defined system transmissions in specified frequency bands, e.g., LTE at 0.7 GHz and 1.7 GHz and pulse radar at 3.0 GHz and 3.5 GHz. Novel aspects of the sensor designs include: (1) local calibrations to indicate health of sensors in the field and to measure system noise level; (2) a standard format for the transfer of calibrated measurements from the sensor to the repository; and (3) benchmark tests on commercial-off-the-shelf (COTS) sensors and software defined radios (SDRs) to assess capabilities and limitations.

A radar sensor prototype was tested in the lab and deployed at Virginia Beach in August 2014 to monitor the 3.5 GHz maritime radar band. In FY 2015, we plan to build and deploy three additional 3.5 GHz sensors near Miami, San Diego, and San Francisco.

References

[1] M. Cotton, M. Souryal, J. Wepman, M. Ranganathan, J. Kub, S. Engelking, Y. Lo, H. Ottke, R. Kaiser, and D. Anderson, “An Overview of the NTIA/NIST Spectrum Monitoring Pilot Program,” International Workshop on Smart Spectrum at IEEE WCNC 2015, New Orleans, LA, March 9–12, 2015.

[2] M. Cotton and R. Dalke, “Spectrum Occupancy Measurements of the 3550–3650 MHz Maritime Radar Band Near San Diego, CA,” NTIA TR-14-500, Jan. 2014.

For more information about this project, contact Michael G. Cotton.