NSF SWIFT: Passive Active Spectrum Sharing (CU-PASS)

Project Description:

Hat Creek Satellites.
Spectrum sharing between passive and active systems has not been well researched. Deployed methods of spectrum sharing require some means of detecting whether a radio frequency (RF) band is being actively used. Passive systems do not transmit, so no means are available to detect whether a passive system is operating. Currently, passive systems are protected by prohibiting all transmissions in specific frequency bands, or by designating geographic radio quiet zones (RQZs) within which transmissions are prohibited at all frequencies. However, increasing numbers of wireless devices are believed to be increasing the levels of ambient RF noise. Further, the increasing demand for RF spectrum is forcing more spectrum sharing between disparate radio services. New and innovative means are required to enable co-existence of passive and active services while making more spectrum available for the increasing number of active users. Additionally, to maximize the effectiveness of sharing and to protect the interests of both communities, the spectrum sharing mechanisms must be dynamic, secure and address Personally Identifiable Information (PII) concerns.

Project Goals:

Green Bank Telescope.
Systematic longitudinal surveys of RF noise around a major metropolitan area, the Denver-91¸£ÀûÉç area in Colorado and on the campus of the University of Colorado will be conducted to establish baseline RF noise levels across wide frequency bands (initially up to 6 GHz with plans/designs to increase up to 12 GHz). The SWIFT CU-PASS team will also perform multiple longitudinal surveys to establish the baseline RF spectrum environment surrounding a representative passive system, the Hat Creek Radio Observatory (HRCO) in Northern California.

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The objectives of the long-term RF baseline noise are:

  • Analysis and characterization of RF noise with respect to environmental parameters to identify patterns. The team will also explore RF noise mitigation approaches based on the results.

  • Exploration of new approaches to dynamic spectrum sharing between passive and active services.

  • Quantitative analysis of dynamic spectrum sharing mechanisms extended to enable sharing between passive and active services.

  • Exploration of approaches to optimize the efficiency and security of dynamic spectrum sharing.

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​ExplorationÌýof operational mechanisms for a National Radio Dynamic Zone (NRDZ). PASS will make multiple contributions to the scientific community, including:

  • Tested, documented, and publicly accessible best practices for RF noise measurement.

  • Documented data and metadata formats for RF noise measurements, and open RF noise data sets to enable multi-institutional collaboration in measurement and analysis.

  • Tools and metrics for quantitative analysis of dynamic spectrum sharing effectiveness.

  • Processes for optimizing the effectiveness and security of dynamic spectrum sharing.

  • Preliminary operational definition and requirements for a NRDZ.

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The PASS project will have a broad impact beyond contributions to research and engineering. The same results, along with the exploration of security approaches will inform the commercial world as it develops and deploys systems that exploit spectrum sharing to gain spectrum access. Documents and workshops that result from the PASS project will inform the curricula of institutions training the next generation of RF engineers and scientists. The RF noise measurements and analysis, quantitative evaluation of spectrum sharing mechanisms, and NRDZ requirements will inform spectrum policy makers.

This project addresses three core intellectual challenges. The first is the systematic treatment of RF noise. This treatment will result in the definition of data structures, databases, and analytic tools to support collaborative surveys, analyses, and characterizations of RF noise. An important contribution of this project is the definition of open source data structures and software for measurement and analysis of RF noise, along with acquisition and publication of a baseline RF noise survey that can be analyzed and built on by a larger community. The second challenge is development and quantitative analysis of mechanisms for bi-directional spectrum sharing between passive and active systems. This project will generate open-source data, tools, and scenarios that can be used by the community to perform apple-to-apple comparisons of spectrum sharing protocols. The third challenge is to define a National Radio Dynamic Zone (NRDZ). This project will perform the experimentation and analysis to generate preliminary requirements for an NRDZ. The results of the project will be published with data available online to support community-wide data collection and analysis to refine the NRDZ concept.Ìý

The impact of this project will be felt in three primary domains: the research and engineering (R&E) domain, the educational domain, and the regulatory domain. In the R&E domain, both government and industry developers will benefit from open source data formats and tools for RF measurement and analysis, and analysis of spectrum sharing. The results from this project will transition effectively into many other areas of wireless co-existence. In the educational domain, over the next 5, 10, or 20 years, the demand for RF engineers and scientists will increase. PASS will document the best practices and lessons learned over the course of the project to help educate the next generation of scientists and engineers in the basics of measurement surveys and analyses of both RF noise and spectrum sharing. In the regulatory domain, bi-directional sharing is currently just a concept. This project will research and evaluate approaches to bi-directional spectrum sharing that will both demonstrate the possibility and quantify the effectiveness. Bi-directional sharing has potential for application to many instances of passive-active sharing as well as active-active sharing. Government regulators will also benefit from quantitative data about RF noise, spectrum sharing, and securing spectrum sharing.