ABSTRACT

This project investigates methods to mitigate radio-frequency interference. The research team will implement new approaches, which are needed because traditional electromagnetic (radio-frequency) spectrum monitoring approaches are losing effectiveness. The continuing growth of wireless communications requires the limited available spectrum to be used ever more efficiently. To pack wireless systems more tightly, transmitters and receivers are evolving to use directional antennas that can steer away from interference. Directional transmissions mean a sensor at a single location can no longer rely on detecting all nearby transmissions, and when the sensor does observe an incoming signal, it cannot easily predict what other devices or locations are impacted. SweepSpace seeks to overcome these limitations and provide new spatial and directional information that enables safely increasing communications and sensing capacity without increasing spectrum cost. This project evaluates the new methods and the SweepSpace prototype through analysis, laboratory tests and limited field experiments. The project will provide training for the next-generation workforce for wireless communications and spectrum science by engaging graduate, undergraduate, and high-school students, including students from underrepresented groups. SweepSpace sensor kits, based on a low-cost software defined radio, will be created for use in workshops, demonstrations, and classrooms.

SweepSpace is a generalized spectrum sensing architecture designed to report all spatio-temporal activity in a spatial-frequency volume. Complete knowledge of transmissions requires the deployment of a dense network of sensors; it requires each sensor to detect all incoming signals across a wide range of frequencies; and it requires each sensor to identify the direction of all incoming signals. Rapid sweeping across 3D space over a wide band enables a low-cost sensor with a single moderate-bandwidth receiver to frequently sample every channel in a wide range and to frequently sample all incident directions via a sweeping phased array antenna. The team will investigate the use of off-the-shelf components to develop a prototype low-cost SweepSpace node. They will investigate 1) reconstruction of a full spatio-temporal activity map from samples that are sparse across space, time, frequency, and incident direction; 2) enhancing the directional precision of individual sensors; 3) optimizing the placement and parameterization of the; and 4) identifying spatio-temporal holes for safe insertion of new activity. They will also investigate single-sensor questions, such as minimum detectability bounds, risk of missed detections and false positives, and optimal scheduling policies, and they will characterize the probability of missed detections by a network of sensors. The project includes development of risk mitigation tools that can be used by others to tailor SweepSpace for their use cases.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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