VINES: Track 1: Spectrum Coexistence and Integration for Mega LEO and Direct-to-Handset Satellite Networks

Satellites orbiting close to Earth, known as Low Earth Orbit (LEO) satellites, are rapidly changing how people stay connected. LEO systems already provide internet access to remote areas, and newer services have begun to allow ordinary smartphones to connect directly to satellites in remote settings. However, as more LEO service providers launch their own satellite networks, these systems must share the same radio frequency spectrum without causing harmful interference to one another or to existing cell phone networks. This project organizes its technical work into two research thrusts. Thrust 1 develops fundamental new principles to determine how many independent LEO constellations, and how many satellites per constellation, can coexist in shared spectrum before performance collapses. It analyzes both non-cooperative and cooperative satellite-to-terminal association strategies, derives coexistence feasibility frontiers, and studies the security risks introduced by inter-constellation information sharing. Thrust 2 addresses the integration of satellite networks with terrestrial cellular networks to serve smartphones directly from space, a paradigm called Direct-to-Cellular. It develops new fundamentals for maximizing area spectral efficiency at the rural-to-urban transition boundary and proposes a novel direct wireless link between terrestrial base stations and LEO satellites, called the Integrated Terrestrial-Satellite Network link, to enable tight synchronization, coordinated scheduling, and a resilient backup to GPS. Both thrusts will be validated through high-fidelity open-source simulation and hardware-in-the-loop experimentation. This project develops the scientific and engineering foundations needed to make that sharing reliable, fair, and efficient, so that people in rural and disaster-affected communities can enjoy robust, uninterrupted connectivity. The open-source simulation tools and curated datasets released under this project will serve as shared infrastructure for the research community. Engagement with federal regulators and industry partners, including ongoing relationships with major satellite and cellular operators, will help translate findings into principled spectrum policy at a moment when billions of dollars are being invested and national regulations are being written. Students will gain hands-on research experience through new course modules, senior design projects, and community challenges. 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.