NeTS: Small: Near-Field ISAC: Exploiting XL Arrays for Targeted Sensing and Communication

There is growing interest in wireless technologies that enable devices not only to communicate, but also to sense their surrounding environments using shared hardware and spectrum. Such technologies, known as integrated sensing and communication (ISAC), are key enablers for future applications like public safety, smart factories, and immersive wireless experiences. This project focuses on ISAC systems operating at high-frequency bands such as millimeter-wave and terahertz, which support high data rates and fine sensing resolution. However, the severe signal loss at these frequencies requires the use of extremely large (XL) antenna arrays to provide sufficient beamforming gain. This project addresses key challenges in such systems by developing technologies that allow wireless signals to focus not only on specific directions, but also at specific distances, improving both communication and sensing performance. In addition, the project explores new methods to protect transmitted information from eavesdroppers, enhancing the security of wireless communications and sensing in ISAC systems. By enabling shared use of spectrum and hardware, this project promotes more flexible wireless infrastructure, strengthens national competitiveness in next-generation wireless technologies, supports innovation-driven economic growth, and contributes to public safety through enhanced environmental awareness. This project establishes a unified framework for near-field integrated sensing and communication (NF-ISAC), focusing on extremely large (XL) antenna arrays operating in near-field conditions, where conventional far-field models break down. Key challenges addressed include spherical wavefronts, range-angle coupling, and nonlinear phase variations inherent in near-field propagation. Research activities span three thrusts. Thrust 1 develops computationally efficient and scalable NF-ISAC system design using advanced optimization tools. Thrust 2 focuses on fundamental signal processing algorithms for NF-ISAC systems, including multi-beam scanning based on random partitioning and compressive sensing to reduce scanning time, clustered channel modeling for efficient estimation, and structured methods for super-resolution localization using fragmented time-frequency resources in dense, dynamic near-field environments. Thrust 3 explores physical-layer security techniques using beamfocusing and symbol-level precoding to protect transmissions against passive eavesdroppers, even without knowledge of their positions. Together, these advances enable highly accurate, secure, and efficient joint communication and sensing, with broad applications in healthcare, robotics, and intelligent environments. The project’s outcomes are expected to support the development of next-generation wireless systems with enhanced performance, security, and adaptability. 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.