Enhancing Non-line-of-sight ISAC with Position-Aware Beamforming

Millimeter-wave (mmWave) technology represents a promising avenue in integrated sensing and communication (ISAC), leveraging wide bandwidth to accommodate growing demands for high data-rate communication and high-resolution radar sensing. However, in non-line-of-sight (NLOS) scenarios, mmWave signals suffer from severe attenuation, and integrating precise radar sensing into bandwidth-limited communication systems remains an open problem. To address this, we propose an NLOS-ISAC system that jointly provides accurate target positioning and robust communication. Our approach synthesizes many narrowband signals into a virtual wideband radar via stepped-frequency techniques, eliminating the need for additional hardware. By fusing time-of-flight (ToF) measurements of multipath reflections with environmental maps, the system achieves submeter positioning accuracy for NLOS targets. Building on these position estimates, we then employ position-aware beamforming to significantly enhance the NLOS communication throughput. Extensive experimental results demonstrate that the proposed NLOS-ISAC system reliably achieves high-accuracy localization while improving data rates in challenging NLOS environments.