Abstract

Modern vehicles have evolved from a transportation mode into an intelligent cabin on the road. High-throughput, low-latency communication and accurate in-car occupant sensing are fundamental parts of modern in-cabin systems. However, existing in-car communication and sensing solutions are not well suited for smart cabin applications. In this summary, we propose an in-cabin near-field integrated sensing and communication (ISAC) system that can focus the beam to a given spatial point. Compared with far-field beamforming, near-field operation enables true beam focusing using phase-only tunable elements. With the introduction of reconfigurable intelligent surfaces (RIS), such focusing can also be realized when the direct line of sight is blocked, creating virtual paths to otherwise unreachable targets. We provide theoretical analysis showing that typical cabin distances fall within the Fresnel region when the RIS side length exceeds 8 cm at 28 GHz, making near-field beam focusing viable. Experimental results further demonstrate that under realistic cabin geometries, RIS-aided near-field ISAC can restore blocked communication links and enable accurate occupant detection. These findings indicate that phase-only near-field beamforming, supported by RIS, is a promising solution for future smart cabin applications.

Citation

Ziyu Chen, Alvin Yang, Matthew T. Kouchi, Wayne A. Shiroma, Aaron T. Ohta, Yao Zheng, Hanqing Guo, “RIS-Aided Near-Field ISAC for Smart Vehicle Cabins,” 2026 United States National Committee of URSI National Radio Science Meeting (USNC-URSI NRSM), 2026, pp. 352–353. doi: 10.23919/NRSM68586.2026.11550943.

Download BibTeX citation · DOI: 10.23919/NRSM68586.2026.11550943