Extremely Large-Aperture Arrays for V2X Communication, Localization and Sensing.

Future sixth-generation (6G) vehicular networks are expected to support connected, autonomous, and cooperative driving through ultra-reliable, low-latency, and context-aware vehicle-to-everything (V2X) communications. In this paper, we investigate the role of extremely large-aperture arrays (ELAAs) deployed on board vehicles as a key enabler for the joint enhancement of communication, localization, and sensing functionalities, with particular focus on V2X sidelink transmissions. Leveraging the large spatial aperture of ELAAs, advanced beamfocusing and line-of-sight (LOS)-multiple-input multiple-output (MIMO) techniques are reviewed to improve communication reliability and spatial multiplexing in highly dynamic vehicular scenarios. Moreover, we analyze vehicular near-field single-anchor localization and sensing enabled by large arrays, as well as predictive beamforming strategies based on Doppler analysis that enable the estimation of multiple velocity components of surrounding objects and vehicles. This paper highlights the tight interplay between communication and sensing, demonstrating how it can enhance performance across these domains. Our analysis provides insights into the potential of ELAA-based integrated sensing and communication (ISAC) architectures for next-generation vehicular networks.