Unlocking Potentials of Near-Field Propagation: ELAA-Empowered Integrated Sensing and Communication
Zhenyao He, Wei Xu, Zhaohui Yang, Hong Shen, Ningning Fu, Yongming Huang, Zhaoyang Zhang, Xiaohu You
Abstract
The exploration of extremely large antenna arrays (ELAAs) using high-frequency spectrum has led to a paradigm shift in the electromagnetic radiation field, transitioning from the common use case of far-field propagation to near-field propagation. This shift necessitates the modification of the conventional planar-wavefront approximation to more accurate spherical waves, exerting a profound impact on wireless transmission technologies encompassing communication and sensing. Concurrently, integrated sensing and communication (ISAC) has gained prominence in the context of the sixth-generation (6G) wireless networks owing to its ability to cater to the ever-increasing demands of future networks. In line with this evolving trend, this article presents a systematic investigation on ELAA-empowered near-field ISAC. We begin by introducing the fundamentals of near-field propagation with an emphasis on its double-edged effects on near-field communications. Then, we turn to near-field sensing and expound upon various typical applications. Following separate elaboration on communications and sensing, we articulate in-depth advantages of ELAA-empowered ISAC in near field, particularly including featured opportunities arising from the dual-functional integrations, potential ISAC applications benefiting from the additional degrees-of-freedom in near field, and enabling of other complementary technologies. Finally, we outline key technical challenges that merit further exploration in the realm of ELAA-empowered near-field ISAC.