Unlocking Potentials of Near-Field Propagation: ELAA-Empowered Integrated Sensing and Communication

TL;DR

This paper investigates the use of extremely large antenna arrays in near-field propagation for integrated sensing and communication, highlighting new opportunities and challenges in 6G wireless networks.

Contribution

It provides a systematic analysis of ELAA-enabled near-field ISAC, emphasizing its advantages, applications, and technical challenges in the context of 6G.

Findings

Near-field propagation requires spherical wave models instead of planar waves.

ELAA enhances ISAC by offering additional degrees of freedom and dual-functional capabilities.

Key technical challenges include modeling complexities and hardware implementation issues.

Abstract

The exploration of extremely large antenna arrays (ELAAs) using high-frequency spectrum has led to a paradigm shift in 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 systematical 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 to near-field communications. Then, we turn to near-field sensing and expound upon various typical applications. Following the separate elaborations 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 enablements of other complementary technologies. Finally, we outline key technical challenges that merit further exploration in the realm of ELAA-empowered near-field ISAC.