Near-Field Fading Channel Modeling for ELAAs: From Communication to ISAC

TL;DR

This paper introduces a comprehensive near-field fading channel model for ELAA systems in 6G, supporting communication and ISAC, incorporating spherical wave effects, shadow fading, and sensing impacts, based on 3GPP standards.

Contribution

It proposes a novel 3D near-field fading channel framework for ELAA systems that integrates LoS/NLoS, spherical wave, and shadow fading effects, aligned with industry standards.

Findings

The model captures the impact of sensing objects on ISAC performance.

Parameters are based on 3GPP specifications, ensuring standard compliance.

Framework supports future ELAA system design and transceiver development.

Abstract

Extremely large aperture array (ELAA) is anticipated to serve as a pivotal feature of future multiple-input multiple-output (MIMO) systems in 6G. Near-field (NF) fading channel models are essential for reliable link-level simulation and ELAA system design. In this article, we propose a framework designed to generate NF fading channels for both communication and integrated sensing and communication (ISAC) applications. The framework allows a mixed of line of sight (LoS) and non-LoS (NLoS) links. It also considers spherical wave model and spatially non-stationary shadow fading. Based on this framework, we propose a three-dimensional (3D) fading channel model for ELAA systems deployed with a uniform rectangular array (URA). It can capture the impact of sensing object for ISAC applications. Moreover, all parameters involved in the framework are based on specifications or measurements from the 3rd Generation Partnership Project (3GPP) documents. Therefore, the proposed framework and channel model have the potential to contribute to the standard in various aspects, including ISAC, extra-large (XL-) MIMO, and reconfigurable intelligent surface (RIS) aided MIMO systems. Finally, future directions for ELAA are presented, including not only NF channel modeling but also the design of next-generation transceivers.