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

Jiuyu Liu, Yi Ma, Ahmed Elzanaty, Rahim Tafazolli

TL;DR

A three-dimensional (3D) fading channel model for ELAA systems deployed with a uniform rectangular array (URA) can capture the impact of sensing object for ISAC applications and have the potential to contribute to the standard in various aspects.

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.

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

TL;DR

A three-dimensional (3D) fading channel model for ELAA systems deployed with a uniform rectangular array (URA) can capture the impact of sensing object for ISAC applications and have the potential to contribute to the standard in various aspects.

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.
Paper Structure (21 sections, 4 figures)

This paper contains 21 sections, 4 figures.

Table of Contents

  1. Introduction
  2. Overview of Current ELAA Channel Models
  3. Contributions of This Article
  4. The Framework of ELAA Fading Channel Model for Communication and Sensing
  5. The Proposed 3D Fading Channel Model
  6. The Numerical Demonstration
  7. The Proposed 3D Fading Channel for Communication
  8. Window Generation in Horizontal Direction
  9. Window Generation in Vertical Direction
  10. Pathloss, Small-Scale Fading, and Shadow fading
  11. The Proposed 3D Fading Channel for Sensing
  12. Discussion: Standards Related Contributions
  13. Future Directions
  14. Modeling the Channel Correlation of Different MTs
  15. Modeling the Behavior of NF Shadow Fading
  16. ...and 6 more sections

Figures (4)

  • Figure 1: A comparison between NF-MIMO and FF-MIMO channels, where the NF-MIMO channel allow a mix of LoS and NLoS links. The figure demonstrates a typical 3GPP use case for ISAC known as intrusion detection 3gpp.22.837. In XL-MIMO systems, the sensing target might only obstruct a fraction of the LoS links.
  • Figure 2: The framework of ELAA fading channel model for both communication and ISAC applications. The proposed framework only requires the coordinates of ELAA, MT and sensing objects, and does not rely on the geometric information of the propagation environment, such as buildings or clusters.
  • Figure 3: The numerical demonstration of the proposed fading channel model deploying a URA with 100 × 200 service antennas. There are two MTs and a sphere sensing object. It is obvious that the proposed channel model allows a mixed of LoS and NLoS links.
  • Figure 4: of the proposed fading channel model in the same Monte Carlo experiment as Fig. \ref{['fig_LoS']}. Every element is normalized by the maximum element.