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Near-field Communications with Extremely Large-Scale Uniform Arc Arrays: Channel Modelling and Performance Analysis

Guoyu Li, Changsheng You, Guanyu Shang, Shaochuan Wu

Abstract

In this letter, we propose a new conformal array architecture, called extremely large-scale uniform arc array (XL-UAA), to improve near-field communication performance. Specifically,under the non-uniform spherical wavefront channel model, we establish mathematical modeling and performance analysis for XL-UAAs. It is shown that XL-UAAs have larger direction-dependent Rayleigh distance and uniform power distance than the conventional XL uniform linear arrays (XL-ULAs). Moreover, a closed-form expression for the signal-to-noise ratio (SNR) is obtained, which depends on collective properties of XL-UAAs, such as the distance between the user and the array center,as well as the arc radius. In addition, we show that the asymptotic SNR of XL-UAAs with the number of antennas depends on the projection distance of the user to the middle of the arc array. Finally, numerical results verify that XL-UAAs achieve a higher SNR than XL-ULAs, especially at larger user incident angles.

Near-field Communications with Extremely Large-Scale Uniform Arc Arrays: Channel Modelling and Performance Analysis

Abstract

In this letter, we propose a new conformal array architecture, called extremely large-scale uniform arc array (XL-UAA), to improve near-field communication performance. Specifically,under the non-uniform spherical wavefront channel model, we establish mathematical modeling and performance analysis for XL-UAAs. It is shown that XL-UAAs have larger direction-dependent Rayleigh distance and uniform power distance than the conventional XL uniform linear arrays (XL-ULAs). Moreover, a closed-form expression for the signal-to-noise ratio (SNR) is obtained, which depends on collective properties of XL-UAAs, such as the distance between the user and the array center,as well as the arc radius. In addition, we show that the asymptotic SNR of XL-UAAs with the number of antennas depends on the projection distance of the user to the middle of the arc array. Finally, numerical results verify that XL-UAAs achieve a higher SNR than XL-ULAs, especially at larger user incident angles.

Paper Structure

This paper contains 12 sections, 3 theorems, 18 equations, 3 figures.

Table of Contents

  1. Introduction
  2. System Model
  3. Near-field Communication Performance for XL-UAAs
  4. Rayleigh distance for XL-UAAs
  5. The DDRayl distance
  6. UPD
  7. SNR analysis for XL-UAA
  8. Numerical Results
  9. Conclutions
  10. Proff of Theorem 1
  11. Proff of Corollary 1
  12. Proff of Corollary 2

Key Result

Theorem 1

Given the MRC beamforming, the received SNR at the XL-UAA in sum_SNR can be expressed as where $U(x,y) = \arctan \left( \frac{(x^2 + y^2 + 2xy\cos{\phi}) \sqrt{\frac{L}{2y-L}}-2xy\sin{\phi}}{x^2 - y^2}\right) + \arctan \left( \frac{(x^2 + y^2 + 2xy\cos{\phi}) \sqrt{\frac{L}{2y-L}}+2xy\sin{\phi}}{x^2 - y^2}\right)$.

Figures (3)

  • Figure 1: The geometrical relationship between the XL-UAA and user in the near-field region.
  • Figure 2: Comparison of the DDRayl distance and UPD.
  • Figure 3: The SNRs for XL-UAA and XL-ULA.

Theorems & Definitions (6)

  • Theorem 1
  • proof
  • Corollary 1
  • proof
  • Corollary 2
  • proof