Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Huygens-Fresnel Model Based Position-Aided Phase Configuration for 1-Bit RIS Assisted Wireless Communication

Xiao Zheng, Wenchi Cheng, Jiangzhou Wang

TL;DR

The paper tackles the CSI overhead challenge in near-field RIS-assisted wireless links by proposing a CSI-free, position-aided phase configuration that leverages Fresnel-zone geometry. It introduces impedance-based 1-bit RIS elements with joint absorption and reflection modes and a two-step TPOSJ scheme to judiciously ON/OFF elements, complemented by a Huygens-Fresnel-based power-flow model to quantify reflected power. The framework extends to MISO and multi-RIS deployments, analyzes complexity and mobility robustness, and demonstrates via simulations that CSI-free configurations can achieve near-ideal performance with added resilience to position error. Overall, the approach offers a low-complexity, geometry-driven alternative to channel-estimation-centric RIS design, suitable for high-frequency, near-field scenarios and IoT-oriented deployments.

Abstract

Reconfigurable intelligent surface (RIS), composed of nearly passive elements, is regarded as one of the potential paradigms to support multi-gigabit data in real-time. However, in traditional CSI (channel state information) driven frame, the training overhead of channel estimation greatly increases as the number of RIS elements increases to intelligently manipulate the reflected signals. To conveniently use the reflected signal without complex CSI feedback, in this paper we propose a position-aided phase configuration scheme based on the property of Fresnel zone. In particular, we design the impedance based discrete RIS elements with joint absorption mode and reflection mode considering the fabrication complexities, which integrated the property of the Fresnel zone to resist the impact of position error. Then, with joint absorption and 1-bit reflection mode elements, we develop the two-step position-aided ON/OFF states judgement (TPOSJ) scheme and the frame structure to control the ON/OFF state of RIS, followed by analyzing the impacts of mobility and position error on our proposed scheme. Also, we derive the Helmholtz-Kirchhoff integral theorem based power flow. Simulations show that the proposed scheme can manipulate the ON/OFF state intelligently without complex CSI, thus verifying the practical application of our proposed scheme.

Huygens-Fresnel Model Based Position-Aided Phase Configuration for 1-Bit RIS Assisted Wireless Communication

TL;DR

The paper tackles the CSI overhead challenge in near-field RIS-assisted wireless links by proposing a CSI-free, position-aided phase configuration that leverages Fresnel-zone geometry. It introduces impedance-based 1-bit RIS elements with joint absorption and reflection modes and a two-step TPOSJ scheme to judiciously ON/OFF elements, complemented by a Huygens-Fresnel-based power-flow model to quantify reflected power. The framework extends to MISO and multi-RIS deployments, analyzes complexity and mobility robustness, and demonstrates via simulations that CSI-free configurations can achieve near-ideal performance with added resilience to position error. Overall, the approach offers a low-complexity, geometry-driven alternative to channel-estimation-centric RIS design, suitable for high-frequency, near-field scenarios and IoT-oriented deployments.

Abstract

Reconfigurable intelligent surface (RIS), composed of nearly passive elements, is regarded as one of the potential paradigms to support multi-gigabit data in real-time. However, in traditional CSI (channel state information) driven frame, the training overhead of channel estimation greatly increases as the number of RIS elements increases to intelligently manipulate the reflected signals. To conveniently use the reflected signal without complex CSI feedback, in this paper we propose a position-aided phase configuration scheme based on the property of Fresnel zone. In particular, we design the impedance based discrete RIS elements with joint absorption mode and reflection mode considering the fabrication complexities, which integrated the property of the Fresnel zone to resist the impact of position error. Then, with joint absorption and 1-bit reflection mode elements, we develop the two-step position-aided ON/OFF states judgement (TPOSJ) scheme and the frame structure to control the ON/OFF state of RIS, followed by analyzing the impacts of mobility and position error on our proposed scheme. Also, we derive the Helmholtz-Kirchhoff integral theorem based power flow. Simulations show that the proposed scheme can manipulate the ON/OFF state intelligently without complex CSI, thus verifying the practical application of our proposed scheme.
Paper Structure (16 sections, 2 theorems, 49 equations, 10 figures, 2 tables, 1 algorithm)

This paper contains 16 sections, 2 theorems, 49 equations, 10 figures, 2 tables, 1 algorithm.

Table of Contents

  1. Introduction
  2. System Model
  3. Fraunhofer Distance of Element and Array
  4. Impedance Based 1-bit Element
  5. Geometric Relations
  6. CSI-free Phase Configuration Scheme
  7. Combining Fresnel Zone with Geometry
  8. TPOSJ Scheme
  9. Extension to MISO and Multi-RIS case
  10. Feasibility Analysis
  11. Position-Driven Frame Structure
  12. Huygens-Fresnel-based Power Flow
  13. Performance Evaluation
  14. Conclusions
  15. Proof of Proposition 1
  16. ...and 1 more sections

Key Result

Theorem 1

The lengths of $\rm PQ$ and $\rm R_\bot Q$ are and respectively.

Figures (10)

  • Figure 1: The system model of RIS-assisted wireless communication.
  • Figure 2: The 3D schematic diagram of the Fresnel zone and the geometric relations.
  • Figure 3: The proposed position-driven frame structure.
  • Figure 4: The closed boundary of Rx, Tx, and individual RIS element.
  • Figure 5: The impact of azimuth and elevation angle on the sinc function. (a), (b) The impact of $\theta^i_{mn}$ and $\phi^i_{mn}$ when $\theta^i_{mn}=\phi^i_{mn}=0$. (c), (d) The impact of $\theta^i_{mn}$ and $\theta^r_{mn}$ when $\phi^i_{mn}=\phi^r_{mn}=\pi/6$. (e), (f) The impact of $\phi^i_{mn}$ and $\phi^r_{mn}$ when $\theta^i_{mn}=\theta^r_{mn}=\pi/6$.
  • ...and 5 more figures

Theorems & Definitions (6)

  • Theorem 1
  • Remark 1
  • Theorem 2
  • Remark 2
  • Remark 3
  • Remark 4