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mmMirror: Device Free mmWave Indoor NLoS Localization Using Van-Atta-Array IRS

Yihe Yan, Zhenguo Shi, Yanxiang Wang, Cheng Jiang, Chun Tung Chou, Wen Hu

TL;DR

mmMirror addresses the challenge of device-free indoor NLoS localization by integrating a Van Atta Array–based IRS with FMCW mmWave radar. The system introduces a novel antenna-encoding scheme for radar-to-IRS communication and a time-slot allocation strategy that adaptively focuses sensing on Areas of Interest, enabling real-time, multi-radar, multi-target operation. Through a 24 GHz hardware prototype, mmMirror demonstrates centimeter-level localization accuracy up to $3$ m, robust radar–IRS communication (BER $<10^{-1}$ up to $2$ m and $60$°), and up to $42\%$–$75\%$ reductions in scanning latency depending on scenario. These results suggest strong potential for practical deployment in factories, warehouses, and healthcare settings to enhance safety in human–robot interaction without requiring target-side devices or LiDAR.

Abstract

Industry 4.0 is transforming manufacturing and logistics by integrating robots into shared human environments, such as factories, warehouses, and healthcare facilities. However, the risk of human-robot collisions, especially in Non-Line-of-Sight (NLoS) scenarios like around corners, remains a critical challenge. Existing solutions, such as vision-based and LiDAR systems, often fail under occlusion, lighting constraints, or privacy concerns, while RF-based systems are limited by range and accuracy. To address these limitations, we propose mmMirror, a novel system leveraging a Van Atta Array-based millimeter-wave (mmWave) reconfigurable intelligent reflecting surface (IRS) for precise, device-free NLoS localization. mmMirror integrates seamlessly with existing frequency-modulated continuous-wave (FMCW) radars and offers: (i) robust NLoS localization with centimeter-level accuracy at ranges up to 3 m, (ii) seamless uplink and downlink communication between radar and IRS, (iii) support for multi-radar and multi-target scenarios via dynamic beam steering, and (iv) reduced scanning latency through adaptive time slot allocation. Implemented using commodity 24 GHz radars and a PCB-based IRS prototype, mmMirror demonstrates its potential in enabling safe human-robot interactions in dynamic and complex environments.

mmMirror: Device Free mmWave Indoor NLoS Localization Using Van-Atta-Array IRS

TL;DR

mmMirror addresses the challenge of device-free indoor NLoS localization by integrating a Van Atta Array–based IRS with FMCW mmWave radar. The system introduces a novel antenna-encoding scheme for radar-to-IRS communication and a time-slot allocation strategy that adaptively focuses sensing on Areas of Interest, enabling real-time, multi-radar, multi-target operation. Through a 24 GHz hardware prototype, mmMirror demonstrates centimeter-level localization accuracy up to m, robust radar–IRS communication (BER up to m and °), and up to – reductions in scanning latency depending on scenario. These results suggest strong potential for practical deployment in factories, warehouses, and healthcare settings to enhance safety in human–robot interaction without requiring target-side devices or LiDAR.

Abstract

Industry 4.0 is transforming manufacturing and logistics by integrating robots into shared human environments, such as factories, warehouses, and healthcare facilities. However, the risk of human-robot collisions, especially in Non-Line-of-Sight (NLoS) scenarios like around corners, remains a critical challenge. Existing solutions, such as vision-based and LiDAR systems, often fail under occlusion, lighting constraints, or privacy concerns, while RF-based systems are limited by range and accuracy. To address these limitations, we propose mmMirror, a novel system leveraging a Van Atta Array-based millimeter-wave (mmWave) reconfigurable intelligent reflecting surface (IRS) for precise, device-free NLoS localization. mmMirror integrates seamlessly with existing frequency-modulated continuous-wave (FMCW) radars and offers: (i) robust NLoS localization with centimeter-level accuracy at ranges up to 3 m, (ii) seamless uplink and downlink communication between radar and IRS, (iii) support for multi-radar and multi-target scenarios via dynamic beam steering, and (iv) reduced scanning latency through adaptive time slot allocation. Implemented using commodity 24 GHz radars and a PCB-based IRS prototype, mmMirror demonstrates its potential in enabling safe human-robot interactions in dynamic and complex environments.
Paper Structure (22 sections, 8 equations, 18 figures, 3 tables, 3 algorithms)

This paper contains 22 sections, 8 equations, 18 figures, 3 tables, 3 algorithms.

Table of Contents

  1. Introduction
  2. Background Knowledge
  3. FMCW Signal Model
  4. Van Atta Array
  5. Non-Retroreflective Van Atta Array
  6. Reflection-Based NLoS Localization
  7. mmMirror System Design
  8. mmMirror Overview
  9. mmMirror Hardware Design
  10. IRS-Radar Communication
  11. Localization Procedure
  12. Adaptive Resource (Time Slot) Allocation
  13. Performance Evaluation
  14. mmMirror Prototyping
  15. Evaluation Setup
  16. ...and 7 more sections

Figures (18)

  • Figure 1: A typical scene of a collision. The robot and human are navigating around an L-shaped corridor with obstructed visibility. The lack of proper NLoS sensing results in a potential collision at the intersection point.
  • Figure 2: A Typical NLoS Environment Layout
  • Figure 3: mmMirror System Overview.
  • Figure 4: 4-Way Reflective VAA Antenna Design.
  • Figure 5: Radar to IRS communication in mmMirror.
  • ...and 13 more figures