NF-SecRIS: RIS-Assisted Near-Field Physical Layer Security via Secure Location Modulation

2025-11-04

AI Summary

To address the limitation of conventional physical-layer security (PLS) in 6G wireless networks—namely, its reliance solely on angular-domain protection and inability to simultaneously secure the distance dimension—this paper proposes a near-field two-dimensional (2D) PLS communication scheme leveraging ultra-massive reconfigurable intelligent surfaces (RIS). By jointly exploiting near-field spatial–temporal coding and secure position modulation, the scheme achieves, for the first time, dual-dimensional (angle and distance) PLS in the near-field regime without requiring transmitter–receiver synchronization. The proposed low-complexity modulation framework is compatible with diverse constellation mappings and supports multiple modulation formats. Experimental results demonstrate that the legitimate receiver achieves a bit error rate (BER) below 10⁻⁴, whereas eavesdroppers located at different angles or distances exhibit BERs exceeding 40%, thereby validating the effectiveness and robustness of the 2D PLS design.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Computer Vision: Multi-modal Vision
• Intelligent Robots: Multimodal Perception & Sensor Fusion

Application Category

• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments

Abstract

The 6G wireless networks impose extremely high requirements on physical layer secure communication. However, the existing solutions usually can only achieve one-dimensional physical layer security (PLS) in the angle dimension, and cannot achieve PLS in the range dimension. In this paper, we propose the NF-SecRIS system, the first range-angle-dependent (2D) PLS near-field communication system based on ultra-large-scale reconfigurable intelligent surface (RIS). We propose the secure location modulation scheme to synthesize the near-field spatial-temporal coding pattern of RIS with extremely low complexity. It ensures that only legitimate user can receive the raw constellations, while potential eavesdroppers at other ranges or angles can only receive the obfuscated constellations. NF-SecRIS operates without requiring synchronization with either transmitter or receiver. We implement a prototype of NF-SecRIS and conduct comprehensive experiments with multiple modulation schemes. The results show that the bit error rate (BER) of legitimate user is below 10^{-4}, while eavesdroppers at other ranges or angles suffer from BER exceeding 40%. It validates the implementation of 2D PLS in near-field communications.

Problem

• Achieving 2D physical layer security in near-field communications
• Enabling secure location modulation via RIS with low complexity
• Protecting transmissions from eavesdroppers at different ranges and angles

Innovation

• Uses ultra-large-scale RIS for near-field communication
• Implements secure location modulation for 2D PLS
• Operates without transmitter or receiver synchronization