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Sensing Safety Analysis for Vehicular Networks with Integrated Sensing and Communication (ISAC)

Tingyu Shui, Walid Saad, Mingzhe Chen

TL;DR

This work exposes a new sensing-safety vulnerability in Integrated Sensing and Communication (ISAC) vehicular networks by showing how a malicious Reconfigurable Intelligent Surface (RIS) can spoof an RSU's sensing of a vehicular user. It develops a time-varying phase-shift design and an adjustable-delay RIS to contaminate the RSU's estimates of echo delay, Doppler shift, and angle-of-departure, and derives the feasible spoofing frequency set $\mathcal{A}$ as a function of system parameters such as the RIS size $M$, delay step $\Delta T$, and beam direction $\theta_0$. The analysis reveals that the spoofing can drive the Doppler estimate to $\hat{\mu}_{\mathrm{V}} = \Delta \tilde{\mu}$ and severely distort AoD estimation, with simulations showing spoofed velocity from $0.1$ to $14.9$ m/s and AoD errors up to $65^{\circ}$ even under modest beam misalignment. The results highlight a practical threat to ISAC-based beam tracking and CAV safety, motivating development of sensing-safety defenses against RIS-based spoofing.

Abstract

Integrated sensing and communication (ISAC) emerged as a key feature of next-generation 6G wireless systems, allowing them to achieve high data rates and sensing accuracy. While prior research has primarily focused on addressing communication safety in ISAC systems, the equally critical issue of sensing safety remains largely ignored. In this paper, a novel threat to the sensing safety of ISAC vehicle networks is studied, whereby a malicious reconfigurable intelligent surface (RIS) is deployed to compromise the sensing functionality of a roadside unit (RSU). Specifically, a malicious attacker dynamically adjusts the phase shifts of an RIS to spoof the sensing outcomes of a vehicular user (VU)'s echo delay, Doppler shift, and angle-of-departure (AoD). To achieve spoofing on Doppler shift estimation, a time-varying phase shift design on the RIS is proposed. Furthermore, the feasible spoofing frequency set with respect to the Doppler shift is analytical derived. Analytical results also demonstrate that the maximum likelihood estimator (MLE) of the AoD can be significantly misled under spoofed Doppler shift estimation. Simulation results validate our theoretical findings, showing that the RIS can induce a spoofed velocity estimation from 0.1 m/s to 14.9 m/s for a VU with velocity of 10 m/s, and can cause an AoD estimation error of up to 65^{\circ} with only a 5^{\circ} beam misalignment.

Sensing Safety Analysis for Vehicular Networks with Integrated Sensing and Communication (ISAC)

TL;DR

This work exposes a new sensing-safety vulnerability in Integrated Sensing and Communication (ISAC) vehicular networks by showing how a malicious Reconfigurable Intelligent Surface (RIS) can spoof an RSU's sensing of a vehicular user. It develops a time-varying phase-shift design and an adjustable-delay RIS to contaminate the RSU's estimates of echo delay, Doppler shift, and angle-of-departure, and derives the feasible spoofing frequency set as a function of system parameters such as the RIS size , delay step , and beam direction . The analysis reveals that the spoofing can drive the Doppler estimate to and severely distort AoD estimation, with simulations showing spoofed velocity from to m/s and AoD errors up to even under modest beam misalignment. The results highlight a practical threat to ISAC-based beam tracking and CAV safety, motivating development of sensing-safety defenses against RIS-based spoofing.

Abstract

Integrated sensing and communication (ISAC) emerged as a key feature of next-generation 6G wireless systems, allowing them to achieve high data rates and sensing accuracy. While prior research has primarily focused on addressing communication safety in ISAC systems, the equally critical issue of sensing safety remains largely ignored. In this paper, a novel threat to the sensing safety of ISAC vehicle networks is studied, whereby a malicious reconfigurable intelligent surface (RIS) is deployed to compromise the sensing functionality of a roadside unit (RSU). Specifically, a malicious attacker dynamically adjusts the phase shifts of an RIS to spoof the sensing outcomes of a vehicular user (VU)'s echo delay, Doppler shift, and angle-of-departure (AoD). To achieve spoofing on Doppler shift estimation, a time-varying phase shift design on the RIS is proposed. Furthermore, the feasible spoofing frequency set with respect to the Doppler shift is analytical derived. Analytical results also demonstrate that the maximum likelihood estimator (MLE) of the AoD can be significantly misled under spoofed Doppler shift estimation. Simulation results validate our theoretical findings, showing that the RIS can induce a spoofed velocity estimation from 0.1 m/s to 14.9 m/s for a VU with velocity of 10 m/s, and can cause an AoD estimation error of up to 65^{\circ} with only a 5^{\circ} beam misalignment.
Paper Structure (10 sections, 4 theorems, 20 equations, 5 figures)

This paper contains 10 sections, 4 theorems, 20 equations, 5 figures.

Table of Contents

  1. Introduction
  2. System Model
  3. Signal Model
  4. Sensing Spoofing by Malicious RIS
  5. Design and Analysis of RIS Spoofing
  6. Dynamic Phase Shifts Design
  7. Impact on Doppler Shift Estimation
  8. Impact on AoD MLE
  9. Simulation Results and Analysis
  10. Conclusion

Key Result

Lemma 1

If the number of RIS reflecting elements satisfies $M \gg \sqrt{ \frac{\kappa_{\textrm{V}}}{4 \pi \eta}} \frac{\lambda}{S} \left| \frac{f(N_t, \frac{\pi}{2} (\cos{\theta_0} - \cos{\theta_{\textrm{V}}}) )}{f(N_t, \frac{\pi}{2} (\cos{\theta_0} - \cos{\theta_{\textrm{R}}}) )} \right|$, an infeasible s

Figures (5)

  • Figure 1: System model of the considered ISAC network under the spoofing of a malicious RIS.
  • Figure 2: The architecture of the adjustable-delay RIS.
  • Figure 3: Feasible spoofing velocity versus beam steering direction.
  • Figure 4: Spoofing velocity range versus number of RIS reflecting elements.
  • Figure 5: Impact of Doppler shift spoofing on the resulted MLE of AoD.

Theorems & Definitions (9)

  • Remark 1
  • Lemma 1
  • proof
  • Lemma 2
  • proof
  • Theorem 1
  • proof
  • Theorem 2
  • proof