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arxiv: 2604.14097 · v1 · submitted 2026-04-15 · 📡 eess.SP

Towards SAFE-ISAC: STAR-RIS-Aided Joint Jamming Suppression and Target Concealment

Radwa Sultan This is my paper

Pith reviewed 2026-05-10 12:19 UTC · model grok-4.3

classification 📡 eess.SP
keywords STAR-RISISACjamming suppressiontarget concealmentreconfigurable intelligent surfaceintegrated sensing and communicationsecurityQoS optimization
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The pith

A STAR-RIS can jointly suppress jamming power and conceal an ISAC target from malicious detectors while satisfying all QoS constraints.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper examines a single-cell bistatic integrated sensing and communication network under coordinated active jamming and malicious detection attacks. It proposes the SAFE-ISAC framework that deploys a simultaneous transmit and reflect reconfigurable intelligent surface to minimize jamming gain in the reflection subspace and reduce the malicious detector's SINR in the transmission subspace. The non-convex joint optimization is decoupled into two subproblems solved respectively by the Dinkelbach method with semidefinite programming relaxation and the Polak-Ribiere Riemannian conjugate gradient algorithm. Numerical evaluations confirm that the optimized STAR-RIS responses achieve effective jamming mitigation and target concealment while meeting communication and sensing quality-of-service requirements, outperforming existing benchmarks.

Core claim

In a bistatic ISAC system facing simultaneous jamming and malicious detection, a STAR-RIS with independently tunable transmission and reflection coefficients can be configured to jointly minimize jamming gain and detection probability through decoupled subspace optimization, thereby suppressing the attacks without violating the required communication and sensing QoS levels.

What carries the argument

The STAR-RIS whose transmission and reflection responses are optimized separately in the transmission subspace (via Dinkelbach and SDP) and reflection subspace (via Riemannian conjugate gradient) to achieve joint jamming suppression and target concealment.

If this is right

  • The scheme maintains all communication and sensing QoS requirements while countering both jamming and detection threats.
  • It delivers superior jamming mitigation and target concealment performance relative to existing benchmarks.
  • The decoupling enables tractable solution of an otherwise intractable joint minimization problem.
  • The framework directly addresses the need for robust architectures against sophisticated attacks in modern wireless systems.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If the negligible-loss decoupling holds, the same STAR-RIS configuration principle could be tested in multi-cell ISAC deployments or with multiple coordinated attackers.
  • Real-world viability would hinge on how quickly the Riemannian and Dinkelbach solvers converge under time-varying channels not examined here.
  • The approach implicitly suggests that passive surfaces can replace active hardware for simultaneous security and sensing functions, an extension left for future hardware validation.

Load-bearing premise

The non-convex joint optimization problem can be decoupled into independent transmission and reflection subproblems with negligible performance loss, and perfect channel state information is available for the optimization.

What would settle it

An experiment or simulation showing that the decoupled subproblem solutions produce substantially higher residual jamming gain or detection probability than a joint solution, or that the scheme violates QoS under realistic imperfect CSI, would falsify the central claim.

Figures

Figures reproduced from arXiv: 2604.14097 by Radwa Sultan.

Figure 1
Figure 1. Figure 1: STAR RIS-aided ISAC System. is then divided into two subproblems. The first subproblem, in the STAR-RIS transmission subspace, aims to minimize the malicious detector’s detection probability under the detection constraints of the legitimate detector. By applying Fractional Programming (FP) and Semidefinite Relaxation (SDR), the subproblem is reformulated into a standard Semidefinite Pro￾gramming (SDP) prob… view at source ↗
Figure 2
Figure 2. Figure 2: Residual jamming Vs Nj . IV. NUMERICAL ANALYSIS In this section, we evaluate the proposed SAFE-ISAC framework through extensive numerical simulations. Its per￾formance is assessed by comparing the resulting malicious SINR and residual jamming gain against two benchmarks: a random-phase STAR-RIS-assisted model and a conventional reflective RIS-assisted model. Unless otherwise specified, the simulation param… view at source ↗
Figure 5
Figure 5. Figure 5: Malicious detection SINR Vs malicious detector’s [PITH_FULL_IMAGE:figures/full_fig_p006_5.png] view at source ↗
read the original abstract

Designing robust architectures that can mitigate sophisticated attacks is now a key priority for modern wireless systems. This paper investigates a single-cell bistatic integrated sensing and communication (ISAC) network facing simultaneous coordinated active jamming and malicious detection. These threats aim to disrupt the downlink communication and detect the presence of the ISAC target, respectively. To counter these attacks, we propose the SAFE-ISAC framework, which utilizes a simultaneous transmit and reflect reconfigurable intelligent surface (STAR-RIS) to jointly suppress jamming power and reduce the malicious detector's Signal-to-Interference-plus-Noise Ratio (SINR). We formulate a joint minimization problem for jamming gain and detection probability by optimizing the STAR-RIS reflection and transmission responses. This non-convex problem is decoupled into two subproblems: i) malicious detection mitigation in the transmission subspace, solved using the Dinkelbach method and Semidefinite Programming (SDP) relaxation, and ii) jamming suppression in the reflection subspace, addressed via Polak-Reib\'ere Riemannian conjugate gradient algorithm. Numerical results validate that the proposed scheme effectively achieves jamming mitigation and target concealment while meeting all communication and sensing Quality-of-Service (QoS) requirements, compared to existing benchmarks.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 3 minor

Summary. The manuscript proposes the SAFE-ISAC framework for a single-cell bistatic ISAC network under coordinated active jamming and malicious detection. It uses a STAR-RIS to jointly minimize jamming gain and the malicious detector's detection probability by optimizing the transmission and reflection coefficients, subject to communication and sensing QoS constraints. The resulting non-convex problem is decoupled into a transmission-subspace subproblem solved via the Dinkelbach method and SDP relaxation, and a reflection-subspace subproblem solved via the Polak-Ribiere Riemannian conjugate gradient algorithm. Numerical results are presented to claim that the scheme achieves effective jamming mitigation and target concealment while satisfying all QoS requirements, outperforming existing benchmarks.

Significance. If the decoupling incurs only negligible loss, the work offers a practical algorithmic approach to physical-layer security in ISAC systems by leveraging STAR-RIS for simultaneous jamming suppression and target concealment. The use of established techniques (Dinkelbach, SDP relaxation, and Riemannian CG) is a strength, as is the explicit formulation from SINR and detection probability expressions. The numerical validation against benchmarks, if reproducible, would support the framework's relevance for secure wireless sensing and communication.

major comments (2)
  1. [Optimization Problem and Solution Approach] Optimization sections (following the problem formulation): The joint minimization over STAR-RIS transmission and reflection coefficients is decoupled into independent transmission and reflection subproblems. Because the effective channels, interference terms, and received signals at the legitimate receiver and malicious detector couple the two subspaces through the same STAR-RIS elements, independent optimization is not guaranteed to be optimal. No analytical bound on the sub-optimality gap is derived, and no comparison against an alternating-optimization baseline is provided. This directly affects the load-bearing claim that numerical results validate the scheme's effectiveness.
  2. [System Model] System model and assumptions (Section II): The optimization relies on perfect CSI. No robustness analysis or worst-case formulation under CSI estimation errors is included, yet the central performance claims (meeting QoS while mitigating jamming and detection) depend on accurate knowledge of the channels used in the SINR and detection probability expressions.
minor comments (3)
  1. [Abstract] Abstract: 'Polak-Reibère' should be corrected to 'Polak-Ribiere'.
  2. [Numerical Results] Numerical results section: The abstract and results claim validation without reporting the number of Monte Carlo trials, confidence intervals, or convergence behavior of the Riemannian CG algorithm; adding these would strengthen the evidence.
  3. [Figures] Figures: Legends and axis labels for benchmark comparisons should be enlarged for clarity; ensure all curves are distinguishable in black-and-white printing.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive and detailed comments. We address each major comment point by point below, acknowledging where the observations are valid and outlining specific revisions to the manuscript.

read point-by-point responses

  1. Referee: [Optimization Problem and Solution Approach] Optimization sections (following the problem formulation): The joint minimization over STAR-RIS transmission and reflection coefficients is decoupled into independent transmission and reflection subproblems. Because the effective channels, interference terms, and received signals at the legitimate receiver and malicious detector couple the two subspaces through the same STAR-RIS elements, independent optimization is not guaranteed to be optimal. No analytical bound on the sub-optimality gap is derived, and no comparison against an alternating-optimization baseline is provided. This directly affects the load-bearing claim that numerical results validate the scheme's effectiveness.

    Authors: We agree that decoupling the joint optimization into separate transmission and reflection subproblems does not guarantee global optimality, since the effective channels and interference terms couple the subspaces via the shared STAR-RIS elements. This separation was adopted to render the non-convex problem tractable by applying Dinkelbach with SDP relaxation to the transmission subproblem and the Polak-Ribiere Riemannian conjugate gradient method to the reflection subproblem. The numerical results demonstrate that the resulting scheme outperforms the considered benchmarks in jamming suppression and target concealment while satisfying the QoS constraints. To strengthen the validation, we will revise the manuscript to include a comparison against an alternating-optimization baseline that iteratively solves the two subproblems, thereby quantifying any performance gap, and we will add an explicit remark noting the absence of an analytical sub-optimality bound as a limitation of the current approach. revision: yes

  2. Referee: [System Model] System model and assumptions (Section II): The optimization relies on perfect CSI. No robustness analysis or worst-case formulation under CSI estimation errors is included, yet the central performance claims (meeting QoS while mitigating jamming and detection) depend on accurate knowledge of the channels used in the SINR and detection probability expressions.

    Authors: The referee is correct that the optimization and performance evaluation assume perfect CSI, which is stated in Section II. This assumption allows us to focus on the derivation of the SAFE-ISAC framework and the proposed algorithmic solution. The numerical results and claims are therefore conditioned on perfect channel knowledge. In the revised manuscript we will expand the discussion of this assumption in the system model section, clarify its implications for the reported QoS and security metrics, and add a short paragraph outlining possible robust extensions (such as worst-case or stochastic robust formulations) as future work. A complete robustness analysis with new derivations and simulations lies beyond the scope of the present contribution. revision: partial

Circularity Check

0 steps flagged

No circularity in derivation; optimization and numerical validation are independent of inputs

full rationale

The paper starts from explicit system-model-derived SINR and detection-probability expressions, formulates a joint minimization over STAR-RIS coefficients, decouples the non-convex problem into transmission and reflection subproblems, and applies standard solvers (Dinkelbach+SDP, Riemannian CG). The final numerical claims are outcomes of running these algorithms on the formulated objective; they do not reduce by construction to the input expressions or to any fitted parameters. No self-citations, ansatzes, or renamings are load-bearing for the central result. The decoupling step is an approximation whose sub-optimality gap is not bounded, but this is a correctness concern rather than a circularity reduction.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 1 invented entities

Review performed on abstract only; full derivations, channel models, and numerical setup are unavailable, so the ledger is necessarily incomplete and conservative.

axioms (2)
  • domain assumption Perfect channel state information is available at the optimizer
    Required to formulate and solve the reflection/transmission coefficient optimization.
  • domain assumption STAR-RIS elements can be independently controlled in amplitude and phase for both transmission and reflection
    Fundamental to the proposed joint suppression and concealment mechanism.
invented entities (1)
  • SAFE-ISAC framework no independent evidence
    purpose: Name for the proposed STAR-RIS optimization scheme
    Branding for the joint jamming-suppression and target-concealment design; no new physical entity.

pith-pipeline@v0.9.0 · 5506 in / 1369 out tokens · 36115 ms · 2026-05-10T12:19:28.842080+00:00 · methodology

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