Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2605.08718

Sensing-Aided Secure Multicast in Rotatable Antenna-Enabled ISAC Systems

Zequan Wang·Liang Yin·Chongjun Ouyang·Hao Xu·Yunan Sun·Yitong Liu·Hongwen Yang
View original source ↗Read source document ↗Export metadata ↓

Abstract

Acquiring the channel state information (CSI) of passive eavesdroppers remains a fundamental challenge in physical layer security. The sensing capability of integrated sensing and communication (ISAC) systems enables estimation of a potential eavesdropper's angle of departure (AoD) before secure transmission. Accordingly, a sensing-aided secure multicast scheme is proposed using a rotatable antenna (RA) architecture that combines array-level and element-level rotations with analog beamforming. The scheme comprises eavesdropper sensing and secure communication stages. In the sensing stage, the maximum likelihood estimator (MLE) and corresponding Cramer--Rao bound (CRB) are derived for eavesdropper AoD estimation. The two rotation levels are then optimized through cyclic coordinate search to minimize the worst-case CRB. The resulting AoD estimate and CRB determine the center and width of the angular uncertainty region, respectively. In the communication stage, the constant-modulus analog beamformer and RA configuration are jointly optimized to maximize the worst-case secrecy rate over this region. After angular discretization and smooth approximation, the resulting problem is solved using a product-space joint optimization framework. Numerical simulation results validate the convergence and effectiveness of the proposed algorithms. It is demonstrated that i) the proposed RA-enabled sensing design effectively improves the eavesdropper AoD estimation accuracy; ii) a high and nearly constant secrecy rate is maintained over the uncertainty region; and iii) the joint optimization of the two rotation levels yields lower CRBs and higher secrecy rates than schemes employing either a fixed-position array or a single rotation level.

Explore related subjects

cs.ITeess.SPmath.IT

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Zequan Wang, Liang Yin, Chongjun Ouyang, Hao Xu, Yunan Sun, Yitong Liu, Hongwen Yang. 2026-09-13. Sensing-Aided Secure Multicast in Rotatable Antenna-Enabled ISAC Systems. https://arxiv.org/abs/2605.08718

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

On the Distribution of Age of Information in Time-varying Updating Systems

Age of Information (AoI) is a crucial metric for quantifying information freshness in real-time systems where the sampling rate of data packets is time-varying. Evaluating AoI under such conditions is challenging, as system states become temporally correlated and traditional stationary analysis is inapplicable. We investigate an $M_{t}/G/1/1$ queueing system with a time-varying sampling rate and probabilistic preemption, proposing a novel analytical framework based on multi-dimensional partial differential equations (PDEs) to capture the time evolution of the system's status distribution. To solve the PDEs, we develop a decomposition technique that breaks the high-dimensional PDE into lower-dimensional subsystems. Solving these subsystems allows us to derive the Aol distribution at arbitrary time instances. We show AoI does not exhibit a memoryless property, even with negligible processing times, due to its dependence on the historical sampling process. Our framework extends to the stationary setting, where we derive a closed-form expression for the Laplace-Stieltjes Transform (LST) of the steady-state AoI. Numerical experiments reveal AoI exhibits a non-trivial lag in response to sampling rate changes. Our results also show that no single preemption probability or processing time distribution can minimize Aol violation probability across all thresholds in either time-varying or stationary scenarios. Finally, we formulate an optimization problem and propose a heuristic method to find sampling rates that reduce costs while satisfying AoI constraints.

cs.IT↗
arXiv2026

Properties of Random Code Ensembles over Classical-Quantum Channels

We show two properties of i.i.d. code ensembles over classical-quantum (CQ) channels with arbitrary output states. The first property is that the probability distribution of the error exponent across the ensemble accumulates above a threshold that is strictly larger than the CQ random coding exponent (RCE) at low rates, while coinciding with it at rates close to the mutual information of the channel. This result, combined with the works by Dalai, Renes, Li and Yang and Cheng and Liu, implies that the ensemble distribution of error exponents concentrates around the CQ RCE in the high rate regime. Moreover, in the same rate region the threshold we derive coincides with the ensemble-average of the exponent, that is, the CQ typical random coding (TRC) exponent. The second property we derive is that the probability that a randomly selected code from an ensemble contains a nested code of the same rate such that each of its codewords achieves the CQ expurgated exponent goes to one asymptotically in the codeword length. Such nested code can be obtained by expurgating a vanishingly small fraction of codewords as the codeword length increases. This result refines Holevo's work [5], which proved that the expurgated exponent can be achieved by discarding the worst half of the codewords from at least one code in the ensemble.

cs.IT↗
arXiv2026

Taming Subpacketization without Sacrificing Communication: A Packet Type-based Framework for D2D Coded Caching

Finite-length design is essential for making coded caching practical, as the optimal communication gains of existing schemes often require prohibitively large subpacketization. This paper studies rate-optimal device-to-device (D2D) coded caching with reduced subpacketization. We propose a packet type-based (PT) framework that exploits the geometric structure induced by user grouping. Under this structure, subfiles, packets, and multicast groups are classified into types, allowing the originally symmetric Ji-Caire-Molisch (JCM) design~\cite{ji2016fundamental} to be systematically relaxed without sacrificing the optimal D2D communication rate. The key feature of the PT framework is that subpacketization reduction is achieved through two complementary mechanisms: \emph{subfile saving}, by excluding redundant subfile types, and \emph{further-splitting saving}, by assigning type-dependent further-splitting factors to subfiles through transmitter selection. The type-dependent splitting factors are then coordinated across multicast group types to produce a globally consistent file-splitting structure. Based on this framework, we construct several classes of rate-optimal D2D coded caching schemes that strictly improve upon the JCM subpacketization. The proposed schemes achieve either order-wise reductions in the number of users or constant-factor reductions over broad memory regimes, while preserving the optimal rate. These results reveal a structural distinction between D2D and shared-link coded caching: unlike in the shared-link setting, full symmetric subpacketization is not necessary for rate-optimal D2D caching.

cs.IT↗