pwc-archive/papers-with-abstracts huggingface dataset:
ARSAR-Net: Intelligent SAR Imaging with Adaptive Regularization
Authors: Shiping Fu, Yufan Chen, Zhe Zhang, Xiaolan Qiu, Qixiang Ye
Date: 2025-06-23 00:00:00

Deep unfolding networks have recently emerged as a promising approach for synthetic aperture radar (SAR) imaging. However, baseline unfolding networks, typically derived from iterative reconstruction algorithms such as the alternating direction method of multipliers (ADMM), lack generalization capability across scenes, primarily because their regularizers are empirically designed rather than learned from data. In this study, we introduce a learnable regularizer into the unfolding network and propose a SAR imaging network with adaptive regularization (ARSAR-Net), which aims to generalize across heterogeneous scenes including offshore ships, islands, urban areas, and mountainous terrain. Furthermore, two variants of ARSAR-Net are developed, targeting improved imaging efficiency and reconstruction quality, respectively. Extensive validation through simulated and real-data experiments demonstrates three key advantages of ARSAR-Net: (1) a 50% increase in imaging speed over existing unfolding networks, (2) a PSNR gain of up to 2.0 dB in imaging quality, and (3) enhanced adaptability to complex scenes. These advancements establish a new paradigm for computationally efficient and generalizable SAR imaging systems.
Characterization of Rydberg-Atom Signal Reception of Dual-Frequency Signals Coupled with Two Energy Levels
Authors: Hao Wu, Chongwu Xie, Xinyuan Yao, Kang-Da Wu, Shanchi Wu, Rui Ni, Guo-Yong Xiang, Chen Gong
Date: 2025-06-26 00:00:00

Rydberg atomic sensors have been adopted for novel radio frequency (RF) measurement technique and the sensing capability for signals in multiple frequencies makes it attractive for multi-user communication. However, unlike traditional antennas where the signals in multiple frequencies are orthogonal, the received signals of atomic sensors corresponding to different energy levels will be downconverted to the baseband simultaneously, resulting in multi-user interference. Thus, in this paper, we analyze the mutual interference characteristics of two RF signals with different carrier frequencies coupling different energy levels. We introduce the joint response coefficient based on the receiver characteristics and analyze the interference of one user to another. We analyze the bit-error rate (BER) and symbol-error rate (SER) for two signals coupling two different energy levels. We also conduct experiments to validate the BER and SER results.
Point Cloud Environment-Based Channel Knowledge Map Construction
Authors: Yancheng Wang, Wei Guo, GuanYing Chen, Ye Zhang, Shuguang Cui
Date: 2025-06-26 00:00:00

Channel knowledge map (CKM) provides certain levels of channel state information (CSI) for an area of interest, serving as a critical enabler for environment-aware communications by reducing the overhead of frequent CSI acquisition. However, existing CKM construction schemes adopt over-simplified environment information, which significantly compromises their accuracy. To address this issue, this work proposes a joint model- and data-driven approach to construct CKM by leveraging point cloud environmental data along with a few samples of location-tagged channel information. First, we propose a novel point selector to identify subsets of point cloud that contain environmental information relevant to multipath channel gains, by constructing a set of co-focal ellipsoids based on different time of arrival (ToAs). Then, we trained a neural channel gain estimator to learn the mapping between each selected subset and its corresponding channel gain, using a real-world dataset we collected through field measurements, comprising environmental point clouds and corresponding channel data. Finally, experimental results demonstrate that: For CKM construction of power delay profile (PDP), the proposed method achieves a root mean squared error (RMSE) of 2.95 dB, significantly lower than the 7.32 dB achieved by the conventional ray-tracing method; for CKM construction of received power values, i.e., radio map, it achieves an RMSE of 1.04 dB, surpassing the Kriging interpolation method with an RMSE of 1.68 dB.
Analysis of Null Related Beampattern Measures and Signal Quantization Effects for Linear Differential Microphone Arrays
Authors: Shweta Pal, Arun Kumar, Monika Agrawal
Date: 2025-06-26 00:00:00
Tasks: Quantization

A differential microphone array (DMA) offers enhanced capabilities to obtain sharp nulls at the cost of relatively broad peaks in the beam power pattern. This can be used for applications that require nullification or attenuation of interfering sources. To the best of our knowledge, the existing literature lacks measures that directly assess the efficacy of nulls, and null-related measures have not been investigated in the context of differential microphone arrays (DMAs). This paper offers new insights about the utility of DMAs by proposing measures that characterize the nulls in their beam power patterns. We investigate the performance of differential beamformers by presenting and evaluating null-related measures namely null depth (ND) and Null Width (NW) as a function of depth level relative to the beam power pattern maxima. A study of signal quantization effects due to data acquisition for 1st, 2nd and 3rd order linear DMAs and for different beampatterns i.e. dipole, cardioid, hypercardioid and supercardioid is presented. An analytical expression for the quantized beamformed output for any general $ N^{th} $ order DMA is formulated. Simulation results of the variation of ND with number of quantization bits and the variation of NW as a function of depth are also presented and inferences are drawn. Lab experiments are conducted in a fully anechoic room to support the simulation results. The measured beampattern exhibits a pronounced null depth, confirming the effectiveness of the experimental setup.
Co-Design of Sensing, Communications, and Control for Low-Altitude Wireless Networks
Authors: Haijia Jin, Jun Wu, Weijie Yuan, Fan Liu, Yuanhao Cui
Date: 2025-06-26 00:00:00
Tasks: Scheduling

The rapid advancement of Internet of Things (IoT) services and the evolution toward the sixth generation (6G) have positioned unmanned aerial vehicles (UAVs) as critical enablers of low-altitude wireless networks (LAWNs). This work investigates the co-design of integrated sensing, communication, and control ($\mathbf{SC^{2}}$) for multi-UAV cooperative systems with finite blocklength (FBL) transmission. In particular, the UAVs continuously monitor the state of the field robots and transmit their observations to the robot controller to ensure stable control while cooperating to localize an unknown sensing target (ST). To this end, a weighted optimization problem is first formulated by jointly considering the control and localization performance in terms of the linear quadratic regulator (LQR) cost and the determinant of the Fisher information matrix (FIM), respectively. The resultant problem, optimizing resource allocations, the UAVs' deployment positions, and multi-user scheduling, is non-convex. To circumvent this challenge, we first derive a closed-form expression of the LQR cost with respect to other variables. Subsequently, the non-convex optimization problem is decomposed into a series of sub-problems by leveraging the alternating optimization (AO) approach, in which the difference of convex functions (DC) programming and projected gradient descent (PGD) method are employed to obtain an efficient near-optimal solution. Furthermore, the convergence and computational complexity of the proposed algorithm are thoroughly analyzed. Extensive simulation results are presented to validate the effectiveness of our proposed approach compared to the benchmark schemes and reveal the trade-off between control and sensing performance.
Doppler Estimation and Compensation Techniques in LoRa Direct-to-Satellite Communications
Authors: Jamil Farhat, Gianni Pasolini, Enrico Paolini, Muhammad Asad Ullah, Richard Demo Souza
Date: 2025-06-25 00:00:00

Within the LPWAN framework, the LoRa modulation adopted by LoRaWAN technology has garnered significant interest as a connectivity solution for IoT applications due to its ability to offer low-cost, low-power, and long-range communications. One emerging use case of LoRa is DtS connectivity, which extends coverage to remote areas for supporting IoT operations. The satellite IoT industry mainly prefers LEO because it has lower launch costs and less path loss compared to Geostationary orbit. However, a major drawback of LEO satellites is the impact of the Doppler effect caused by their mobility. Earlier studies have confirmed that the Doppler effect significantly degrades the LoRa DtS performance. In this paper, we propose four frameworks for Doppler estimation and compensation in LoRa DtS connectivity and numerically compare the performance against the ideal scenario without the Doppler effect. Furthermore, we investigate the trade-offs among these frameworks by analyzing the interplay between spreading factor, and other key parameters related to the Doppler effect. The results provide insights into how to achieve robust LoRa configurations for DtS connectivity.
Coherent Track-Before-Detect
Authors: Mingchao Liang, Florian Meyer
Date: 2025-06-22 00:00:00
Tasks: Autonomous Driving, Bayesian Inference, Integrated sensing and communication

Accurately tracking an unknown and time-varying number of objects in complex environments is a significant challenge but a fundamental capability in a variety of applications, including applied ocean sciences, surveillance, autonomous driving, and wireless communications. Conventional Bayesian multiobject tracking (MOT) methods typically employ a detect-then-track (DTT) approach, where a frontend detector preprocesses raw sensor data to extract measurements for MOT. The irreversible nature of this preprocessing step can discard valuable object-related information, particularly impairing the ability to resolve weak or closely spaced objects. The track-before-detect (TBD) paradigm offers an alternative by operating directly on sensor data. However, existing TBD approaches introduce simplifications to facilitate the development of inference methods, such as assuming known signal amplitudes or conditional independence between sensor measurements given object states. These assumptions can lead to suboptimal performance and limit the applicability of the resulting TBD methods in realistic scenarios. This paper introduces coherent TBD based on a comprehensive signal model for sensor data. The new model accounts for sensor data correlations and amplitude fluctuations, enabling the accurate representation of the physics of the data-generating process in TBD. Coherent TBD is suitable for a wide range of problems in active and passive radar, active and passive sonar, as well as integrated sensing and communication systems. Based on a factor graph representation of the new measurement model, a scalable belief propagation (BP) method is developed to perform efficient Bayesian inference. Experimental results, performed with both synthetic and real data, demonstrate that the proposed method outperforms state-of-the-art conventional MOT methods.
Multi-Objective Reinforcement Learning for Cognitive Radar Resource Management
Authors: Ziyang Lu, Subodh Kalia, M. Cenk Gursoy, Chilukuri K. Mohan, Pramod K. Varshney
Date: 2025-06-25 00:00:00
Tasks: Deep Reinforcement Learning, Management, Multi-Objective Reinforcement Learning, reinforcement-learning, Reinforcement Learning

The time allocation problem in multi-function cognitive radar systems focuses on the trade-off between scanning for newly emerging targets and tracking the previously detected targets. We formulate this as a multi-objective optimization problem and employ deep reinforcement learning to find Pareto-optimal solutions and compare deep deterministic policy gradient (DDPG) and soft actor-critic (SAC) algorithms. Our results demonstrate the effectiveness of both algorithms in adapting to various scenarios, with SAC showing improved stability and sample efficiency compared to DDPG. We further employ the NSGA-II algorithm to estimate an upper bound on the Pareto front of the considered problem. This work contributes to the development of more efficient and adaptive cognitive radar systems capable of balancing multiple competing objectives in dynamic environments.
Compact Analytical Model for Real-Time Evaluation of OAM-Based Inter-Satellite Links
Authors: Mohammad Taghi Dabiri, Mazen Hasna
Date: 2025-06-25 00:00:00

This paper presents an efficient analytical framework for evaluating the performance of inter-satellite communication systems utilizing orbital angular momentum (OAM) beams under pointing errors. An accurate analytical model is first developed to characterize intermodal crosstalk caused by beam misalignment in OAM-based inter-satellite links. Building upon this model, we derive efficient expressions to analyze and optimize system performance in terms of bit error rate (BER). Unlike traditional Monte Carlo-based methods that are computationally intensive, the proposed approach offers accurate performance predictions. This enables a substantial decrease in computation time while maintaining high accuracy, thanks to the use of analytical expressions for both crosstalk and BER. This fast and accurate evaluation capability is particularly critical for dynamic low Earth orbit (LEO) satellite constellations, where network topology and channel conditions change rapidly, requiring real-time link adaptation. Furthermore, we systematically design and evaluate asymmetric OAM mode sets, which significantly outperform symmetric configurations in the presence of pointing errors. Our results also reveal key insights into the interaction between beam divergence, tracking accuracy, and link distance, demonstrating that the proposed framework enables real-time optimization of system parameters with high fidelity. The analytical findings are rigorously validated against extensive Monte Carlo simulations, confirming their practical applicability for high-mobility optical wireless systems such as LEO satellite networks.
Physical Limits of Entanglement-Based Quantum Key Distribution over Long-Distance Satellite Links
Authors: Mohammad Taghi Dabiri, Mazen Hasna, Saif Al-Kuwari, Khalid Qaraqe
Date: 2025-06-25 00:00:00

Entanglement-based quantum key distribution (QKD) protocols, such as E91 and BBM92, offer strong information-theoretic security and are naturally suited for satellite-to-satellite QKD (SatQKD) links. However, implementing these protocols over long-distance inter-satellite free-space optical (FSO) channels poses critical physical-layer challenges that are not addressed in the existing literature. In particular, photon losses due to beam divergence, pointing errors, and background noise can severely degrade the key generation rate and quantum bit error rate (QBER), especially under narrow receiver field-of-view (FoV) constraints. This paper presents a comprehensive performance analysis of entanglement-based inter-satellite QKD, focusing on photon-level modeling and the impact of practical impairments. We develop analytical expressions for signal detection probabilities, background photon influence, multi-pair emissions, and QBER, incorporating key parameters such as link distance, transmitter tracking jitter, receiver misalignment, and photon pair generation rate. Simulation results reveal the nonlinear sensitivity of system performance to tracking error and FoV limitations, and highlight optimal parameter regimes that jointly maximize secret key rate while maintaining QBER below acceptable thresholds. The proposed model provides actionable design insights for reliable and efficient deployment of entanglement-based SatQKD systems.
Precise Near-Field Beam Training with DFT Codebook based on Amplitude-only Measurement
Authors: Zijun Wang, Shawn Tsai, Rama Kiran, Rui Zhang
Date: 2025-06-25 00:00:00

Extremely large antenna arrays (ELAAs) operating in high-frequency bands have spurred the development of near-field communication, driving advancements in beam training and signal processing design. In this work, we present a low-complexity near-field beam training scheme that fully utilizes the conventional discrete Fourier transform (DFT) codebook designed for far-field users. We begin by analyzing the received beam pattern in the near field and derive closed-form expressions for the beam width and central gain. These analytical results enable the definition of an angle-dependent, modified Rayleigh distance, which effectively distinguishes near-field and far-field user regimes. Building on the analysis, we develop a direct and computationally efficient method to estimate user distance, with a complexity of O(1), and further improve its accuracy through a simple refinement. Simulation results demonstrate significant gains in both single- and multi-user settings, with up to 2.38 dB SNR improvement over exhaustive search. To further enhance estimation accuracy, we additionally propose a maximum likelihood estimation (MLE) based refinement method, leveraging the Rician distribution of signal amplitudes and achieving accuracy close to the Cramer--Rao bound (CRB). Simulation shows the single-user and multi-user achievable rates can both approach those obtained with ideal channel state information.
MC for Agriculture: A Framework for Nature-inspired Sustainable Pest Control
Authors: Fardad Vakilipoor, Nora Hirschmann, Julian Schladt, Stefan Schwab, Annette Reineke, Robert Schober, Kathrin Castiglione, Maximilian Schaefer
Date: 2025-06-25 00:00:00

In agriculture, molecular communication (MC) is envisioned as a framework to address critical challenges such as smart pest control. While conventional approaches mostly rely on synthetic plant protection products, posing high risks for the environment, harnessing plant signaling processes can lead to innovative approaches for nature-inspired sustainable pest control. In this paper, we investigate an approach for sustainable pest control and reveal how the MC paradigm can be employed for analysis and optimization. In particular, we consider a system where herbivore-induced plant volatiles (HIPVs), specifically methyl salicylate (MeSA), is encapsulated into microspheres deployed on deployed on plant leaves. The controlled release of MeSA from the microspheres, acting as transmitters (TXs), supports pest deterrence and antagonist attraction, providing an eco-friendly alternative to synthetic plant protection products. Based on experimental data, we investigate the MeSA release kinetics and obtain an analytical model. To describe the propagation of MeSA in farming environments, we employ a three dimensional (3D) advection-diffusion model, incorporating realistic wind fields which are predominantly affecting particle propagation, and solve it by a finite difference method (FDM). The proposed model is used to investigate the MeSA distribution for different TX arrangements, representing different practical microsphere deployment strategies. Moreover, we introduce the coverage effectiveness index (CEI) as a novel metric to quantify the environmental coverage of MeSA. This analysis offers valuable guidance for the practical development of microspheres and their deployment aimed at enhancing coverage and, consequently, the attraction of antagonistic insects.
Differential Transformer-driven 6G Physical Layer for Collaborative Perception Enhancement
Authors: Soheyb Ribouh, Osama Saleem, Mohamed Ababsa
Date: 2025-06-25 00:00:00
Tasks: Autonomous Driving, Autonomous Vehicles

The emergence of 6G wireless networks promises to revolutionize vehicular communications by enabling ultra-reliable, low-latency, and high-capacity data exchange. In this context, collaborative perception techniques, where multiple vehicles or infrastructure nodes cooperate to jointly receive and decode transmitted signals, aim to enhance reliability and spectral efficiency for Connected Autonomous Vehicle (CAV) applications. In this paper, we propose an end-to-end wireless neural receiver based on a Differential Transformer architecture, tailored for 6G V2X communication with a specific focus on enabling collaborative perception among connected autonomous vehicles. Our model integrates key components of the 6G physical layer, designed to boost performance in dynamic and challenging autonomous driving environments. We validate the proposed system across a range of scenarios, including 3GPP-defined Urban Macro (UMa) channel. To assess the model's real-world applicability, we evaluate its robustness within a V2X framework. In a collaborative perception scenario, our system processes heterogeneous LiDAR and camera data from four connected vehicles in dynamic cooperative vehicular networks. The results show significant improvements over state-of-the-art methods, achieving an average precision of 0.84, highlighting the potential of our proposed approach to enable robust, intelligent, and adaptive wireless cooperation for next-generation connected autonomous vehicles.
Revisiting CHAMPAGNE: Sparse Bayesian Learning as Reweighted Sparse Coding
Authors: Dylan Sechet, Matthieu Kowalski, Samy Mokhtari, Bruno Torrésani
Date: 2025-06-25 00:00:00
Tasks: Computational Efficiency

This paper revisits the CHAMPAGNE algorithm within the Sparse Bayesian Learning (SBL) framework and establishes its connection to reweighted sparse coding. We demonstrate that the SBL objective can be reformulated as a reweighted $\ell_{21}$-minimization problem, providing a more straightforward interpretation of the sparsity mechanism and enabling the design of an efficient iterative algorithm. Additionally, we analyze the behavior of this reformulation in the low signal-to-noise ratio (SNR) regime, showing that it simplifies to a weighted $\ell_{21}$-regularized least squares problem. Numerical experiments validate the proposed approach, highlighting its improved computational efficiency and ability to produce exact sparse solutions, particularly in simulated MEG source localization tasks.
Active RIS Enabled NLoS LEO Satellite Communications: A Three-timescale Optimization Framework
Authors: Ziwei Liu, JunYan He, Shanshan Zhao, Meng Hua, Bin Lyu, Xinjie Zhao, Gengxin Zhang
Date: 2025-06-25 00:00:00

In this letter, we study an active reconfigurable intelligent surfaces (RIS) assisted Low Earth orbit (LEO) satellite communications under non-line-of-sight (NLoS) scenarios, where the active RIS is deployed to create visual line-of-sight links for reliable communication. To address the challenges of high energy consumption caused by frequent beamforming updates in active RIS, we propose a three-timescale optimization framework that jointly designs the transmit beamforming, RIS beamforming, and RIS direction vectors based on their characteristics. The goal is to maximize the system achievable rate while reducing energy consumption by controlling the RIS beamforming switching frequency. Then, a two-layer solution framework is developed, incorporating fractional programming (FP), alternating optimization (AO), successive approximation (SCA), and penalty-based methods, to obtain the optimized solution. Simulation results demonstrate that the proposed scheme can effectively improve system performance and reduce the energy consumption of the active RIS.