pwc-archive/papers-with-abstracts huggingface dataset:
Uplink OFDM Channel Prediction with Hybrid CNN-LSTM for 6G Non-Terrestrial Networks
Authors: Bruno De Filippo, Carla Amatetti, Alessandro Vanelli-Coralli
Date: 2025-02-13 00:00:00

Wireless communications are typically subject to complex channel dynamics, requiring the transmission of pilot sequences to estimate and equalize such effects and correctly receive information bits. This is especially true in 6G non-terrestrial networks (NTNs) in low Earth orbit, where one end of the communication link orbits around the Earth at several kilometers per second, and a multi-carrier waveform, such as orthogonal frequency division multiplexing (OFDM), is employed. To minimize the pilot overhead, we remove pilot symbols every other OFDM slot and propose a channel predictor to obtain the channel frequency response (CFR) matrix in absence of pilots. The algorithm employs an encoder-decoder convolutional neural network and a long short-term memory layer, along with skip connections, to predict the CFR matrix on the upcoming slot based on the current one. We demonstrate the effectiveness of the proposed predictor through numerical simulations in tapped delay line channel models, highlighting the effective throughput improvement. We further assess the generalization capabilities of the model, showing minimal throughput degradation when testing under different Doppler spreads and in both line of sight (LoS) and non-LoS propagation conditions. Finally, we discuss computational-complexity-related aspects of the lightweight hybrid CNN-LSTM architecture.
Joint Attention Mechanism Learning to Facilitate Opto-physiological Monitoring during Physical Activity
Authors: Xiaoyu Zheng, Sijung Hu, Vincent Dwyer, Mahsa Derakhshani, Laura Barrett
Date: 2025-02-13 00:00:00
Tasks: Generative Adversarial Network, Photoplethysmography (PPG)

Opto-physiological monitoring is a non-contact technique for measuring cardiac signals, i.e., photoplethysmography (PPG). Quality PPG signals directly lead to reliable physiological readings. However, PPG signal acquisition procedures are often accompanied by spurious motion artefacts (MAs), especially during low-to-high-intensity physical activity. This study proposes a practical adversarial learning approach for opto-physiological monitoring by using a generative adversarial network with an attention mechanism (AM-GAN) to model motion noise and to allow MA removal. The AM-GAN learns an MA-resistant mapping from raw and noisy signals to clear PPG signals in an adversarial manner, guided by an attention mechanism to directly translate the motion reference of triaxial acceleration to the MAs appearing in the raw signal. The AM-GAN was experimented with three various protocols engaged with 39 subjects in various physical activities. The average absolute error for heart rate (HR) derived from the MA-free PPG signal via the AM-GAN, is 1.81 beats/min for the IEEE-SPC dataset and 3.86 beats/min for the PPGDalia dataset. The same procedure applied to an in-house LU dataset resulted in average absolute errors for HR and respiratory rate (RR) of less than 1.37 beats/min and 2.49 breaths/min, respectively. The study demonstrates the robustness and resilience of AM-GAN, particularly during low-to-high-intensity physical activities.
Rate-Splitting Multiple Access for 6G: Prototypes, Experimental Results and Link/System level Simulations
Authors: Sundar Aditya, Yong Jin Daniel Kim, David Vargas, David Redgate, Onur Dizdar, Neil Bhushan, Xinze Lyu, Sibo Zhang, Stephen Wang, Bruno Clerckx
Date: 2025-02-13 00:00:00
Tasks: ISAC, Management

Rate-Splitting Multiple Access (RSMA) is a powerful and versatile physical layer multiple access technique that generalizes and has better interference management capabilities than 5G-based Space Division Multiple Access (SDMA). It is also a rapidly maturing technology, all of which makes it a natural successor to SDMA in 6G. In this article, we describe RSMA's suitability for 6G by presenting: i) link and system level simulations of RSMA's performance gains over SDMA in realistic environments, and (ii) pioneering experimental results that demonstrate RSMA's gains over SDMA for key use cases like enhanced Mobile Broadband (eMBb), and Integrated Sensing and Communications (ISAC). We also comment on the status of standardization activities for RSMA.
Kise-Manitow's Hand in Space: Securing Communication and Connections in Space
Authors: Nesrine Benchoubane, Gunes Karabulut Kurt
Date: 2025-02-13 00:00:00
Tasks: All

The lunar Gateway is a complex system-of-systems (SoS) requiring secure, resilient integration of all its systems. This paper develops controls for its early systems to secure command and data handling (C&DH) and evaluates their effectiveness through a case study on collision impact propagation originating from Canadarm3. We demonstrate that a baseline security strategy with stringent, standardized controls reduces failure impact by up to 70%, underscoring the importance of consistent security integration across all systems.
A Unifying View of OTFS and Its Many Variants
Authors: Qinwen Deng, Yao Ge, Zhi Ding
Date: 2025-02-13 00:00:00

High mobility environment leads to severe Doppler effects and poses serious challenges to the conventional physical layer based on the widely popular orthogonal frequency division multiplexing (OFDM). The recent emergence of orthogonal time frequency space (OTFS) modulation, along with its many related variants, presents a promising solution to overcome such channel Doppler effects. This paper aims to clearly establish the relationships among the various manifestations of OTFS. Among these related modulations, we identify their connections, common features, and distinctions. Building on existing works, this work provides a general overview of various OTFS-related detection schemes and performance comparisons. We first provide an overview of OFDM and filter bank multi-carrier (FBMC) by demonstrating OTFS as a precoded FBMC through the introduction of inverse symplectic finite Fourier transform (ISFFT). We explore the relationship between OTFS and related modulation schemes with similar characteristics. We provide an effective channel model for high-mobility channels and offer a unified detection representation. We provide numerical comparisons of power spectrum density (PSD) and bit error rate (BER) to underscore the benefit of these modulation schemes in high-mobility scenarios. We also evaluate various detection schemes, revealing insights into their efficacies. We discuss opportunities and challenges for OTFS in high mobility, setting the stage for future research and development in this field.
Joint Transceiver Design for RIS Enhanced Dual-Functional Radar-Communication with Movable Antenna
Authors: Ran Yang, Zheng Dong, Peng Cheng, Yue Xiu, Yan Li, Ning Wei
Date: 2025-02-13 00:00:00

Movable antennas (MAs) have shown significant potential in enhancing the performance of dual-functional radar-communication (DFRC) systems. In this paper, we investigate the MA-based transceiver design for DFRC systems, where a reconfigurable intelligent surface (RIS) is employed to enhance the communication quality in dead zones. To enhance the radar sensing performance, we formulate an optimization problem to maximize the radar signal-to-interference-plus-noise ratio (SINR) by jointly optimizing the beamforming vectors, receiving filter, antenna positions, and RIS reflecting coefficients. To tackle this challenging problem, we develop a fractional programming-based optimization framework, incorporating block coordinate descent (BCD), successive convex approximation (SCA), and penalty techniques. Simulation results demonstrate that the proposed method can significantly improve the radar SINR and achieve a satisfactory balance between the radar and communication performance compared with existing benchmark schemes.
Data Sensor Fusion In Digital Twin Technology For Enhanced Capabilities In A Home Environment
Authors: Benjamin Momoh, Salisu Yahaya
Date: 2025-02-13 00:00:00
Tasks: Sensor Fusion

This paper investigates the integration of data sensor fusion in digital twin technology to bolster home environment capabilities, particularly in the context of challenges brought on by the coronavirus pandemic and its economic effects. The study underscores the crucial role of digital transformation in not just adapting to, but also mitigating disruptions during the fourth industrial revolution. Using the Wit Motion sensor, data was collected for activities such as walking, working, sitting, and lying, with sensors measuring accelerometers, gyroscopes, and magnetometers. The research integrates Cyber-physical systems, IoT, AI, and robotics to fortify digital twin capabilities. The paper compares sensor fusion methods, including feature-level fusion, decision-level fusion, and Kalman filter fusion, alongside machine learning models like SVM, GBoost, and Random Forest to assess model effectiveness. Results show that sensor fusion significantly improves the accuracy and reliability of these models, as it compensates for individual sensor weaknesses, particularly with magnetometers. Despite higher accuracy in ideal conditions, integrating data from multiple sensors ensures more consistent and reliable results in real-world settings, thereby establishing a robust system that can be confidently applied in practical scenarios.
A procedure for assessing of machine health index data prediction quality
Authors: Daniel Kuzio, Radosław Zimroz, Agnieszka Wyłomańska
Date: 2025-02-12 00:00:00
Tasks: Exponential degradation, Multi-class Classification, Prognosis

The paper discusses the challenge of evaluating the prognosis quality of machine health index (HI) data. Many existing solutions in machine health forecasting involve visually assessing the quality of predictions to roughly gauge the similarity between predicted and actual samples, lacking precise measures or decisions. In this paper, we introduce a universal procedure with multiple variants and criteria. The overarching concept involves comparing predicted data with true HI time series, but each procedure variant has a specific pattern determined through statistical analysis. Additionally, a statistically established threshold is employed to classify the result as either a reliable or non-reliable prognosis. The criteria include both simple measures (MSE, MAPE) and more advanced ones (Space quantiles-inclusion factor, Kupiec's POF, and TUFF statistics). Depending on the criterion chosen, the pattern and decision-making process vary. To illustrate effectiveness, we apply the proposed procedure to HI data sourced from the literature, covering both warning (linear degradation) and critical (exponential degradation) stages. While the method yields a binary output, there is potential for extension to a multi-class classification. Furthermore, experienced users can use the quality measure expressed in percentage for more in-depth analysis.
Instantaneous directional channel measurements at 14 GHz and 160 GHz via a virtual circular array
Authors: Wilhelm Keusgen, Taro Eichler
Date: 2025-02-12 00:00:00

In this paper a novel frequency-scalable rotary platform design is introduced which allows for flexible directional channel measurements using different types of antennas, and which can also be used with frequency extenders for measurements up to the THz region. The measurement platform has been applied to measure the channel properties including the direction of arrival at the FR3 frequency 14 GHz and in the D-band at 160 GHz in a large hall indoor environment with LOS distances up to 40 m. The results show very good agreement of strong path components for both frequencies as well as interesting dependencies of delay spread, angular spread, and Ricean K- factor on distance and frequency and can be used to parameterize a path loss model.
Compression of Site-Specific Deep Neural Networks for Massive MIMO Precoding
Authors: Ghazal Kasalaee, Ali Hasanzadeh Karkan, Jean-François Frigon, François Leduc-Primeau
Date: 2025-02-12 00:00:00
Tasks: Neural Architecture Search, Neural Network Compression, Quantization

The deployment of deep learning (DL) models for precoding in massive multiple-input multiple-output (mMIMO) systems is often constrained by high computational demands and energy consumption. In this paper, we investigate the compute energy efficiency of mMIMO precoders using DL-based approaches, comparing them to conventional methods such as zero forcing and weighted minimum mean square error (WMMSE). Our energy consumption model accounts for both memory access and calculation energy within DL accelerators. We propose a framework that incorporates mixed-precision quantization-aware training and neural architecture search to reduce energy usage without compromising accuracy. Using a ray-tracing dataset covering various base station sites, we analyze how site-specific conditions affect the energy efficiency of compressed models. Our results show that deep neural network compression generates precoders with up to 35 times higher energy efficiency than WMMSE at equal performance, depending on the scenario and the desired rate. These results establish a foundation and a benchmark for the development of energy-efficient DL-based mMIMO precoders.
A Low-Complexity Plug-and-Play Deep Learning Model for Massive MIMO Precoding Across Sites
Authors: Ali Hasanzadeh Karkan, Ahmed Ibrahim, Jean-François Frigon, François Leduc-Primeau
Date: 2025-02-12 00:00:00
Tasks: Computational Efficiency, Domain Generalization, Meta-Learning

Massive multiple-input multiple-output (mMIMO) technology has transformed wireless communication by enhancing spectral efficiency and network capacity. This paper proposes a novel deep learning-based mMIMO precoder to tackle the complexity challenges of existing approaches, such as weighted minimum mean square error (WMMSE), while leveraging meta-learning domain generalization and a teacher-student architecture to improve generalization across diverse communication environments. When deployed to a previously unseen site, the proposed model achieves excellent sum-rate performance while maintaining low computational complexity by avoiding matrix inversions and by using a simpler neural network structure. The model is trained and tested on a custom ray-tracing dataset composed of several base station locations. The experimental results indicate that our method effectively balances computational efficiency with high sum-rate performance while showcasing strong generalization performance in unseen environments. Furthermore, with fine-tuning, the proposed model outperforms WMMSE across all tested sites and SNR conditions while reducing complexity by at least 73$\times$.
ReMAC:Digital Multiple Access Computing by Repeated Transmission
Authors: Xiaojing Yan, Saeed Razavikia, Carlo Fischione
Date: 2025-02-12 00:00:00

In this paper, we consider the ChannelComp framework, where multiple transmitters aim to compute a function of their values at a common receiver while using digital modulations over a multiple access channel. ChannelComp provides a general framework for computation by designing digital constellations for over-the-air computation. Currently, ChannelComp uses a symbol-level encoding. However, encoding repeated transmissions of the same symbol and performing the function computation using the corresponding received sequence may significantly improve the computation performance and reduce the encoding complexity. In this paper, we propose a new scheme where each transmitter repeats the transmission of the same symbol over multiple time slots while encoding such repetitions and designing constellation diagrams to minimize computational errors. We formally model such a scheme by an optimization problem, whose solution jointly identifies the constellation diagram and the repetition code. We call the proposed scheme ReMAC. To manage the computational complexity of the optimization, we divide it into two tractable subproblems. We verify the performance of ReMAC by numerical experiments. The simulation results reveal that ReMAC can reduce the computation error in noisy and fading channels by approximately up to 7.5$dB compared to standard ChannelComp, particularly for product functions.
Direction Finding for Software Defined Radios with Switched Uniform Circular Arrays
Authors: Lennart Werner, Markus Gardill, Marco Hutter
Date: 2025-02-12 00:00:00

Accurate Direction of Arrival (DoA) estimation is critical for applications in robotics and communication, but high costs and complexity of coherent multi-channel receivers hinder accessibility. This work proposes a cost-effective DoA estimation system for continuous wave (CW) signals in the 2.4 GHz ISM band. A two-channel software-defined radio (SDR) with time-division multiplexing (TDM) enables pseudo-coherent sampling of an eight-element uniform circular array (UCA) with low hardware complexity. A central reference antenna mitigates phase jitter and sampling errors. The system applies an enhanced MUSIC algorithm with spatial smoothing to handle light multipath interference in indoor and outdoor environments. Experiments in an anechoic chamber validate accuracy under ideal conditions, while real-world tests confirm robust performance in multipath-prone scenarios. With 5 Hz DoA updates and post-processing to enhance tracking, the system provides an accessible and reliable solution for DoA estimation in real-world environments.
LoRa Fine Synchronization with Two-Pass Time and Frequency Offset Estimation
Authors: Joachim Tapparel, Andreas Burg
Date: 2025-02-12 00:00:00

LoRa is currently one of the most widely used low-power wide-area network (LPWAN) technologies. The physical layer leverages a chirp spread spectrum modulation to achieve long-range communication with low power consumption. Synchronization at long distances is a challenging task as the spread signal can lie multiple orders of magnitude below the thermal noise floor. Multiple research works have proposed synchronization algorithms for LoRa under different hardware impairments. However, the impact of sampling frequency offset (SFO) has mostly either been ignored or tracked only during the data phase, but it often harms synchronization. In this work, we extend existing synchronization algorithms for LoRa to estimate and compensate SFO already in the preamble and show that this early compensation has a critical impact on the estimation of other impairments such as carrier frequency offset and sampling time offset. Therefore it is critical to recover long-range signals.
Bistatic Micro-Doppler Analysis of a Vertical Takeoff and Landing (VTOL) Drone in ICAS Framework
Authors: Heraldo Cesar Alves Costa, Saw James Myint, Carsten Andrich, Sebastian W. Giehl, Dieter Novotny, Julia Beuster, Christian Schneider, Reiner S. Thomä
Date: 2025-02-12 00:00:00

Integrated Communication and Sensing (ICAS) is a key technology that enables sensing functionalities within the next-generation mobile communication (6G). Joint design and optimization of both functionalities could allow coexistence, therefore it advances toward joint signal processing and using the same hardware platform and common spectrum. Contributing to ICAS sensing, this paper presents the measurement and analysis of the micro-Doppler signature of Vertical Takeoff and Landing (VTOL) drones. Measurement is performed with an OFDM-like communication signal and bistatic constellation, which is a typical case in ICAS scenarios. This work shows that micro-Doppler signatures can be used to precisely distinguish flight modes, such as take-off, landing, hovering, transition, and cruising.
Dynamic Power Allocation in OFDM ISAC for Time of Arrival Estimation
Authors: Ali Al Khansa, Giyyarpuram Madhusudan, Guillaume Larue, Louis-Adrien Dufrene
Date: 2025-02-12 00:00:00
Tasks: Integrated sensing and communication, ISAC

Resource allocation in Integrated Sensing and Communication (ISAC) systems is critical for balancing communication and sensing performance. This paper introduces a novel dynamic power allocation strategy for Orthogonal Frequency Division Multiplexing (OFDM) ISAC systems, optimizing communication capacity while adhering to Peak Side-lobe Level (PSL) and sensing accuracy constraints, particularly for Time of Arrival (ToA) estimation. Unlike conventional methods that address either PSL or accuracy in isolation, our approach dynamically allocates power to satisfy both constraints. Additionally, it prioritizes communication when sensing performance is insufficient, avoiding any loss in communication capacity. Numerical results validate the importance of considering both sensing constraints and demonstrate the effectiveness of the proposed dynamic power allocation strategy.
Enhanced Load Forecasting with GAT-LSTM: Leveraging Grid and Temporal Features
Authors: Ugochukwu Orji, Çiçek Güven, Dan Stowell
Date: 2025-02-12 00:00:00
Tasks: Graph Attention, Load Forecasting

Accurate power load forecasting is essential for the efficient operation and planning of electrical grids, particularly given the increased variability and complexity introduced by renewable energy sources. This paper introduces GAT-LSTM, a hybrid model that combines Graph Attention Networks (GAT) and Long Short-Term Memory (LSTM) networks. A key innovation of the model is the incorporation of edge attributes, such as line capacities and efficiencies, into the attention mechanism, enabling it to dynamically capture spatial relationships grounded in grid-specific physical and operational constraints. Additionally, by employing an early fusion of spatial graph embeddings and temporal sequence features, the model effectively learns and predicts complex interactions between spatial dependencies and temporal patterns, providing a realistic representation of the dynamics of power grids. Experimental evaluations on the Brazilian Electricity System dataset demonstrate that the GAT-LSTM model significantly outperforms state-of-the-art models, achieving reductions of 21. 8% in MAE, 15. 9% in RMSE and 20. 2% in MAPE. These results underscore the robustness and adaptability of the GAT-LSTM model, establishing it as a powerful tool for applications in grid management and energy planning.
A Generalized Converted Measurement Kalman Filter
Authors: Steven V. Bordonaro, Tod E. Luginbuhl, Michael J. Walsh
Date: 2025-02-12 00:00:00

This report derives a generalized, converted measurement Kalman filter for the class of filtering problems with a linear state equation and nonlinear measurement equation, for which a bijective mapping exists between the state and measurement coordinate systems. For these problems, a procedure is developed for mapping the observed measurements and their covariance matrices from measurement coordinates to state coordinates, such that the converted measurements are unbiased and the converted measurement covariance matrices are independent of the states and observed measurements. In cases where not all measurement coordinates are observed, predicted measurements of these coordinates are introduced as substitutes, and the impact of these measurements on the filter is mitigated by an information zeroing operation on the corresponding rows and columns of the converted measurement inverse-covariance matrix. Filter performance is demonstrated on two well-known target-tracking problems and is compared with the performance of the standard extended and unscented Kalman filters for these problems. These examples show the proposed filter obtains lower mean squared error, better consistency, and less track loss than either the extended Kalman filter or the unscented Kalman filter.