IEEE Open Journal of the Communications Society最新文献

{"title":"Tiled Array Design for Multi-Beam Joint Communication and Sensing: Channel Matching Method","authors":"Hadi Alidoustaghdam;André B. J. Kokkeler;Yang Miao","doi":"10.1109/OJCOMS.2025.3616790","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3616790","url":null,"abstract":"The integration of sensing and communication capabilities within a single platform is a significant advantage of sixth-generation (6G) communication systems. Multi-beam technology offers an efficient front-end solution for joint communication and sensing (JCAS) at the base station (BS), enabling simultaneous communication with multiple users and sensing multiple targets through analog beamforming. This work introduces a scenario-based tiling array design methodology for a JCAS BS, employing a tiled planar array (TPA) that emphasizes cost-effectiveness, modularity, and scalability. We adopt a low-complexity channel-matching method to optimize the tiles by leveraging self- and cross-correlations of communication and sensing channels. Key performance metrics for this design include the signal-to-interference-plus-noise ratio (SINR) for both communication and sensing tasks. Numerical results indicate that the optimum design of TPAs for JCAS necessitates a proper knowledge of the scenario and environment in which the apertures will be employed. In conflicting scenarios, such as communication operates in non-line-of-sight (NLOS) conditions while sensing relies on line-of-sight (LOS), the scatterers that enable communication also appear as clutter to the sensing function. For example, if NLoS communication clusters fully obstruct the radar targets, the JCAS system can suffer up to a 10 dB drop in sensing SINR; however, these clusters can benefit communication, when the scatterers are positioned in regions of higher aperture gain.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8477-8495"},"PeriodicalIF":6.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11186162","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145255953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the MISO Broadcast Channel With Finite Constellations and Imperfect CSIT: Rate-Splitting, SDMA, NOMA, and Space-Time Block Coding","authors":"Álvaro Pendás-Recondo;Jesús Alberto López-Fernández;Rafael González Ayestarán","doi":"10.1109/OJCOMS.2025.3614772","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3614772","url":null,"abstract":"The multiple-input single-output broadcast channel (MISO-BC) models a scenario in which a transmitter equipped with multiple antennas communicates with multiple single-antenna receivers over the same time, frequency, and code resource block. Strategies for managing inter-user interference in this setting are typically studied under the assumptions of either Gaussian signaling (GS) and/or perfect channel state information at the transmitter (CSIT). In this paper, we consider a more realistic model for practical wireless communications where the transmitted signals are drawn from finite input constellations, referred to as discrete signaling (DS), and where the transmitter has imperfect CSIT. Well-known multiple access (MA) strategies for the MISO-BC based on linear precoding, namely rate-splitting multiple access (RSMA), space-division multiple access (SDMA), and power-domain non-orthogonal multiple access (NOMA), are studied under this formulation and compared with space-time block coding (STBC) techniques that exploit similar concepts for managing inter-user interference, while relying solely on statistical magnitude CSIT. The precoding and decoding formulations of each strategy are described within a unified framework, and key differences between GS and DS in managing inter-user interference are identified. Furthermore, a novel space-time RSMA (ST-RSMA) design is proposed, and the previously considered ST-NOMA scheme is generalized for more than two transmit antennas. Extensive numerical results under Rayleigh block-fading channels, based on symbol error rate (SER) and bit error rate (BER) Monte Carlo simulations, are presented across various scenarios, including different numbers of antennas, transmission rates, CSIT quality levels, and channel strength disparities among users. Based on these results, the strengths and weaknesses of each strategy are identified, and the most suitable approach for each scenario is determined.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8422-8441"},"PeriodicalIF":6.3,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11182302","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145255877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of RIS-Assisted Links: Toward Reliable and Low-Latency Communications","authors":"Ahmed I. Abdulshakoor;Najah Abu Ali;Hossam S. Hassanein","doi":"10.1109/OJCOMS.2025.3614548","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3614548","url":null,"abstract":"Reconfigurable intelligent surface (RIS) has recently emerged as a promising technology to enhance the performance of wireless communication networks. While outage probability has been widely analyzed in RIS-assisted systems, the impact of packet delay remains largely unexplored, despite its critical role in ensuring Quality of Service (QoS) for delay-sensitive applications. This paper presents a comprehensive analysis of packet delay in single and double RIS-assisted communication systems. The analysis derives the signal-to-noise ratio (SNR) distribution under Nakagami-m fading conditions, explicitly incorporating small-scale fading, inter-RIS channel correlations, and RIS phase errors–factors often ignored in previous studies. The RIS phase error, arising from imperfect channel estimation or limited phase control precision, is modeled by a von Mises distribution. Using these distributions, we establish closed-form expressions for average packet delay, providing a novel characterization of RIS-assisted communication performance. Additionally, an outage probability analysis is conducted for the double RIS scenario, capturing the effects of inter-RIS fading and cascaded channel interactions to offer a more complete performance characterization. Performance evaluations, comprising numerical and simulation-based tests, examine the impact of key system parameters, including the number of RIS reflecting elements, fading severity, transmit SNR, and user-RIS distance on outage and delay. Results demonstrate that increasing the number of reflecting elements improves both delay and outage performance, with double RIS configurations outperforming single setups in supporting higher target rates, extending communication coverage, and reducing latency. These results provide insights for optimizing RIS deployment in next-generation wireless networks, particularly for ultra-reliable low-latency communications (URLLC) and real-time applications.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8442-8459"},"PeriodicalIF":6.3,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11178242","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145255908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hierarchical Multimodal Federated Learning Over Cell-Free Massive MIMO Systems","authors":"S. Mohammad Sheikholeslami;Pai Chet Ng;Konstantinos N. Plataniotis","doi":"10.1109/OJCOMS.2025.3614440","DOIUrl":"10.1109/OJCOMS.2025.3614440","url":null,"abstract":"Cell-Free massive MIMO (CF-mMIMO) is a promising technology for enabling Federated Learning (FL) in the next generation of wireless networks due to its uniform service coverage. However, existing approaches that optimize FL over CF-mMIMO networks rely on a single Control Unit (CU), limiting scalability in terms of geographic coverage and user participation, while also overlooking multimodal data heterogeneity, which further increases latency. To address these challenges, we propose Hierarchical Multimodal Federated Learning (HMFL) over CF-mMIMO networks, which employs multiple CUs, managed by a Cloud Data Center (CDC). Instead of a single CU for global aggregation, HMFL uses a hierarchical approach where each CU aggregates local updates from the users before forwarding the edge models to the CDC for global aggregation. Moreover, we formulate an optimization problem for long-term decision-making in HMFL over CF-mMIMO networks, aiming to balance latency and user participation under a long-term energy budget. To solve this problem, we propose Long-Term Device-Modality Selection and Resource Allocation (LT-DeMoSRA) that employs optimization techniques to enable per-round decision-making with a long-term perspective over CUs without requiring future information. Additionally, our HMFL framework personalizes the fusion process based on the available modalities for each user, ensuring more adaptive and efficient multi-modal learning. Experimental results demonstrate that HMFL over multi-CU CF-mMIMO networks supports a larger number of users and outperforms existing alternatives by reducing training latency and improving user participation for both unimodal and multi-modal data.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8111-8127"},"PeriodicalIF":6.3,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11178236","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Joint Mobility-Driven Adaptive Power Control and Priority-Aware Bandwidth Allocation for AoI and Energy Optimization in WBANs","authors":"Muhammad Morshed Alam;Muhammad Yeasir Arafat;Tamim Hossain;Md. Labibul Haque Labib;Md. Shafkat Kamal;Md. Rakibur Rahman Nayem;Md. Ratul Islam;Md. Noor-A-Rahim;Dirk Pesch","doi":"10.1109/OJCOMS.2025.3612475","DOIUrl":"10.1109/OJCOMS.2025.3612475","url":null,"abstract":"Wireless Body Area Networks (WBANs) are recognized as innovative technology for personal health monitoring. In WBANs, physiological sensor data must be transmitted to the local processing unit (LPU) with minimal age of information (AoI) based on sensor data priority. However, the limited resources of sensors, such as energy, computational capacity, caching and bandwidth, make AoI minimization challenging. Additionally, dynamic radio links caused by body movement and interference further complicate the task. This study aims to minimize the weighted cost of time average AoI and energy consumption by adaptively controlling the transmit power based on real-time distance variations between the sensor and LPU, while allocating priority-aware bandwidth under quality of service and resource constraints in continuous decision space. To solve the non-linear problem, a particle filter-assisted Lagrange relaxation with Karush–Kuhn–Tucker conditions (PF-LKKT) framework is proposed. A recursive particle filter based on received signal strength and motion-sensor data is employed for accurate distance estimation. Then, according to the distance variation adaptively transmit power and data priority-aware bandwidth is jointly allocated. Simulation results demonstrate the superiority of the proposed framework over existing techniques.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8095-8110"},"PeriodicalIF":6.3,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11177546","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Joint Power Allocation, User-Subarray Pairing, and Analog Beamforming for the Spatial Non-Stationary Extremely Large-Scale MIMO","authors":"Xiuyu Zhang;Jianping Zheng","doi":"10.1109/OJCOMS.2025.3613469","DOIUrl":"10.1109/OJCOMS.2025.3613469","url":null,"abstract":"In this paper, we study the downlink precoding of spatial non-stationary (SnS) extremely large-scale multiple-input multiple-output (XL-MIMO) in the near-field channel with uniform spherical wave (USW) and mixed line-of-sight and non-line-of-sight environments. First, we present a novel precoding scheme by replacing the digital beamforming (BF) in the conventional hybrid BF with user-subarray pairing network. The presented scheme utilizes the SnS channel characteristic efficiently, and can facilitate the high-speed implementation and the deployment of low-resolution digital-to-analog converters. Next, we study the optimizations to maximize both the sum-rate and min-rate by designing the power allocation, user-subarray pairing network, and analog BF jointly. For the sum-rate maximization, we first reformulate the corresponding nonconvex problem by the quadratic transformation to facilitate the further processing. Then, the alternating optimization framework is utilized to optimize the variables alternately. Concretely, the Riemannian conjugate gradient method, projected gradient ascent method, and mathematical programming with equilibrium constraints alternating direction method are employed to optimize the analog BF, power allocation, and user-subarray pairing network, respectively. For the min-rate maximization, we extend the aforementioned solutions by proper modifications. Finally, the effectiveness of the proposed optimization algorithms is verified through computer simulations.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8142-8157"},"PeriodicalIF":6.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11175566","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Designing Heterogeneous GNNs With Desired Permutation Properties for Wireless Resource Allocation","authors":"Jianyu Zhao;Chenyang Yang;Tingting Liu;Shuangfeng Han;Xiaoyun Wang","doi":"10.1109/OJCOMS.2025.3612442","DOIUrl":"10.1109/OJCOMS.2025.3612442","url":null,"abstract":"Graph neural networks (GNNs) have been designed for learning a variety of resource allocation policies, i.e., the mappings from environment parameters to allocated resources, thanks to their superior performance, and the potential in enabling size generalizability and scalability. These merits are rooted in leveraging permutation prior, i.e., satisfying the permutation property of the policy to be learned (referred to as desired permutation property). Many wireless policies have complex permutation properties, and heterogeneous GNNs (HetGNNs) ought to be used to satisfy these properties. Two key factors enable a HetGNN to satisfy desired permutation property: a heterogeneous graph and the architecture of the HetGNN, both are usually designed heuristically for a specific problem. In this paper, we strive to provide a systematic and general approach for the design to satisfy the desired permutation property. We first propose a method for constructing a graph to learn a policy, where the edges and their types are defined for the sake of satisfying complex permutation properties. Then, we provide three sufficient conditions with rigorous proof for ensuring a HetGNN to satisfy the desired permutation property when learning over an appropriate graph. These conditions suggest a method for designing the HetGNN with desired permutation property by tying its processing, combining, and pooling functions based on the types of vertices and edges of the graph. We focus on two representative examples – power allocation in multi-cell-multi-user systems and hybrid precoding in multi-user multi-antenna systems – for demonstrating how to apply the proposed methods and validating the impact of exploiting permutation prior through simulations.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8049-8077"},"PeriodicalIF":6.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11174999","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"From Sub-6 GHz to Millimeter-Wave: Dynamic Indoor Measurements, Channel Characteristics and Performance Evaluation","authors":"Faruk Pasic;Mariam Mussbah;Markus Hofer;Sebastian Caban;Stefan Schwarz;Thomas Zemen;Markus Rupp;Christoph F. Mecklenbräuker","doi":"10.1109/OJCOMS.2025.3613504","DOIUrl":"10.1109/OJCOMS.2025.3613504","url":null,"abstract":"Future wireless communication systems will extend the employed frequency bands from sub-6 GHz to millimeter wave (mmWave) bands to achieve higher data rates. To investigate different propagation characteristics between sub-6 GHz and mmWave bands in indoor environments, it is essential to conduct multi-band channel measurements. In this work, we perform dynamic channel measurements using a measurement setup that enables comparing sub-6 GHz and mmWave bands in a fair manner. Measurements are conducted in an indoor environment at center frequencies of 2.55 GHz and 25.5 GHz at transmitter velocities of 50 km/h and 100 km/h. Based on the acquired measurement data, we conduct a comparative analysis of the multi-band propagation characteristics. Specifically, we compare the channels in terms of root-mean-square (RMS) delay spread, Rician K-factor, RMS Doppler spread and RMS angular spread. Additionally, we evaluate the system performance at both frequency bands in terms of achievable spectral efficiency derived from the measured channels. Our results show that differences in delay-domain parameters (RMS delay spread and Rician K-factor) and angular-domain (RMS angular spread) are relatively minor and are unlikely to significantly impact system design. However, the RMS Doppler spread increases proportionally with carrier frequency and transmitter velocity, causing channel state information (CSI) at mmWave frequencies to become outdated much more rapidly. This imposes a substantial performance limitation for mmWave systems in dynamic scenarios.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8190-8208"},"PeriodicalIF":6.3,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11175577","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An SDR-Based Test Platform for 5G NTN Prototyping and Validation","authors":"Lu Hou;Kan Zheng;Jie Mei;Cheng Huang","doi":"10.1109/OJCOMS.2025.3610869","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3610869","url":null,"abstract":"The integration of satellite communication into 5G has been formalized in 3GPP Release 17 through the specification of Non-Terrestrial Networks (NTN), marking a significant step toward achieving global connectivity. However, the early-stage maturity of 5G NTN standards and the lack of commercial NTN-capable equipment hinder extensive performance validation and system prototyping. To address this gap, this paper proposes a software-defined radio (SDR) test platform with General-Purpose Processor (GPP) processing, leveraging Amarisoft’s 5G NTN protocol stack software while performing custom system integration and adaptation for real satellite operation. The platform supports bidirectional communication between an SDR-based NTN gNB and UE emulator through a Geostationary Earth Orbit (GEO) satellite link, with full compliance to 3GPP NTN specifications. We provide detailed insights into the system architecture, SDR hardware–software co-design, and satellite gateway adaptations. Through field trials, we evaluate the performance metrics including downlink throughput and round-trip time. Results validate the feasibility and effectiveness of SDR-based platforms for NTN testing, and highlight their potential in bridging current implementation gaps before widespread commercial deployment.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"7758-7766"},"PeriodicalIF":6.3,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11173197","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145141663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Virtual Extremely Large Antenna Arrays: Emulating Near-Field Wideband Beamforming in Dense Cell-Free Networks","authors":"Georgios Mylonopoulos;Giovanni Interdonato;Stefano Buzzi;Pei Liu","doi":"10.1109/OJCOMS.2025.3612338","DOIUrl":"10.1109/OJCOMS.2025.3612338","url":null,"abstract":"Cell-free (CF) massive MIMO (m-MIMO) architectures operating under Rician fading conditions are investigated, with a focus on position-aware signal processing and Bayesian channel estimation. By treating distributed access points (APs) as components of a virtual extremely large aperture array (V-ELAA), the paper leverages near-field (NF) propagation and geometric channel characteristics of CF systems and highlights their potential to deliver fine-grained spatial resolution and improved communication and localization performance. We propose a Cramér-Rao-based analysis to quantify localization accuracy, revealing that accurate user positioning enhances channel estimation performance, especially as the channel becomes increasingly deterministic due to a dominant line-of-sight (LoS) component. Numerical evaluations of effective degrees of freedom (EDoF) across different deployment densities demonstrate the spatial diversity advantage of the CF architectures with respect to co-located m-MIMO deployments. Results show that the considered CF m-MIMO network deployment may approach perfect CSI performance through accurate localization. Finally, scalable user-centric CF implementations are examined, highlighting favorable tradeoffs between computational complexity and achievable SE.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"8078-8094"},"PeriodicalIF":6.3,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11173588","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}