IEEE Open Journal of the Communications Society最新文献

{"title":"Efficient Symbol Detection for Holographic MIMO Communications With Unitary Approximate Message Passing","authors":"Yabo Guo;Zhengdao Yuan;Peng Sun;Yi Song;Qinghua Guo;Zhongyong Wang","doi":"10.1109/OJCOMS.2025.3542860","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3542860","url":null,"abstract":"Holographic multiple-input multiple-output (HMIMO) technology holds great promise for delivering high energy and spectral efficiency, boosting system capacity, enhancing diversity, and achieving other significant performance gains. In this work, we focus on the issue of HMIMO symbol detection, which is challenging due to the non-ideal characteristics of the HMIMO near-field (NF) channel matrix introduced by the dyadic Green’s function. These characteristics, such as high-dimensional, ill-conditioned, correlated or rank-deficient, pose considerable difficulties for effective symbol detection. To tackle this problem, we propose an efficient symbol detection algorithm by leveraging the structures of HMIMO NF channel. Specifically, by exploiting the block symmetry of the fully polarized NF channel model, we first decompose the high-dimensional signal model into multiple low-dimensional sub-models, which reduces the computational complexity of preprocessing for the channel matrix compared to its predecessor, thus permitting the design of efficient symbol detection algorithms. Then, building upon these multiple sub-signal models, we formulate the symbol detection problem within a probabilistic framework and construct the corresponding factor graph. By utilizing this factor graph and unitary approximate message passing (UAMP), we propose an efficient Bayesian symbol detection algorithm. The proposed symbol detection algorithm effectively mitigates the adverse effects caused by imperfections in the HMIMO NF polarized channel matrix. Simulation results verify the proposed method outperforms the conventional symbol detector.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1363-1371"},"PeriodicalIF":6.3,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10891486","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519856","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":"Variable-Rate Incremental-Redundancy HARQ for Finite Blocklengths","authors":"Yu Fu;Angel Lozano;Hongwen Yang","doi":"10.1109/OJCOMS.2025.3541238","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3541238","url":null,"abstract":"Incremental redundancy (IR) hybrid automatic repeat request (HARQ) is a staple component of modern wireless systems, instrumental for efficient and reliable low-latency communication. To further improve the performance, the blocklengths—and therefore the incremental rates—of the various transmissions can be released from being fixed. This paper optimizes these variable blocklengths in truncated IR-HARQ, with the goal of maximizing the overall throughput at any desired operating point (meaning any combination of signal-to-noise ratio and target error rate). The optimization relies on a finite-blocklength information-theoretical analysis, whereby the block error rate emerges as a function of the channel capacity and the channel dispersion. Numerical results confirm that the optimized variable-rate IR-HARQ significantly outperforms its fixed-rate counterpart, both with ideal codes and with a 5G commercial code. Additionally, a heuristic scheme that mimics the behavior of the optimized solution, but is simpler to implement, is set forth and shown to essentially attain the same performance.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1413-1422"},"PeriodicalIF":6.3,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10883043","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496576","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":"The Role of Digital Twin in 6G-Based URLLCs: Current Contributions, Research Challenges, and Next Directions","authors":"Antonino Masaracchia;Dang van Huynh;Trung Q. Duong;Octavia A. Dobre;Arumugam Nallanathan;Berk Canberk","doi":"10.1109/OJCOMS.2025.3540287","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3540287","url":null,"abstract":"Substantial improvements in the area of ultra reliable and low-latency communication (URLLC) capabilities, as well as possibilities of meeting the rising demand for high-capacity and high-speed connectivity are expected to be achieved with the deployment of next generation 6G wireless communication networks. This thank to the adoption of key technologies such as unmanned aerial vehicles (UAVs), reflective intelligent surfaces (RIS), and mobile edge computing (MEC), which hold the potential to enhance coverage, signal quality, and computational efficiency. However, the integration of these technologies presents new optimization challenges, particularly for ensuring network reliability and maintaining stringent latency requirements. The Digital Twin (DT) paradigm, coupled with artificial intelligence (AI) and deep reinforcement learning (DRL), is emerging as a promising solution, enabling real-time optimization by digitally replicating network devices to support informed decision-making. This paper reviews recent advances in DT-enabled URLLC frameworks, highlights critical challenges, and suggests future research directions for realizing the full potential of 6G networks in supporting next-generation services under URLLCs requirements.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1202-1215"},"PeriodicalIF":6.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10879074","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455289","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":"Trustworthy Reputation for Federated Learning in O-RAN Using Blockchain and Smart Contracts","authors":"Farhana Javed;Josep Mangues-Bafalluy;Engin Zeydan;Luis Blanco","doi":"10.1109/OJCOMS.2025.3540159","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3540159","url":null,"abstract":"This paper proposes a blockchain-enabled framework to enhance trust, transparency, and collaboration in Open Radio Access Network (O-RAN) infrastructures through Federated Learning (FL). Traditional O-RAN architectures and centralized machine learning approaches face challenges when integrating multi-vendor environments, primarily due to lack of trust, proprietary data concerns, and limited interoperability. Our solution transitions from implicit trust, where the reliability of contributions is assumed, to explicit trust, where reputation is verifiably established on-chain. We introduce a blockchain-based reputation mechanism that evaluates the accuracy, integrity, and quality of participants’ model updates within the FL process. Smart contracts automate critical tasks-such as participant registration, model update verification, and reputation scoring-ensuring that data inputs directly influence accountability in a tamper-proof, transparent manner. By deploying the framework on a scalable Layer 2 blockchain (Polygon) testnet and proposing the use of a blockchain oracle within this architectural framework for secure off-chain computations, this work focuses on a conceptual architectural approach by aligning with O-RAN’s architecture to propose and deploy a Decentralized Application (DApp) on the blockchain. The proposed framework emphasizes a conceptual design over performance optimization and is structured to naturally benefit from ongoing improvements in blockchain scalability, which may reduce latency and enhance operational efficiency over time. Smart contracts for crucial processes and reputation calculation are included within our proposed DApp. The implementation of this work is publicly accessible <uri>https://github.com/farhanajaved/Reputation_O-RAN</uri>.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1343-1362"},"PeriodicalIF":6.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10879031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143489187","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":"Efficient Spatial Channel Estimation in Extremely Large Antenna Array Communication Systems: A Subspace Approximated Matrix Completion Approach","authors":"Zhiwei Chen;Quanfeng Yao;Yi Zhong;Junliang Ye;Xiaohu Ge","doi":"10.1109/OJCOMS.2025.3539936","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3539936","url":null,"abstract":"Matrix completion techniques are widely employed to estimate the channel matrix from partially observed channel measurements. However, its computational complexity is cubic in the number of antennas, which is non-scalable for extremely large-scale antenna array (ELAA) communication systems. To address this issue, in this paper the ELAA channel matrix completion is reformulated as a proximal gradient descent (PGD) problem, where the subgradient of the nuclear norm is computed by singular value thresholding (SVT) operator and the proximal gradient of the <inline-formula> <tex-math>$L_{1}$ </tex-math></inline-formula> norm is derived using a softthresholding operator. To mitigate the computational overhead caused by subspace orthogonalization in the SVT operation, a novel subspace-approximated (SA)-SVT-PGD algorithm is designed. This algorithm exploits the subspace similarity of the channel’s Gram matrix in consecutive PGD iterations and enables concurrent subspace orthogonalization during PGD updates. By eliminating the specific nested loop for the subspace orthogonalization, the computational complexity of the SA-SVT-PGD algorithm is proportional to the product between the number of antennas and the square of rank of the channel matrix. Simulation results demonstrate that the SA-SVT-PGD algorithm can reduce the convergence time by 71.7% compared with the traditional SVT-PGD algorithm.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1216-1230"},"PeriodicalIF":6.3,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10877855","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143455293","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 Performance of STAR-RIS-Aided mmWave MIMO–NOMA Transmission Using Stochastic Geometry: Phase Shift Error Case","authors":"Farid Tabee Miandoab;Behzad Mozaffari Tazehkand","doi":"10.1109/OJCOMS.2025.3539966","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3539966","url":null,"abstract":"This work combines non-orthogonal multiple-access (NOMA) and millimeter-wave (mmWave) in a reconfigurable intelligent surface (RIS)-aided multiple-input multiple-output (MIMO) communication system, in which the RIS can simultaneously transmit and reflect signals (STAR-RIS). To adjust the STAR-RIS phase shift responses, we consider scenarios where the cascade channel phase information is available either perfectly or imperfectly. The stochastic geometric model is utilized to model the locations of the randomly deployed users. The users are divided into the cell-center users’ group and the cell-edge users’ group. To implement NOMA, we consider two user selection frameworks: 1) random user selection and 2) nearest user selection. For random users selection, one user from each group is randomly selected to be paired, while one user from each group with the shortest distance relative to STAR-RIS is selected in the nearest user selection strategy. To reduce system overhead and latency caused by the requirement to obtain channel state information (CSI) of all users, a beamforming approach is employed in the base station (BS). We derive the effective channel powers and provide the analytical expressions of the outage probability and outage sum rate for scenarios with and without error in the phase shift response of STAR-RIS. Besides, we provide an asymptotic analysis and derive the lower bound for outage probability when there are phase errors in the STAR-RIS phase shifts. We further analyze the impact of active STAR-RIS and imperfect CSI on the system performance. Simulation results are provided to validate our analyses and illustrate the effectiveness of establishing unobstructed transmission and reflection links in dead zones, thereby enhancing the reliability of communications.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1328-1342"},"PeriodicalIF":6.3,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10877923","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465635","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":"Measuring Mobile Starlink Performance: A Comprehensive Look","authors":"Dominic Laniewski;Eric Lanfer;Nils Aschenbruck","doi":"10.1109/OJCOMS.2025.3539836","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3539836","url":null,"abstract":"With the recent success of Low Earth Orbit (LEO) satellite networks, such as SpaceX’s Starlink, measuring their performance has been of great interest to the community. While stationary Starlink performance has been extensively assessed on a globalized view, mobile - in-motion - usage is relatively new. A first look at its performance has only been taken by three studies so far. In this paper, we take a comprehensive look at mobile Starlink performance from the measurement perspective by answering the following three research questions: (1) How does mobile Starlink performance differ in different regions of the world? (2) How does the mobile performance compare to stationary performance? (3) How does obstruction impact mobile performance? To answer these questions, we conduct our own 300 km long test-drive on the German Autobahn (highway) with car velocities up to 140 km/h. We compare our results to the datasets of the other three studies and to stationary measurements. To the best of our knowledge, we are the first to deeper analyze the impact of obstructions on the performance. For this, we map bridges crossing the highway to our measurements and find that these short total obstructions cause significant burst packet loss, RTT spikes, and throughput drops. We show that mobility-induced instabilities can have a severe negative impact on the performance of higher-level applications such as HTTP bulk file transfer.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1266-1283"},"PeriodicalIF":6.3,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10877858","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465627","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":"Toward Proactive, Secure and Efficient Space-Air-Ground Communications: Generative AI-Based DRL Framework","authors":"Amayika Kakati;Guoquan Li;Elhadj Moustapha Diallo;Lilian Chiru Kawala;Nasir Hussain;Abuzar B. M. Adam","doi":"10.1109/OJCOMS.2025.3539355","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3539355","url":null,"abstract":"The rapid growth of low-Earth-orbit (LEO) satellites has enabled integrated space-air-ground networks to provide seamless connectivity to mobile users. However, these networks face challenges such as physical layer security risks from line-of-sight channels and the energy constraints of high-altitude platforms (HAPs), necessitating solutions for secure communication and energy efficiency. In this work, we address the challenges of energy efficiency and secure communication in space-air-ground networks, which are becoming critical with the increasing deployment of LEO satellites to support high-mobility users. We propose a novel downlink architecture where high-altitude platforms (HAPs) assist the LEO satellite in serving ground users. To tackle the demands of secrecy energy efficiency (SEE) in this dynamic and complex network, we formulate a non-convex optimization problem that jointly considers HAP trajectory, user-HAP association, and beamforming. The problem’s non-convexity makes it computationally challenging to solve in polynomial time. To overcome these challenges, we introduce a generative artificial intelligence (GAI)-based deep reinforcement learning (DRL) framework, named Gen-DRL, which leverages generative adversarial networks to empower its agents. This framework dynamically predicts and adapts to changes in the space-air-ground network environment by optimizing key parameters such as channel states, HAP trajectories, user associations, and beamforming. Compared to conventional methods, the proposed Gen-DRL achieves significant improvements in SEE by effectively managing complex interdependencies among multiple agents and intelligently adapting to the network’s goals and constraints. Extensive simulation results demonstrate that Gen-DRL consistently outperforms existing state-of-the-art frameworks in terms of secrecy energy efficiency, robustness to dynamic user locations, and adaptability to varying network parameters. This work provides new insights into the design of secure and energy-efficient space-air-ground networks, highlighting the potential of GAI-based DRL for future communication systems.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1284-1298"},"PeriodicalIF":6.3,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10876168","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465628","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":"Generalized BER Performance Analysis for SIC-Based Uplink NOMA","authors":"Mahmoud AlaaEldin;Emad Alsusa;Mohammad Al-Jarrah;Karim G. Seddik;Michail Matthaiou","doi":"10.1109/OJCOMS.2025.3539185","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3539185","url":null,"abstract":"Non-orthogonal multiple access (NOMA) is well known for enhancing the spectral and energy efficiency by allowing multiple users to share the network resources more effectively. While most existing studies focus on downlink NOMA, this paper shifts the focus to uplink NOMA, presenting novel generalized closed-form bit error rate (BER) performance analysis for imperfect successive interference cancellation (SIC) receivers under fading channels. To accommodate various scenarios, the derived expressions are generalized for any arbitrary rectangular/square M-ary quadrature amplitude modulation order, number of NOMA users, and number of base station antennas. It is shown that these expressions are essential for designing optimal uplink power allocation (PA) strategies and mitigating SIC error floors, as evidenced by the proposed PA algorithm which achieves significant performance gains. The results also show that the BER performance of uplink NOMA can surpass that of its orthogonal multiple access counterpart under certain operating conditions and equivalent transmission rates and powers.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1246-1265"},"PeriodicalIF":6.3,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10873839","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465629","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":"Tight Approximation of Achievable Rates in RIS-Based Multi-User MIMO Systems Under Channel Estimation Constraints","authors":"Samar I. Farghaly;Mohamed I. Ismail;Mostafa M. Fouda;Ahmed S. Alwakeel","doi":"10.1109/OJCOMS.2025.3539229","DOIUrl":"https://doi.org/10.1109/OJCOMS.2025.3539229","url":null,"abstract":"The rapid and low-power configuration capabilities of Reconfigurable Intelligent Surfaces (RISs) have made them an attractive option for future wireless networks in terms of energy efficiency. They have the ability to greatly increase connection and facilitate low-latency communications. However, because RIS-based systems often have a large number of RIS unit elements and unique hardware constraints, accurate and low-overhead channel estimate remains a crucial challenge. In this study, we offer a channel estimation framework and concentrate on the uplink of a multi-user multiple-input multiple-output (MU-MIMO) communication system driven by RIS. Our primary goal is to enhance the achievable rate and system capacity. We derive a closed-form deterministic expression for the uplink achievable rate under practical scenarios where channel state information (CSI) is not directly known and must be estimated. In contrast to previous studies assuming perfect CSI, our approach incorporates the channel estimation process, leading to a more realistic performance assessment. Extensive simulations validate the tightness of our derived expression compared to the actual achievable rate across various system parameters (with discrepancies typically within 2-5%). The results highlight the significant impact of RIS on system performance enhancement, even with imperfect CSI. Our findings provide crucial insights into the deployment and optimization of RIS-assisted multi-user wireless networks, underscoring their potential for substantial improvements in rate and capacity.","PeriodicalId":33803,"journal":{"name":"IEEE Open Journal of the Communications Society","volume":"6 ","pages":"1299-1327"},"PeriodicalIF":6.3,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10873836","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143465626","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}