{"title":"6G for Sustainability: A Drip on the Heatplate, Small Steps With a Big Impact","authors":"Ihsane Gryech;Abdul Saboor;Alexander Marinšek;Franco Minucci;François Rottenberg;Véronique Moeyaert;Bruno Quoitin;Véronique Georlette;Sofie Pollin","doi":"10.1109/TGCN.2026.3654530","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3654530","url":null,"abstract":"The evolution of 6G networks is a pivotal time to align technological advances with global sustainability objectives, specifically the United Nations’ Sustainable Development Goals (SDGs). This Systematic Literature Review (SLR) examines how 6G technologies approach sustainability through energy efficiency, reducing e-waste, reducing emissions, smart cities, and governance frameworks. We identify that SDG 9 (Industry, Innovation, and Infrastructure), SDG 7 (Affordable and Clean Energy), and SDG 13 (Climate Action) are the most frequently targeted SDGs in 6G and its development. In addition to the latest key innovations in 6G, our findings reveal research gaps and directions forward. The “drips on the heatplate” analogy represents how individually small but well-timed sustainability efforts can accumulate to reduce future communication networks’ environmental strain significantly. This review highlights the existing trends of SDG integration in 6G and emphasizes the need for sustainability to be a core part of 6G design in the future.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1811-1828"},"PeriodicalIF":6.7,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Joint Optimization of UAV Trajectory and Number of Reflecting Elements for UAV-Mounted Intelligent Reflecting Surface-Assisted Data Collection in Wireless Sensor Networks Under Transmission Prioritized Scheme","authors":"Hong Zhao;Hongbin Chen;Shichao Li;Ling Zhan","doi":"10.1109/TGCN.2026.3654945","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3654945","url":null,"abstract":"To address the non-line-of-sight (NLOS) transmission challenge between wireless sensor nodes (SNs) and a fusion center in smart agriculture, the uncrewed aerial vehicle (UAV)-mounted intelligent reflecting surfaces (IRS) is applied to assist data collection in wireless sensor networks in this paper. The fly-hover-communicate protocol (FHCP) is considered, where the UAV visits a set of hovering positions and communicates with one corresponding SN while hovering at each position. The optimization problem of making a trade-off between spectrum and energy efficiency (EE) under the transmission prioritized scheme (TPS) in FHCP is analyzed. For the single-SN case, the problem is decomposed into two sub-problems: UAV trajectory and number of reflecting elements (NoRE) optimization. For the multi-SN case, it is decomposed into three sub-optimization problems: user association, NoRE, and UAV trajectory planning. An efficient alternating optimization algorithm incorporating the genetic algorithm, conditional judgment-binary search algorithm, and successive convex approximation algorithm are applied to tackle this problem. Simulation results indicate that the TPS effectively increases EE compared with that when the UAV hovers directly above each SN.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1854-1866"},"PeriodicalIF":6.7,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hao Lin;Ainur Zhaikhan;Mustafa A. Kishk;Hesham ElSawy;Mohamed-Slim Alouini
{"title":"Energy-as-a-Service for RF-Powered IoE Networks: A Percolation Theory Approach","authors":"Hao Lin;Ainur Zhaikhan;Mustafa A. Kishk;Hesham ElSawy;Mohamed-Slim Alouini","doi":"10.1109/TGCN.2026.3654813","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3654813","url":null,"abstract":"Due to the involved massive number of devices, radio frequency (RF) energy harvesting is indispensable to realize the foreseen Internet-of-Everything (IoE) within 6G networks. Analogous to the cellular networks concept, shared energy stations (ESs) are foreseen to supply energy-as-a-service (EaaS) in order to recharge devices that belong to different IoE operators who are offering diverse use cases. Considering the capital expenditure (CAPEX) for ES deployment along with their finite wireless energy transfer (WET) zones, spatial energy gaps are plausible. Furthermore, the ESs deployment cannot cover 100% of the energy-harvesting devices of all coexisting IoE use cases. In this context, we utilize percolation theory to characterize the feasibility of large-scale device-to-device (D2D) connectivity of IoE networks operating under EaaS platforms. Assuming that ESs and IoE devices follow independent Poisson point processes (PPPs), we construct a connectivity graph for the IoE devices that are within the WET zones of ESs. Continuum percolation on the constructed graph is utilized to derive necessary and sufficient conditions for large-scale RF-powered D2D connectivity in terms of the required IoE device density and communication range along with the required ESs density and WET zone size. Fixing the IoE network parameters along with the size of WET zones, we obtain the approximate critical value of the ES density that ensures large-scale connectivity using the inner-city and Gilbert disk models. Inspired by the structure of bounds, we propose an structured approximation for the critical ES density function, which is consistent with the conclusions from the classical Gilbert disk model. Our proposed structured approximation is necessary to minimize the EaaS CAPEX under the IoE connectivity constraint.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"2037-2051"},"PeriodicalIF":6.7,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146175713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Joint Optimization on Trajectory and Velocity for Minimum Completion Time in UAV-Enabled Wireless-Powered WSN","authors":"Jing Guo;Feihang Qiu;Lei Lei;Xu Zhang","doi":"10.1109/TGCN.2026.3654603","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3654603","url":null,"abstract":"Uncrewed aerial vehicle (UAV) has been regarded as an efficient approach for enabling battery-less wireless sensor network (WSN). In this article, an energy-limited UAV is utilized to complete the information collection task of a group of battery-less sensor nodes (SNs) in a fly-while-communication scheme. A joint trajectory and velocity optimization framework decomposes the completion time minimization problem into three subproblems: cluster head selection and sorting (P1), smooth trajectory planning (P2), and velocity optimization (P3). With the cluster heads selected by an energy-based clustering algorithm, a B-spline-based trajectory of UAV is designed and optimized. Then, the velocity optimization is implemented to fulfill the communication demand of SNs and the energy consumption constraint of the UAV. Numerical results reveal that the proposed algorithm adjusts the velocity during communication and allocates more fly-while-communication time to meet different communication demands. The task completion time of the proposed method is 43% shorter than that of the fly-hover-communication-based method and is 15% shorter than that of the Bézier curve-based method.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1829-1840"},"PeriodicalIF":6.7,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Error Performance Characterization of LoRa-Based Direct-to-Satellite IoT","authors":"Quantao Yu;Deepak Mishra;Hua Wang;Dongxuan He;Jinhong Yuan;Michail Matthaiou","doi":"10.1109/TGCN.2026.3653969","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3653969","url":null,"abstract":"Recently, Long-Range (LoRa)-based direct-to-satellite Internet-of-Things (DtS-IoT) has garnered widespread attention from both academia and industry due to its capability to provide pervasive connectivity in an energy-efficient and cost-effective manner. A rigorous error performance analysis of such a new paradigm is quite essential for future green IoT communications. In this paper, we provide a novel analytical framework to characterize the error performance of LoRa-based DtS-IoT systems by leveraging an empirically-verified satellite-to-ground channel model. To enable a practical performance analysis, non-coherent detection is considered in the presence of interference along with the relative time and frequency offsets, where the corresponding decision metrics are theoretically derived. Based on this, closed-form symbol and bit error rate expressions are obtained by approximating the impact of the overall interference distributed within the decision metrics by that of the peak interference. Moreover, the impact of some key system parameters, such as the spreading factor (SF), bandwidth, and the end-device’s (ED’s) location, on the error performance is thoroughly investigated. The validity of our theoretical analysis is substantiated by extensive numerical simulations, where further insights are obtained into the error performance improvements of LoRa-based DtS-IoT systems.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1879-1893"},"PeriodicalIF":6.7,"publicationDate":"2026-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaoxuan Hu;Liang Shan;Jialin Hua;Jin Qi;Zhenjiang Dong;Bin Xu;Yanfei Sun
{"title":"Joint Resource Allocation and Task Offloading for Heterogeneous Cloud-Edge-End Networks Assisted by NOMA","authors":"Xiaoxuan Hu;Liang Shan;Jialin Hua;Jin Qi;Zhenjiang Dong;Bin Xu;Yanfei Sun","doi":"10.1109/TGCN.2026.3653056","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3653056","url":null,"abstract":"To address the challenges of computational task offloading for resource-constrained, heterogeneous terminals in the 6G Industrial Internet of Things (IIoT), which generate computation-intensive and resource-efficient tasks in real time, we propose a Digital Twin(DT)-driven cloud-edge-end collaborative resource allocation and task offloading (RATO) model that accounts for both latency and energy consumption. First, we establish a cloud-edge-end collaborative communication and computation framework by integrating cloud computing with edge computing, accommodating terminal and edge server heterogeneity, and employing Non-Orthogonal Multiple Access (NOMA) communication along with key authentication mechanisms to ensure secure communications. Next, Digital Twin technology is utilized for real-time monitoring of the physical environment, considering simulation bias to construct accurate DT entities. Finally, we employ a DT-driven multi-agent deep deterministic policy gradient (DT-MADDPG) algorithm to derive the optimal task scheduling strategy. Simulation results demonstrate that the proposed model significantly outperforms existing schemes in terms of delay, energy cost, load balancing of edge servers, and Quality of Service (QoS) for terminals.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1765-1778"},"PeriodicalIF":6.7,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Evangelos Koutsonas;Alexandros-Apostolos A. Boulogeorgos;Stylianos E. Trevlakis;George C. Alexandropoulos;Theodoros A. Tsiftsis;Rui Zhang
{"title":"SORIS: A Self-Organized Reconfigurable Intelligent Surface Architecture for Wireless Communications","authors":"Evangelos Koutsonas;Alexandros-Apostolos A. Boulogeorgos;Stylianos E. Trevlakis;George C. Alexandropoulos;Theodoros A. Tsiftsis;Rui Zhang","doi":"10.1109/TGCN.2026.3652239","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3652239","url":null,"abstract":"In this paper, a new reconfigurable intelligent surface (RIS) hardware architecture, called self-organized RIS (SORIS), is proposed. The architecture incorporates a microcontroller connected to a single-antenna receiver operating at the same frequency as the RIS unit elements, operating either in transmission or reflection mode. The transmitting RIS elements enable the low latency estimation of both the incoming and outcoming channels at the microcontroller’s side. In addition, a machine learning approach for estimating the incoming and outcoming channels involving the remaining RIS elements operating in reflection mode is devised. Specifically, by appropriately selecting a small number of elements in transmission mode, and based on the channel reciprocity principle, the respective channel coefficients are first estimated, which are then fed to a low-complexity neural network that, leveraging spatial channel correlation over RIS elements, returns predictions of the channel coefficients referring to the rest of elements. In this way, the SORIS microcontroller acquires channel state information, and accordingly reconfigures the panel’s metamaterials to assist data communication between a transmitter and a receiver, without the need for separate connections with them. Moreover, the impact of channel estimation on the proposed solution, and a detailed complexity analysis for the used model, as well as a wiring density and control signaling analysis, is performed. The feasibility and efficacy of the proposed self-organized RIS design and operation are verified by Monte Carlo simulations, providing useful guidelines on the selection of the RIS elements for operating in transmission mode for initial channel estimation.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1749-1764"},"PeriodicalIF":6.7,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Habtamu Demeke Mihertie;Zhengqiang Wang;Mohamed Amine Ouamri;Elhadj Moustapha Diallo;Xingwang Li
{"title":"Energy Efficiency Maximization for Aerial Intelligent Reflecting Surface-Assisted MISO Systems","authors":"Habtamu Demeke Mihertie;Zhengqiang Wang;Mohamed Amine Ouamri;Elhadj Moustapha Diallo;Xingwang Li","doi":"10.1109/TGCN.2026.3653184","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3653184","url":null,"abstract":"Energy efficiency (EE) is a critical requirement for next-generation wireless networks, motivating the use of rate-splitting multiple access (RSMA) and intelligent reflecting surfaces (IRSs) as low-power, interference-resilient technologies. This paper studies EE maximization in a UAV-mounted IRS-assisted multi-user MISO downlink under practical hardware impairments. A communication-centric EE metric is adopted, and the optimization of RSMA precoders, common-rate allocation, IRS phase shifts, and UAV placement is formulated as a non-convex problem. To solve it efficiently, we develop an alternating optimization framework based on successive convex approximation (SCA) and rank-one relaxation. Simulation results reveal that the proposed aerial IRS-assisted RSMA design achieves substantial EE gains over NOMA and SDMA baselines and remains robust to distortion, IRS size variations, and dynamic user conditions, highlighting its suitability for energy-constrained 6G deployments.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1894-1908"},"PeriodicalIF":6.7,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Attention-Based Hierarchical-DRL With Mask for Multi-Timescale Caching, Association, and Secure Content Delivery in UAV-Enabled ISAC Networks","authors":"Gezahegn Abdissa Bayessa;Rong Chai;Chengchao Liang;Qinyuan Wang;Jun Li;Qianbin Chen","doi":"10.1109/TGCN.2026.3651458","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3651458","url":null,"abstract":"In this research, we investigate the long-term secure content delivery problem in uncrewed aerial vehicle (UAV)-enabled integrated sensing and communication (ISAC) networks. We consider that ISAC-assisted UAVs are allowed to store user-requested contents, provide content delivering service to users, and perform eavesdropper detection. However, the openness of UAV-enabled networks makes the content delivery network more susceptible to security threats. To address the eavesdropper detection, we propose a Cramér-Rao Lower Bound (CRLB) and an extended Kalman Filter (EKF)-based location estimation algorithm. We then examine the secrecy throughput of users and formulate the joint user association, UAV deployment, content caching, communication, and sensing beamforming problem as a long-term secure throughput maximization problem. As the formulated problem is a mixed-integer non-linear programming problem (MINLP) and cannot be solved conveniently, we decompose it into two subproblems, namely, a long-timescale content caching subproblem, and a short-timescale user association, UAV deployment, communication and sensing beamforming subproblem. To solve the subproblems, we transform it into a Markov decision process (MDP) and we propose an attention-based hierarchical deep reinforcement learning (HDRL) with an action mask and design a double deep Q-network (DDQN) algorithm to obtain the long-timescale and an attention-based DDQN with an action mask for short-timescale strategies. Specifically, we first obtain a long-timescale strategy for content caching. Given the long-timescale strategy, we then obtain the short-timescale user association, UAV deployment, communication, and sensing beamforming strategy. Simulation results demonstrate the effectiveness of the proposed algorithms.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1779-1794"},"PeriodicalIF":6.7,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Low-Power Semantic Communication Framework for Multimodal Fusion via Non-Binary Polar Codes","authors":"Baoxin Su;Shufeng Li;Junwei Zhang;Libiao Jin","doi":"10.1109/TGCN.2026.3651522","DOIUrl":"https://doi.org/10.1109/TGCN.2026.3651522","url":null,"abstract":"Multimodal semantic communication enables efficient and accurate cross-modal information transmission, yet precisely integrating semantic information from different modalities in dynamic communication environments remains challenging. To address this, this paper proposes a non-binary polar coding and decoding scheme for multimodal semantic feature fusion. This approach limits channel coding during the training phase to reduce overhead, while leveraging the high coding gain of non-binary polar codes and a deep neural network-based fast decoder to decrease complexity and power consumption. In the semantic module, we design a feature fusion network based on attention mechanisms and residual modules to more accurately capture cross-modal semantic features. For transmission, an adaptive non-binary polar (ANP) encoding strategy is introduced, while a neural network-driven non-binary polar (DNP) decoder is employed in the decoding part. Simulation results demonstrate that the proposed system significantly improves transmission efficiency and reliability while reducing bit error rate, and effectively lowers transmission power consumption.","PeriodicalId":13052,"journal":{"name":"IEEE Transactions on Green Communications and Networking","volume":"10 ","pages":"1867-1878"},"PeriodicalIF":6.7,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}