IET NetworksPub Date : 2026-02-20DOI: 10.1049/ntw2.70026
Ardavan Rahimian
{"title":"Steady-State Spread Bounds for Graph Diffusion via Laplacian Regularisation in Networked Systems","authors":"Ardavan Rahimian","doi":"10.1049/ntw2.70026","DOIUrl":"https://doi.org/10.1049/ntw2.70026","url":null,"abstract":"<p>We study how far a diffusion process on a graph can deviate from a designed starting pattern when the pattern is generated via Laplacian regularisation. Under standard stability conditions for undirected, entrywise nonnegative graphs, we give a closed-form, instance-specific upper bound on the steady-state spread, measured as the relative change between the final and initial profiles. The bound separates two effects: (i) an irreducible term determined by the graph's maximum node degree and (ii) a design-controlled term that shrinks as the regularisation strength increases (with an inverse square law). This leads to a design rule: Given any target limit on spread, one can choose a sufficient regularisation strength in closed form. Although one motivating application is array beamforming—where the initial pattern is the squared magnitude of the beamformer weights—the result applies to any scenario that first enforces Laplacian smoothness and then evolves by linear diffusion on a graph. Overall, the guarantee is nonasymptotic, easy to compute and certifies the maximum steady-state deviation.</p>","PeriodicalId":46240,"journal":{"name":"IET Networks","volume":"15 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2026-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ntw2.70026","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147320893","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}
IET NetworksPub Date : 2026-01-24DOI: 10.1049/ntw2.70024
Youhai Zhang, Yujie Ma
{"title":"Performance Optimisation Framework for Wireless Sensor Networks Based on Multi-Algorithm Collaboration","authors":"Youhai Zhang, Yujie Ma","doi":"10.1049/ntw2.70024","DOIUrl":"https://doi.org/10.1049/ntw2.70024","url":null,"abstract":"<p>This paper presents an integrated optimisation framework for wireless sensor networks (WSNs) designed to manage the competing demands of energy efficiency, latency reduction, throughput improvement and communication reliability under dynamic and large-scale deployment conditions. The framework reorganises and enhances three core optimisation methods—genetic algorithm (GA), particle swarm optimisation (PSO) and an improved NSGA-II—by embedding adaptive behaviours and topology-aware decision logic. The GA is strengthened through a zone-oriented crossover mechanism and a sink-distribution-based initialisation strategy, which enhance coverage robustness and fault tolerance. The PSO module applies self-adjusting learning coefficients and QoS-aware routing constraints to maintain efficient path selection under varying load conditions. The improved NSGA-II incorporates an adaptive selection mechanism and a direction-guided crossover operator to better balance energy consumption and delay in multi-objective optimisation. Simulation results show that the proposed framework consistently outperforms federated DDQN and adaptive MOPSO across all performance indicators. It also demonstrates superior multi-objective convergence quality, achieving an IGD of 0.03 and an HV of 0.87. Overall, the framework enhances the scalability, resilience and operational efficiency of WSNs and provides practical guidance for adaptive scheduling in complex real-world environments.</p>","PeriodicalId":46240,"journal":{"name":"IET Networks","volume":"15 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ntw2.70024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146091328","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}
IET NetworksPub Date : 2026-01-24DOI: 10.1049/ntw2.70025
Wenjian Zhang, Ping Li
{"title":"Deep Reinforcement Learning Reconfigurable Smart Surface Sensing MAC Protocol for Terahertz Mesh Networks","authors":"Wenjian Zhang, Ping Li","doi":"10.1049/ntw2.70025","DOIUrl":"https://doi.org/10.1049/ntw2.70025","url":null,"abstract":"<p>Terahertz (THz) communication is a key enabler for 6G wireless networks but suffers from severe path loss and dynamic blockage, making conventional MAC protocols inefficient. This paper proposes a reconfigurable intelligent surface–based deep reinforcement learning MAC (RIS-DRL-MAC) framework that enables cross-layer optimisation between the physical and MAC layers. By embedding RIS perception features—such as equivalent channel gain and link stability—into the state space and jointly optimising beam direction, channel access and RIS phase configuration through a distributed twin delayed deep deterministic policy gradient (TD3) algorithm, the protocol achieves adaptive environment control. Simulation results show that, under dynamic blockage and high-load conditions, RIS-DRL-MAC improves network throughput by up to 90%, reduces access delay by 50% and maintains over 90% link availability compared with baseline schemes. The proposed method establishes a closed loop of sensing, decision and environment reconfiguration, providing an effective solution for reliable and energy-efficient THz mesh networking.</p>","PeriodicalId":46240,"journal":{"name":"IET Networks","volume":"15 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2026-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/ntw2.70025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146096541","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}