Optical Switching and Networking最新文献

{"title":"Optical intelligent reflecting surface-assisted NOMA for VLC system: Fundamentals, potentials, open research issues, and future trends","authors":"S.A.H. Mohsan ,&nbsp;Haoyu Huang ,&nbsp;Yi Hao ,&nbsp;Qian Li ,&nbsp;H.Y. Fu","doi":"10.1016/j.osn.2026.100852","DOIUrl":"10.1016/j.osn.2026.100852","url":null,"abstract":"<div><div>Recently, visible light communication (VLC) has garnered substantial interest as a promising complement to radio frequency (RF) communication due to its low-cost, high data rate, huge bandwidth, RF-free interference, enhanced security, and license-free spectrum. However, owing to the propagation characteristics of light, VLC is vulnerable to critical challenges in practical scenarios such as short bandwidth of light emitting diodes (LEDs), pointing errors, beam misalignment and inevitable occlusion. In this context, non-orthogonal multiple access (NOMA) and optical intelligent reflecting surface (OIRS) are two emerging techniques to overcome performance degradation of existing VLC systems. These burgeoning technologies offer unique potentials within the realm of VLC systems. The operating principle of NOMA is power allocation based on channel conditions and OIRS can smartly control the optical propagation channel, which motivate us to study OIRS-assisted NOMA-VLC systems for multi-user high-speed communications. Particularly, this study is primarily attributed to OIRS integration for exploiting reflected propagation, which significantly addresses the inherent signal blockage problems encountered in VLC systems. Furthermore, we have categorized the advantages of such unique integration as: the improvement of signal quality, the control of optical channel, the enhancement of communication security, and interference cancellation. In addition, we have discussed key factors pertaining to the tuning mechanism, channel characteristics, deployment, and performance metrics of OIRS in detail. We have summarized key potentials and challenges for OIRS-assisted NOMA-VLC systems. Finally, we lay out a number of open research issues and trends for future breakthrough novelties in this domain.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"60 ","pages":"Article 100852"},"PeriodicalIF":3.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Routing and spectrum allocation in elastic optical networks under unicast and multicast traffic: A survey","authors":"Yaghoub Khorasani ,&nbsp;Akbar Ghaffarpour Rahbar ,&nbsp;Mohammad Jafari-Beyrami","doi":"10.1016/j.osn.2026.100855","DOIUrl":"10.1016/j.osn.2026.100855","url":null,"abstract":"<div><div>With the rapid advancement of global bandwidth consumption rates and the increasing number of Internet users, Elastic Optical Networks (EONs) have become more prominent than ever. EONs can handle the required bandwidth by providing high bandwidth and flexibly allocating spectrum to each demand. However, there are several challenges, such as fragmentation, crosstalk, energy consumption, and routing and spectrum allocation in EONs. With the expansion of geographical coverage and the increase in the number of users, Routing and Spectrum allocation (RSA) have become one of the most important issues and challenges in EONs, which can affect the performance of EONs. RSA plays a central role in ensuring efficient spectrum utilization, low blocking probability, and enhanced network performance. In recent years, RSA has received a lot of attention from researchers in unicast traffic, while multicast traffic is used in many applications and is very popular. This review provides a comprehensive and systematic review of RSA strategies for unicast and multicast traffic, and a complete classification of RSA objectives in both types of traffic. Furthermore, we critically analyze the strengths and limitations of each category and highlight their applicability in practical scenarios. Performance comparisons and simulation results are included to provide insight into the efficiency of the different algorithms. Finally, we identify open challenges and outline promising research directions for future RSA design in EONs.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"60 ","pages":"Article 100855"},"PeriodicalIF":3.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146209519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 survey on general and optical ISAC: Fundamental limits, design approaches, and future directions","authors":"Alireza Ghazavi Khorasgani","doi":"10.1016/j.osn.2026.100853","DOIUrl":"10.1016/j.osn.2026.100853","url":null,"abstract":"<div><div>This survey provides a comprehensive study of the fundamental performance limits and design principles of general and optical Integrated Sensing and Communication (O-ISAC) systems, addressing critical gaps in the existing literature. We introduce the concept of ISAC, emphasising its pivotal role in next-generation networks for applications such as Intelligent Transport Systems (ITS) and smart cities, while highlighting the advantages of O-ISAC, particularly in high-bandwidth, low-latency, and interference-reduced Free-Space Optics (FSO) systems. A detailed comparison of optical sensing and communication systems with RF-centric designs reveals the absence of a fundamental performance tradeoff analysis for O-ISAC, motivating further investigation from an information-theoretic perspective. Our contributions include the characterisation of Pareto-optimal rate–distortion (R–D) and capacity–distortion (C–D) regions for O-ISAC, leveraging multi-antenna configurations and nonlinear SRC relationships to enhance system performance. We introduce practical estimators, such as Maximum A Posteriori (MAP) and Maximum Likelihood Estimation (MLE), which asymptotically achieve the Cramer–Rao Bound (CRB) in high-SNR regimes. Furthermore, we propose novel algorithms to determine optimal input distributions for the C–D region. These findings lay the foundation for future research in practical transceiver design, probabilistic shaping, and optimisation of O-ISAC systems, with potential applications in multi-antenna and distributed target systems. Our work sets the stage for O-ISAC to emerge as a transformative technology in next-generation wireless networks, particularly for ITS and high-performance optical systems.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"60 ","pages":"Article 100853"},"PeriodicalIF":3.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146153042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"DenseFormer-UVLC: Intelligent hybrid deep learning framework for adaptive beam steering and modulation in underwater visible light communication","authors":"Wessam M. Salama ,&nbsp;Moustafa H. Aly ,&nbsp;Samah Alshathri ,&nbsp;Walid El-Shafai","doi":"10.1016/j.osn.2026.100851","DOIUrl":"10.1016/j.osn.2026.100851","url":null,"abstract":"<div><div>Underwater Visible Light Communication (UVLC) is a promising solution for short-range underwater applications due to its high data rates and spectral efficiency. This paper presents an intelligent bidirectional UVLC system that incorporates real-time beam adaptation and intelligent modulation control to enhance communication robustness. The system integrates Software-Defined Radios (SDRs), an ultra-wide field-of-view photodetector, and a 470 nm Li-Fi transmitter, all coordinated through a simulated servo-driven beam-steering mechanism. This configuration enables dynamic adjustment of beam divergence angles to maximize received optical power and maintain stable communication across diverse underwater environments. Pulse Position Modulation (PPM) is employed, and a comparative evaluation between 4-PPM and 8-PPM is conducted. While 8-PPM provides higher data throughput, 4-PPM demonstrates superior noise robustness and lower Bit Error Rate (BER), particularly under misalignment and degraded channel conditions. A key contribution of this work is DenseFormer, a hybrid Deep Learning (DL) architecture that combines the global contextual modeling capability of Transformer encoders with the spatial feature extraction strengths of DenseNet169. Trained on a large synthetic dataset, DenseFormer effectively predicts the complex interdependencies among angular position, divergence angle, modulation type, and received optical power, thereby enabling data-driven BER and power optimization. Comparative analysis shows that DenseFormer substantially outperforms the baseline DenseNet169 model in prediction accuracy and generalization. Simulation results demonstrate up to 98 % BER reduction in Non-Line-of-Sight (NLoS) scenarios, 50 % BER reduction at critical misalignment angles, and a 47.4 % increase in received power in low-signal angular regions. Overall, this work demonstrates that combining deep learning, SDR-based Li-Fi transceivers, and adaptive beam control enables durable, high-throughput, and resilient UVLC suitable for next-generation underwater communication systems.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"60 ","pages":"Article 100851"},"PeriodicalIF":3.1,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145995695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Intelligent service RMSA in elastic optical networks: deep Q-networks","authors":"Huanlin Liu ,&nbsp;Dongxin An ,&nbsp;Yong Chen ,&nbsp;Xiang Chen ,&nbsp;Jiachen Zou ,&nbsp;Haonan Chen ,&nbsp;Bing Ma","doi":"10.1016/j.osn.2025.100841","DOIUrl":"10.1016/j.osn.2025.100841","url":null,"abstract":"<div><div>Elastic optical networks (EONs) face with more intense resource competition and difficulties in ensuring service quality for time-varying services. This study uses deep Q-network to optimize routing, modulation and spectrum allocation (DQN-RMSA) for time-varying services. The DQN is introduced to combine the deep reinforcement learning (DRL) framework and Q-network to manage RMSA by sliding windows for time-varying services. Specifically, a priority-aware state representation is adopted to integrate time-varying service characteristics and network resource state capturing by the DRL agent. An enhanced prioritized experience replay mechanism with a Sumtree structure is used to accelerate convergence by prioritizing critical learning samples. Moreover, a delayed action is designed by using Markov decision process (MDP) to monitor state transition for improving the performance of RMSA, and the delay action is reflected in the reward function to balance delay and resource utilization in terms of decreasing blocking probability. Simulation results demonstrate that DQN-RMSA can achieve superior performance over traditional heuristic and other DRL methods, with notable improvements in service blocking probability, delay tolerance, and spectrum utilization. The DQN-RMSA can adapt to fluctuations in time-varying service, highlighting its potential for achieving self-optimization and robust resource allocation in dynamic environments.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"59 ","pages":"Article 100841"},"PeriodicalIF":3.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145731343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 semi-supervised ML-driven strategy for fault detection and localization in optical networks","authors":"Andrei N. Ribeiro ,&nbsp;Fabrício R. Lobato ,&nbsp;Moisés F. Silva ,&nbsp;João C.W.A. Costa","doi":"10.1016/j.osn.2025.100831","DOIUrl":"10.1016/j.osn.2025.100831","url":null,"abstract":"<div><div>The continuous emergence of data-intensive online applications has required efforts to ensure the reliability of high data transmissions provided by optical networks. Considering that these systems are susceptible to faults that can affect their functioning, providing practical and accurate fault management approaches becomes vital. Therefore, this paper presents a semi-supervised approach based on an autoencoder (AE) model for detecting and localizing faults in optical networks. Since data from fault conditions is often absent in practical scenarios, a semi-supervised training strategy is applied, using only data from normal operating conditions. We can track fault occurrences based on the reconstruction error (RE) generated by the AE, which can serve as fault indicators (FIs), as data from normal and faulty conditions will produce different REs. Moreover, the proposed approach can localize faults by detecting them individually for each piece of equipment in the network. A dataset derived from an optical testbed is used for performance evaluation, focusing on accuracy and Type I and Type II errors. Results demonstrate that the standard AE outperformed PCA and other semi-supervised methods, including Variational AE and LSTM-AE, achieving an average fault detection accuracy of approximately 92.05%, with Type I and Type II error rates of about 7% and 0.9%, respectively.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"59 ","pages":"Article 100831"},"PeriodicalIF":3.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145613794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Uplink postponing with downlink matching: A low-latency and energy-efficient resource allocation scheme for TDM-PONs having heterogeneous ONU propagation delays","authors":"Yunxin Lv,&nbsp;Pengcheng Li,&nbsp;Meihua Bi,&nbsp;Yanrong Zhai,&nbsp;Hao Chi","doi":"10.1016/j.osn.2025.100828","DOIUrl":"10.1016/j.osn.2025.100828","url":null,"abstract":"<div><div>A low-latency and energy-efficient resource allocation scheme is proposed and investigated for time division multiplexing passive optical networks (TDM-PONs) having heterogeneous optical network unit (ONU) propagation delays. By (a) properly postponing the uplink transmissions of ONUs and (b) in each polling cycle, searching the postponed uplink transmissions and selecting the next ONU to poll based on the time overlap between uplink and downlink transmissions as well as the resultant channel idle time, the proposed scheme minimizes both the overall operating time of each ONU and the channel idle time caused by heterogeneous ONU propagation delays. Consequently, available sleep time for each ONU is ensured, and high channel utilization efficiency is secured, thereby resulting in the energy-efficient and low-latency performance of the proposed scheme. Simulation results indicate that for a 10G-EPON with ONU propagation delays distributed in the range from 25 μs to 200 μs, the proposed scheme can significantly reduce the average packet delay compared to the conventional schemes, and is more energy-efficient in delivering data under a 1 ms delay constraint.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"58 ","pages":"Article 100828"},"PeriodicalIF":3.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145314872","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Selection of candidate paths based on diversity in resource allocation problems on optical networks","authors":"Yuta Mori,&nbsp;Maiko Shigeno","doi":"10.1016/j.osn.2025.100826","DOIUrl":"10.1016/j.osn.2025.100826","url":null,"abstract":"<div><div>Optical networks play an essential role as an infrastructure supporting advanced information and communication technology. Elastic Optical Networks (EONs) have been designed to improve frequency resource utilization efficiency and enable flexible and efficient network operations. In EONs, the Routing and Spectrum Allocation (RSA) problem — which involves determining routes of transmission and allocating frequency resources — is a critical issue for efficient network operation. Traditionally, the k-Shortest Paths (kSP) approach has been widely used for candidate transmission routes. However, kSP often leads to the concentration of transmission on specific links, creating bottlenecks for resource allocation. To address this challenge, we propose three novel candidate path selection methods for the RSA problem: (1) ensuring path diversity through similarity constraints via 0–1 integer programming, (2) clustering based on path similarity, and (3) suppressing link sharing through node pair grouping. Numerical experiments performed to assure the effectiveness of our proposed methods, and confirmed that introducing path diversity can yield high-quality solutions to the RSA problem under specific scenarios.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"58 ","pages":"Article 100826"},"PeriodicalIF":3.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145261960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Incremental placement of wavelength-selective switching nodes in Semi-Filterless Optical Networks","authors":"Ting-Yi Cheng,&nbsp;Der-Rong Din","doi":"10.1016/j.osn.2025.100830","DOIUrl":"10.1016/j.osn.2025.100830","url":null,"abstract":"<div><div>We study Semi-Filterless Optical Networks (Semi-FON), where a limited number of Wavelength Selective Switch (WSS) nodes are deployed incrementally to improve spectrum utilization at low cost. We address two coupled problems under new WSS placements: (i) reconstructing the fiber-tree substrate and (ii) allocating spectrum to minimize the maximum spectrum-slot usage. We propose two complementary reconstruction strategies — Subtree and Single-Link — combined with a greedy spectrum-minimization allocator. The methods support single- and two-level FON architectures and guarantee connectivity for arbitrary source–destination pairs.</div><div>Simulations on connected fixed topologies and several random topologies across multiple sizes and edge densities (under fixed and random traffic) reveal a robust two-phase behavior: early selections deliver sharp objective reductions, followed by diminishing returns. Subtree consistently achieves lower objectives with only a few WSS placements and reaches a plateau quickly, making it attractive under tight budgets. With larger budgets, Single-Link can continue making small but steady improvements and may eventually match or surpass Subtree. Runtime scales more strongly with network size than density, but remains practical for the evaluated regimes. Overall, Semi-FON with the proposed strategies substantially reduces peak spectrum usage while enabling cost-aware, incremental deployment.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"58 ","pages":"Article 100830"},"PeriodicalIF":3.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145441600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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":"Survivable Elastic Optical Network: A survey of failure scenarios and solutions","authors":"Amit Khanjan Sarma,&nbsp;Sanjib K. Deka,&nbsp;Nityananda Sarma","doi":"10.1016/j.osn.2025.100823","DOIUrl":"10.1016/j.osn.2025.100823","url":null,"abstract":"<div><div>Survivable Elastic Optical Networks (SEON) are at the forefront of high-speed, flexible, and bandwidth-efficient optical communication. Modern flex-grid Elastic Optical Networks (EON) allocate variable-width frequency slots to match heterogeneous traffic demands and modulation formats; the survivability mechanisms discussed here operate at the spectrum slot layer and are agnostic to the underlying transponder waveform. Despite these advantages, ensuring survivability against diverse failures, including single-link, multi-link, node and hardware outages, remains a major challenge. This paper presents a comprehensive survey of SEON survivability, with a particular emphasis on classifying solutions according to different failure scenarios. State-of-the-art strategies such as Dedicated Path Protection, Shared Backup Path Protection, segmented and span restoration, and p-cycle protection are systematically analyzed and compared. Unlike previous surveys, this work integrates a classification framework with performance insights, highlighting how existing mechanisms fare under different types of failures. To bridge existing gaps, we also discuss open research challenges, including centralized control, spectrum management, AI-driven resilience, physical layer impairments and disaster recovery. Furthermore, we outline the potential of a hybrid protection paradigm combining state-aware traffic splitting, dynamic allocation, and vulnerability scoring to improve spectrum utilization and reduce blocking probability. By linking failure scenarios with recovery strategies and future research needs, this survey provides a unique perspective to guide the design of scalable, adaptive and intelligent SEON architectures.</div></div>","PeriodicalId":54674,"journal":{"name":"Optical Switching and Networking","volume":"58 ","pages":"Article 100823"},"PeriodicalIF":3.1,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145183879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}