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NTT Technical Review 2022年第9期20卷 40-46页

作者： Takahashi, Hiroshi Kawata, Hideo Koyama, Ryo Tanaka, Ryo Otsuki, Shinya Goto, Kazuto Tadokoro, Masashi Access Network Management Project NTT Access Network Service Systems Laboratories Japan Optical Access Systems Project NTT Access Network Service Systems Laboratories Japan Access Network Media Project NTT Access Network Service Systems Laboratories Japan Civil Engineering Project NTT Access Network Service Systems Laboratories Japan Wireless Access Systems Project NTT Access Network Service Systems Laboratories Japan Wireless Entrance Systems Project NTT Access Network Service Systems Laboratories Japan Access Network Operation Project NTT Access Network Service Systems Laboratories Japan

NTT Access network Service systems Laboratories was established in Tsukuba City on July 20, 1972 as Tsukuba Telecommunication Construction engineering Development Center. Since then, it has been renamed several times during the era of the Nippon Telegraph and Telephone Public Corporation and the Nippon Telegraph and Telephone Corporation (NTT). In July 2022, the Laboratories' Tsukuba Research and Development (R&D) Center celebrated its 50th anniversary. This article introduces the 50-year history of the Tsukuba R&D Center, focusing on the large-scale experimental facilities that supported R&D activities in Tsukuba. © 2022 Nippon Telegraph and Telephone Corp.. All rights reserved.

关键词： Optical fibers

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Cache Allocation in Multi-Tenant Edge Computing: An Online Model-Based Reinforcement Learning Approach

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IEEE Transactions on Cloud Computing 2025年第2期13卷 459-472页

作者： Ben-Ameur, Ayoub Araldo, Andrea Chahed, Tijani Dán, György Institut Polytechnique de Paris SAMOVAR Telecom SudParis Palaiseau91120 France KTH Royal Institute of Technology Division of Network and Systems Engineering School of Electrical Engineering and Computer Science Stockholm11428 Sweden

We consider a network Operator (NO) that owns Edge Computing (EC) resources, virtualizes them and lets third party Service Providers (SPs) run their services, using the allocated slice of resources. We focus on one specific resource, i.e., cache space, and on the problem of how to allocate it among several SPs in order to minimize the backhaul traffic. Due to confidentiality guarantees, the NO cannot observe the nature of the traffic of SPs, which is encrypted. Allocation decisions are thus challenging, since they must be taken solely based on observed monitoring information. Another challenge is that not all the traffic is cacheable. We propose a data-driven cache allocation strategy, based on Reinforcement Learning (RL). Unlike most RL applications, in which the decision policy is learned offline on a simulator, we assume no previous knowledge is available to build such a simulator. We thus apply RL in an online fashion, i.e., the model and the policy are learned by directly perturbing and monitoring the actual system. Since perturbations generate spurious traffic, we thus need to limit perturbations. This requires learning to be extremely efficient. To this aim, we devise a strategy that learns an approximation of the cost function, while interacting with the system. We then use such an approximation in a Model-Based RL (MB-RL) to speed up convergence. We prove analytically that our strategy brings cache allocation boundedly close to the optimum and stably remains in such an allocation. We show in simulations that such convergence is obtained within few minutes. We also study its fairness, its sensitivity to several scenario characteristics and compare it with a method from the state-of-the-art. © 2013 IEEE.

关键词： Contrastive Learning

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R&D Challenges in Solving Social-infrastructure Problems

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NTT Technical Review 2022年第9期20卷 21-26页

作者： Awata, Teruhisa Civil Engineering Project NTT Access Network Service Systems Laboratories Japan

To solve problems surrounding social-infrastructure projects, such as a declining workforce, proliferation of aging facilities, increasing maintenance and renewal costs, and frequent disasters, and to create a "smart world, " NTT Access network Service systems Laboratories is engaged in research and development centered on three pillars: (i) digital transformation of maintenance and operations, (ii) construction of safe and secure social-infrastructure facilities, and (iii) use of assets such as facilities and operations. In this article, the technologies related to these three pillars are introduced. © 2022 Nippon Telegraph and Telephone Corp.. All rights reserved.

关键词： Maintenance

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Digital Twins for Security Automation 36

Digital Twins for Security Automation

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36th IEEE/IFIP network Operations and Management Symposium, NOMS 2023

作者： Hammar, Kim Stadler, Rolf Division of Network and Systems Engineering Kth Royal Institute of Technology Sweden

ISBN: (纸本)9781665477161

We present a novel emulation system for creating high-fidelity digital twins of IT infrastructures. The digital twins replicate key functionality of the corresponding infrastructures and allow to play out security scenarios in a safe environment. We show that this capability can be used to automate the process of finding effective security policies for a target infrastructure. In our approach, a digital twin of the target infrastructure is used to run security scenarios and collect data. The collected data is then used to instantiate simulations of Markov decision processes and learn effective policies through reinforcement learning, whose performances are validated in the digital twin. This closed-loop learning process executes iteratively and provides continuously evolving and improving security policies. We apply our approach to an intrusion response scenario. Our results show that the digital twin provides the necessary evaluative feedback to learn near-optimal intrusion response policies. © 2023 IEEE.

关键词： network security

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Operation to Achieve Robust networks

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NTT Technical Review 2023年第12期21卷 17-23页

作者： Okamoto, Jun Shibata, Tomoko Tahara, Mitsuho Fujiwara, Masakatsu Masuda, Masataka Executive Research Engineer Supervisor Communication Traffic Quality and Operation Research Project NTT Network Service Systems Laboratories Japan Executive Research Engineer Supervisor Access Network Operation Project NTT Access Network Service Systems Laboratories Japan Executive Manager Network Operation Project NTT Network Innovation Center Japan Planning Department NTT Information Network Laboratory Group Japan Senior Research Engineer Supervisor Traffic Engineering Research Group Communication Traffic Quality and Operation Research Project NTT Network Service Systems Laboratories. Japan

Large-scale communication-infrastructure failures have a tremendous impact on daily life and economic activities, requiring more resilient networks. We at NTT laboratories aim to achieve robust networks that minimize service impact by improving network adaptability to system failures and shorten recovery time by improving network resilience. This article describes our research and development efforts in operation-related technologies to achieve robust networks. © 2023 Nippon Telegraph and Telephone Corp.. All rights reserved.

关键词： Economics

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NW-AI Self-evolving Framework for Fault-tolerant Robust networks

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NTT Technical Review 2023年第12期21卷 33-36页

作者： Takahashi, Yousuke Ikeuchi, Hiroki Watanabe, Akio Traffic Engineering Research Group Communication Traffic Quality and Operation Research Project NTT Network Service Systems Laboratories Japan

We at NTT laboratories are focusing on the research and development of zero-touch operations using artificial intelligence (AI) for early recovery from network failures, which requires learning a large amount of network failure data. We have established a framework that allows AI to learn autonomously by artificially generating a large amount of network failures in a simulated environment and learning how to respond to them. This article describes the concept of this framework and how AI learns in the framework. © 2023 Nippon Telegraph and Telephone Corp.. All rights reserved.

关键词： Computer system recovery

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STUDY ON MACHINE LEARNING-BASED PREDICTION OF INTENSITY FLUCTUATIONS IN HORIZONTAL OPTICAL PROPAGATION 41

STUDY ON MACHINE LEARNING-BASED PREDICTION OF INTENSITY FLUC...

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41st International Communications Satellite systems Conference, ICSSC 2024

作者： Takenaka, Hideki Ishii, Shoken Takayama, Yoshihisa Faculty of Systems Design Tokyo Metropolitan University Japan Department of Communication and Network Engineering Tokai University Japan

ISBN: (纸本)9781837242689

This study investigates the potential of machine learning to predict signal power fluctuations in free-space optical communications, impacted by atmospheric fluctuations. Conducted over a 600-meter terrestrial link, optical reception intensities were recorded at a sampling rate of 10 kHz, then averaged to 1 kHz to reduce the computational load for subsequent machine learning processes. The study employed 80% of this data for training and 20% for validation. It was demonstrated that within the spatial coherence time of atmospheric turbulence, the fluctuations in received signal intensity can be accurately predicted using machine learning. © The Institution of engineering & Technology 2024.

关键词： Adversarial machine learning

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Conjectural Online Learning with First-order Beliefs in Asymmetric Information Stochastic Games 63

Conjectural Online Learning with First-order Beliefs in Asym...

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63rd IEEE Conference on Decision and Control, CDC 2024

作者： Li, Tao Hammar, Kim Stadler, Rolf Zhu, Quanyan New York University Department of Electrical and Computer Engineering United States Kth Royal Institute of Technology Division of Network and Systems Engineering Sweden

ISBN: (纸本)9798350316339

Asymmetric information stochastic games (AISGs) arise in many complex socio-technical systems, such as cyberphysical systems and IT infrastructures. Existing computational methods for AISGs are primarily offline and can not adapt to equilibrium deviations. Further, current methods are limited to particular information structures to avoid belief hierarchies. Considering these limitations, we propose conjectural online learning (COL), an online learning method under generic information structures in AISGs. COL uses a forecaster-actorcritic (FAC) architecture, where subjective forecasts are used to conjecture the opponents' strategies within a lookahead horizon, and Bayesian learning is used to calibrate the conjectures. To adapt strategies to nonstationary environments based on information feedback, COL uses online rollout with cost function approximation (actor-critic). We prove that the conjectures produced by COL are asymptotically consistent with the information feedback in the sense of a relaxed Bayesian consistency. We also prove that the empirical strategy profile induced by COL converges to the Berk-Nash equilibrium, a solution concept characterizing rationality under subjectivity. Experimental results from an intrusion response use case demonstrate COL's faster convergence over state-of-the-art reinforcement learning methods against nonstationary attacks. © 2024 IEEE.

关键词： Cost functions

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Survey of Commercial Wi-Fi Devices' Energy Detection Mechanism

Survey of Commercial Wi-Fi Devices' Energy Detection Mechani...

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2024 IEEE International Conference on Consumer Electronics, ICCE 2024

作者： Bailey, Jeffrey Liu, Stone Lambadaris, Ioannis Max, Sebastian Sugirtharaj, David Carleton University Department of Systems and Computer Engineering Ottawa Canada Radio Network Research Ericsson Germany Ericsson Sweden

ISBN: (纸本)9798350324136

This paper presents an experimental survey of the capabilities of commercial IEEE 802.11 (Wi-Fi) devices to detect the state of the wireless medium. Wi-Fi devices use a Clear Channel Assessment (CCA) mechanism to determine if the wireless medium is occupied. By subjecting Wi-Fi devices to Gaussian interference signals transmitted through a Universal Software Radio Peripheral (USRP), we assess their CCA behavior. Moreover, we perform a deeper investigation of the Ericsson AP6321 Wi-Fi Access Point prompted by privileged access to its internal operations. Our findings highlight variations between different Wi-Fi devices' CCA mechanisms and reveal floating CCA thresholds. Since CCA forms the fundamental basis for Wi-Fi operation, this study provides insights into coexistence of Wi-Fi with itself and dissimilar technologies. Because future Narrow Band Frequency Hopping (NB FH) systems are a potential technology that commercial Wi-Fi devices need to coexist with, we provide an extended survey of the capability of Wi-Fi devices to detect NB FH signals in unlicensed bands. This survey demonstrates that rapidly changing, on-off signalling does not have a disproportionate impact on Wi-Fi performance. © 2024 IEEE.

关键词： Adaptive Noise Floor Clear Channel Assessment (CCA) Coexistence Dynamic On-Off (DOF) Interference Energy Detection Threshold (EDT) Narrow Band Frequency Hopping (NB FH)

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Channel Simulation Method of Multi-beam Flexible Forwarding Satellite

Channel Simulation Method of Multi-beam Flexible Forwarding ...

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2024 IEEE International Conference on Unmanned systems, ICUS 2024

作者： Li, Jiaying Hu, Liujing Hu, Xianghui Institute of Network Information Beijing China School of Systems Science and Engineering Sun Yat-Sen University Guangzhou China

ISBN: (纸本)9798350384185

With the development of antenna technology and digital channelization technology, multi-beam and flexible forwarding have been widely used in satellite communications payloads. At the same time, it is a challenge to simulate the multi-beam flexible forwarding satellite channel. Based on digital channelization technology, this paper proposes a channel simulation method suitable for multi-beam flexible forwarding satellite communications system, which realizes the exchange of arbitrary multi-channel combinations. The simulation channel is verified to be real and effective through experiments, and can be used for the beam switching and networking application capability verification of the satellite mobile communications terminal, which can effectively improve the efficiency of its performance test and effectiveness evaluation. © 2024 IEEE.

关键词： Satellite communication systems

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