3,205 research outputs found

    Scalability and Congestion Control in Broadband Intelligent and Mobile Networks

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    The use of mobile communication networks has increased rapidly in the last two decades. This growth is expected to continue at a high rate in the foreseeable \ud future. Consequently, issues such as network scalability and overload/congestion control cannot be overlooked and must be taken into account in the design and operation of these networks. Scalability is the ability of the network to accommodate an increasing number of users, more and diversified services, expanding geographical coverage, etc., while maintaining high availability of network resources and preserving quality of service requirements. In the design process of a large network and its underlying protocols, several alternatives may be proposed to allow for scalable solutions. In the presence of a large number of potential active users, overload at parts of the network is likely to occur, at least occasionally, during busy hours or due to some unexpected events. In the absence of proper control to help avoid overloads and to quickly dissipate them when they occur, congestion may persist for extended periods of time, leading to unacceptable delays and high blocking rate of service requests. Therefore, it is crucial that the network be equipped with algorithms to protect critical network entities from becoming overloaded; i.e., congestion control algorithms. The first main focus of this thesis is network scalability. A methodology for the modeling and quantitative analysis of scalability is introduced and applied for the evaluation of a prototype Broadband Intelligent Network (B-IN) that has been developed in the European ACTS projects "INSIGNIA" and "EXODUS". The second main focus of this thesis is network congestion control. Novel congestion control algorithms are proposed for the same B-IN prototype developed in the ACTS projects "INSIGNIA" and "EXODUS". Important qualitative criteria are identified for the evaluation of these algorithms, and extensive performance experimentation is carried out to demonstrate their effectiveness and superiority in comparison with other known congestion control solutions

    A Survey on Communication Networks for Electric System Automation

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    Published in Computer Networks 50 (2006) 877–897, an Elsevier journal. The definitive version of this publication is available from Science Direct. Digital Object Identifier:10.1016/j.comnet.2006.01.005In today’s competitive electric utility marketplace, reliable and real-time information become the key factor for reliable delivery of power to the end-users, profitability of the electric utility and customer satisfaction. The operational and commercial demands of electric utilities require a high-performance data communication network that supports both existing functionalities and future operational requirements. In this respect, since such a communication network constitutes the core of the electric system automation applications, the design of a cost-effective and reliable network architecture is crucial. In this paper, the opportunities and challenges of a hybrid network architecture are discussed for electric system automation. More specifically, Internet based Virtual Private Networks, power line communications, satellite communications and wireless communications (wireless sensor networks, WiMAX and wireless mesh networks) are described in detail. The motivation of this paper is to provide a better understanding of the hybrid network architecture that can provide heterogeneous electric system automation application requirements. In this regard, our aim is to present a structured framework for electric utilities who plan to utilize new communication technologies for automation and hence, to make the decision making process more effective and direct.This work was supported by NEETRAC under Project #04-157

    A survey of self organisation in future cellular networks

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    This article surveys the literature over the period of the last decade on the emerging field of self organisation as applied to wireless cellular communication networks. Self organisation has been extensively studied and applied in adhoc networks, wireless sensor networks and autonomic computer networks; however in the context of wireless cellular networks, this is the first attempt to put in perspective the various efforts in form of a tutorial/survey. We provide a comprehensive survey of the existing literature, projects and standards in self organising cellular networks. Additionally, we also aim to present a clear understanding of this active research area, identifying a clear taxonomy and guidelines for design of self organising mechanisms. We compare strength and weakness of existing solutions and highlight the key research areas for further development. This paper serves as a guide and a starting point for anyone willing to delve into research on self organisation in wireless cellular communication networks

    Future Trends and Challenges for Mobile and Convergent Networks

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    Some traffic characteristics like real-time, location-based, and community-inspired, as well as the exponential increase on the data traffic in mobile networks, are challenging the academia and standardization communities to manage these networks in completely novel and intelligent ways, otherwise, current network infrastructures can not offer a connection service with an acceptable quality for both emergent traffic demand and application requisites. In this way, a very relevant research problem that needs to be addressed is how a heterogeneous wireless access infrastructure should be controlled to offer a network access with a proper level of quality for diverse flows ending at multi-mode devices in mobile scenarios. The current chapter reviews recent research and standardization work developed under the most used wireless access technologies and mobile access proposals. It comprehensively outlines the impact on the deployment of those technologies in future networking environments, not only on the network performance but also in how the most important requirements of several relevant players, such as, content providers, network operators, and users/terminals can be addressed. Finally, the chapter concludes referring the most notable aspects in how the environment of future networks are expected to evolve like technology convergence, service convergence, terminal convergence, market convergence, environmental awareness, energy-efficiency, self-organized and intelligent infrastructure, as well as the most important functional requisites to be addressed through that infrastructure such as flow mobility, data offloading, load balancing and vertical multihoming.Comment: In book 4G & Beyond: The Convergence of Networks, Devices and Services, Nova Science Publishers, 201
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