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International conference on Transparent optical networks

作者： Miguel N. Pimenta Izzat Darwazeh University College London London UK

ISBN: (纸本)9781424412488;142441248X

Code Division Multiple Access (CDMA) was first proposed in the context of Wire-less communications to achieve high-speed connectivity, random asynchronous operation and network control simplification. Recent developments in optical networks have led to growing interest on the adoption of the same technique in the optical domain to develop new generations of access and Local Area networks [1]. One of the main practical difficulties is the implementation of the encoding and decoding hardware [2]. Traditionally, all-optical devices have been proposed to implement encoders and correlators of the OCDMA networks. Such approaches rely on the use of Fiber Bragg Gratings (FBGs) [3, 4] or optical delay lines [5]. Although many OCDMA systems have been successfully demonstrated and implemented, the migration from laboratory to real world has been slower than expected. This is mainly due to the thermal variability of the FBGs and the difficulty to achieve good spectral characteristics such as flat group delay and low ripple in the reflection spectrum. The designs relying on optical delay lines suffer from lack of tunability since, with the existing techniques, it is impossible to achieve accurate time delays for high speeds [6].

关键词： Circuit synthesis optical fiber networks Multiaccess communication High speed optical techniques Fiber gratings Bragg gratings Delay lines Context communication system control optical fiber LAN

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Flat Cellular (UMTS) networks

Flat Cellular (UMTS) Networks

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IEEE conference on Wireless communications and networking

作者： Peter Bosch Louis Samuel Sape Mullender Paul Polakos Gee Rittenhouse Bell Laboratories USA

Traditionally, cellular systems have been built in a hierarchical manner: many specialized cellular access network elements that collectively form a hierarchical cellular system. When 2G and later 3G systems were designed there was a good reason to make system hierarchical: from a cost-perspective it was better to concentrate traffic and to share the cost of processing equipment over a large set of users while keeping the base stations relatively cheap. However, we believe the economic reasons for designing cellular systems in a hierarchical manner have disappeared: in fact, hierarchical architectures hinder future efficient deployments. In this paper, we argue for completely flat cellular wireless systems, which need just one type of specialized network element to provide radio access network (RAN) functionality, supplemented by standard IP-based network elements to form a cellular network. While the reason for building a cellular system in a hierarchical fashion has disappeared, there are other good reasons to make the system architecture flat: (1) as wireless transmission techniques evolve into hybrid ARQ systems, there is less need for a hierarchical cellular system to support spatial diversity; (2) we foresee that future cellular networks are part of the Internet, while hierarchical systems typically use interfaces between network elements that are specific to cellular standards or proprietary. At best such systems use IP as a transport medium, not as a core component; (3) a flat cellular system can be self scaling while a hierarchical system has inherent scaling issues; (4) moving all access technologies to the edge of the network enables ease of converging access technologies into a common packet core; and (5) using an IP common core makes the cellular network part of the Internet.

关键词： Cellular networks 3G mobile communication Land mobile radio cellular systems Radio access networks IP networks Hierarchical systems Telecommunication traffic Costs Base stations Buildings

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CyNC: a MATLAB/SimuLink toolbox for network calculus 07

CyNC: a MATLAB/SimuLink toolbox for network calculus

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Proceedings of the 2nd international conference on Performance evaluation methodologies and tools

作者： Henrik Schioler Hans P. Schwefel Martin B. Hansen Aalborg University Aalborg Denmark

ISBN: (纸本)9789639799004

This paper presents a graphical integrated modelling and performance-analysis tool based on deterministic network calculus (DNC) and implemented as an open source toolbox for the MATLAB/SimuLink environment. The paper introduces briefly the main concepts from network calculus and especially recent results for systems with cyclic dependencies, which appear in cases of cyclic data/work flow or counter directional resource and work flows. A number of network element types are supported including various arbitration/scheduling disciplines such as: Fixed Priorities, FIFO, TDMA, round robin/token passing and EDF along with packetization, flow control and flow convergence. These are all presented in the paper together with auxiliary tools like worst case backlog and delay calculations. Implementation details of general interest are presented along with illustrative examples demonstrating the virtues of the separate modelling elements and the overall tool framework. Discussion is provided concerning issues in system stability and the ability of DNC to provide usefull estimates of stability limits. Likewise current activities to support synchronous communication and flow control within the tool are presented.

关键词： tools network calculus real time systems modelling performance analysis

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Techno-economic issues in future telecom networks

Techno-economic issues in future telecom networks

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optical Fiber communication - OFC 2007 Collocated National Fiber Optic Engineers conference (OFC 2007), vol.2

作者： Andrew Lord Martin Wade BT OP8 B29 Polaris House Adastral Park Martlesham Heath Ipswich UK IP5 3RE

Long-reach access coupled to a large flat all-optical core network via a core node switch is a strong contender for the most economic future network architecture. This paper looks at implications for the core.

ISBN: (纸本)1557528306

关键词： Dense wavelength division multiplexing network restoration optical components optical networks optical performance monitoring Packet switching Fiber optics and optical communications (060.0060) Fiber optics communications (060.2330) networks (060.4250)

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Enhancing Locality in Two-Dimensional Space through Integrated Computation and Data Mappings

Enhancing Locality in Two-Dimensional Space through Integrat...

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International conference on VLSI Design

作者： Mahmut Kandemir Ozcan Ozturk Vijay S. R. Degalahal Computer Science and Engineering Department Pennsylvania State University USA Intel

ISBN: (纸本)9780769527628;0769527620

As the number of processors used in chip multiprocessors keeps increasing, NoC (network-on-chip) based multiprocessor architectures are becoming increasingly important. While the last couple of years have witnessed numerous proposals regarding how to architect NoC based parallel computing platforms, code and data mapping issues in these architectures have largely been ignored. In particular, there are very few papers so far focusing on providing compiler support for NoC based chip multiprocessor systems. Our goal in this paper is to demonstrate how an optimizing compiler can map data and computation to NoC nodes in a locality-aware manner such that the energy spent in data communications is minimized. The proposed approach formulates this locality problem within a linear algebraic framework and discusses two alternate solution strategies that determine appropriate computation/data mappings in NoC. Our experimental evaluation compares this proposed scheme against two alternate optimization strategies, one that optimizes data mapping alone and the other one that optimizes computation mapping alone. The collected results indicate that our approach improves energy consumption by about 25% with respect to a scheme that does not consider locality of communication during NoC mapping. More importantly, our results reveal that neither optimized data mapping alone nor optimized computation mapping alone is sufficient for achieving the best locality and the compiler needs to consider both in a coordinated fashion. In fact, our results show that the proposed approach improves energy consumption over the pure data mapping and pure computation mapping oriented schemes by around 22% and 20%, respectively, when considering all eight application codes we tested

关键词： network-on-a-chip Optimizing compilers Computer architecture Energy consumption Testing Computer networks Proposals Parallel processing Data communication Computer science

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First mile wireless and beyond: Future applications for wireless in oil and gas

First mile wireless and beyond: Future applications for wire...

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International conference on Computer as a Tool (EUROCON 2007)

作者： Munro, Michael Cisco Systems Inc.

ISBN: (纸本)9781424408122

Oil field asset owners and operators face two primary issues in exploration and production;asset productivity and operating efficiency. Typically, operators do not have visibility to sense the current state of the oil field and respond with actions to reduce well down-time or increase the oil flow. These sense-and-respond capabilities have been limited by the remoteness of this "First Mile" and its fundamental lack of connectivity. Recent advances in wireless technologies resolve this limitation, and operators are looking to extend the office experience into the first mile, creating sophisticated sense and respond capabilities that increase asset productivity while reducing costs and improving communication and collaboration. This paper will briefly review current state of wireless in oil and gas and discuss the future applications enabled by first mile wireless, including: Converged Health, Safety, and Environmental communications: enabling all responders to communicate across disparate radio networks, and phone systems in a unified conversation to accelerate and improve incident response Asset and personnel tracking systems: leveraging location based services to transform plant operations and health, safety, and environmental response Real-time video collaboration to field: taking field and collaboration center beyond voice and data, enabling workers in the center to *see* what is happening in the field Automated sensor networks for monitoring production control systems: Monitor temperature, pressure, flow, vibration and other environmental situations to improve operations and reduce downtime Integrated physical security systems: provide improved camera coverage and authorized access to any camera stream from anywhere to increase safety and improve incident response Real-time vehicle fleet access, onshore and offshore: connect with mobile vehicles and staff using the best possible network backbone, including satellite, 3G, GPRS, or WiFi enabling anytime, anywhere

关键词： IEEEtran conference proceedings paper wireless digital oilfield Cisco

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MPLS Traffic Engineering in Satellite networks

MPLS Traffic Engineering in Satellite Networks

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International conference on Complex, Intelligent and Software Intensive systems, CISIS

作者： Arjan Durresi Mimoza Durresi Fatos Xhafa Department of Computer Science Louisiana State University Baton Rouge Louisiana USA Department of Information and Communication Engineering Fukuoka Institute of Technology Fukuoka Japan

Broadband satellite constellation networks will be required to carry all types of IP traffic, real time interactive traffic as well as non-real time traffic, warranting the need for appropriate QoS for these different traffic flows. In this paper we investigate the need for MPLS traffic engineering in GEO/MEO/LEO satellite networks to address QoS issues. We compare the service received by TCP and UDP flows when they share a link and when they are routed on explicit MPLS traffic trunks. Since MPLS traffic trunks allow non-shortest path links also to be used, the total network throughput goes up with proper traffic engineering. If UDP and TCP flows are mixed in a trunk, TCP flows receive reduced service as the UDP flows increase their rates. Also, we found that with MPLS traffic engineering we can protect real time traffic and VoIP traffic from packet loss and excessive jitter by separating them from other congestion unresponsive flows

关键词： Multiprotocol label switching Telecommunication traffic Low earth orbit satellites Routing Packet switching Satellite constellations Frequency IP networks Propagation delay Traffic control

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An Open IMS Testbed for exploring Wireless Service Evolution and network architecture Evolution towards SAE and LTE

An Open IMS Testbed for exploring Wireless Service Evolution...

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International conference on Wireless Broadband and Ultra Wideband communications (AusWireless)

作者： Niklas Blum Fabricio Carvalho de Gouveia Thomas Magedanz Fraunhofer Institute of Open Communication Systems (FOKUS) Berlin Germany

Modern telecommunication networks and classical roles of Operators are subject to fundamental changes. Standardization bodies and Industry are specifying and integrating Next Generation network (NGN) infrastructures and NGN services based on an all IP paradigm. The Internet Engineering Task Force (IETF), European Telecommunications Standards Institute (ETSI), Third Generation Partnership Project (3GPP), 3GPP2 and Open Mobile alliance (OMA) are working on technological issues to enable services using Internet technology and Service Orientated architectures (SOA). Furthermore, first thoughts on the architectural and bearer evolution of NGN is taking place under the notion of Long Term Evolution (LTE) and System architecture Evolution (SAE). This paper reports about our approach of extending the existing IP Multimedia Subsystem (IMS) Playground @ FOKUS towards a LTE/SAE testbed and two prototypic services, a single network agnostic Voicemail application and a 3G circuit-switched to packet-switched handover scenario as a proof-of-concept for the environment.

关键词： LTE SAE 3GPP ETSI TISPAN IP Multimedia Subsystem Next Generation networks Service Delivery Platform

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Design issues of building block structure communications for power electronic system

Design issues of building block structure communications for...

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37th IEEE Power Electronics Specialist conference (PESC 2006)

作者： Zhang, Yao Ma, Hao Xu, Fei Zhejiang Univ Coll Elect Engn Hangzhou 310027 Peoples R China

ISBN: (纸本)9780780397163

Some novel communication strategies for power electronic system are presented in this paper, and design issues can be described from bottom to top layer, like building block. The basic communication unit as the bottom layer plays the leading role in the overall design. Based on the variance of the control mode and the demand in communication, power electronic device (PED) or power electronic system (PES) can be divided into one or several salve nodes in bottom communication layer. The complex communication architecture, the higher level, is described in detail from the point of view of field bus, connection for Internet and completely distributed network. architecture for each communication design, key feature of the network, and diverse application example are discussed. Two novel plans about completely distributed network for PED/PES and the method of information grouping are proposed.

关键词： Power electronics Topology Real-time systems network topology Delays Multiaccess communication control systems

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Security issues in SCADA networks

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COMPUTERS & SECURITY 2006年第7期25卷 498-506页

作者： Igure, Vinay M. Laughter, Sean A. Williams, Ronald D. Univ Virginia Charles L Brown Dept Elect & Comp Engn Charlottesville VA 22904 USA

The increasing interconnectivity of SCADA (Supervisory control and Data Acquisition) networks has exposed them to a wide range of network security problems. This paper provides an over-view of all the crucial research issues that are involved in strengthening the cyber security of SCADA networks. The paper describes the general architecture of SCADA networks and the properties of some of the commonly used SCADA communication protocols. The general security threats and vulnerabilities in these networks are discussed followed by a survey of the research challenges facing SCADA networks. The paper discusses the ongoing work in several SCADA security areas such as improving access control, firewalls and intrusion detection systems, SCADA protocol analyses, cryptography and key management, device and operating system security. Many trade and research organizations are involved in trying to standardize SCADA security technologies. The paper concludes with an overview of these standardization efforts. (c) 2006 Elsevier Ltd. all rights reserved.

关键词： SCADA network security critical infrastructure security SCADA protocol analysis firewalls intrusion detection systems SCADA cryptography

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