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IEEE Conference on Wireless communications and Networking

作者： Hoang Nam Nguyen S. Olariu P. Todorova Institute of Communication Networks Technical University of of Vienna Vienna Austria Department of Computer Science Old Dominion University Norfolk VA USA FhG Fokus Berlin Germany

ISBN: (纸本)0780373766

Multimedia LEO satellite networks will play an important role in providing truly global coverage required by mobile personal communication services. Due to the high mobility inherent to LEO systems, a number of challenging technical problems arise. The first contribution of this work is to propose a realistic mobility model, taking into account the rotation of the Earth, which was systematically ignored in the literature. Our second contribution is a novel resource reservation strategy, termed sequential probabilistic resource reservation (SPR), specifically designed to minimize connection interruption due to handoffs. Finally, we propose a novel connection admission control (CAC) algorithm, differentiating real-time and non-real-time services. Performance results obtained by simulation show that the novel mobility model is essential for a realistic network performance evaluation and that the novel SPR strategy offers low handoff blocking probability for both service classes and low new call blocking probability for non-real-time connections.

关键词： Low earth orbit satellites Artificial satellites Admission control Personal communication networks Telecommunication traffic Bandwidth Switches communication networks computer science Mobile computing

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Information dissemination in multihop inter-vehicle networks

Information dissemination in multihop inter-vehicle networks

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International Conference on Intelligent Transportation

作者： T. Kosch C. Schwingenschlogl Li Ai BMW Research Department Munich Germany Department of Computer Science applied Informatics Cooperative Systems Group Munich University of Technology Germany Department of Electrical Engineering and Information Technology Institute of Communication Networks Munich University of Technology Germany Department of Electrical Engineering and Information Technology Munich University of Technology Germany

In addition to the integration of vehicles into traditional networks (e.g. access to the Internet via cellular) the Ad-hoc connection of vehicles within a limited area is a technology that promises a lot of innovative and exciting services. This paper starts with the description of some services to motivate Ad-hoc networking in the vehicular environment. It then gives an overview of the current challenges (especially routing protocols) in this field. If the geographic position of the network nodes is known, better performance can be achieved with the utilization of so called geocast routing-algorithms. An overview of geocast-routing is given and shortcomings of the existing protocols for the usage in inter-vehicle Ad-hoc networks are explained. Finally we make a proposal for a vehicle-optimized geocast routing, protocol that is based on AODV and present our prototype implementation.

关键词： Intelligent networks Spread spectrum communication Routing protocols Vehicles Mobile communication Testing IP networks Data communication Wireless LAN Broadcasting

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Evolutionary negotiation in agent-mediated commerce 6

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6th International computer science Conference on Active Media Technology, AMT 2001

作者： Choi, Samuel P.M. Liu, Jiming Chan, Sheung-Ping Department of Computer Science Hong Kong Baptist University Hong Kong Interactive Communication Online Networks Hong Kong

ISBN: (纸本)9783540430353

Automated negotiation has become increasingly important since the advent of electronic commerce. In an efficient market, goods are not necessarily traded in a fixed price, and instead buyers and sellers negotiate among themselves to reach a deal that maximizes the payoffs of both parties. In this paper, a genetic agent-based model for bilateral, multi-issue negotiation is studied. The negotiation agent employs genetic algorithms and attempts to learn its opponent’s preferences according to the history of the counter offers based upon the stochastic approximation. We also consider two types of agents: level- 0 agents are only concerned with their own interest while level-1 agents consider also their opponents’ utility. Our goal is to develop an automated negotiator that guides the negotiation process so as to maximize both parties’ payoff. © Springer-Verlag Berlin Heidelberg 2001.

关键词： Stochastic systems

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Variable redundancy coding for mobile channels

Variable redundancy coding for mobile channels

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IEEE Symposium on computers and communications (ISCC)

作者： W. Adi M. Ben-Aoun N. Kassab Institute for Computer and Communication Networks Engineering Technical University of Braunschweig Germany Ajman University of Science and Technology UAE

ISBN: (纸本)0769511775

Mobile data channels carry different communication services with different data formats and rates. In modern CDMA systems as in UMTS, such different data rates and services are carried in a fixed frame. This results with some free data gaps in the frame. A novel coding concept called variable redundancy coding (VRC) to replace the currently used bit repetition for filling such gaps is presented. The key idea behind the proposed VRC is simple: instead of repeating bits to match the channel rate, block code redundancy bits are stuffed in the free gaps. Such VRC bits particularly improve the frame error rate (FER) and at the same time fill the free gaps. This results in a more efficient overall channel throughput, as the data throughput depends mainly on the frame error rate and on the ARQ strategy employed. A particular VRC technique based on the burst error correcting Fire code is presented and is shown to be effective to optimize the overall system performance.

关键词： Redundancy Error analysis Throughput Mobile communication Multiaccess communication 3G mobile communication Filling Block codes Automatic repeat request Error correction codes

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The dependence of Internet user traffic characteristics on access speed

The dependence of Internet user traffic characteristics on a...

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Conference on Local computer networks (LCN)

作者： N. Vicari S. Kohler J. Charzinski Institute of Computer Science Am Hubland University of Würzburg Wurzburg Germany Information and Communication Networks Siemens AG Munchen Germany

A variety of Internet traffic characterization and source models already exist. Since the origin of the analyzed data differs, a comparison of the reported traffic characteristics is difficult. In this paper we analyze an IP packet trace and relate the trace data to the user access speed recorded at the same time. The obtained characteristics are contrasted with a second data set measured within an ADSL field trial. This second data set represents a limit in Internet usage, since, the high speed access was provided free of charge. This comparison leads to some interesting insights showing whether and how the access speed influences the Internet user behavior and thus the generated source traffic. The derived Internet traffic characterization is a first step to a generalized parametric Internet traffic model.

关键词： Internet Traffic control Telecommunication traffic Data analysis IP networks Modems Velocity measurement computer science Time factors Spine

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A wireless ATM MAC protocol with combined hybrid ARQ and adaptive scheduling

A wireless ATM MAC protocol with combined hybrid ARQ and ada...

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IEEE VTS 50th Vehicular Technology Conference, VTC 1999-Fall

作者： Huang, Hui Tsang, Danny H.K. Ko, Tsz-Mei Kuehn, Paul J. Dept. of Electrical and Electronic Engineering Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong Institute of Communication Networks and Computer Eng. University of Stuttgart Stuttgart Germany

ISBN: (纸本)0780354354

A combined hybrid ARQ error control and adaptive scheduling scheme is proposed for TDMA/TDD MAC protocols in wireless ATM networks. Type-II hybrid ARQ is chosen as the error recovery scheme, while adaptive fair-queueing is designed to achieve a fair and efficient resource allocation. In particular, the weight of a connection used in the fair-queueing algorithm is dynamically adjusted according to the varying channel conditions and the types of services. Simulation results show that the proposed scheme can achieve better throughput and transfer reliability with minimized delay and cell loss rate when compared with the conventional MAC layer control. © 1999 IEEE.

关键词： Time division multiple access

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A wireless ATM MAC protocol with combined hybrid ARQ and adaptive scheduling

A wireless ATM MAC protocol with combined hybrid ARQ and ada...

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IEEE Conference on Vehicular Technology (VTC)

作者： Hui Huang D.H.K. Tsang Tsz-Mei Ko P.J. Kuehn Department of Electrical & Electronic Engineering Hong Kong University of Science and Technology Hong Kong China Institute of Communication Networks & Computer Engineering University of Stuttgart Stuttgart Germany

A combined hybrid ARQ error control and adaptive scheduling scheme is proposed for TDMA/TDD MAC protocols in wireless ATM networks. The type-II hybrid ARQ is chosen as the error recovery scheme, while adaptive fair-queueing is designed to achieve a fair and efficient resource allocation. In particular, the weight of a connection used in the fair-queueing algorithm is dynamically adjusted according to the varying channel conditions and the types of services. Simulation results show that the proposed scheme can achieve better throughput and transfer reliability with minimized delay and cell loss rate when compared with the conventional MAC layer control.

关键词： Media Access Protocol Wireless application protocol Automatic repeat request Error correction Adaptive scheduling Time division multiple access Resource management Heuristic algorithms Throughput Delay

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Hierarchical scheduling with adaptive weights for W-ATM

Hierarchical scheduling with adaptive weights for W-ATM

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IEEE Workshop on ATM

作者： Hui Huang D.H.K. Tsang R. Sigle P.J. Kuehn Department of Electrical & Electronic Engineering Hong Kong University of Science and Technology Kowloon Hong Kong China Institute of Communication Networks & Computer Engineering University of Stuttgart Stuttgart Germany Communication Technology Daimler Benz Aerospace Ulm Germany

The medium access control (MAC) protocol is one of the key components for providing quality of service (QoS) in wireless ATM (W-ATM) networks. In this paper, we propose a hierarchical scheduling scheme coupled with fair queueing algorithms with adaptive weights. This scheme is intended to be applicable to a TDMA/TDD-based MAC protocol. Specifically, the performance of the fair-queueing algorithm using fixed weights and adaptive weights are investigated. Simulation results show that the proposed hierarchical fair-queueing scheduling with adaptive weights (HAW) can yield a lower cell transfer delay and higher channel utilization while maintaining fairness among multiple users.

关键词： Adaptive scheduling Media Access Protocol Time division multiple access Access protocols Quality of service Delay Bandwidth Wireless application protocol Asynchronous transfer mode Downlink

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An adaptive channel reservation scheme for soft handoff in cellular DS-CDMA systems

An adaptive channel reservation scheme for soft handoff in c...

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IEEE Conference on Vehicular Technology (VTC)

作者： J.W. Chang D.K. Sung J.H. Ahn J.H. Kim Communication Networks Research Laboratory Department of Electrical Engineering Korea Advanced Institute of Science and Technology South Korea Electronics and Telecommunications Research Institute South Korea Center for Advanced Computer Studies University of Southwestern Louisiana USA

In DS-CDMA systems, soft handoff techniques provide seamless connections of mobile call between cells. The reserved capacity for soft handoff calls is required to sufficiently support calls in a soft handoff region. However, since the capacity required by soft handoff calls varies according to environmental factors, the conventional fixed reserved capacity can be excessive if the required channel capacity by soft handoff calls is small and this may cause a considerable amount of unnecessary blocking of new calls. We propose an adaptive channel reservation scheme which reserves channel capacity as much act necessary according to the variation of soft handoff requests. A simulation result shows that the blocking probability of new coils is reduced by 33% compared with the conventional fixed channel reservation scheme and that it is even larger as the offered load decreases or the maximum reserved capacity increases.

关键词： Multiaccess communication Time division multiple access Frequency division multiaccess Channel capacity Interference Cellular networks Quality of service Intelligent networks communication networks Laboratories

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A DISTRIBUTED MEDIA ACCESS PROTOCOL FOR PACKET RADIO networks AND PERFORMANCE ANALYSIS .2. NETWORK SET-UP TIME AND DATA RATE

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INTERNATIONAL JOURNAL OF communication SYSTEMS 1995年第1期8卷 49-63页

作者： POND, LC LI, VOK Communication Sciences Electrical Engineering Systems University of Southern California Los Angeles CA 90089-2565 U.S.A. Lawrence C. Pond received the M.Sc. and Ph.D. degrees in electrical engineering from the University of Southern California in 1983 and 1990 respectively. Dr. Pond is currently a scientist at Hughes Space and Communications Company having joined in 1980. He has worked in the fields of communication system design mobile communication network and spacecraft payload design. He is currently working on the development of satellite-based ATM transport and switching architectures for BISDN and Defense Information System Network amlications. Dr. Pond is a member of IEEE. Victor O. K. Li was born in Hong Kong in 1954. He received his SB SM and Sc.D. degrees in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology Cambridge Massachusetts in 1977 1979 and 1981 respectively. Since February 1981 he has been with the University of Southern California (USC) LOS Angeles California where he is Professor of Electrical Engineering and Director of the USC Communication Sciences Institute. He has published 150 technical papers and has lectured and consulted extensively around the world. His research interests include high-speed communication networks personal communication networks intelligent networks distributed databases queueing theory graph theory and applied probability. Dr. Li is very active in the Institute of Electrical and Electronic Engineers (IEEE) having been a member of the Computer Communications Technical Committee since 1983 and having served as Chairman from 1987–1989. He served as Chairman of the Los Angeles Chapter of the IEEE Information Theory Group from 1983–1985. He is the Steering Committee Chair of the International Conference on Computer Communications and Networks (IC3 N) General Chair of the 1st Annual IC3N held in San Diego California in June 1992 General Chair and Technical Program Chair of the 4th IEEE Workshop on Comp

In this, the second part of a two-part paper, the required time for establishing a mobile packet radio network using the virtual circuit and time division multiple access protocol developed in Part 1 is analysed. Tools are developed to determine the virtual circuit and network set-up times in terms of the channel bandwidth allocated to establish and maintain the network. The tools are then extended to include the effects of user mobility. Then these results are combined with the network capacity results of Part 1 to analyse the trade-off between the data rate and set-up time of the network. Next a hierarchical architecture is proposed and the network data rate versus set-up time trade-off of this architecture is analysed using these tools. This architecture is shown to both provide a higher data rate and establish faster than flat networks of the same number of nodes.

关键词： PACKET RADIO NETWORK EPLRS DISTRIBUTED NETWORK TDMA VIRTUAL CIRCUITS MULTIHOP NETWORK BOUNDED DELAY MOBILITY NETWORK SET-UP TIME HIERARCHICAL NETWORK NETWORK DATA RATE

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