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Communication Technology Proceedings, 2000. WCC - ICCT 2000. International Conference on

Date 21-25 Aug. 2000

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  • 2000 International Conference on Communication Technology Proceedings [front matter]

    Publication Year: 2000 , Page(s): 0_1 - 27
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  • Practical traffic grooming scheme for single-hub SONET/WDM rings

    Publication Year: 2000 , Page(s): 1193 - 1200 vol.2
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    In SONET/WDM networks, one fiber supports multiple wavelengths and each wavelength supports several low rate tributary streams. "Traffic grooming" then is defined as properly using a SONET add/drop multiplexer (ADM) to electronically multiplex and demultiplex the required tributary traffic patterns with minimal resource cost (wavelengths and ADMs). This paper studies the traffic grooming problem in single hub SONET/WDM networks and extends existing results. We analyze the real deployments, generalize their results, and study practical special cases. We prove that a two-fiber bidirectional line-switched ring (BLSR/2) would never be more expensive than a unidirectional path-switched ring (UPSR) under any traffic pattern. We also present the exact minimum costs of uniform traffic in both UPSR and BLSR/2. We give approximation algorithms for optimal grooming of non-uniform traffic. Finally, we consider how to select the line speeds if there are two different line speeds available. View full abstract»

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  • Author index

    Publication Year: 2000 , Page(s): 1 - 8
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  • Dilution of position in the Doppler-range satellite positioning algorithm

    Publication Year: 2000 , Page(s): 1141 - 1144 vol.2
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    Depending on different types of users, several algorithms, one of which combines Doppler and range measurements for positioning computation and which is called the D-R algorithm, can be used in software design in a satellite positioning system. The D-R algorithm can be selected for a stationary user in certain circumstance where only few satellites can be tracked simultaneously due to shielding. This paper studies the characteristics of geometric dilution of precision (GDOP) in the D-R algorithm and tries to give an outline of this algorithm. The simulation results given are instructive for positioning system constellation design as well as receiver positioning software design View full abstract»

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  • Service-integrated selective DWDM in metro area

    Publication Year: 2000 , Page(s): 1184 - 1187 vol.2
    Cited by:  Papers (1)
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    Although dense wavelength division multiplexing (DWDM) technology has been very successful in the long haul market, its penetration into the metro/access market requires new architecture and innovational techniques to integrate the various services into one platform, beyond merely providing bandwidth expansion. The new metro optical platform not only has to reduce the cost associated with optical technology, but also has to provide the flexibility and scalability on demand to meet the special need of unpredictable traffic growth in the metro environment. A metro ring selective WDM architecture with integrated service solutions and simplified multi-layer network management system (NMS) is presented in this paper View full abstract»

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  • 3D motion estimation of head and shoulders in videophone sequences

    Publication Year: 2000 , Page(s): 1180 - 1183 vol.2
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    In this paper, an approach for 3D motion estimation of head and shoulders of persons in videophone sequences is presented. Since head and shoulders are linked together by the neck, constraints for the motion of head and shoulders exist which are exploited to improve the motion estimation. In this paper, the human neck joint is modeled by a spherical joint between head and shoulders and its 3D position is calculated. Then, rotation and translation of the shoulders are estimated and propagated to the head. Finally, a rotation of the head around the neck joint is estimated. The presented approach is applied to the videophone sequences Akiyo and Claire. Compared with an approach without using a neck joint, anatomically correct positions of head and shoulders are estimated View full abstract»

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  • Grouped parallel multiuser detector for CDMA mobile communication

    Publication Year: 2000 , Page(s): 1514 - 1517 vol.2
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    A novel grouped parallel multiuser detector is proposed and the algorithm is derived. The complexity of this detector is linear to the number of users and the performance is better than the decorrelating detector. The detection delay is smaller than the decision-feedback detector. Numerical results show that the BER of the grouped parallel multiuser detector goes to some value when the MAI power is 3 dB higher than the useful signal power, so this detector can resist the near-far effect efficiently for CDMA mobile communication View full abstract»

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  • Optical switching board implementing wavelength routing supervision for optical cross-connects in WDM OTN

    Publication Year: 2000 , Page(s): 1188 - 1192 vol.2
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    This paper proposes and demonstrates two supervision schemes to monitor wavelength routing for optical cross-connects (OXCs) in WDM optical transport networks. The influence of the supervision methods on the differential loss of the OXC is studied. Experiments demonstrate that an alarm can be sent out immediately by the supervision circuit when errors occur in the optical switches. Guard time protection is introduced to the supervision circuits to prevent them from sending an alarm by mistake. These supervision schemes can be used in the optical layer management for fault detection and network restoration View full abstract»

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  • Analysis of partial parallel interference cancellation in DS-CDMA system with timing errors

    Publication Year: 2000 , Page(s): 1518 - 1521 vol.2
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    We study partial parallel interference cancellation in a DS-CDMA system with timing errors. We show that by multiplying symbol estimates by a factor less than unity in early stages of cancellation, the performance of parallel cancellation can be improved relative to full (“brute force”) cancellation. BER performance is a function of the factor and the “best factor” can be far less than one. In practical systems, timing errors need to be considered. This paper considers the effect of timing errors on the selection of “best factor”. We show that due to the timing error the interference cancellation is less reliable and a smaller factor of cancellation need be employed View full abstract»

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  • Sender delay comparison of IP-based reliable synchronous collaboration communication

    Publication Year: 2000 , Page(s): 1254 - 1257 vol.2
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    Synchronous collaboration is one of the most important fields of CSCW (computer supported cooperative work). IP multicasting is becoming the main trend of synchronous collaboration. But little of the current synchronous collaboration literature pays attention to the conditional superiority of IP multicasting over IP unicasting under a certain packet error rate. In this paper, we compare the sender delay performance of two reliable synchronous collaboration schemes which are based on IP unicasting and IP multicasting and show that IP multicasting is not always superior to IP unicasting in synchronous collaboration. In networks with low packet error rate and to a certain range of number of receivers, IP multicasting has the lower sender delay and superior scalability; while in networks with high packet loss rate and to a large user number, IP multicasting is inferior to the IP unicasting. In addition, we also conclude the communication principle which is to apply IP multicasting in low packet-error-rate environment and to apply IP unicasting in high packet-error-rate environment View full abstract»

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  • Feedback suppression in reliable multicast protocol

    Publication Year: 2000 , Page(s): 1436 - 1439 vol.2
    Cited by:  Patents (10)
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    Feedback implosion is one of the crucial issues confronting the scalability of reliable multicast protocols. Generally, there are two ways of solving this feedback implosion problem-timer-based and structure-based approaches. In the timer-based approach, when a receiver needs to send feedback, it multicasts the feedback to all receivers earlier than the other receivers, and hence suppresses others from returning feedback in response to the same event. The structure-based approach depends on intermediate network elements to consolidate feedback arising from the same event. It hence significantly reduces the number of feedback messages arriving at the sender from a single event. In this paper, we present an effective end-to-end NACK suppression algorithm which could solve the problem caused by correlative packet loss and independent packet loss among receivers View full abstract»

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  • Semantic expression in management information exchange

    Publication Year: 2000 , Page(s): 1416 - 1420 vol.2
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    This paper presents semantic expression of management information and an information exchange model. They are particularly suitable for management integration in a multi-vendor environment and adaptation to new technologies and services in network management View full abstract»

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  • A H.263 compatible error resilient video coder

    Publication Year: 2000 , Page(s): 1157 - 1160 vol.2
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    We present an error resilient video coder compatible with the ITU-T H.263 standard. Resynchronization flag insertion, error detection, localization and concealment in the decoder, and dynamic programming mode selection based on error tracking are the three main adopted error-resilient strategies. An information feedback method, which utilizes the H.263 video bit stream but does not modify its syntax, is described. Simulation results for the binary symmetric channel (BSC) with random bit errors are given to show the robustness of the proposed video coder View full abstract»

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  • Different decoding methods for multilevel coded modulation over Rayleigh fading channels

    Publication Year: 2000 , Page(s): 1542 - 1545 vol.2
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    Based on a “capacity rule“, the performance of multilevel coding (MLC) schemes with different decoding methods, which are multistage decoding (MSD) and parallel decoding on level (PDL), is investigated. The work is done for 8ASK modulation and three mapping strategies over Rayleigh fading channels are used. In each scheme BCH codes with different code lengths are used as component codes. Numerical results indicate that MSD is a sub-optimal decoding method of MLC, while PDL is most robust if block partitioning (BP) is used. For Ungerboeck partitioning (UP) and a mixed partitioning (MP) strategy, MSD is strongly recommended for the MLC system, while for the BP strategy, PDL is suggested as a simple decoding method compared with MSD View full abstract»

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  • SDL-based hierarchical model for multicasting in PNNI

    Publication Year: 2000 , Page(s): 1440 - 1444 vol.2
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    The PNNI protocol is an ATM Forum recommendation and may be adopted by ITU-T in the near future. The most distinctive and attractive feature of PNNI (private network-network interface) network is its hierarchical network structure. However, such a theoretical and abstract hierarchical idea requires a formalized and concrete method to be applied to its implementation. In this paper, we propose a mathematical model of PNNI. We extend this approach to our PNNI routing model and realize it using a formal language-SDL (specification and description language)(see WaiKin Chan et al., ICCT'98, vol.2.2 s41-09, 1998). The partial SDL specifications are presented. The mathematical model described in this paper can also be used in modelling of other hierarchical networks View full abstract»

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  • A fast algorithm for video codec

    Publication Year: 2000 , Page(s): 1161 - 1164 vol.2
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    This paper presents a very fast algorithm for a video codec based on H.263. This algorithm includes “fast motion detection”, “fast motion estimation”, and “referred frame selection”. By the algorithm we implement a software-based multipoint-to-multipoint videoconferencing system over an IP network. In the system one can see and talk with other participants (up to 4) in real time simultaneously View full abstract»

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  • An intelligent network architecture based on active network technology

    Publication Year: 2000 , Page(s): 1081 - 1086 vol.2
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    The emerging technology of active networks is one for future directions of communication networks, where users can inject their programs into the network infrastructure. The increasing number of supplementary services, the development of new types of services and several years of usage show some drawbacks of intelligent networks (IN). This paper looks at the impact of active network technology on the traditional IN. We present a novel IN architecture enhanced by active network technology, which can not only overcome some drawbacks of traditional IN, but can also keep existing resources. We also describe a way of supporting intelligent services based on active packets (capsules), which results in better performance and fault tolerance compared to traditional IN service implementations View full abstract»

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  • A practical scheduling algorithm for input-buffered switch

    Publication Year: 2000 , Page(s): 1059 - 1064 vol.2
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    Input-buffering is preferentially used in high-speed commercial and experimental routers and switches. The cell scheduling algorithms are critical components in input-buffered switches. They have a significant impact on the throughput, stability and guaranteed quality of service (QoS) of input-buffered switches. The longest queue first (LQF) algorithm can achieve 100% throughput for input-buffered switches, but is not starvation-free. That is, there are some queues will never be serviced. This paper proposes a modified LQF algorithm called mLQF. It can achieve 100% throughput and is starvation-free View full abstract»

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  • A modular environment for modelling and simulating multimedia conferencing over interconnected networks

    Publication Year: 2000 , Page(s): 1220 - 1227 vol.2
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    To carry out a realistic simulation of multimedia communications, it is necessary for a simulation environment to be able to model a number of traffic conditions for different media streams, and to support a variety of network systems operating in a set of interconnected networks. In this paper, we describe a modular environment, called M5, for modelling, simulating and analysing multimedia conferencing over interconnected heterogeneous networks. While the high-level simulation is driven by discrete events, the low-level network simulations are implemented as computational engines based on the statistical models of the individual network systems. In addition, the environment is equipped with software modules for network specification, traffic generation and result visualisation. The simulation of the two popular network standards, namely CSMA/CD and ATM networks, will also be discussed in the paper View full abstract»

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  • A new scheme for WDM-based passive optical access network

    Publication Year: 2000 , Page(s): 1201 - 1204 vol.2
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    Wavelength division multiplexing (WDM) offers the potential to transport very high bit rates in access systems serving residential and small business customers. In this paper, we present a new scheme that combines the advantages of WDMA and TDMA for a broadband fiber access network, and propose a medium access control (MAC) protocol that can easily realize full service access View full abstract»

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  • Message efficient reliable broadcast algorithm

    Publication Year: 2000 , Page(s): 1445 - 1448 vol.2
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    As a non-blocking atomic commitment protocol, there is uniform timed reliable broadcast (UTRB) which is proposed by O. Babaoglu and S. Toueg (see “Non-blocking atomic commitment”, “Distributed systems”, 2nd edition, Addison Wesley, chapter 6, 1993). They proposed the UTRB2 that is the most message-efficient UTRB in the literature. We consider two-complexity metrics for UTRB algorithms: time and number of messages. In this paper, we describe a new UTRB protocol, called UTRB5, which is more efficient than UTRB2 in the number of messages and time View full abstract»

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  • Research of bound multicast tree

    Publication Year: 2000 , Page(s): 1453 - 1456 vol.2
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    In multicast communication, messages are sent to multiple destinations that belong to the same multicast group. One of the core issues in providing such mechanisms is routing. Typical approaches of multicast routing require the transmission of packets along the branches of a tree spanning the source and destination nodes. In order to improve multicast routing quality under interactive real-time application conditions, this paper provides minimum cost multicast trees based on end-to-end delay and delay variation constraints. We first discuss the minimum cost multicast network model and its mathematical model based on bound delay and delay variation, and then provide the heuristic algorithm to solve the problem and show the time complexity analysis View full abstract»

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  • Time-critical multimedia components and cell delay jitter

    Publication Year: 2000 , Page(s): 1364 - 1371 vol.2
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    The delivery of multimedia services easily faces the problem of guaranteeing the required delay performance for delay sensitive service components. The problem is especially severe with isochronous service components, such as voice and video. The transport network should guarantee, e.g., required bit rate, end-to-end delay, delay variation and error ratio performance, for each tributary of a multimedia service stream regardless of the other traffic or the number of network nodes transversed en route. In this paper, we study the change of delay variation of constant bit rate traffic in the presence of Poisson and MMPP (Markov-modulated Poisson process) distributed background load. A simulation model is deduced and simulation results, based on the model, are presented. Finally, some confirming measurement results are given View full abstract»

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  • Guaranteed rate scheduling with adaptable excess bandwidth distribution

    Publication Year: 2000 , Page(s): 1457 - 1464 vol.2
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    Although guaranteed rate (GR) schedulers such as WFQ (weighted fair queueing) can provide a hard delay bound for a leaky-bucket-conditioned traffic flow, the bandwidth requirement is high if the flow is bursty. On the other hand, the GR property is insensitive to how instantaneous excess bandwidth is distributed by a GR scheduler. Such excess bandwidth could be adaptively distributed to improve delay distribution tails. We present a sub-class of GR schedulers, called general dynamic guaranteed rate queueing (GDGRQ), for networks with fixed packet sizes. While keeping the GR property, GDGRQ schedulers can dynamically and arbitrarily distribute any excess bandwidth within short periods. GDGRQ is a framework for the design of schedulers that can both provide hard delay bounds and adaptively distribute excess bandwidth in order to control delay distribution tails and deliver statistical delay quality of service (QoS) View full abstract»

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  • The implement of optimum demodulator for STTD in WCDMA

    Publication Year: 2000 , Page(s): 1534 - 1537 vol.2
    Cited by:  Papers (1)
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    In the IMT2000 DS-CDMA scheme, space time block coding-based transmit antenna diversity (STTD) is adopted as an anti-fading technique. We discuss the mathematical model of the STTD, and deduce an optimum demodulation algorithm for practical implementation. We analyze the performance of the optimum demodulator. Our scheme based on this model is easy to implement and has a good performance View full abstract»

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