SBT/IEEE International Symposium on Telecommunications

3-6 Sept. 1990

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Displaying Results 1 - 25 of 117
  • SBT/IEEE International Telecommunications Symposium. ITS '90 Symposium Record (Cat. No.90CH2901-7)

    Publication Year: 1990
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    Freely Available from IEEE
  • A novel baud-length memory FSE

    Publication Year: 1990, Page(s):292 - 296
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    The author presents a novel fractionally spaced equalizer (FSE) that spans a single symbol period. It is derived from the parametric estimates of a time-invariant or slowly time-varying baseband equivalent channel. The parametric channel estimates are assumed to be obtainable from a training sequence prior to data acquisition. The performance of the FSE depends to a large extent on how well the ch... View full abstract»

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  • Frequency division multiplexing with channel constraints

    Publication Year: 1990, Page(s):287 - 291
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    Modulation via Fourier transform division multiplexing (FTDM) has been suggested for transmission over channels whose signal-to-noise ratios, as functions of frequency, are far from flat. Original designs following the classical water-pouring theorem left a large gap between the theoretical promise of the method and the actual rates achieved. The author presents heuristic input-power allocations f... View full abstract»

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  • Operations support systems in Italy: experiences and perspectives of integration

    Publication Year: 1990, Page(s):572 - 576
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (540 KB)

    The progressive integration of telecommunication networks and services requires a parallel integration of administration operation maintenance and provisioning (AOM&P) activities. Integrated AOM&P support has to be defined with a top-down approach, while the implementation of the integration plan should follow a bottom-up approach. The telecommunication management network (TMN) architectur... View full abstract»

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  • Analysis of buffer reservation holding times under a processor sharing queueing discipline and setup control

    Publication Year: 1990, Page(s):161 - 165
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    The authors model the buffer reservation (allocation) holding time as the sojourn time in an M/M/1/K processor sharing queue, where K corresponds to the limit on the number of active virtual circuits sharing a congested trunk's bandwidth. They evaluate the exact results for the M/M/1/K processor sharing sojourn time distribution and show that it is of phase-type. Numeric... View full abstract»

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  • Calculation of the bit error probability in a direct sequence spread spectrum system with code division multiple access

    Publication Year: 1990, Page(s):282 - 286
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    After a short introduction to the direct-sequence spread-spectrum system under study and a description of the model used for reception, the code sequences are selected. These sequences, obtained from Gold code sequences with m=9, are selected using an empirical method which tries to minimize the influence of one code sequence upon others. After selecting the code sequences the bit error p... View full abstract»

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  • Optimal multi-h phase codes for full response continuous phase signaling

    Publication Year: 1990, Page(s):509 - 513
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Multi-h full response CPM (continuous-phase modulated) signals are analyzed at preselected numbers of states in contrast to the standard method of analyzing them at preselected numbers of modulation indices. Optimal multi-h phase codes which produce the highest minimum Euclidean distance are presented according to the number of states. Three orders of multi-h signaling are considered in the optima... View full abstract»

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  • PC workstation for Ethernet monitoring and management

    Publication Year: 1990, Page(s):568 - 570
    Cited by:  Papers (2)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    The authors present a monitoring and management workstation for IEEE 802.3 networks (Ethernet) based on a PC-AT. The monitor performs traffic analysis, detects active machines in the network, maintains a network database with information regarding network topology and machines, filters specific packets or protocols, and can also work as a traffic generator. The system has a user friendly interface... View full abstract»

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  • Delay analysis of a packet voice multiplexer

    Publication Year: 1990, Page(s):155 - 160
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    The performance of a statistical multiplexer whose inputs consist of a superposition of voice packets from c trunks is studied. Voice calls are established according to a Poisson process and call holding times have a general distribution. Each voice call, while in progress, generates packets at fixed intervals of Δ. Thus, when n calls are in progress, the packet generation ... View full abstract»

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  • Vector quantization with size-constrained codebooks

    Publication Year: 1990, Page(s):186 - 190
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    An algorithm for calculating lower bounds to the performance of all size-constrained vector quantizers has been derived earlier. Applications to the AR(1) source have shown that these lower bounds are very close to the actual rate-distortion curves, even for small sizes of the output alphabet. In this algorithm, however, the codebook changes with rate. In a number of applications it is desirable t... View full abstract»

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  • MLSE equalization and decoding for multipath-fading channels

    Publication Year: 1990, Page(s):276 - 281
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    A combined MLSE (maximum likelihood sequence estimation) equalizer and decoder with D-diversity reception is analyzed for slowly time-varying frequency-selective Rayleigh fading channels. An upper bound on the (decoded) bit error probability is derived. This bound is tight for high signal-to-noise ratios or when diversity reception is employed. A method based on a one-directional stack al... View full abstract»

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  • On the design of a high performance ATM metropolitan area network

    Publication Year: 1990, Page(s):503 - 508
    Cited by:  Papers (1)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    Some aspects of the design of high-performance ATM (asynchronous transfer mode)-compatible MANs (metropolitan area networks) are discussed. In particular, throughput and fairness parameters are examined. As far as fairness is concerned, a merit figure is proposed, and an evaluation procedure is presented. A general approach to cope with the above-mentioned aspects is discussed and, as a proposed s... View full abstract»

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  • Resource management in a hierarchical network

    Publication Year: 1990, Page(s):563 - 567
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    A distributed algorithm for resource management in a hierarchical network is introduced which uses dynamic information about the system state in local and wide area networks. The algorithm uses broadcast information to make decision about process transfer and message routing, considering processor availability and system security. The algorithm establishes a path from the source to the destination... View full abstract»

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  • PBXKAN: a microprocessor-based system for modernization of telephone switching stations

    Publication Year: 1990, Page(s):150 - 154
    Cited by:  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    The PBXKAN system consists of dedicated microprocessors which replace the PBX and KAN modules of the Ericsson ARF-102 telephone exchange, improving the way of handling PBX groups and line classes. The microprocessor make it possible to perform other tasks such as traffic measurements and line supervision, besides reducing the switching time. These microprocessors are connected to an operator's ter... View full abstract»

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  • Complexity reduction of CELP coders

    Publication Year: 1990, Page(s):181 - 185
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    The authors propose a modification of the classical CELP (code-excited linear predictive) algorithm in order to reduce its computational complexity and required memory size, while preserving the quality of the reconstructed speech. Rather than performing the individual weighting of each candidate sequence, the authors suggest a global implementation of the vocal tract weighting function at the cod... View full abstract»

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  • Computer random simulation on multipath fading

    Publication Year: 1990, Page(s):207 - 211
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    A method is presented in which a computer is used to randomly simulate the statistical distributions of frequency selective fading. Relationships between the in-band frequency correlation coefficient and antenna height, the ground reflection coefficient, and the frequency bandwidth are randomly simulated. Using this method, frequency selective fading was randomly simulated over the Pacem 2 experim... View full abstract»

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  • FEC coding for RH/MFSK multiple-access spread spectrum systems

    Publication Year: 1990, Page(s):271 - 275
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    Forward error control (FEC) coding for frequency-hopping multiple frequency shift keying (FH/MFSK) multiple-access systems is analyzed, taking into account synchronous as well as asynchronous other-user interference. For both cases capacity and cut-off-rate are investigated and exact expressions for the basic system parameters are derived. Various types of FEC codes are considered. Systems employi... View full abstract»

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  • Leaky bucket analysis for ATM networks

    Publication Year: 1990, Page(s):498 - 502
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    The authors investigate input rate control in ATM (asynchronous transfer mode) networks. More specifically, they focus on the policing mechanisms, whose function is to assure that the sources abide by their initial specification. They study one such mechanism, the leaky bucket, and use the uniform arrival and service model, as well as simulation to study its effectiveness in bursty traffic. They s... View full abstract»

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  • Fiber optics use in digital integrated telecommunication systems in mining works

    Publication Year: 1990, Page(s):468 - 472
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    The advantages of fiber optic applications in mining works are examined, the main specific transmission applications are studied, and an integrated digital network project is presented. The integrated digital network permits the transmission of a great variety of signals such as telephony, data, and video from and to the mining processes. The network uses optical fibers as the medium of transmissi... View full abstract»

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  • Hierarchical image coding with pyramid DPCM

    Publication Year: 1990, Page(s):558 - 562
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    The authors apply DPCM (differential pulse code modulation) to pyramid coding strategy, and show that, for practical quantizers, lower bit rates than regular DPCM are required for high-quality resulting images. The pyramid DPCM is relatively simple, feasible, and allows a processing interval between samples that is longer than the sampling interval. A blockwise scheme for multiresolution which cou... View full abstract»

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  • An extension of the Smith construction for self-orthogonal array codes

    Publication Year: 1990, Page(s):10 - 13
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB)

    An extension of the Smith construction for self-orthogonal array codes is presented. The information bit array, originally two-dimensional, now becomes multidimensional. Array codes obtained with this construction are not self-orthogonal. Decoding is therefore rather more complex, but the codes are more efficient than those of the Smith construction View full abstract»

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  • On the performance of a packet switch with twin optical transmitters

    Publication Year: 1990, Page(s):49 - 54
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    A packet switch based on electrooptical technologies is presented. It is composed of N VLSI chips which interface the input and output links with the internal optical interconnection network. Its simulation, when loaded with homogeneous input and output traffic, showed that two packets at a time must be first extracted from each input buffer and then transmitted on the optical interconnec... View full abstract»

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  • Voice conference switching in digital telephone exchanges

    Publication Year: 1990, Page(s):143 - 149
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    The authors present several algorithms which could be used to perform conference connections in a digital telephone exchange, including a newly proposed algorithm. These algorithms are analyzed from both the performance and implementation points of view. Finally, the implementation of the conference switching function in TROPICO-RA, the Brazilian medium/large telephone exchange, is described. The ... View full abstract»

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  • Analysis of the quantization effects of LMS complex algorithm in digital adaptive filters

    Publication Year: 1990, Page(s):307 - 311
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    A novel theoretical formulation is developed for the errors due to the digital implementation of the LMS algorithm in adaptive filters. An analytic expression is determined for the mean-square error at the output of the adaptive filter. This expression is valid both for transient conditions and for the steady state. The convergence conditions of the algorithm are studied and a very simple and usef... View full abstract»

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  • Adaptive error control based on type-I hybrid-ARQ protocols

    Publication Year: 1990, Page(s):176 - 180
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    An adaptive error control technique based on the use of type-I hybrid-ARQ protocols is presented. Nonstationary channels are modeled as finite-state Markov chains. The system counts the number of retransmission requests during an observation interval called a frame and, together with knowledge of the code in use and a set of thresholds, estimates the state of the channel. The code which maximizes ... View full abstract»

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