By Topic

Singapore ICCS/ISITA '92. 'Communications on the Move'

Date 0-0 0

Filter Results

Displaying Results 1 - 25 of 295
  • Carrier synchronization under Doppler shift of the nongeostationary satellite communication systems

    Publication Year: 1992, Page(s):466 - 470 vol.2
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (395 KB)

    The satellite communication systems with low-altitude nongeostationary orbits have many valuable features; however, the signals suffer the effects of Doppler shift whose value and drift rate are very large compared with those in the systems with geostationary or highly elliptical orbits. The paper discusses the effects of this Doppler shift in the low-altitude orbital satellite communication syste... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Communications on the Move. Singapore. ICCS/ISITA '92(Cat. No.92TH0479-6)

    Publication Year: 1992
    Request permission for commercial reuse | PDF file iconPDF (44 KB)
    Freely Available from IEEE
  • Conference authentication and key distribution service in the RHODOS distribution system

    Publication Year: 1992, Page(s):284 - 289 vol.1
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (489 KB)

    The paper reports on the development of a conference authentication and key distribution service for distributed systems. The authors demonstrate that it is possible to develop such a service as an integral part of the RHODOS distributed operating system, subject to some requirements and extensions to the original Koyama-Ohta system. The basic RHODOS requirement is that users cannot be trusted, an... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Coherent detection of coded/uncoded MPSK sequences over the Gaussian channel with unknown carrier phase using a Viterbi decoder

    Publication Year: 1992, Page(s):1312 - 1316 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    Using the approach of simultaneous ML estimation of digital sequence and unknown carrier phase, the authors develop a new suboptimum ML soft decoder which achieves coherent detection performance if the carrier phase is time-invariant. This decoder does not require any explicit recovery of coherent references, involves only linear operations in the metric computation, and can be implemented efficie... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A TDM-like protocol for Gbit/s metropolitan area networks

    Publication Year: 1992, Page(s):715 - 719 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    Describes the concept of a new protocol TDM-like, which overcomes the performance degradation of Fasnet by eliminating the RTD limitation, and studies its performance by means of computer simulation. The performance is simulated under a range of access allocation algorithms, number of stations and different cycle length. A preliminary comparison with the pi-persistent protocol in terms of... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Some analyses on signature analysis with distortionless data compression

    Publication Year: 1992, Page(s):1088 - 1092 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (260 KB)

    This paper shows that from the point of view of aliasing errors and the expected values of the wasting test cost caused by misjudging faulty circuits to be fault-free, there are instances where signature analysis with no (circuit output) compression(SA-NC) is preferable to signature analysis with single MISR(SA-MISR) or multiple input shift registers. It is proposed to apply distortionless sequenc... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A blind sequence detection over rapidly time-varying channels and its algebraic structure

    Publication Year: 1992, Page(s):1317 - 1321 vol.3
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    A blind sequence detection without explicit estimation of unknown and rapidly time-varying channel response is proposed. The algorithm proceeds in on-line manner like the Viterbi algorithm for Maximum Likelihood Sequence Estimation. Under noise-free assumption, the author presents its algebraic structure and proves that the true sequence can be detected View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Enhancements of the Fasnet protocol for Gbit/s metropolitan area networks

    Publication Year: 1992, Page(s):720 - 724 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    As MANs are increasingly being conceived to provide a short term solution to the realization of a public integrated broadband service environment for which absolute equality in bandwidth allocation will be mandatory, access fairness will become an important criterion in the choice of an access protocol. Access fairness is inherent in cyclic protocols such as Fasnet. But the performance of Fasnet d... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The modified Alopex algorithm and its circuit architecture

    Publication Year: 1992, Page(s):1093 - 1095 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (116 KB)

    A modified algorithm of pattern extraction is presented and its circuit architecture described. The algorithm has been implemented and tested by a C language program on a SUN4/330 Workstation. The software package is applied to placement in VLSI design and gate arrangement in gate matrix layout View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A comparison of different noise prediction schemes for high rate digital subscriber loop transmission

    Publication Year: 1992, Page(s):1322 - 1326 vol.3
    Cited by:  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    These schemes are the double side forward filter (DSFF) and the additional noise predictor (NP) schemes. Their optimal coefficient sets are derived under the minimum mean squared error criterion. Numerical examples show that both systems offer almost the same performance gain, over the system with only single side forward filter. In a system using a detector, however, the DSFF scheme needs only a ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance evaluation of the DQDB layer in IEEE 802.6 metropolitan area networks

    Publication Year: 1992, Page(s):725 - 729 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    The authors analyse the medium access control service offered to the logical link control (LLC) sublayer by the DQDB layer. The MCF block is responsible of a segmentation process that makes the segment sources of the queue arbitrated (QA) block much more bursty than classic mathematical models for bursty data sources. The considered scenario is that of a LAN interconnected to a MAN and using a tra... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new method for the study of hazard and the uses of it

    Publication Year: 1992, Page(s):1096 - 1100 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    The present paper considers the problem of hazard in digital structures. The first stage to be achieved is a rigorous analysis of hazard in combinatorial logic circuits already existing, and whose physical implementation is well known. The analysis method suggested is developed on the scheme of the time constants method. The second stage consists of studies on the functioning of a finite automaton... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the exponential twisting in efficient Monte Carlo simulation

    Publication Year: 1992, Page(s):1327 - 1331 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    Various variance reduction techniques known as importance sampling methods have been employed successfully in the communications and statistical literature to reduce significantly the computational burden of brute-force Monte Carlo. This paper illustrates the use of large deviations theory as a powerful tool for designing highly computationally efficient and flexible importance sampling schemes. A... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new neural network model based approach to unsupervised image segmentation

    Publication Year: 1992, Page(s):1404 - 1408 vol.3
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    This paper proposes a new neural network model UMAN in which the generalized information entropy is used as the quantitative description and measurement of the system stability and asymptotication, and the disadvantage of generalized energy functions is avoided. The improved Kohonen nonlinear mapping structure not only enhances the clustering features, but also reduces the redundant information. I... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reception of GPS signal on diversified terrain

    Publication Year: 1992, Page(s):813 - 815 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    A portable GPS (global positioning system) receiver was used to test GPS signal reception in Singapore where many different terrain can be found. The paper reports on some of the measurement results. A brief description of GPS and a discussion on the relationship between signal reception and positioning accuracy using GPS are also presented View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • 2-mode delay lock loop for mobile communications

    Publication Year: 1992, Page(s):730 - 734 vol.2
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    A tracking scheme employing two tracking modes is proposed and its usefulness is confirmed by computer simulations. The simulation results show that the proposed scheme leads to a great improvement of the jitter performance in multipath fading channels View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Performance analysis of an ATM multiplexer with different classes of bursty sources

    Publication Year: 1992, Page(s):167 - 172 vol.1
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    An ATM multiplexer with different classes of bursty sources is considered for evaluation of the effects of bursty traffic variations on its performance. A discrete-time Markov chain model is developed to obtain cell loss probability both for the whole set of sources and for each class. Calculations carried out for the particular case of two classes, with a first class behaving as declared at call ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A trial of simulator for building management systems

    Publication Year: 1992, Page(s):953 - 957 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    Modern office buildings, most of them are called intelligent/smart buildings, are required to be equipped with precise, flexible and reliable Building Management Systems (BMSs) to improve the comfort and safety for the occupants. Therefore, for BMSs, it is becoming important to achieve quick and accurate responses under given conditions; however, we are actually faced with some cases which show a ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multidimensional coded modulation by assigning code vectors to a signal point

    Publication Year: 1992, Page(s):1101 - 1105 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    This paper proposes and investigates a multidimensional coded modulation system with a new mapping scheme. If several codewords are mapped each to a modulated signal point and distinguishable in decoding, then transmission rate can decrease even for the same code rate. Such mapping and decoding schemes are described for multidimensional trellis coded modulation (TCM). It is proposed to use a block... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • PIN-FET receiver design for optical fibre digital PPM systems

    Publication Year: 1992, Page(s):1028 - 1032 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    This paper considers system performance with a causal noise whitening filter and shows that at 50 Mbit/s the sensitivity is within 0.5 dB of ideal detection and 6.7 dB better than PCM. A 565 Mbit/s system is also considered and it is demonstrated that to allow operation at this bit-rate the cut-off frequency of the noise whitening filter must be greater than the noise corner frequency so as to red... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical fibre local access network software tools

    Publication Year: 1992, Page(s):1332 - 1336 vol.3
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (296 KB)

    Details are presented of a software package which combines the theoretical models developed in the course of a research programme with experimental data obtained from devices used in U.K. field trials of fibre in the local access network. This package could provide a rapid prototyping test-bed on which the early design and planning of the access network could be structured. The limits of optical n... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An eliminating highest error criterion in Hopfield neural network for bilevel image restoration

    Publication Year: 1992, Page(s):1409 - 1411 vol.3
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    In this approach to bilevel image restoration the autoconnections of the network generally weight more heavily than interconnections. This characteristic exists in general degradation models of image restoration and can be utilized to guide the network to be updated more efficiently. A criterion for choice of the neurons to be updated at each step is proposed. An algorithm using the criterion conv... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improvement of the stability of the normalized LMS method under noisy environment

    Publication Year: 1992, Page(s):1186 - 1189 vol.3
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    On the learning identification algorithm the value of echo return loss enhancement (ERLE) after saturation fluctuates for colored input signal under noisy environment. This paper proposes to improve the stability of ERLE by controlling the relaxation factor α, using the norm ||x&oarr;(j)||2 of input signal x&oarr;(j) View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new GSC beamformer employing DOA estimation and null steering

    Publication Year: 1992, Page(s):816 - 820 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    A new generalized sidelobe canceller (GSC) beamforming structure employing direction-of-arrival (DOA) estimation and null steering technique is presented. It has the advantages that the quiescent response of the beamformer can be closely maintained and that the adaptive dimension of the beamformer can be reduced to about half of that of the full processor. Theoretical justification on the proposed... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Time division duplex technique for power control in selection diversity reception direct sequence spread spectrum communications

    Publication Year: 1992, Page(s):735 - 739 vol.2
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (244 KB)

    A time division duplex (TDD) direct sequence spread spectrum communication (DS-SS) system is proposed for operation in multipath Rayleigh fading environments such as indoor communication channels. It is shown that utilising the TDD technique is advantageous for various reasons such as the simplification of the DS-SS transmitter and receivers, more efficient frequency bandwidth utilisation and the ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.