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IEEE Transactions on Information Theory

Issue 6 • Date Nov 1993

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Displaying Results 1 - 21 of 21
  • The number of nonlinear shift registers that produce all vectors of weight ⩽t

    Publication Year: 1993, Page(s):1989 - 1990
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    It has been shown that it is possible to generate a cycle on a nonlinear shift register to contain all vectors of length n and Hamming weight ⩽t. It is shown how to count the number of different ways this can be done on a truth table of minimum density. Specifically, it is shown how a theorem on spanning subtrees on a graph can be used to evaluate the number of sequences that contain vectors o... View full abstract»

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  • Minimal-change order and separability in linear codes

    Publication Year: 1993, Page(s):1988 - 1989
    Cited by:  Papers (5)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    A linear code is said to be in minimal-change order if each codeword differs from its predecessor by a word of minimum weight. A rule is presented for constructing such an order in the case in which the code has a basis of codewords with minimum weight. Some consequences concerning the ranking and separability are mentioned View full abstract»

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  • Shaping multidimensional signal spaces. I. Optimum shaping, shell mapping

    Publication Year: 1993, Page(s):1799 - 1808
    Cited by:  Papers (46)  |  Patents (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (712 KB)

    The structure of the regions which provide the optimum tradeoff between γs (shaping gain) and CER (constellation-expansion ratio) and between γs and PAR (peak to average power ratio) in a finite dimensional space is introduced. Analytical expressions are derived for the corresponding tradeoff curves. In general, the initial parts of the curves have a steep slope. ... View full abstract»

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  • Sonar sequences from Costas arrays and the best known sonar sequences with up to 100 symbols

    Publication Year: 1993, Page(s):1985 - 1987
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    The authors construct new and improved sonar sequences by applying rotation, multiplication, and shearing transformations to Costas sequence constructions. A catalog of the best known sonar sequences with up to 100 symbols is given View full abstract»

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  • Shaping multidimensional signal spaces. II. Shell-addressed constellations

    Publication Year: 1993, Page(s):1809 - 1819
    Cited by:  Papers (25)  |  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (988 KB)

    For Pt. I, see ibid., pp. 1799-1808, Nov. 1993. By appropriately selecting the boundary of a multidimensional signal constellation used for data transmission, the average energy of the constellation can be reduced. Reduction in the average energy (shaping gain) is obtained at the price of increasing the constellation-expansion ratio (CERs ) and the peak-to-average-power ratio (PAR). The... View full abstract»

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  • Privacy, additional information and communication

    Publication Year: 1993, Page(s):1930 - 1943
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1140 KB)

    Two parties, each holding one input of a two-variable function, communicate in order to determine the value of the function. Each party wants to expose as little of its input as possible to the other party. The authors prove tight bounds on the minimum amount of information about the individual inputs that must be revealed in the computation of most functions and of some specific ones. They also s... View full abstract»

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  • Geometrically uniform partitions of L×MPSK constellations and related binary trellis codes

    Publication Year: 1993, Page(s):1773 - 1798
    Cited by:  Papers (28)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1948 KB)

    The theory of geometrically uniform trellis codes is applied to the case of multidimensional PSK (phase shift keying) constellations. The symmetry group of an L×MPSK (M-ary PSK) constellation is completely characterized. Conditions for rotational invariance of geometrically uniform partitions of a signal constellation are given. Through suitable algorithms, geometrically uniform partitions o... View full abstract»

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  • A queueing theoretic approach to the delay analysis for the FCFS 0.487 conflict resolution algorithm

    Publication Year: 1993, Page(s):1887 - 1906
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1588 KB)

    The authors apply their queuing-theoretic delay analysis methodology to several variations of the FCFS 0.487 conflict resolution algorithm. In this approach, the main component of the packet delay is viewed as a queuing problem in which each window selected by the channel access algorithm is a customer requiring conflict resolution as its service. The authors' methodology is extended to handle all... View full abstract»

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  • Cascading runlength-limited sequences

    Publication Year: 1993, Page(s):1976 - 1984
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    In magnetic or optical storage devices, it is often required to map the data into runlength-limited sequences. To ensure that cascading such sequences does not violate the runlength constraints, a number of merging bits are inserted between two successive sequences. A theory is developed in which the minimum number of merging bits is determined, and the efficiency of a runlength-limited fixed-leng... View full abstract»

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  • Coded M-DPSK with built-in time diversity for fading channels

    Publication Year: 1993, Page(s):1820 - 1839
    Cited by:  Papers (25)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1524 KB)

    Good coded modulation for fading channels requires built-in time diversity. Under a constraint on the interleaving delay, the authors construct and compare three categories of coded M-DPSK (M-ary differential phase-shift keying) schemes with 4⩽M⩽16 for fading channels: two-dimensional trellis-coded, multidimensional trellis-coded, and block-coded. General rules for designing these schemes ... View full abstract»

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  • On asymptotic optimality of a sliding window variation of Lempel-Ziv codes

    Publication Year: 1993, Page(s):1840 - 1846
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (464 KB)

    The authors modify the algorithm of Z. Ziv and A. Lempel (1977), LZ77, restricting pointers to start only at the boundary of a previously parsed phrase in a window. Although the number of parsed phrases should increase more than those in LZ77, the number of bits needed to encoded pointers is considerably reduced since the number of possible positions to be encoded is much smaller. It is shown that... View full abstract»

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  • Granular quantization noise in the first-order delta-sigma modulator

    Publication Year: 1993, Page(s):1944 - 1956
    Cited by:  Papers (14)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (968 KB)

    A unified approach to analyzing the granular quantization error of the first-order ΔΣ modulator is presented. The approach handles many of the previously analyzed input sequences in addition to a large class of new input sequences. By averaging over the arbitrarily small amount of circuit noise assumed to be present at the analog input to the ΔΣ modulator, a simple expressi... View full abstract»

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  • A tree-structured piecewise linear adaptive filter

    Publication Year: 1993, Page(s):1907 - 1922
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1064 KB)

    The authors propose and analyze a novel architecture for nonlinear adaptive filters. These nonlinear filters are piecewise linear filters obtained by arranging linear filters and thresholds in a tree structure. A training algorithm is used to adaptively update the filter coefficients and thresholds at the nodes of the tree, and to prune the tree. The resulting tree-structured piecewise linear adap... View full abstract»

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  • New asymptotic results in parallel distributed detection

    Publication Year: 1993, Page(s):1847 - 1863
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1224 KB)

    The performance of a parallel distributed detection system is investigated as the number of sensors tends to infinity. It is assumed that the i.i.d. sensor data are quantized locally into m-ary messages and transmitted to the fusion center for binary hypothesis testing. The boundedness of the second moment of the postquantization log-likelihood ratio is examined in relation to the asymptotic error... View full abstract»

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  • Channel shaping to maximize minimum distance

    Publication Year: 1993, Page(s):1957 - 1961
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (428 KB)

    The problem of jointly selecting optimal transmitted signals and the channel frequency response, assuming the channel is linear and time-invariant, is considered where the minimum L2 distance between channel outputs is the optimization criterion. Results indicate that, for a fixed information rate, as the length of the inputs goes to infinity the optimal channel frequency response is a ... View full abstract»

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  • An upper bound on the performance of a novel feedforward perceptron equalizer

    Publication Year: 1993, Page(s):1923 - 1929
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (500 KB)

    The emulation of a nonadaptive, binary, decision-feedback equalizer, operating on a noiseless, finite impulse response channel, by a feedforward multilayer processor is considered. This feedforward perceptron equalizer comprises a triangular array of bandlimiting processing elements. The functional similarity between the two systems is exploited to obtain a tight upper bound on the probability of ... View full abstract»

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  • Nonparametric cyclic-polyspectral analysis of AM signals and processes with missing observations

    Publication Year: 1993, Page(s):1864 - 1876
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (952 KB)

    By viewing discrete-time amplitude-modulated signals and processes with missing observations as cyclostationary signals, nonparametric, mean-square-sense consistent, and asymptotically normal single record estimators are developed for their kth-order cumulants and polyspectra, along with the asymptotic covariances. The proposed estimation schemes use cyclic cumulants and polyspectra, and are theor... View full abstract»

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  • On the minimum description length principle for sources with piecewise constant parameters

    Publication Year: 1993, Page(s):1962 - 1967
    Cited by:  Papers (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB)

    Universal lossless coding in the presence of finitely many abrupt changes in the statistics of the source, at unknown points, is investigated. The minimum description length (MDL) principle is derived for this setting. In particular, it is shown that, for any uniquely decipherable code, for almost every combination of statistical parameter vectors governing each segment, and for almost every vecto... View full abstract»

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  • Tracking mobile users in wireless communications networks

    Publication Year: 1993, Page(s):1877 - 1886
    Cited by:  Papers (74)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (948 KB)

    Tracking strategies for mobile wireless networks are studied. A cellular architecture in which base stations that are interconnected by a wired network communicate with mobile units via wireless links is assumed. The cost of utilizing the wireless links for the actual tracking of mobile users is considered. A tracking strategy in which a subset of all base stations is selected and designed as repo... View full abstract»

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  • Limits of conditional expectations

    Publication Year: 1993, Page(s):1967 - 1972
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    Convergence of conditional expectations is considered. The convergence results for conditional expectations are shown to be the same as when the absolutely continuous change of measure can be made directly. A filtering application is examined. If the approximating model uses noise increments with a density which must have compact support, conditions are given which ensure the expected convergence ... View full abstract»

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  • Increased information rate by oversampling

    Publication Year: 1993, Page(s):1973 - 1976
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (380 KB)

    A noiseless ideal low-pass filter, followed by a limiter, is normally used as a binary data channel by sampling the output once per Nyquist interval. Detectors that sample more often encounter intersymbol interference, but can be used in ways that increase the information rate. A signaling system that achieves an information rate of 1.072 b/Nyquist interval by allowing the detector to sample at ti... View full abstract»

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Aims & Scope

IEEE Transactions on Information Theory publishes papers concerned with the transmission, processing, and utilization of information.

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Meet Our Editors

Editor-in-Chief
Frank R. Kschischang

Department of Electrical and Computer Engineering