IEEE Transactions on Information Theory

Volume 41 Issue 3 • May 1995

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Displaying Results 1 - 25 of 35
  • Optimum soft-output detection for channels with intersymbol interference

    Publication Year: 1995, Page(s):704 - 713
    Cited by:  Papers (113)  |  Patents (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (958 KB)

    In contrast to the conventional Viterbi algorithm (VA) which generates hard-outputs, an optimum soft-output algorithm (OSA) is derived under the constraint of fixed decision delay for detection of M-ary digital signals in the presence of intersymbol interference and additive white Gaussian noise. The OSA, a new type of the conventional symbol-by-symbol maximum a posteriori probability algorithm, r... View full abstract»

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  • Comment on "Optimality of the sequential probability ratio test for nonstationary observations" by Y. Liu and S.D. Blostein

    Publication Year: 1995
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (102 KB)

    For original paper see IEEE Trans. Inform. Theory, vol.38, p.177-82 (1992). Liu and Blostein (1992) consider sequential tests with varying stopping bounds (NSPRT) for testing simple hypotheses on independent but nonstationary observations. They state a considerable generalization of the famous Wald-Wolfowitz theorem [1948] on the (simultaneous) minimization of the expected sample sizes for given e... View full abstract»

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  • On spectra of BCH codes

    Publication Year: 1995, Page(s):786 - 788
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    Derives an estimate for the error term in the binomial approximation of spectra of BCH codes. This estimate asymptotically improves on the bounds by Sidelnikov (1971), Kasami et al. (1985), and Sole (1990) View full abstract»

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  • Information-theoretic approach to unimodal density estimation

    Publication Year: 1995, Page(s):824 - 829
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (444 KB)

    Extends the maximum entropy information-theoretic density estimation method to provide a technique which guarantees that the resulting density is unimodal. The method inputs data in the form of moment or quantile constraints and consequently can handle both data-derived and non-data-derived information View full abstract»

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  • Coding for two-head recording systems

    Publication Year: 1995, Page(s):747 - 755
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (644 KB)

    A reduction in the track width in disc-recording systems results in a desirable increase in areal density, but also in the undesirable appearance of inter-track interference (ITI) and loss of signal-to-noise ratio (SNR). One way the effects of ITI may be alleviated is through the use of multiple-head systems simultaneously writing and reading a number of adjacent tracks. In this paper we investiga... View full abstract»

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  • Subgroup subcodes

    Publication Year: 1995, Page(s):781 - 785
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (384 KB)

    Subgroup subcodes and their duals which can be considered as an extension of subfield subcodes and trace codes are defined. Some of their basic properties are investigated. Examples of good subgroup subcodes are included View full abstract»

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  • Error-locator ideals for algebraic-geometric codes

    Publication Year: 1995, Page(s):819 - 824
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    The error locations for an algebraic-geometric code C*(D,mP) are exactly the common zeros (that is, a projective variety V(I)) of a set (ideal) I of error-locator functions. The paper gives a one-dimensional Berlekamp-Massey version of the Feng-Rao (1993) algorithm for decoding algebraic-geometric codes C*(D,mP). This produces a generating set for I (as an ideal) of size at most ρ (the smalles... View full abstract»

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  • The context-tree weighting method: basic properties

    Publication Year: 1995, Page(s):653 - 664
    Cited by:  Papers (347)  |  Patents (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (820 KB)

    Describes a sequential universal data compression procedure for binary tree sources that performs the “double mixture.” Using a context tree, this method weights in an efficient recursive way the coding distributions corresponding to all bounded memory tree sources, and achieves a desirable coding distribution for tree sources with an unknown model and unknown parameters. Computational... View full abstract»

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  • Covering properties of convolutional codes and associated lattices

    Publication Year: 1995, Page(s):732 - 746
    Cited by:  Papers (17)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1108 KB)

    The paper describes Markov methods for analyzing the expected and worst case performance of sequence-based methods of quantization. We suppose that the quantization algorithm is dynamic programming, where the current step depends on a vector of path metrics, which we call a metric function. Our principal objective is a concise representation of these metric functions and the possible trajectories ... View full abstract»

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  • Two remarks on a paper by Moreno and Kumar [binary Reed-Muller codes]

    Publication Year: 1995, Page(s):859 - 861
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    O. Moreno and P.V. Kumar (IEEE Trans. Inform. Theory, vol.39, no.5, September 1993) showed how Deligne's theorem can be applied to coding theory. They studied certain subcodes of binary Reed-Muller codes and estimated the associated character sums over a field of q2 elements. They obtained bounds of the order 𝒪(q). The present paper shows that in one case one can improve the coeffi... View full abstract»

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  • Constructing SCN bases in characteristic 2

    Publication Year: 1995, Page(s):790 - 794
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB)

    A simple deterministic algorithm to construct a normal basis of GF(qn) over GF(q) (q=pr, p prime) is given. When p=2, the authors deduce a (self complementary normal-SCN) basis of GF(q n) over GF(q) for n odd, or n=2t, t odd. In characteristic 2 these cases are known to be the only possible ones for which there exists an SCN basis View full abstract»

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  • On the second generalized Hamming weight of the dual code of a double-error-correcting binary BCH code

    Publication Year: 1995, Page(s):805 - 808
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    The generalized Hamming weight of a linear code is a new notion of higher dimensional Hamming weights. Let C be an [n,k] linear code and D be a subcode. The support of D is the cardinality of the set of not-always-zero bit positions of D. The rth generalized Hamming weight of C, denoted by dr(C), is defined as the minimum support of an r-dimensional subcode of C. It was shown by Wei (19... View full abstract»

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  • New models and algorithms for future networks

    Publication Year: 1995, Page(s):769 - 780
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1228 KB)

    In future networks, transmission and switching capacity will dominate processing capacity. The authors investigate the way in which distributed algorithms should be changed in order to operate efficiently in this new environment. They introduce a class of new models for distributed algorithms which make explicit the difference between switching and processing. Based on these new models they define... View full abstract»

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  • Algebraic construction of cyclic codes over Z8 with a good Euclidean minimum distance

    Publication Year: 1995, Page(s):815 - 818
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    Let S(8) denote the set of the eight admissible signals of an 8PSK communication system. The alphabet S(8) is endowed with the structure of Z8, the set of integers taken modulo 8, and codes are defined to be Z8-submodules of Z8n. Three cyclic codes over Z8 are then constructed. Their length is equal to 6, 8, and 7, and they, respectively, cont... View full abstract»

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  • A universal finite memory source

    Publication Year: 1995, Page(s):643 - 652
    Cited by:  Papers (127)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (864 KB)

    An irreducible parameterization for a finite memory source is constructed in the form of a tree machine. A universal information source for the set of finite memory sources is constructed by a predictive modification of an earlier studied algorithm-Context. It is shown that this universal source incorporates any minimal data-generating tree machine in an asymptotically optimal manner in the follow... View full abstract»

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  • Improved redundancy of a version of the Lempel-Ziv algorithm

    Publication Year: 1995, Page(s):723 - 731
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    The Lempel-Ziv data compression algorithm has the property that for finite-memory sources the redundancy ρn (defined as the difference between the average code rate and the entropy when the memory size is n) is O (log log n/log n). We suggest a new version of the algorithm with redundancy ρn=O (1/log n) View full abstract»

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  • Construction and evaluation of trellis-coded quantizers for memoryless sources

    Publication Year: 1995, Page(s):853 - 859
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    New constructions of trellis waveform coders, trellis-coded quantizers, and trellis-coded vector quantizers are proposed. The performances of the new quantizers are determined for the memoryless Laplacian, Gaussian, and uniform sources. They are better than (for the Gaussian and Laplacian sources) or equal to (for the uniform source) the best previously published results View full abstract»

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  • On primitive BCH codes with unequal error protection capabilities

    Publication Year: 1995, Page(s):788 - 790
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    Presents a class of binary primitive BCH codes that have unequal-error-protection (UEP) capabilities. The authors use a previous result on the span of their minimum weight vectors to show that binary primitive BCH codes, containing second-order punctured Reed-Muller (RM) codes of the same minimum distance, are binary-cyclic UEP codes. The values of the error correction levels for this class of bin... View full abstract»

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  • On-line density estimators with high efficiency

    Publication Year: 1995, Page(s):829 - 833
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (344 KB)

    Presents on-line procedures for estimating density functions and their derivatives. At each step, M terms are updated. By increasing M the efficiency compared to the traditional off-line kernel density estimator tends to one. Already for M=2, it exceeds 99.1% for kernel orders and derivatives of practical interest View full abstract»

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  • State diagram connectivity and its effects on the decoding of shift-register-based codes

    Publication Year: 1995, Page(s):756 - 761
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (600 KB)

    Coding performance is limited not only by Shannon's (1950) bounds but also by the complexity of decoders. Decoder complexity is in turn governed by the need for the different pieces of the machine to communicate with one another. This paper calculates lower limits on the intra-system information flow for the Viterbi decoding of shift-register-based codes, e.g., convolutional codes. These limits pr... View full abstract»

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  • Fixed-rate universal lossy source coding and rates of convergence for memoryless sources

    Publication Year: 1995, Page(s):665 - 676
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (856 KB)

    A fixed-rate universal lossy coding scheme is introduced for independent and identically distributed (i.i.d.) sources. It is shown for finite alphabet sources and arbitrary single letter distortion measures that as the sample size n grows the expected distortion obtained using this universal scheme converges to Shannon's distortion rate function D(R) at a rate O(log n/n). The scheme can be extende... View full abstract»

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  • Linear codes for the sum mod-2 multiple-access channel with restricted access

    Publication Year: 1995, Page(s):794 - 799
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (464 KB)

    Transmission of information through a multiple-access-modulo-2 adder channel is addressed for the situation that out of a fixed family of N potential users at most some m, m<N are active simultaneously. The authors assign codes to the N users in a way that the receiver is able to correct any t or less errors and separate the s⩽m messages without a priori knowledge of the subset of active us... View full abstract»

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  • Four nonexistence results for ternary linear codes

    Publication Year: 1995, Page(s):800 - 805
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (460 KB)

    It is proved that ternary codes with parameters [15,8,6], [15,9,5], [16,6,8], and [16,7,7] do not exist. This result solves the problem of finding optimal ternary linear codes of length at most 21. A table is given, showing the exact value of d3(n,k) for n⩽21 with the earliest references View full abstract»

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  • On the relation between filter maps and correction factors in likelihood ratios

    Publication Year: 1995, Page(s):833 - 836
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    The robust form of the likelihood ratio for a signal in the presence of white noise has an additional term in the exponent called the correction factor which corresponds to the trace of the conditional covariance of the signal given the observations. The authors show that this correction term is nothing but the trace of the symmetrized Frechet derivative of the nonlinear filter map and hence the l... View full abstract»

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  • Shadow codes and weight enumerators

    Publication Year: 1995, Page(s):762 - 768
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (480 KB)

    The technique of using shadow codes to build larger self-dual codes is extended to codes over arbitrary fields. It is shown how to build the codes and how to determine the new weight enumerator as well. For codes over fields equipped with a square root of -1 and not of characteristic 2, a self-dual code of length n+2 can be built from a self-dual code of length n; for codes over a field without a ... 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
Prakash Narayan 

Department of Electrical and Computer Engineering