IEEE Transactions on Information Theory

Volume 41 Issue 4 • Jul 1995

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Displaying Results 1 - 25 of 38
  • Decoding algorithms with input quantization and maximum error correction capability

    Publication Year: 1995, Page(s):1126 - 1133
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (604 KB)

    Decoding that uses soft-decision information but with multiple low-complexity decoders are investigated. These decoders correct only errors and erasures. The structure of the receiver consists of a bank of z demodulators followed by errors- and erasures-correcting decoders operating in parallel. Each demodulator has a threshold for determining when to erase a given symbol. We assign a cost f(&thet... View full abstract»

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  • Symmetric capacity and signal design for L-out-of-K symbol-synchronous CDMA Gaussian channels

    Publication Year: 1995, Page(s):1072 - 1082
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (760 KB)

    We consider the symbol-synchronous Gaussian L-out-of-K code-division multiaccess channel, and obtain the capacity region and the upper and lower bounds to the symmetric capacity. The capacity region is found to be the same with or without frame synchronism. The lower bound depends on the signature waveforms through the eigenvalues of the SNR-weighted crosscorrelation matrix. We find a sufficient c... View full abstract»

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  • A comment on “A rate of convergence result for a universal D-semifaithful code”

    Publication Year: 1995, Page(s):1200 - 1202
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (188 KB)

    In the above paper (see ibid., vol.39, no.3, p.813-20, 1993) Yu and Speed propose a universal pointwise D-semifaithful code whose expected compression ratio, for discrete memoryless sources, approaches the rate-distortion function at a rate O(n-1 log n). They also conjecture that this is the fastest achievable convergence rate for pointwise D-semifaithful codes. In this correspondence, ... View full abstract»

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  • Nonlinear filters for linear models (a robust approach)

    Publication Year: 1995, Page(s):1001 - 1009
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    We consider the altering problem for linear models where the driving noises may be quite general, nonwhite and non-Gaussian, and where the observation noise may only be known to belong to a finite family of possible disturbances. Using diffusion approximation methods, we show that a certain nonlinear filter minimizes the asymptotic filter variance. This nonlinear filter is obtained by choosing at ... View full abstract»

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  • Error-correcting two-dimensional modulation codes

    Publication Year: 1995, Page(s):1116 - 1126
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1032 KB)

    Modulation coding, to limit the number of consecutive zeros in a data stream, is essential in digital magnetic recording/playback systems. Additionally, such systems require error-correction coding to ensure that the decoded output matches the recorder input, even if noise is present. Typically, these two coding steps have been performed independently, although various methods of combining them in... View full abstract»

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  • New directions in the theory of identification via channels

    Publication Year: 1995, Page(s):1040 - 1050
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (728 KB)

    Studies two problems in the theory of identification via channels. The first problem concerns the identification via channels with noisy feedback. Whereas for Shannon's transmission problem the capacity of a discrete memoryless channel does not change with feedback, it is known that the identification capacity is affected by feedback. The authors study its dependence on the feedback channel. They ... View full abstract»

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  • Invertibility conditions of a class of moment matrices and applications

    Publication Year: 1995, Page(s):1196 - 1199
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    We consider a multivariable polynomial with random variables as arguments. All the monoids of this polynomial are arranged to define a random vector for which we study the correlation matrix. We establish necessary and sufficient invertibility conditions of this matrix, and investigate some applications View full abstract»

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  • Threshold detection in correlated non-Gaussian noise fields

    Publication Year: 1995, Page(s):976 - 1000
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1728 KB)

    Classical threshold detection theory for arbitrary noise and signals, based on independent noise samples, i.e., using only the first-order probability density of the noise, is generalized to include the critical additional statistical information contained in the (first-order) covariances of the noise. This is accomplished by replacing the actual, generalized noise by a “quasi-equivalent&rdq... View full abstract»

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  • A new construction for n-track (d, k) codes with redundancy

    Publication Year: 1995, Page(s):1107 - 1115
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    A new construction for n-track (d, k) codes with redundancy r, referred to as (d, k; n, r) codes, is presented. This construction applies single-track (d, k+Δk) codes (with certain extra constraints and appropriate amounts of delay) on each of the n tracks. This construction achieves a large part of the capacity increases possible when using (d, k; n, r) codes, has simple encoders and decode... View full abstract»

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  • Rates of convergence of nearest neighbor estimation under arbitrary sampling

    Publication Year: 1995, Page(s):1028 - 1039
    Cited by:  Papers (54)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (808 KB)

    Rates of convergence for nearest neighbor estimation are established in a general framework in terms of metric covering numbers of the underlying space. The first result is to find explicit finite sample upper bounds for the classical independent and identically distributed (i.i.d.) random sampling problem in a separable metric space setting. The convergence rate is a function of the covering numb... View full abstract»

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  • A counterexample to a Voronoi region conjecture

    Publication Year: 1995, Page(s):1195 - 1196
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    Given a 2D-symmetric lattice Λ, it was conjectured by Forney (1989) that the projection of the Voronoi region R(Λ) onto two coordinates equals the Voronoi region of the constituent 2D-sublattice Λν2. We present a three-dimensional counterexample View full abstract»

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  • New optimal ternary linear codes

    Publication Year: 1995, Page(s):1182 - 1185
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    The class of quasi-twisted (QT) codes is a generalization of the class of quasi-cyclic codes, similar to the way constacyclic codes are a generalization of cyclic codes. In this paper, rate 1/p QT codes over GF(3) are presented which have been constructed using integer linear programming and heuristic combinatorial optimization. Many of these attain the maximum possible minimum distance for any li... View full abstract»

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  • The capacity of average and peak-power-limited quadrature Gaussian channels

    Publication Year: 1995, Page(s):1060 - 1071
    Cited by:  Papers (107)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1068 KB)

    The capacity C(ρa, ρp) of the discrete-time quadrature additive Gaussian channel (QAGC) with inputs subjected to (normalized) average and peak power constraints, ρa and ρp respectively, is considered. By generalizing Smith's results for the scalar average and peak-power-constrained Gaussian channel, it is shown that the capacity achieving... View full abstract»

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  • Upper bounds and Hamming spheres under the DC constraint

    Publication Year: 1995, Page(s):1138 - 1145
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    Upper bounds on the rate of codes in DC-constrained spaces are derived for imbalances 3, 4, and 5. The new bounds are based on the identification and size calculation of the minimal Hamming spheres. A new combination of the Hamming and Plotkin (1960) bounds for constrained spaces is obtained View full abstract»

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  • The Leech lattice, the octacode, and decoding algorithms

    Publication Year: 1995, Page(s):1097 - 1106
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (836 KB)

    New multilevel constructions of the Golay code and the Leech lattice are presented. These are derived from the Turyn construction and the “holy construction” with the octacode as the glue code. Further, we show that the “holy construction” of the Leech lattice with the octacode as the glue code is essentially different from the permuted Turyn construction, although both con... View full abstract»

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  • Sup-norm approximation bounds for networks through probabilistic methods

    Publication Year: 1995, Page(s):1021 - 1027
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    We consider the problem of approximating a smooth target function and its derivatives by networks involving superpositions and translations of a fixed activation function. The approximation is with respect to the sup-norm and the rate is shown to be of order O(n-1/2); that is, the rate is independent of the dimension d. The results apply to neural and wavelet networks and extend the wor... View full abstract»

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  • Fast parallel algorithms for decoding Reed-Solomon codes based on remainder polynomials

    Publication Year: 1995, Page(s):873 - 885
    Cited by:  Papers (19)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (848 KB)

    The problem of decoding cyclic error correcting codes is one of solving a constrained polynomial congruence, often achieved using the Berlekamp-Massey or the extended Euclidean algorithm on a key equation involving the syndrome polynomial. A module-theoretic approach to the solution of polynomial congruences is developed here using the notion of exact sequences. This technique is applied to the We... View full abstract»

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  • Constructing a better cyclic code than cyclic Reed-Solomon code

    Publication Year: 1995, Page(s):1191 - 1194
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    Problems of computing the generator polynomial for a (q+1, q-d+2) reversible cyclic BCH code over GF(q), q=pm, having the minimum Hamming distance d, are presented. The considered code is almost as short as a Reed-Solomon (RS) code but it generates codewords with two information symbols more than the codewords of RS code with the same minimum Hamming distance View full abstract»

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  • Bennett's integral for vector quantizers

    Publication Year: 1995, Page(s):886 - 900
    Cited by:  Papers (67)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1184 KB)

    This paper extends Bennett's (1948) integral from scalar to vector quantizers, giving a simple formula that expresses the rth-power distortion of a many-point vector quantizer in terms of the number of points, point density function, inertial profile, and the distribution of the source. The inertial profile specifies the normalized moment of inertia of quantization cells as a function of location.... View full abstract»

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  • Variable-rate tree-structured vector quantizers

    Publication Year: 1995, Page(s):917 - 930
    Cited by:  Papers (17)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (884 KB)

    In general, growth algorithms for optimal tree-structured vector quantizers do not exist. In this paper we show that if the source satisfies certain conditions; namely, that of diminishing marginal returns; optimal growth algorithms do exist. We present such an algorithm and compare its performance with that of other tree growth algorithms. Even for sources that do not meet the necessary condition... View full abstract»

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  • Superimposed codes for the multiaccess binary adder channel

    Publication Year: 1995, Page(s):1178 - 1182
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    Superimposed codes for multiple-access communication in a binary adder channel are analyzed. The superposition mechanism used in this correspondence is ordinary addition. Each user is assigned a codeword from a superimposed code. It is proved that every constant-weight code C of weight w and maximal correlation c corresponds to a subclass of a disjunctive code D of order m<w/c. Therefore, any m... View full abstract»

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  • MMSE decision-feedback equalizers: finite-length results

    Publication Year: 1995, Page(s):961 - 975
    Cited by:  Papers (218)  |  Patents (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1020 KB)

    This paper extends a number of results on the infinite-length minimum-mean-square-error decision Feedback equalizer (MMSE-DFE) reported by Cioffi, Dudevoir, Eyuboglu and Forney (see IEEE Trans. Commun., 1995) to the finite-length case. Cholesky factorization and displacement structure theory are demonstrated to be two powerful analytical tools for analyzing the finite-length MMSE-DFE. Our objectiv... View full abstract»

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  • Asymptotically optimum detection of a weak signal sequence with random time delays

    Publication Year: 1995, Page(s):1169 - 1174
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    The problem of designing asymptotically optimum detectors for a weak signal sequence with random time delays in the presence of a white Gaussian noise is considered. The multidimensional probability distribution of the time delays is assumed to be known. As a result of asymptotic analysis of the log-likelihood ratio, the asymptotically optimum linear or quadratic detectors and their probability di... View full abstract»

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  • Properties of the x2 mod N pseudorandom number generator

    Publication Year: 1995, Page(s):1155 - 1159
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    In 1986, L. Blum, R.I. Blum, and M. Shub introduced the x2 mod N generator of pseudorandom bit strings and showed, given certain plausible but unproved hypotheses, that it has the desirable cryptographic property of unpredictability. They also studied the period length of the sequences produced by this generator and proposed a way to guarantee that these sequences will have maximum pos... View full abstract»

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  • A simple strategy for constructing a class of DC-free error-correcting codes with minimum distance 4

    Publication Year: 1995, Page(s):1134 - 1137
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    A class of DC-free codes with minimum distance 4 which offer very simple encoding and decoding procedures is presented. Spectral analysis shows that in addition to being DC-free they offer strong spectral suppression at low frequencies. A comparison with similar codes in the literature shows that they provide a good compromise solution to the design of practically realizable, high-rate, DC-free er... 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