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IEEE Transactions on Information Theory

Volume 40 Issue 2 • March 1994

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Displaying Results 1 - 25 of 40
  • The Z/sub 4/-linearity of Kerdock, Preparata, Goethals, and related codes

    Publication Year: 1994, Page(s):301 - 319
    Cited by:  Papers (623)  |  Patents (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1680 KB)

    Certain notorious nonlinear binary codes contain more codewords than any known linear code. These include the codes constructed by Nordstrom-Robinson (1967), Kerdock (1972), Preparata (1968), Goethals (1974), and Delsarte-Goethals (1975). It is shown here that all these codes can be very simply constructed as binary images under the Gray map of linear codes over Z/sub 4/, the integers mod 4 (altho... View full abstract»

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  • An efficient maximum-likelihood-decoding algorithm for linear block codes with algebraic decoder

    Publication Year: 1994, Page(s):320 - 327
    Cited by:  Papers (86)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (679 KB)

    A new soft decoding algorithm for linear block codes is proposed. The decoding algorithm works with any algebraic decoder and its performance is strictly the same as that of maximum-likelihood-decoding (MLD). Since our decoding algorithm generates sets of different candidate codewords corresponding to the received sequence, its decoding complexity depends on the received sequence. We compare our d... View full abstract»

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  • Maximum likelihood and lower bounds in system identification with non-Gaussian inputs

    Publication Year: 1994, Page(s):328 - 339
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (950 KB)

    We consider the problem of estimating the parameters of an unknown discrete linear system driven by a sequence of independent identically distributed (i.i.d.) random variables whose probability density function (PDF) may be non-Gaussian. We assume a general system structure that may contain causal and noncausal poles and zeros. The parameters characterizing the input PDF may also be unknown. We de... View full abstract»

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  • Blind identification and equalization based on second-order statistics: a time domain approach

    Publication Year: 1994, Page(s):340 - 349
    Cited by:  Papers (818)  |  Patents (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (927 KB)

    A new blind channel identification and equalization method is proposed that exploits the cyclostationarity of oversampled communication signals to achieve identification and equalization of possibly nonminimum phase (multipath) channels without using training signals. Unlike most adaptive blind equalization methods for which the convergence properties are often problematic, the channel estimation ... View full abstract»

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  • Binary communications through noisy, non-Gaussian channels

    Publication Year: 1994, Page(s):350 - 362
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1271 KB)

    New and unifying analytical tools are developed and used to evaluate the bit error probability, false alarm and detection probabilities that result when binary information is communicated through a random channel further disturbed by additive white Gaussian noise. The class of channels modeled here are those which envelop the received electric field with an arbitrary space-time complex envelope. T... View full abstract»

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  • Concentrated Cramer-Rao bound expressions

    Publication Year: 1994, Page(s):363 - 371
    Cited by:  Papers (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (753 KB)

    We present a method to simplify the analytical computation of the Cramer-Rao bound. The method circumvents bound calculations for so-called nuisance parameters. Under mild regularity conditions the technique, which replaces expectations with almost sure limits, can significantly lower the analytical complexity as compared to traditional methods. The dimension of a matrix that requires computation ... View full abstract»

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  • On almost-sure bounds for the LMS algorithm

    Publication Year: 1994, Page(s):372 - 383
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (914 KB)

    Almost-sure (a.s.) bounds for linear, constant-gain, adaptive filtering algorithms are investigated. For instance, under general pseudo-stationarity and dependence conditions on the driving data {/spl psi/k,k=1,2,3,...}, {Y/sub k/,k=0,1,2,...} a.s. convergence and rates of a.s. convergence (as the algorithm gain /spl epsiv//spl rarr/0) are established for the LMS algorithm h/sub k+1//sup /spl epsi... View full abstract»

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  • Optimal sequential probability assignment for individual sequences

    Publication Year: 1994, Page(s):384 - 396
    Cited by:  Papers (49)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1363 KB)

    The problem of sequential probability assignment for individual sequences is investigated. The authors compare the probabilities assigned by any sequential scheme to the performance of the best "batch" scheme (model) in some class. For the class of finite-state schemes and other related families, they derive a deterministic performance bound, analogous to the classical (probabilistic) minimum desc... View full abstract»

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  • Error exponents for distributed detection of Markov sources

    Publication Year: 1994, Page(s):397 - 408
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1001 KB)

    The paper considers a binary hypothesis testing system in which two sensors simultaneously observe a discrete-time finite-valued stationary ergodic Markov source and transmit M-ary messages to a Neyman-Pearson central detector. The size M of the message alphabet increases at most subexponentially with the number of observations. The asymptotic behavior of the type II error rate is investigated as ... View full abstract»

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  • On coding without restrictions for the AWGN channel

    Publication Year: 1994, Page(s):409 - 417
    Cited by:  Papers (160)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (773 KB)

    Many coded modulation constructions, such as lattice codes, are visualized as restricted subsets of an infinite constellation (IC) of points in the n-dimensional Euclidean space. The author regards an IC as a code without restrictions employed for the AWGN channel. For an IC the concept of coding rate is meaningless and the author uses, instead of coding rate, the normalized logarithmic density (N... View full abstract»

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  • The performance of type-I trellis coded hybrid-ARQ protocols over AWGN and slowly fading channels

    Publication Year: 1994, Page(s):418 - 428
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (946 KB)

    A method is described for modifying trellis coded modulation systems for use in type-1 hybrid-ARQ protocols. The difference between the partial path metric of the survivor and that of the best nonsurvivor at each node in the trellis is used to determine the desirability of a retransmission request for a given received packet. Bounds on the reliability and throughput performance of the resulting er... View full abstract»

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  • Corrective memory by a symmetric sparsely encoded network

    Publication Year: 1994, Page(s):429 - 438
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (803 KB)

    A neural network that retrieves stored binary vectors, when probed by possibly corrupted versions of them, is presented. It employs sparse ternary internal coding and autocorrelation (Hebbian) storage. It is symmetrically structured and, consequently, can be folded into a feedback configuration. Bounds on the network parameters are derived from probabilistic considerations. It is shown that when t... View full abstract»

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  • Good weights and hyperbolic kernels for neural networks, projection pursuit, and pattern classification: Fourier strategies for extracting information from high-dimensional data

    Publication Year: 1994, Page(s):439 - 454
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1352 KB)

    Fourier approximation and estimation of discriminant, regression, and density functions are considered. A preference order is established for the frequency weights in multiple Fourier expansions and the connection weights in single hidden-layer neural networks. These preferred weight vectors, called good weights (good lattice weights for estimation of periodic functions), are generalizations for a... View full abstract»

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  • On the posterior-probability estimate of the error rate of nonparametric classification rules

    Publication Year: 1994, Page(s):475 - 481
    Cited by:  Papers (11)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (710 KB)

    The posterior-probability estimate of the classification error rate of some nonparametric classification rules is studied. The variance of the estimator is shown to have same remarkable distribution-free properties for the k-nearest neighbor, kernel, and histogram rules. We also investigate the bias of the estimate and establish its consistency and upper bounds. The version of the estimate calcula... View full abstract»

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  • Rational approximation techniques for analysis of neural networks

    Publication Year: 1994, Page(s):455 - 466
    Cited by:  Papers (21)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1258 KB)

    Artificial neural networks are comprised of an interconnected collection of certain nonlinear devices; examples of commonly used devices include linear threshold elements, sigmoidal elements, and radial-basis elements. We employ results from harmonic analysis and the theory of rational approximation to obtain almost tight lower bounds on the size (i.e., number of elements) of neural networks. The ... View full abstract»

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  • Lower bounds on threshold and related circuits via communication complexity

    Publication Year: 1994, Page(s):467 - 474
    Cited by:  Papers (17)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (763 KB)

    Using communication complexity concepts and techniques, we derive linear (/spl Omega/(n)) and almost-linear (/spl Omega/(n/logn)) lower bounds on the size of circuits implementing certain functions. Our approach utilizes only basic features of the gates used, hence the bounds hold for general families of gates of which the symmetric and threshold gates are special cases. Each of the bounds derived... View full abstract»

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  • Improved coding techniques for preceded partial-response channels

    Publication Year: 1994, Page(s):482 - 493
    Cited by:  Papers (15)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1279 KB)

    A coset of a convolutional code may be used to generate a zero-run length limited trellis code for a 1-D partial-response channel. The free squared Euclidean distance, d/sub free//sup 2/, at the channel output is lower bounded by the free Hamming distance of the convolutional code. The lower bound suggests the use of a convolutional code with maximal free Hamming distance, d/sub max/(R,N), for giv... View full abstract»

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  • Partial period autocorrelations of geometric sequences

    Publication Year: 1994, Page(s):494 - 502
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (803 KB)

    For a binary pseudorandom sequence {S/sub i/} with period N, the partial period autocorrelation function A/sub S/(/spl tau/,k,D) is defined by correlating the portion of the sequence within a window of size D, and start position k, with the portion in another window of the same size but starting /spl tau/ steps later in the sequence. A distribution of possible partial period autocorrelation values... View full abstract»

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  • No binary quadratic residue code of length 8m-1 is quasi-perfect

    Publication Year: 1994, Page(s):503 - 504
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (215 KB)

    The class of binary quadratic residue (QR) codes of length n=8m-1 contains two perfect codes. These are the (7,4,3) Hamming code and the (23,12,7) Golay code. However, it is proved in the present paper that there are no quasi-perfect QR codes of length 8m-1. Finally, this result is generalized to all binary self-dual codes of length N>72.<<ETX>> View full abstract»

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  • Some new constructions for simplex codes

    Publication Year: 1994, Page(s):504 - 507
    Cited by:  Papers (10)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (369 KB)

    Three constructions for n-dimensional regular simplex codes /spl alpha//sub i/, 0/spl les/i/spl les/n, are proposed, two of which have the property that /spl alpha//sub i/ for 1/spl les/i/spl les/n is a cyclic shift of /spl alpha//sub 1/. The first method is shown to work for all the positive integers n=1,2,... using only three real values. It turns out that these values are rational whenever n+1 ... View full abstract»

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  • Parallelized Huffman and Hu-Tucker searching

    Publication Year: 1994, Page(s):508 - 510
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    Forests constructed by the binary Huffman (1952) and Hu-Tucker (1971) algorithms solve parallelized search problems. Bounds on the resulting minimum average search lengths for items occurring with given probabilities are established.<<ETX>> View full abstract»

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  • New binary codes

    Publication Year: 1994, Page(s):510 - 512
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (322 KB)

    We report on the construction of many binary linear codes improving the tables of the best known codes. We obtained our results by applying the following known constructions: shortening and puncturing codes by analyzing their duals; and transferring a [64,8,43] code over GF(4) into a binary code and applying various constructions to the resulting code.<<ETX>> View full abstract»

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  • A note on the method of poles for code construction

    Publication Year: 1994, Page(s):512 - 517
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (629 KB)

    The method of poles is a method for constructing a rate 1:1 finite state code from K-ary data into a constrained channel S, where S is recognized by a given local automaton and S has capacity at least log(k). We characterize those automata to which the method of poles applies in the case where h(S)=log(k). The code produced by the method of poles has a sliding-block decoder. We also give an upper ... View full abstract»

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  • Bounds on constant weight codes correcting localized errors

    Publication Year: 1994, Page(s):517 - 521
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (422 KB)

    We derive upper and lower bounds for constant weight codes on a channel with localized errors. Coding for channels with localized errors is a new branch of coding theory. From a practical point of view it is important to find good, easily decodable codes. From an information theory point of view it is important to investigate how good these codes can be, that is finding the theoretical limits. For... View full abstract»

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  • On ternary complementary sequences

    Publication Year: 1994, Page(s):522 - 526
    Cited by:  Papers (34)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (457 KB)

    A pair of real-valued sequences A=(a/sub 1/,a/sub 2/,...,a/sub N/) and B=(b/sub 1/,b/sub 2/,...,b/sub N/) is called complementary if the sum R(/spl middot/) of their autocorrelation functions R/sub A/(/spl middot/) and R/sub B/(/spl middot/) satisfies R(/spl tau/)=R/sub A/(/spl tau/)+R/sub B/(/spl tau/)=/spl Sigma//sub i=1//sup N$/ -/sup /spl tau//a/sub i/a/sub i+/spl tau//+/spl Sigma//sub j=1//su... 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.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Alexander Barg

Department of Electrical and Computer Engineering and the Institute for Systems Research, University of Maryland

email: abarg-ittrans@ece.umd.edu