IEEE Transactions on Information Theory

Volume 37 Issue 5 • Sept. 1991

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Displaying Results 1 - 25 of 34
  • Geometrically uniform codes

    Publication Year: 1991, Page(s):1241 - 1260
    Cited by:  Papers (278)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2155 KB)

    A signal space code C is defined as geometrically uniform if, for any two code sequences in C, there exists an isometry that maps one sequence into the other while leaving the code C invariant. Geometrical uniformity, a strong kind of symmetry, implies such properties as a) the distance profiles from code sequences in C to all other code sequences are all the same, and b) all Voronoi regions of co... View full abstract»

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  • A strengthening of the Assmus-Mattson theorem

    Publication Year: 1991, Page(s):1261 - 1268
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (660 KB)

    Let w/sub 1/=d,w/sub 2/,...,w/sub s/ be the weights of the nonzero codewords in a binary linear (n,k,d) code C, and let w'/sub 1/, w'/sub 2/, ..., w'/sub 3/, be the nonzero weights in the dual code C1. Let t be an integer in the range 0<t<d such that there are at most d-t weights w'/sub i/ with 0<w'/sub i/ <or=n-t E. F. Assmus and H. F. Mattson, Jr. (1969) proved that the words of any ... View full abstract»

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  • The Gleason-Prange theorem

    Publication Year: 1991, Page(s):1269 - 1273
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    The Gleason-Prange theorem describes a nontrivial automorphism of an extended quadratic residue code. By using the Fourier transform in an appropriate extension field, methods of digital signal processing are used to make the proof transparent and the automorphism intuitive. The theorem is proved both in a field of characteristic tow and in an arbitrary field and is stated simply as a general prop... View full abstract»

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  • A generalization of the Berlekamp-Massey algorithm for multisequence shift-register synthesis with applications to decoding cyclic codes

    Publication Year: 1991, Page(s):1274 - 1287
    Cited by:  Papers (108)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (962 KB)

    A generalization of the Berlekamp-Massey algorithm is presented for synthesizing minimum length linear feedback shift registers for generating prescribed multiple sequences. A more general problem is first considered, that of finding the smallest initial set of linearly dependent columns in a matrix over an arbitrary field, which includes the multisequence problem as a special case. A simple itera... View full abstract»

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  • A class of distortionless codes designed by Bayes decision theory

    Publication Year: 1991, Page(s):1288 - 1293
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (502 KB)

    The problem of distortionless encoding when the parameters of the probabilistic model of a source are unknown is considered from a statistical decision theory point of view. A class of predictive and nonpredictive codes is proposed that are optimal within this framework. Specifically, it is shown that the codeword length of the proposed predictive code coincides with that of the proposed nonpredic... View full abstract»

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  • On codes satisfying Mth-order running digital sum constraints

    Publication Year: 1991, Page(s):1294 - 1313
    Cited by:  Papers (24)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1824 KB)

    Multi level sequences with a spectral null of order M at frequency f, meaning that the power spectral density, and its first 2M-1 derivatives vanish at f, are characterized by finite-state transition diagrams (FSTDs) whose edge labels satisfy bounds on the variation of the Mth-order running digital sum (RDS). Necessary and sufficient conditions for FSTDs with higher order null constraints at DC an... View full abstract»

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  • Information capacity of the stationary Gaussian channel

    Publication Year: 1991, Page(s):1314 - 1326
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (966 KB)

    The averaged information capacity of the mismatched stationary continuous-time Gaussian channel is considered, in the limit as the observation time becomes infinite. It is required only that the signal satisfy a reproducing kernel Hilbert space constraint on expected energy. This requires the, signal energy to be distributed in regions where the noise energy, is not too small, and is the weakest c... View full abstract»

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  • Optimization of signal sets for partial-response channels. I. Numerical techniques

    Publication Year: 1991, Page(s):1327 - 1341
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1608 KB)

    Given a linear, time-invariant, discrete-time channel, the problem of constructing N input signals of finite length K that maximize minimum l/sub 2/ distance between pairs of outputs is considered. Two constraints on the input signals are considered: a power constraint on each of the N inputs (hard constraint) and an average power constraint over the entire set of inputs (soft constraint). The har... View full abstract»

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  • Optimization of signal sets for partial-response channels. II. Asymptotic coding gain

    Publication Year: 1991, Page(s):1342 - 1354
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1272 KB)

    For Pt. I see ibid., vol.37, no.5, p.1327-141 (1991). For a linear, time-invariant, discrete-time channel with a given transfer function H(f), and information rate R bits/T, where T is the symbol interval, an optimal signal set of length K is defined to be a set of 2/sup RK/ inputs of length K that maximizes the minimum l/sub 2/ distance between pairs of outputs. The author studies the minimum dis... View full abstract»

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  • A vector quantizer for the Laplace source

    Publication Year: 1991, Page(s):1355 - 1365
    Cited by:  Papers (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (943 KB)

    The low complexity, nearly optimal vector quantizer (VQ) is a generalization of T. R. Fischer's (1986) pyramid VQ and is similar in structure to the unrestricted polar quantizers previously presented for the independent Gaussian source. An analysis of performance is presented with results for both the product code pyramid VQ and the unrestricted version. This analysis, although asymptotic in natur... View full abstract»

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  • Minimal distance lexicographic codes over an infinite alphabet

    Publication Year: 1991, Page(s):1366 - 1368
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (282 KB)

    The author investigates the properties of minimal distance lexicographic codes, or lexicode, over the ordered infinite alphabet N=(0,1,2...). The author presents a method for computing the basis of such a code. It is shown that any lexicographic code S with minimal distance d has a unique basis where each basis vector is a one followed by a string of zeros, followed by d-1 nonzero digits a/sub ij/... View full abstract»

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  • Innovations informational equivalence for a class of observations with independent non-Gaussian noise

    Publication Year: 1991, Page(s):1369 - 1378
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (738 KB)

    The problem of innovations informational equivalence for observations with non-Gaussian additive noise is addressed. It is assumed that the additive noise is a non-Gaussian continuous martingale with an almost surely absolutely continuous quadratic covariation process. Under the assumptions of stochastic independence between the signal and the noise and of square integrability conditions on them, ... View full abstract»

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  • Controlled stochastic model of a communication system with multiple sources

    Publication Year: 1991, Page(s):1379 - 1387
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (701 KB)

    A stochastic model of buffering in a data communication system is considered, with source and sink transmission parameters depending on the number of active sources. For models in this control setting the authors analyze an effective numerical method for evaluating the equilibrium distribution of buffer content. The theoretical basis of the method is established first. Then, it is shown that the m... View full abstract»

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  • Elliptic and almost hyperbolic symmetries for the Woodward ambiguity function (radar)

    Publication Year: 1991, Page(s):1388 - 1398
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (859 KB)

    The authors deal with the radar ambiguity functions and their symmetries. It is well known that Hermite functions give rise to elliptic symmetries. Hermite functions are eigenvectors of the harmonic-oscillator Schrodinger operator. It is shown that the situation is essentially the same for hyperbolic symmetries: the signals are eigenvectors of the Schrodinger operator associated to the hyperbolic ... View full abstract»

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  • Error and erasure control (d,k) block codes

    Publication Year: 1991, Page(s):1399 - 1408
    Cited by:  Papers (11)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1076 KB)

    New combinatorial and algebraic techniques are presented for systematically different (d,k) block codes capable of detecting and correcting single bit-errors, single-peak shift-errors, double adjacent-errors and multiple adjacent erasures. Constructions utilizing channel side information, such as the magnetic recording ternary channel output string, or erasures, do not impose any restriction on Th... View full abstract»

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  • On the monotonic property of the probability of undetected error for a shortened code

    Publication Year: 1991, Page(s):1409 - 1411
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    The monotonic property of the probability of undetected error is considered when a shortened code of a linear code over GF(q) is used for error detection on a q-ary symmetric channel. Some conditions are presented under which the probability of undetected error is (or is not) monotonic with respect to the code length or the symbol error probability. It is shown that the probability of undetected e... View full abstract»

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  • Generalized Hamming weights for linear codes

    Publication Year: 1991, Page(s):1412 - 1418
    Cited by:  Papers (317)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (742 KB)

    Motivated by cryptographical applications, the algebraic structure, of linear codes from a new perspective is studied. By viewing the minimum Hamming weight as a certain minimum property of one-dimensional subcodes, a generalized notion of higher-dimensional Hamming weights is obtained. These weights characterize the code performance on the wire-tap channel of type II. Basic properties of generali... View full abstract»

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  • Nonlinear unequal error-protection codes are sometimes better than linear ones

    Publication Year: 1991, Page(s):1418 - 1420
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (258 KB)

    The parameters of some binary nonlinear two-level unequal error-protection (UEP) codes are evaluated and compared with nonexistence bounds for linear UEP codes. The major points is that for UEP codes linearity is an essential restriction. The results demonstrate that at least in certain cases nonlinear codes perform better than linear ones. This is in contrast to the situation for ordinary codes, ... View full abstract»

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  • A new asymptotically optimal code for the positive integers

    Publication Year: 1991, Page(s):1420 - 1429
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (862 KB)

    A new universal binary code for the positive integers is proposed as a modified version of M. Wang's (see ibid., vol.34, p.324-6, Mar. 1988) flag encoding scheme. The codeword length of the new scheme is shorter than Wang's, on an average, for large initial segments of the positive integers. The performance of the new scheme is also compared with that of other universal schemes. Furthermore, it is... View full abstract»

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  • Construction of some binary linear codes of minimum distance five

    Publication Year: 1991, Page(s):1429 - 1432
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (415 KB)

    A method of constructing binary linear codes that have a minimum Hamming distance of five is presented. The author proposes a general formulation of the parity check matrix for the desired code and then derives necessary conditions for the code to have a minimum distance of five. Some new codes that satisfy the necessary conditions are described. Some efficient new codes are obtained. In particula... View full abstract»

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  • A (55,16,19) binary Goppa code and related codes having large minimum distance

    Publication Year: 1991, Page(s):1432 - 1433
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (245 KB)

    A (55,16,19) binary Goppa code is used to construct (57,17,17), (58,17,18), (59,17,19), and (60,17,20) codes. The first two codes have smaller redundancy than previously known codes (linear or nonlinear) of the same length and minimum distance. The last two codes have parameters previously attained only by nonlinear codes.<<ETX>> View full abstract»

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  • Performance of entropy-constrained block transform quantizers

    Publication Year: 1991, Page(s):1433 - 1439
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (705 KB)

    An analysis of the rate-distortion performance of an entropy-constrained block transform quantization scheme operating on first-order stationary Gauss-Markov sources is presented. Uniform threshold quantization is employed to quantize the transform coefficients. An algorithm for optimum stepsize (or, equivalently, entropy) assignment among the quantizers is developed and a simple asymptotic formul... View full abstract»

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  • A new implementation of the Ziv-Lempel incremental parsing algorithm

    Publication Year: 1991, Page(s):1439 - 1440
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (221 KB)

    Combining a note by J. Rissanen (1983) and an idea of enumerative coding, the authors obtain a new implementation of the Ziv-Lempel incremental parsing algorithm for coding and decoding discrete data sequences. The space and the time complexities are linear for both the encoder and the decoder. The authors describe the algorithm.<<ETX>> View full abstract»

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  • Memoryless nonlinear system identification with unknown model order

    Publication Year: 1991, Page(s):1440 - 1450
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (789 KB)

    The problem of identifying a general memoryless input/output system from measurements of inputs and the corresponding outputs is considered. The measured output is sought to be represented as the linear combination of known functions of the input with some additive noise. The choice of model order to be used to fit the data is the main issue addressed, and a cost function involving the prediction ... View full abstract»

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  • Convergence of the sign algorithm for adaptive filtering with correlated data

    Publication Year: 1991, Page(s):1450 - 1457
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (640 KB)

    Convergence of a decreasing gain sign algorithm (SA) for adaptive filtering is analyzed. The presence of the hard limiter in the algorithm makes a rigorous analysis difficult. Therefore, there are few results available. Such results normally include restrictive assumptions such as the assumptions that successive observation vectors are independent and the new error signal of the adaptive filter ha... 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
Alexander Barg

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

email: abarg-ittrans@ece.umd.edu