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IEEE Transactions on Information Theory

Issue 4 • July 1996

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Displaying Results 1 - 25 of 37
  • Fundamentals of Artificial Neural Networks [Book Reviews]

    Publication Year: 1996
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | PDF file iconPDF (424 KB)
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  • Convexity properties in binary detection problems

    Publication Year: 1996, Page(s):1316 - 1321
    Cited by:  Papers (46)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (556 KB)

    The author investigates the convexity properties of error probability in the detection of binary-valued scalar signals corrupted by additive noise. It is shown that the error probability of the maximum-likelihood receiver is a convex function of the signal power when the noise has a unimodal distribution. Based on this property, the results of the optimal time-sharing strategies of transmitters an... View full abstract»

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  • On determining the radar threshold for non-Gaussian processes from experimental data

    Publication Year: 1996, Page(s):1310 - 1316
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (612 KB)

    The problem of detecting radar signals embedded in clutter is an area of great interest. In many radar applications, it is important to set thresholds to achieve a false alarm probability (PF) of 10-5 or lower. Using conventional Monte Carlo techniques, where thresholds are set based on raw percentiles, an extremely large number of samples is required. We use the generalized ... View full abstract»

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  • On the convergence of linear stochastic approximation procedures

    Publication Year: 1996, Page(s):1305 - 1309
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    Many stochastic approximation procedures result in a stochastic algorithm of the form hk+1=hk+1/k(bk-A khk), for all k=1,2,3,... . Here, {bk,k=1,2,3...} is a Rd-valued process, {Ak,k=1,2,3,...} is a symmetric, positive semidefinite R ed×d-valued process, and {hk,k=1... View full abstract»

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  • Some new three-valued crosscorrelation functions for binary m-sequences

    Publication Year: 1996, Page(s):1238 - 1240
    Cited by:  Papers (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (204 KB)

    In 1972 Niho gave various conjectures about the crosscorrelation between a binary maximum-length linear shift register sequence and a decimation of that sequence by an integer d. We prove that the crosscorrelation function for two new values of d takes on precisely three values and thereby confirm two of Niho's conjectures View full abstract»

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  • Analysis of convolutional encoders and synthesis of rate-2/n Viterbi decoders

    Publication Year: 1996, Page(s):1280 - 1285
    Cited by:  Papers (2)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (704 KB)

    In this correspondence, the problem of obtaining efficient hardware for Viterbi decoders for high-rate convolutional encoders is addressed. It is first shown that the graphs describing the interconnection of the add-compare-select units required may be classified in terms of structures of which there are only a small number for a given code constraint length. They correspond to the assignment of i... View full abstract»

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  • Vanishing distortion and shrinking cells

    Publication Year: 1996, Page(s):1303 - 1305
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    We establish an asymptotic connection between vanishing rth-power distortion and shrinking cell diameters for vector quantizers with convex cells. As a consequence, a number of shrinking cell conditions may be easily verified by showing that the quantizers in question have distortion tending to zero. This also plays an important role in the asymptotic analysis of a common greedy growing scheme for... View full abstract»

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  • 7200-phase generalized Barker sequences

    Publication Year: 1996, Page(s):1236 - 1238
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    We present 7200-phase generalized Barker sequences with lengths from 19 to 31. Also, we show the number of known M-phase generalized Barker sequences (M=7200), inequivalent under the group of “Barker-preserving transformations”. The autocorrelation values of Barker sequences are also presented View full abstract»

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  • Group block codes over nonabelian groups are asymptotically bad

    Publication Year: 1996, Page(s):1277 - 1280
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    It is known that group block codes over nonabelian groups of order less than 32 are asymptotically bad. In this correspondence we extend that result, showing that group block codes over nonabelian groups are asymptotically bad, no matter what the order of the group under consideration is View full abstract»

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  • A hierarchical dynamic programming approach to fixed-rate, entropy-coded quantization

    Publication Year: 1996, Page(s):1298 - 1303
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    In quantization of any source with a nonuniform probability density function, the entropy coding of the quantizer output can result in a substantial decrease in bit rate. A straightforward entropy coding scheme faces us with the problem of variable data rate. A solution in a space of dimensionality N is to select an appropriate subset of elements in the N-fold Cartesian product of a scalar quantiz... View full abstract»

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  • Optimal quaternary linear codes of dimension five

    Publication Year: 1996, Page(s):1228 - 1235
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (516 KB)

    Let dq(n,k) be the maximum possible minimum Hamming distance of a q-ary [n,k,d]-code for given values of n and k. It is proved that d4 (33,5)=22, d4(49,5)=34, d4 (131,5)=96, d4(142,5)=104, d4(147,5)=108, d 4(152,5)=112, d4(158,5)=116, d4(176,5)⩾129, d4(180,5)⩾132, d4(190... View full abstract»

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  • Multidimensional M-PSK trellis codes for fading channels

    Publication Year: 1996, Page(s):1093 - 1108
    Cited by:  Papers (15)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (908 KB)

    This paper investigates the code search problem for trellis-coded multidimensional phase modulation for Rayleigh fading channels. New set partitionings for multiple phase-shift keying (M-PSK) are proposed using the effective code length (ECL) and the minimum product distance (PD) as the code design criteria. By using these set-partitionings rules, new multidimensional codes which are optimum for R... View full abstract»

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  • Improved estimates via exponential sums for the minimum distance of Z4-linear trace codes

    Publication Year: 1996, Page(s):1212 - 1216
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 KB)

    An upper hound for Weil-type exponential sums over Galois rings was derived by Kumar, Helleseth, and Calderbank (see ibid., vol.41, no.3, p.456, 1995). This bound leads directly to an estimate for the minimum distance of Z4-linear trace codes. An improved minimum-distance estimate is presented. First, McEliece's result on the divisibility of the weights of binary cyclic codes is extende... View full abstract»

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  • On the traveling salesman problem in binary Hamming spaces

    Publication Year: 1996, Page(s):1274 - 1276
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (228 KB)

    Given a subset X of vertices of the n-cube (i.e., the n-dimensional Hamming space), we are interested in the solution of the traveling salesman problem; namely, the minimal length of a cycle passing through all vertices of X. For a given number M, we estimate the maximum of these lengths when X ranges over all possible choices of sets of M vertices. Asymptotically, our estimates show that for a nu... View full abstract»

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  • A directed search approach for unit-memory convolutional codes

    Publication Year: 1996, Page(s):1290 - 1297
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    A set of heuristic algorithms to numerically search for binary unit-memory convolutional codes (UMC) are presented along with a large number of new codes for 2⩽k⩽8 and code rate 1/4⩽R<1. Combinatorial optimization is used which involves selecting and then pairwise-matching column vectors of the two (n,k) UMC tap weight matrices. The column selection problem is that of finding the be... View full abstract»

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  • Mass formulas for self-dual codes over Z4 and Fq+uFq rings

    Publication Year: 1996, Page(s):1222 - 1228
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    We give a mass formula for quaternary self-dual and type II codes and for self-dual codes over Fq+uFq rings. We define type II codes and compute the number of distinct type II codes. We also give formulas for the number of doubly even binary codes, necessary to compute Nd(n), the number of distinct codes of length n, for any dimension n, and conc... View full abstract»

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  • On the BCJR trellis for linear block codes

    Publication Year: 1996, Page(s):1072 - 1092
    Cited by:  Papers (135)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1704 KB)

    In this semi-tutorial paper, we will investigate the computational complexity of an abstract version of the Viterbi algorithm on a trellis, and show that if the trellis has e edges, the complexity of the Viterbi algorithm is Θ(e). This result suggests that the “best” trellis representation for a given linear block code is the one with the fewest edges. We will then show that, amo... View full abstract»

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  • On the accuracy of estimating the parameters of a regular stationary process

    Publication Year: 1996, Page(s):1202 - 1211
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (604 KB)

    Any regular stationary random processes can be represented as the sum of a purely indeterministic process and a deterministic one. This paper considers the achievable accuracy in the joint estimation of the parameters of these two components, from a single observed realization of the process. An exact form of the Cramer-Rao bound (CRB) is derived, as well as a conditional CRB. The relationships be... View full abstract»

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  • Coding for intersymbol interference channels-combined coding and precoding

    Publication Year: 1996, Page(s):1053 - 1061
    Cited by:  Papers (19)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (820 KB)

    This paper describes a new coding scheme for transmission over intersymbol interference (ISI) channels. This scheme, called ISI coding, combines trellis coding with precoding (used to combat ISI). Like the recently introduced precoding scheme of Laroia, Tretter, and Farvardin (LTF), the ISI coder makes it possible to achieve both shaping and coding gains over ISI channels. By combining coding and ... View full abstract»

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  • On the undetected error probability of binary expansions of Reed-Solomon codes

    Publication Year: 1996, Page(s):1271 - 1274
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (260 KB)

    It has been shown by Kasami and Lin (see IEEE Trans. Commun., vol.32, p.998, 1984) that (n,k) Reed-Solomon codes used over a q-ary symmetric channel are proper. In this correspondence, it is shown that the binary expansions of these codes and their extensions, when used on the binary-symmetric channel, are not necessarily proper. In particular, certain codes of rate less than [1-log2m+{... View full abstract»

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  • Bounds on the minimum distance of the duals of BCH codes

    Publication Year: 1996, Page(s):1257 - 1260
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    We consider primitive cyclic codes of length pm-1 over Fp. The codes of interest here are duals of BCH codes. For these codes, a lower bound on their minimum distance can be found via the adaptation of the Weil bound to cyclic codes. However, this bound is of no significance for roughly half of these codes. We shall fill this gap by giving, in the first part of the correspond... View full abstract»

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  • Minimum mean-squared error transform coding and subband coding

    Publication Year: 1996, Page(s):1179 - 1192
    Cited by:  Papers (20)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1236 KB)

    Knowledge of the power spectrum of a stationary random sequence can be used for quantizing the signal efficiently and with minimum mean-squared error. A multichannel filter is used to transform the random sequence into an intermediate set of variables that are quantized using independent scalar quantizers, and then inverse-filtered, producing a quantized version of the original sequence. Equal wor... View full abstract»

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  • Large families of sequences with near-optimal correlations and large linear span

    Publication Year: 1996, Page(s):1241 - 1248
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (648 KB)

    In order to build spread-spectrum communication systems based on the CDMA paradigm, it is necessary to have large families of binary sequences with low pairwise correlation values. For these systems to have resistance to certain cryptanalytic attacks and resistance to jamming, the sequences must have large linear span. We describe certain families of sequences that have these desirable properties.... View full abstract»

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  • Application of set-membership techniques to symbol-by-symbol decoding for binary data-transmission systems

    Publication Year: 1996, Page(s):1285 - 1290
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    The application of set theory methods to problems in estimation, system identification, and classification is emerging as a viable approach to a number of different problems. This correspondence studies the use of set-membership methods in symbol-by-symbol decoding of binary data in data-transmission systems. Theorems for necessary and sufficient conditions for error-free decoding are presented. F... View full abstract»

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  • A vector quantization approach to universal noiseless coding and quantization

    Publication Year: 1996, Page(s):1109 - 1138
    Cited by:  Papers (50)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2420 KB)

    A two-stage code is a block code in which each block of data is coded in two stages: the first stage codes the identity of a block code among a collection of codes, and the second stage codes the data using the identified code. The collection of codes may be noiseless codes, fixed-rate quantizers, or variable-rate quantizers. We take a vector quantization approach to two-stage coding, in which the... View full abstract»

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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