IEEE Transactions on Information Theory

Volume 42 Issue 4 • July 1996

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Displaying Results 1 - 25 of 37
  • 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 (970 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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  • Capacity penalty due to ideal zero-forcing decision-feedback equalization

    Publication Year: 1996, Page(s):1062 - 1071
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1110 KB)

    We consider the capacity C of a continuous-time channel with frequency response H(f) and additive white Gaussian noise. If H(f)|/sup -2/ behaves like a polynomial of order /spl rho/ at high frequencies, we show that the per-symbol capacity approaches /spl rho//2 nats per channel use at high signal powers. If the receiver uses an ideal zero forcing decision-feedback equalizer (DFE) consisting of a ... 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 (137)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2036 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 /spl Theta/(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, among all t... 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 (1099 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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  • A vector quantization approach to universal noiseless coding and quantization

    Publication Year: 1996, Page(s):1109 - 1138
    Cited by:  Papers (53)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2846 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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  • The Hadamard transform-a tool for index assignment

    Publication Year: 1996, Page(s):1139 - 1151
    Cited by:  Papers (64)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1287 KB)

    We show that the channel distortion for maximum-entropy encoders, due to noise on a binary-symmetric channel, is minimized if the vector quantizer can be expressed as a linear transform of a hypercube. The index assignment problem is regarded as a problem of linearizing the vector quantizer. We define classes of index assignments with related properties, within which the best index assignment is f... View full abstract»

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  • On lattice quantization noise

    Publication Year: 1996, Page(s):1152 - 1159
    Cited by:  Papers (180)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (767 KB)

    We present several results regarding the properties of a random vector, uniformly distributed over a lattice cell. This random vector is the quantization noise of a lattice quantizer at high resolution, or the noise of a dithered lattice quantizer at all distortion levels. We find that for the optimal lattice quantizers this noise is wide-sense-stationary and white. Any desirable noise spectra may... View full abstract»

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  • Analysis of linear prediction, coding, and spectral estimation from subbands

    Publication Year: 1996, Page(s):1160 - 1178
    Cited by:  Papers (44)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1405 KB)

    Linear prediction schemes make a prediction x/spl circ//sub i/ of a data sample x/sub i/ using p previous samples. It has been shown by Woods and O'Neil (1986) as well as Pearlman (1991) that as the order of prediction p/spl rarr//spl infin/, there is no gain to be obtained by coding subband samples. This paper deals with the less well understood theory of finite-order prediction and optimal codin... 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 (1440 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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  • Minimum entropy of error estimation for discrete random variables

    Publication Year: 1996, Page(s):1193 - 1201
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (822 KB)

    The principle of minimum entropy of error estimation (MEEE) is formulated for discrete random variables. In the case when the random variable to be estimated is binary, we show that the MEEE is given by a Neyman-Pearson-type strictly monotonous test. In addition, the asymptotic behavior of the error probabilities is proved to be equivalent to that of the Bayesian test. 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 (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 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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  • Improved estimates via exponential sums for the minimum distance of Z/sub 4/-linear trace codes

    Publication Year: 1996, Page(s):1212 - 1216
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (436 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 Z/sub 4/-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 extended to ... View full abstract»

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  • Optimal binary linear codes and Z/sub 4/-linearity

    Publication Year: 1996, Page(s):1216 - 1222
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (746 KB)

    We give necessary and sufficient conditions for a binary linear code to be Z/sub 4/-linear. Especially we treat optimal, binary linear codes and determine all such codes with minimum weight less or equal to six which are Z/sub 4/-linear. View full abstract»

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  • Mass formulas for self-dual codes over Z/sub 4/ and F/sub q/+uF/sub q/ rings

    Publication Year: 1996, Page(s):1222 - 1228
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    We give a mass formula for quaternary self-dual and type II codes and for self-dual codes over F/sub q/+uF/sub q/ 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 N/sub d/(n), the number of distinct codes of length n, for any dimension n, and conclude that the classification of qu... 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 (629 KB)

    Let d/sub q/(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 d/sub 4/ (33,5)=22, d/sub 4/(49,5)=34, d/sub 4/(131,5)=96, d/sub 4/(142,5)=104, d/sub 4/(147,5)=108, d/sub 4/(152,5)=112, d/sub 4/(158,5)=116, d/sub 4/(176,5)/spl ges/129, d/sub 4/(180,5)/spl ges/132, d/sub 4/(190,5)/spl ges/140, d/sub 4/(195,5)=144, d/sub 4/(20... 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 (267 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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  • Some new three-valued crosscorrelation functions for binary m-sequences

    Publication Year: 1996, Page(s):1238 - 1240
    Cited by:  Papers (35)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (261 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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  • Large families of sequences with near-optimal correlations and large linear span

    Publication Year: 1996, Page(s):1241 - 1248
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1305 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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  • Polyphase Barker sequences up to length 36

    Publication Year: 1996, Page(s):1248 - 1250
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (555 KB)

    Originally, Barker (1953) presented binary sequences for synchronization purposes in telecommunications. A sequence is called a generalized Barker sequence if the magnitude of all autocorrelation sidelobes is less or equal to one. It is shown that uniform complex sequences up to length 36, meeting the Barker (1953) condition, do exist. Examples are given for length 32-36. The sequences were obtain... View full abstract»

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  • A cyclic [6,3,4] group code and the hexacode over GF(4)

    Publication Year: 1996, Page(s):1250 - 1253
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (478 KB)

    A [6,3,4] code E/sub 6/ over an Abelian group A/sub 4/ with four elements is presented. E/sub 6/ is cyclic, unlike the [6,3,4] hexacode H/sub 6/ over GF(4). However, E/sub 6/ and H/sub 6/ are isomorphic when the latter is viewed as a group code. Differences and similarities between E/sub 6/ and H/sub 6/ are discussed. A dual code of E/sub 6/ is presented. Some binary codes, among them the [24,12,8... View full abstract»

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  • Partially hidden Markov models

    Publication Year: 1996, Page(s):1253 - 1256
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (439 KB)

    Partially hidden Markov models (PHMM) are introduced. They differ from the ordinary HMMs in that both the transition probabilities of the hidden states and the output probabilities are conditioned on past observations. As an illustration they are applied to black and white image compression where the hidden variables may be interpreted as representing noncausal pixels. 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 (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (405 KB)

    We consider primitive cyclic codes of length p/sup m/-1 over F/sub p/. 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 correspondence, a lo... View full abstract»

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  • New single-error-correcting codes

    Publication Year: 1996, Page(s):1261 - 1262
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (237 KB)

    A matrix construction of nonlinear error-correcting codes is considered. It is shown how this construction and some related theorems can be applied to old codes to get new codes with minimum distance 3. In total 13 new binary single-error-correcting codes of length at most 511 are obtained. View full abstract»

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  • A generalized Forney formula for algebraic-geometric codes

    Publication Year: 1996, Page(s):1263 - 1268
    Cited by:  Papers (9)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB)

    This correspondence contains a straightforward generalization of decoding of BCH codes to the decoding of algebraic-geometric codes, couched in terms of varieties, ideals, and Grobner bases. This consists of 1) a Berlekamp-Massey-type lattice-shifting row-reduction algorithm with majority voting similar to algorithms in the current literature, 2) a realization that it produces a minimal Grobner ba... View full abstract»

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  • Some remarks on an algorithm of Fitzpatrick

    Publication Year: 1996, Page(s):1269 - 1271
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (347 KB)

    Fitzpatrick's algorithm for solving the classical Reed-Solomon key equation is shown to be related to an algorithm for solving the Welch-Berlekamp key equation. It can be made more efficient when decoding binary BCH codes. Its efficiency is about the same as for the Berlekamp-Massey algorithm. 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