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IEEE Transactions on Information Theory

Issue 7 • Date July 2002

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Displaying Results 1 - 25 of 38
  • Contributors

    Publication Year: 2002, Page(s):2143 - 2150
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    Freely Available from IEEE
  • Variance of the turbo code performance bound over the interleavers

    Publication Year: 2002, Page(s):2078 - 2086
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (558 KB) | HTML iconHTML

    We evaluate the variance of the union performance bound for a rate-1/3 turbo code over all possible interleavers of length N, under the assumption of a maximum-likelihood (ML) decoder. Theoretical and simulation results for turbo codes with two-memory component codes indicate that the coefficient of variation of the bound increases with the signal-to-noise ratio and decreases with the interleaver ... View full abstract»

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  • On delayed prediction of individual sequences

    Publication Year: 2002, Page(s):1959 - 1976
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (658 KB) | HTML iconHTML

    Prediction of individual sequences is investigated for cases in which the decision maker observes a delayed version of the sequence, or is forced to issue his/her predictions a number of steps in advance, with incomplete information. For finite action and observation spaces, it is shown that the prediction strategy that minimizes the worst case regret with respect to the Bayes envelope is obtained... View full abstract»

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  • The q-ary image of some qm-ary cyclic codes: permutation group and soft-decision decoding

    Publication Year: 2002, Page(s):2069 - 2078
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB) | HTML iconHTML

    Using a particular construction of generator matrices of the q-ary image of qm-ary cyclic codes, it is proved that some of these codes are invariant under the action of particular permutation groups. The equivalence of such codes with some two-dimensional (2-D) Abelian codes and cyclic codes is deduced from this property. These permutations are also used in the area of the soft-decision... View full abstract»

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  • On the importance of combining wavelet-based nonlinear approximation with coding strategies

    Publication Year: 2002, Page(s):1895 - 1921
    Cited by:  Papers (68)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (788 KB) | HTML iconHTML

    This paper provides a mathematical analysis of transform compression in its relationship to linear and nonlinear approximation theory. Contrasting linear and nonlinear approximation spaces, we show that there are interesting classes of functions/random processes which are much more compactly represented by wavelet-based nonlinear approximation. These classes include locally smooth signals that hav... View full abstract»

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  • On sequential strategies for loss functions with memory

    Publication Year: 2002, Page(s):1947 - 1958
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (489 KB) | HTML iconHTML

    The problem of optimal sequential decision for individual sequences, relative to a class of competing off-line reference strategies, is studied for general loss functions with memory. This problem is motivated by applications in which actions may have "long-term" effects, or there is a cost for switching from one action to another. As a first step, we consider the case in which the reference strat... View full abstract»

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  • Quasi-cyclic codes over Z4 and some new binary codes

    Publication Year: 2002, Page(s):2065 - 2069
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (325 KB) | HTML iconHTML

    Previously, (linear) codes over Z4 and quasi-cyclic (QC) codes (over fields) have been shown to yield useful results in coding theory. Combining these two ideas we study Z 4-QC codes and obtain new binary codes using the usual Gray map. Among the new codes, the lift of the famous Golay code to Z4 produces a new binary code, a (92, 2... View full abstract»

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  • Analysis of mean-square error and transient speed of the LMS adaptive algorithm

    Publication Year: 2002, Page(s):1873 - 1894
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (959 KB) | HTML iconHTML

    For the least mean square (LMS) algorithm, we analyze the correlation matrix of the filter coefficient estimation error and the signal estimation error in the transient phase as well as in steady state. We establish the convergence of the second-order statistics as the number of iterations increases, and we derive the exact asymptotic expressions for the mean square errors. In particular, the resu... View full abstract»

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  • An axiomatization of partition entropy

    Publication Year: 2002, Page(s):2138 - 2142
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB) | HTML iconHTML

    The aim of this article is to present an axiomatization of a generalization of Shannon's entropy starting from partitions of finite sets. The proposed axiomatization defines a family of entropies depending on a real positive parameter that contains as a special case the Havrda-Charvat (1967) entropy, and thus, provides axiomatizations for the Shannon entropy, the Gini index, and for other types of... View full abstract»

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  • Mutual information approach to blind separation of stationary sources

    Publication Year: 2002, Page(s):1935 - 1946
    Cited by:  Papers (58)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (508 KB) | HTML iconHTML

    This paper presents a unified approach to the problem of blind separation of sources, based on the concept of mutual information. This concept is applied to the whole source sequences as stationary processes and thus provides a universal contrast applicable to both the instantaneous and convolutive mixture cases. For practical implementation, we introduce several degraded forms of this contrast, c... View full abstract»

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  • Convergence of the maximum a posteriori path estimator in hidden Markov models

    Publication Year: 2002, Page(s):1750 - 1758
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (381 KB) | HTML iconHTML

    In a hidden Markov model (HMM) the underlying finite-state Markov chain cannot be observed directly but only by an additional process. We are interested in estimating the unknown path of the Markov chain. The most widely used estimator is the maximum a posteriori path estimator (MAP path estimator). It can be calculated effectively by the Viterbi (1967) algorithm as is, e.g., frequently done in th... View full abstract»

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  • Iterative multiuser joint decoding: unified framework and asymptotic analysis

    Publication Year: 2002, Page(s):1772 - 1793
    Cited by:  Papers (207)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (798 KB) | HTML iconHTML

    We present a framework for iterative multiuser joint decoding of code-division multiple-access (CDMA) signals, based on the factor-graph representation and on the sum-product algorithm. In this framework, known parallel and serial, hard and soft interference cancellation algorithms are derived in a unified way. The asymptotic performance of these algorithms in the limit of large code block length ... View full abstract»

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  • High-rate codes that are linear in space and time

    Publication Year: 2002, Page(s):1804 - 1824
    Cited by:  Papers (855)  |  Patents (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (675 KB) | HTML iconHTML

    Multiple-antenna systems that operate at high rates require simple yet effective space-time transmission schemes to handle the large traffic volume in real time. At rates of tens of bits per second per hertz, Vertical Bell Labs Layered Space-Time (V-BLAST), where every antenna transmits its own independent substream of data, has been shown to have good performance and simple encoding and decoding.... View full abstract»

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  • New extremal self-dual codes of length 62 and related extremal self-dual codes

    Publication Year: 2002, Page(s):2060 - 2064
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (374 KB) | HTML iconHTML

    New extremal self-dual codes of length 62 are constructed with weight enumerators of three different types. Two of these types were not represented by any known code up till now. All these codes possess an automorphism of order 15. Some of them are used to construct extremal self-dual codes of length 60 by the method of subtracting. By additional subtracting, an extremal self-dual [58, 29, 10] cod... View full abstract»

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  • A class of traceability codes

    Publication Year: 2002, Page(s):2094 - 2096
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (230 KB) | HTML iconHTML

    Traceability codes are identifiable parent property (IPP) codes with the additional requirement that the Hamming distance can be used to trace a parent of a word. Traceability codes can be used for constructing digital fingerprints in order to deter users from illegally copying digital data. We construct a class of traceability codes and determine the exact parameters of some of the codes in this ... View full abstract»

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  • Performance of blind and group-blind multiuser detectors

    Publication Year: 2002, Page(s):1849 - 1872
    Cited by:  Papers (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1180 KB) | HTML iconHTML

    In blind (or group-blind) linear multiuser detection, the detector is estimated from the received signals, with the prior knowledge of only the signature waveform of the desired user (or the signature waveforms of some but not all users). The performance of a number of such estimated linear detectors, including the direct-matrix-inversion (DMI) blind linear minimum mean square error (MMSE) detecto... View full abstract»

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  • Optimal filter banks for multiple description coding: analysis and synthesis

    Publication Year: 2002, Page(s):2036 - 2052
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (485 KB) | HTML iconHTML

    Multiple description (MD) coding is a source coding technique for information transmission over unreliable networks. In MD coding, the coder generates several different descriptions of the same signal and the decoder can produce a useful reconstruction of the source with any received subset of these descriptions. In this paper, we study the problem of MD coding of stationary Gaussian sources with ... View full abstract»

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  • A simple upper bound on the redundancy of Huffman codes

    Publication Year: 2002, Page(s):2132 - 2138
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (363 KB) | HTML iconHTML

    Upper bounds on the redundancy of Huffman codes have been extensively studied in the literature. Almost all of these bounds are in terms of the probability of either the most likely or the least likely source symbol. We prove a simple upper bound in terms of the probability of any source symbol View full abstract»

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  • On the asymptotic eigenvalue distribution of concatenated vector-valued fading channels

    Publication Year: 2002, Page(s):2086 - 2091
    Cited by:  Papers (51)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (327 KB) | HTML iconHTML

    The linear vector-valued channel x |→ Πn Mnx + z with z and Mn denoting additive white Gaussian noise and independent random matrices, respectively, is analyzed in the asymptotic regime as the dimensions of the matrices and vectors involved become large. The asymptotic eigenvalue distribution of the channel's covariance matrix is given in terms of an implic... View full abstract»

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  • Improving the sample complexity using global data

    Publication Year: 2002, Page(s):1977 - 1991
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB) | HTML iconHTML

    We study the sample complexity of proper and improper learning problems with respect to different q-loss functions. We improve the known estimates for classes which have relatively small covering numbers in empirical L2 spaces (e.g. log-covering numbers which are polynomial with exponent p<2). We present several examples of relevant classes which have a "small" fat-shattering dimensi... View full abstract»

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  • Asymptotic analysis of blind cyclic correlation-based symbol-rate estimators

    Publication Year: 2002, Page(s):1922 - 1934
    Cited by:  Papers (64)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB) | HTML iconHTML

    This paper considers the problem of blind symbol rate estimation of signals linearly modulated by a sequence of unknown symbols. Oversampling the received signal generates cyclostationary statistics that are exploited to devise symbol-rate estimators by maximizing in the cyclic domain a (possibly weighted) sum of modulus squares of cyclic correlation estimates. Although quite natural, the asymptot... View full abstract»

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  • Asymptotic efficiency of two-stage disjunctive testing

    Publication Year: 2002, Page(s):1741 - 1749
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB) | HTML iconHTML

    We adapt methods originally developed in information and coding theory to solve some testing problems. The efficiency of two-stage pool testing of n items is characterized by the minimum expected number E(n, p) of tests for the Bernoulli p-scheme, where the minimum is taken over a matrix that specifies the tests that constitute the first stage. An information-theoretic bound implies that the natur... View full abstract»

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  • High-performance iterative Viterbi algorithm for conventional serial concatenated codes

    Publication Year: 2002, Page(s):1759 - 1771
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (463 KB) | HTML iconHTML

    The Viterbi algorithm (1967) and conventional serial concatenated codes (CSCC) have been widely applied in digital communication systems over the last 30 years. We show that the Shannon capacity of additive white Gaussian noise (AWGN) channels can be approached by CSCCs and the iterative VA (IVA). We firstly study the algebraic properties of CSCCs. We then present the IVA to decode these codes. We... View full abstract»

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  • Performance of space-time codes for a large number of antennas

    Publication Year: 2002, Page(s):1794 - 1803
    Cited by:  Papers (102)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (445 KB) | HTML iconHTML

    We study the asymptotic behavior of space-time codes when the number of transmit and receive antennas grows to infinity. Specifically, we determine the behavior of pairwise error probabilities with maximum-likelihood (ML) decoding and with three types of receiver interfaces: the ML interface, the linear zero-forcing (ZF) interface, and the linear minimum-mean-square-error (MMSE) interface. Two sit... View full abstract»

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  • Further constructions of resilient Boolean functions with very high nonlinearity

    Publication Year: 2002, Page(s):1825 - 1834
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (411 KB) | HTML iconHTML

    One well-known method of generating key stream sequences for stream ciphers is to combine the outputs of several linear-feedback shift registers (LFSR) using a combining Boolean function. Here we concentrate on the design of good combining Boolean functions. We provide resilient Boolean functions with currently best known nonlinearity. These functions were not known earlier and the issues related ... 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
Frank R. Kschischang

Department of Electrical and Computer Engineering