IEEE Transactions on Information Theory

Volume 48 Issue 7 • 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
  • 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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  • 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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  • Quasi-cyclic codes over Z4 and some new binary codes

    Publication Year: 2002, Page(s):2065 - 2069
    Cited by:  Papers (23)
    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, 22... View full abstract»

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  • Optimal bi-level quantization of i.i.d. sensor observations for binary hypothesis testing

    Publication Year: 2002, Page(s):2105 - 2111
    Cited by:  Papers (46)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (337 KB) | HTML iconHTML

    We consider the problem of binary hypothesis testing using binary decisions from independent and identically distributed (i.i.d). sensors. Identical likelihood-ratio quantizers with threshold λ are used at the sensors to obtain sensor decisions. Under this condition, the optimal fusion rule is known to be a k-out-of-n rule with threshold k. For the Bayesian detection problem, we show that g... 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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  • 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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  • Asymptotics of greedy algorithms for variable-to-fixed length coding of Markov sources

    Publication Year: 2002, Page(s):2022 - 2035
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (605 KB) | HTML iconHTML

    In this paper, alphabet extension for Markov sources is studied such that each extension tree is grown by splitting the node with the maximum value for a weight as a generalization of the leaf probability in Tunstall's (1967) algorithm. We show that the optimal asymptotic rate of convergence of the per-symbol code length to the entropy does not depend on an a priori selected proportional allocatio... View full abstract»

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  • Maximum-likelihood binary shift-register synthesis from noisy observations

    Publication Year: 2002, Page(s):2096 - 2104
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (425 KB) | HTML iconHTML

    We consider the problem of estimating the feedback coefficients of a linear feedback shift register based on noisy observations. The problem of determining feedback coefficients in the absence of noise is now classical (Massey's (1969) algorithm). In the current approach to the problem of estimation with noisy observations, the coefficients are endowed with a probabilistic model. Gradient ascent u... View full abstract»

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  • Asymptotic efficiency of two-stage disjunctive testing

    Publication Year: 2002, Page(s):1741 - 1749
    Cited by:  Papers (20)
    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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  • Performance of space-time codes for a large number of antennas

    Publication Year: 2002, Page(s):1794 - 1803
    Cited by:  Papers (107)
    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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  • Repeated use of codes for error detection five times is bad

    Publication Year: 2002, Page(s):2053 - 2060
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (423 KB) | HTML iconHTML

    The undetected error probabilities of codes when used repeatedly to transmit sequences of messages are studied. It is shown that for any code whose rate is greater than zero but less than one, the coding scheme obtained by the repeated use of the code is bad, if used five times or more, and improper if used four times or more. Furthermore, the repeated use of any linear code, over an alphabet grea... View full abstract»

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  • An axiomatization of partition entropy

    Publication Year: 2002, Page(s):2138 - 2142
    Cited by:  Papers (20)
    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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  • On the rate-distortion region for multiple descriptions

    Publication Year: 2002, Page(s):2012 - 2021
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB) | HTML iconHTML

    We study the problem of source coding with multiple descriptions, which is described as follows. Let X be a discrete memoryless source. There are two encoders, Encoders 1 and 2, and three decoders, Decoders 0, 1, and 2. Encoders 1 and 2 describe the source X at respective rates R1 and R2. Decoder 1 receives the output of Encoder 1 only, and it can recover X with distortion D<... 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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  • Optimal binary one-ended codes

    Publication Year: 2002, Page(s):2125 - 2132
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (358 KB) | HTML iconHTML

    Binary prefix-free codes in which all codewords end with a "1" have been introduced by Berger and Yeung (1990). A recursive method is given here for the construction of all optimal "1"-ended codes with n codewords. It is shown that the set of codes obtained by the construction contains only optimal codes. We also compute recursively the number of essentially different optimal "1"-ended codes with ... View full abstract»

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  • Improving the sample complexity using global data

    Publication Year: 2002, Page(s):1977 - 1991
    Cited by:  Papers (21)
    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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  • 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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  • Iterative multiuser joint decoding: unified framework and asymptotic analysis

    Publication Year: 2002, Page(s):1772 - 1793
    Cited by:  Papers (215)  |  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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  • A note on robust hypothesis testing

    Publication Year: 2002, Page(s):2111 - 2114
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (291 KB) | HTML iconHTML

    We introduce a simple new hypothesis testing procedure, which, based on an independent sample drawn from a certain density, detects which of k nominal densities is the true density closest to, under the total variation (L1) distance. We obtain a density-free uniform exponential bound for the probability of false detection 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 (26)
    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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  • High-rate codes that are linear in space and time

    Publication Year: 2002, Page(s):1804 - 1824
    Cited by:  Papers (870)  |  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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  • A simple upper bound on the redundancy of Huffman codes

    Publication Year: 2002, Page(s):2132 - 2138
    Cited by:  Papers (14)
    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 a relation between information inequalities and group theory

    Publication Year: 2002, Page(s):1992 - 1995
    Cited by:  Papers (49)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (238 KB) | HTML iconHTML

    We establish a one-to-one correspondence between information inequalities and group inequalities. The major implication of our result is that we can prove information inequalities by proving the corresponding group inequalities, and vice versa. By giving a group-theoretic proof for all Shannon-type inequalities, we suggest that new inequalities could be discovered by making use of the rich set of ... 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 (58)
    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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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
Prakash Narayan 

Department of Electrical and Computer Engineering