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IEEE Transactions on Information Theory

Issue 4 • July 2000

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Displaying Results 1 - 25 of 58
  • Contributors

    Publication Year: 2000, Page(s):1697 - 1708
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    Freely Available from IEEE
  • A spread-spectrum communication system protecting information data from interception

    Publication Year: 2000, Page(s):1691 - 1695
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    This correspondence tries to construct a direct-sequence spread-spectrum multiple-access communication system, so that the difficulty of wiretapping from insiders' and outsiders' attacks increases and the worst case error probability decreases, as much as possible. Bent sequences with optimal periodic correlation properties are assigned to users, as spreading sequences corresponding to secret keys View full abstract»

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  • Multiple-access interference reduction for QS-CDMA systems with a novel class of polyphase sequences

    Publication Year: 2000, Page(s):1448 - 1458
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    In this paper, a new class of polyphase sequences for CDMA systems and its generation method are suggested, and the correlation properties of the sequence are investigated. The performance of the sequence in quasi-synchronous CDMA (QS-CDMA) systems is investigated under a frequency-selective, time-nonselective, slow Nakagami fading channel with additive white Gaussian noise (AWGN). It is shown tha... View full abstract»

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  • Minimal L1-norm reconstruction function for oversampled signals: applications to time-delay estimation

    Publication Year: 2000, Page(s):1666 - 1673
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    We consider the problem of the reconstruction of an oversampled band-limited signal and obtain an explicit expression for the reconstruction function with minimal L1-norm. It has good sparseness and localization properties that recommends its use in time-delay estimation but the result may be of interest in other domains. Compared to the standard sine cardinal reconstruction function, i... View full abstract»

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  • Universal lossless compression via multilevel pattern matching

    Publication Year: 2000, Page(s):1227 - 1245
    Cited by:  Papers (36)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    A universal lossless data compression code called the multilevel pattern matching code (MPM code) is introduced. In processing a finite-alphabet data string of length n, the MPM code operates at O(log log n) levels sequentially. At each level, the MPM code detects matching patterns in the input data string (substrings of the data appearing in two or more nonoverlapping positions). The matching pat... View full abstract»

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  • Error exponents for maximum-likelihood and successive decoders for the Gaussian CDMA channel

    Publication Year: 2000, Page(s):1683 - 1691
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    Random-coding error exponents are derived for the Gaussian code-division multiple-access (CDMA) channel for the maximum-likelihood and optimum successive decoders. Error exponents not only specify the capacity region of the channel, which is known, but also give lower bounds on the rate of exponential decay of the average probability of error as a function of the block length of random codes. A co... View full abstract»

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  • A dynamic programming algorithm for constructing optimal “1”-ended binary prefix-free codes

    Publication Year: 2000, Page(s):1637 - 1644
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    The generic Huffman-encoding problem of finding a minimum cost prefix free code is almost completely understood. There still exist many variants of this problem which are not as well understood, though. One such variant, requiring that each of the codewords ends with “1”, has previously been introduced in the literature with the best algorithms known for finding such codes running in e... View full abstract»

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  • Effective interference and effective bandwidth of linear multiuser receivers in asynchronous CDMA systems

    Publication Year: 2000, Page(s):1426 - 1447
    Cited by:  Papers (77)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (480 KB)

    The performance of linear multiuser receivers in terms of the signal-to-interference ratio (SIR) achieved by the users has been analyzed in a synchronous CDMA system under random spreading sequences. In this paper, we extend these results to a symbol-asynchronous but chip-synchronous system and characterize the SIR for linear receivers-the matched-filter receiver the minimum mean-square error (MMS... View full abstract»

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  • Asymptotic performance analysis of Bayesian target recognition

    Publication Year: 2000, Page(s):1658 - 1665
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (440 KB)

    This article investigates the asymptotic performance of Bayesian target recognition algorithms using deformable-template representations. Rigid computer-aided design (CAD) models represent the underlying targets; low-dimensional matrix Lie-groups (rotation and translation) extend them to particular instances. Remote sensors observing the targets are modeled as projective transformations, convertin... View full abstract»

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  • Nested input-constrained codes

    Publication Year: 2000, Page(s):1302 - 1316
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB)

    An input-constrained channel, or simply a constraint, is a set S of words that is generated by a finite labeled directed graph. An encoder for S maps, in a lossless manner, sequences of unconstrained input blocks into sequences of channel blocks, the latter sequences being words of S. In most applications, the encoders are finite-state machines and, thus, presented by state diagrams. In the specia... View full abstract»

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  • A class of Sudan-decodable codes

    Publication Year: 2000, Page(s):1564 - 1572
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    In this article, Sudan's algorithm is modified into an efficient method to list-decode a class of codes which can be seen as a generalization of Reed-Solomon codes. The algorithm is specialized into a very efficient method for unique decoding. The code construction can be generalized based on algebraic-geometry codes and the decoding algorithms are generalized accordingly. Comparisons with Reed-So... View full abstract»

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  • Weak variable-length source coding

    Publication Year: 2000, Page(s):1217 - 1226
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    Given a general source X={Xn}n=1∞ , source coding is characterized by a pair (φn, ψn) of encoder φn, and decoder ψn , together with the probability of error εn≡Pr{ψn(φn(Xn ))≠Xn}. If the length of the encoder output φ View full abstract»

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  • On the minimum distances of Schubert codes

    Publication Year: 2000, Page(s):1535 - 1538
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    Ghorpade and Lachaud (1998) introduced Schubert codes as codes corresponding to the protective system (Tsfasman and Vladut 1991) defined by Schubert subvarieties of Grassmann varieties Gr(l,m). They gave an upper bound for the minimum distances of these codes in Ghorpade and Lachaud and conjectured their true minimum distances. In this note we prove the conjecture in the case of l=2 View full abstract»

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  • A solution to linear estimation problems using approximate Karhunen-Loeve expansions

    Publication Year: 2000, Page(s):1677 - 1682
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB)

    An explicit and efficiently calculable solution is presented to the problem of linear least-mean-squared-error estimation of a signal process based upon noisy observations that is valid for finite intervals. This approach is based on approximate Karhunen-Loeve expansions of a stochastic process and can be extended to estimate a linear operation, in the sense of the quadratic mean, of the signal pr... View full abstract»

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  • Chinese remaindering with errors

    Publication Year: 2000, Page(s):1330 - 1338
    Cited by:  Papers (53)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB)

    The Chinese remainder theorem states that a positive integer m is uniquely specified by its remainder module k relatively prime integers p 1, ···, pk, provided m<Πi=1kpi. Thus the residues of m module relatively prime integers p1<p2<···<pn form a redunda... View full abstract»

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  • Adding a parity-check bit

    Publication Year: 2000, Page(s):1544 - 1545
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (87 KB)

    The article gives a new condition for a q-ary linear code of length n and minimum distance d to be extendable to a code of the same dimension, length n+1, and minimum distance >d View full abstract»

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  • Universal coding of nonstationary sources

    Publication Year: 2000, Page(s):1633 - 1637
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    We investigate the performance of the Lempel-Ziv (1978) incremental parsing scheme on nonstationary sources. We show that it achieves the best rate achievable by a finite-state block coder for the nonstationary source. We also show a similar result for a lossy coding scheme given by Yang and Kieffer (see ibid., vol.42, p.239-45, 1996) which uses a Lempel-Ziv scheme to perform lossy coding View full abstract»

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  • Shannon-theoretic approach to a Gaussian cellular multiple-access channel with fading

    Publication Year: 2000, Page(s):1401 - 1425
    Cited by:  Papers (127)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (744 KB)

    Shannon-theoretic limits on the achievable throughput for a simple infinite cellular multiple-access channel (MAC) model (Wyner 1994) in the presence of fading are presented. In this model, which is modified to account for flat fading, the received signal, at a given cell-site's antenna, is the sum of the faded signals transmitted from all users within that cell plus an attenuation factor α&... View full abstract»

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  • On the training distortion of vector quantizers

    Publication Year: 2000, Page(s):1617 - 1623
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (272 KB)

    The in-training-set performance of a vector quantizer as a function of its training set size is investigated. For squared error distortion and independent training data, worst case type upper bounds are derived on the minimum training distortion achieved by an empirically optimal quantizer. These bounds show that the training distortion can underestimate the minimum distortion of a truly optimal q... View full abstract»

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  • A note on type II convolutional codes

    Publication Year: 2000, Page(s):1510 - 1514
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 KB)

    The result of a search for the world's second type II (doubly-even and self-dual) convolutional code is reported. A rate R=4/8, 16-state, time-invariant, convolutional code with free distance dfree=8 was found to be type II. The initial part of its weight spectrum is better than that of the Golay convolutional code (GCC). Generator matrices and path weight enumerators for some other typ... View full abstract»

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  • Sufficiency, classification, and the class-specific feature theorem

    Publication Year: 2000, Page(s):1654 - 1658
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (176 KB)

    A new proof of the class-specific feature theorem is given. The proof makes use of the observed data as opposed to the set of sufficient statistics as in the original formulation. We prove the theorem for the classical case, in which the parameter vector is deterministic and known, as well as for the Bayesian case, in which the parameter vector is modeled as a random vector with known prior probab... View full abstract»

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  • On random rotations diversity and minimum MSE decoding of lattices

    Publication Year: 2000, Page(s):1584 - 1589
    Cited by:  Papers (23)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    We establish a simple relation between high-diversity multidimensional rotations obtained from totally complex cyclotomic fields and the discrete Fourier transform. The diversity distribution of an Hadamard-like random rotation is derived analytically. It is shown that a random multidimensional rotation exhibits an excellent diversity distribution and can be combined to quadrature amplitude modula... View full abstract»

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  • Two-dimensional weight-constrained codes through enumeration bounds

    Publication Year: 2000, Page(s):1292 - 1301
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    For a rational α∈(0,1), let 𝒜n×m,α be the set of binary n×m arrays in which each row has Hamming weight αm and each column has Hamming weight αn, where αm and αn are integers. (The special case of two-dimensional balanced arrays corresponds to α=1/2 and even values for n and m.) The redundancy of 𝒜n×m,&alpha... View full abstract»

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  • Multihypothesis sequential probability ratio tests. II. Accurate asymptotic expansions for the expected sample size

    Publication Year: 2000, Page(s):1366 - 1383
    Cited by:  Papers (58)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (664 KB)

    For pt. I see ibid. vol.45, p.2448-61, 1999. We proved in pt.I that two specific constructions of multihypothesis sequential tests, which we refer to as multihypothesis sequential probability ratio tests (MSPRTs), are asymptotically optimal as the decision risks (or error probabilities) go to zero. The MSPRTs asymptotically minimize not only the expected sample size but also any positive moment of... View full abstract»

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  • On similarity codes

    Publication Year: 2000, Page(s):1558 - 1564
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    We introduce a biologically motivated measure of sequence similarity for quaternary N-sequences, extending Hamming similarity. This measure is the sum over the length of the sequences of “alphabetic” similarities at all positions. Alphabetic similarities are defined, symmetrically, on the Cartesian square of the alphabet. These similarities equal zero whenever the two elements differ. ... 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