IEEE Transactions on Information Theory

Volume 45 Issue 7 • Nov. 1999

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Displaying Results 1 - 25 of 63
  • On denoising and best signal representation

    Publication Year: 1999, Page(s):2225 - 2238
    Cited by:  Papers (119)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (439 KB)

    We propose a best basis algorithm for signal enhancement in white Gaussian noise. The best basis search is performed in families of orthonormal bases constructed with wavelet packets or local cosine bases. We base our search for the "best" basis on a criterion of minimal reconstruction error of the underlying signal. This approach is intuitively appealing, because the enhanced or estimated signal ... View full abstract»

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  • Polyspectra of ordered signals

    Publication Year: 1999, Page(s):2239 - 2252
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (314 KB)

    Polyspectra are related to Fourier transforms of moment or cumulant functions of any order of random signals. They play an important role in many problems of signal analysis and processing. However, there are only a few statistical models giving explicitly the expression of polyspectra. Ordered signals are signals for which the explicit expression of the moment functions requires that the time ins... View full abstract»

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  • MEM pixel correlated solutions for generalized moment and interpolation problems

    Publication Year: 1999, Page(s):2253 - 2270
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (554 KB)

    In generalized moment problems (signed) measures are searched to fit given observations, or continuous functions are searched to fit given constraints. Known convex methods for solving such problems, and their stochastic interpretations via maximum entropy on the mean (MEM) and in a Bayesian sense are reviewed, with some improvements on previous results. Then the MEM and Bayesian approaches are ex... View full abstract»

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  • Minimax nonparametric classification .I. Rates of convergence

    Publication Year: 1999, Page(s):2271 - 2284
    Cited by:  Papers (36)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    This paper studies minimax aspects of nonparametric classification. We first study minimax estimation of the conditional probability of a class label, given the feature variable. This function, say f, is assumed to be in a general nonparametric class. We show the minimax rate of convergence under square L/sub 2/ loss is determined by the massiveness of the class as measured by metric entropy. The ... View full abstract»

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  • Minimax nonparametric classification. II. Model selection for adaptation

    Publication Year: 1999, Page(s):2285 - 2292
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (190 KB)

    For pt.I see ibid., vol.45, no.7, p.2271-84 (1999). We study nonparametric estimation of a conditional probability for classification based on a collection of finite-dimensional models. For the sake of flexibility, different types of models, linear or nonlinear, are allowed as long as each satisfies a dimensionality assumption. We show that with a suitable model selection criterion, the penalized ... View full abstract»

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  • An implementable lossy version of the Lempel-Ziv algorithm. I. Optimality for memoryless sources

    Publication Year: 1999, Page(s):2293 - 2305
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (333 KB)

    A new lossy variant of the fixed-database Lempel-Ziv coding algorithm for encoding at a fixed distortion level is proposed, and its asymptotic optimality and universality for memoryless sources (with respect to bounded single-letter distortion measures) is demonstrated: as the database size m increases to infinity, the expected compression ratio approaches the rate-distortion function. The complex... View full abstract»

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  • Quantization based on a novel sample-adaptive product quantizer (SAPQ)

    Publication Year: 1999, Page(s):2306 - 2320
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (466 KB)

    In this paper, we propose a novel feedforward adaptive quantization scheme called the sample-adaptive product quantizer (SAPQ). This is a structurally constrained vector quantizer that uses unions of product codebooks. SAPQ is based on a concept of adaptive quantization to the varying samples of the source and is very different from traditional adaptation techniques for nonstationary sources. SAPQ... View full abstract»

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  • On the decoding of convolutional codes on an unknown channel

    Publication Year: 1999, Page(s):2321 - 2332
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (290 KB)

    An algorithm is proposed for universal decoding of convolutional/trellis codes employed over unknown channels. On discrete memoryless channels and at rates below the channel's computational cutoff rate (for a uniform input distribution), the algorithm achieves an asymptotic complexity-performance tradeoff similar to the tradeoff achieved by the Viterbi (1979) algorithm, but with the benefit that t... View full abstract»

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  • Sort-and-match algorithm for soft-decision decoding

    Publication Year: 1999, Page(s):2333 - 2338
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (201 KB)

    Let a q-ary linear (n, k) code C be used over a memoryless channel. We design a decoding algorithm /spl Psi//sub N/ that splits the received block into two halves in n different ways. First, about /spl radic/N error patterns are found on either half. Then the left- and right-hand lists are sorted out and matched to form codewords. Finally, the most probable codeword is chosen among at most n/spl r... View full abstract»

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  • A decoding algorithm with restrictions for array codes

    Publication Year: 1999, Page(s):2339 - 2344
    Cited by:  Papers (12)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (137 KB)

    We present a simple and efficient error correction scheme for array-like data structures. We assume that the channel behaves such that each row of a received array is either error-free or corrupted by many symbol errors. Provided that row error vectors are linearly independent, the proposed decoding algorithm can correct asymptotically one erroneous row per redundant row, even without having relia... View full abstract»

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  • Type IV self-dual codes over rings

    Publication Year: 1999, Page(s):2345 - 2360
    Cited by:  Papers (37)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (436 KB)

    We study Type IV self-dual codes over the commutative rings of order 4. Gleason-type theorems of Type IV codes and their shadow codes are investigated. A mass formula of Type IV codes over these rings are given. We give a classification of Type TV codes over Z/sub 4/ and F2+uF/sub 2/ for reasonable lengths. We also construct a number of optimal Type TV codes. View full abstract»

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  • Quantum shadow enumerators

    Publication Year: 1999, Page(s):2361 - 2366
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (147 KB)

    In a previous paper, Shor and Laflamme (see Phys. Rev. Lett., vol.78, p.1600-02, 1997) define two "weight enumerators" for quantum error-correcting codes, connected by a MacWilliams (1977) transform, and use them to give a linear-programming bound for quantum codes. We extend their work by introducing another enumerator, based on the classical theory of shadow codes, that tightens their bounds sig... View full abstract»

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  • Signal propagation and noisy circuits

    Publication Year: 1999, Page(s):2367 - 2373
    Cited by:  Papers (36)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (161 KB)

    The information carried by a signal decays when the signal is corrupted by random noise. This occurs when a message is transmitted over a noisy channel, as well as when a noisy component performs computation. We first study this signal decay in the context of communication and obtain a tight bound on the rate at which information decreases as a signal crosses a noisy channel. We then use this info... View full abstract»

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  • Linear models for a time-variant permutation generator

    Publication Year: 1999, Page(s):2374 - 2382
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (213 KB)

    A keystream generator, known as RC4, consisting of a permutation table that slowly varies in time under the control of itself, is analyzed by the linear model approach. The objective is to find linear relations among the keystream bits that hold with probability different from one half by using the linear sequential circuit approximation method. To estimate the corresponding correlation coefficien... View full abstract»

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  • The structure of single-track Gray codes

    Publication Year: 1999, Page(s):2383 - 2396
    Cited by:  Papers (19)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    Single-track Gray codes are cyclic Gray codes with codewords of length n, such that all the n tracks which correspond to the n distinct coordinates of the codewords are cyclic shifts of the first track. We investigate the structure of such binary codes and show that there is no such code with 2/sup n/ codewords when n is a power of 2. This implies that the known codes with 2/sup n/-2n codewords. w... View full abstract»

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  • Peak-to-mean power control in OFDM, Golay complementary sequences, and Reed-Muller codes

    Publication Year: 1999, Page(s):2397 - 2417
    Cited by:  Papers (489)  |  Patents (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (613 KB)

    We present a range of coding schemes for OFDM transmission using binary, quaternary, octary, and higher order modulation that give high code rates for moderate numbers of carriers. These schemes have tightly bounded peak-to-mean envelope power ratio (PMEPR) and simultaneously have good error correction capability. The key theoretical result is a previously unrecognized connection between Golay com... View full abstract»

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  • Performance limits of coded diversity methods for transmitter antenna arrays

    Publication Year: 1999, Page(s):2418 - 2433
    Cited by:  Papers (106)  |  Patents (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (300 KB)

    Several aspects of the design and optimization of coded multiple-antenna transmission diversity methods for slowly time-varying channels are explored from an information-theoretic perspective. Both optimized vector-coded systems, which can achieve the maximum possible performance, and suboptimal scalar-coded systems, which reduce complexity by exploiting suitably designed linear precoding, are inv... View full abstract»

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  • Optimum near-far resistance for dual-rate DS/CDMA signals: random signature sequence analysis

    Publication Year: 1999, Page(s):2434 - 2447
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (275 KB)

    Optimum near-far resistance is studied for synchronous dual-rate DS/CDMA systems. Three multirate access schemes are considered: multicode (MC) access where high-rate users multiplex their data bits onto multiple codes and form a single-rate system; variable spreading length (VSL) access where the spreading lengths of signature sequences are inversely proportional to users' data rates; and variabl... View full abstract»

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  • Multihypothesis sequential probability ratio tests .I. Asymptotic optimality

    Publication Year: 1999, Page(s):2448 - 2461
    Cited by:  Papers (161)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (404 KB)

    The problem of sequential testing of multiple hypotheses is considered, and two candidate sequential test procedures are studied. Both tests are multihypothesis versions of the binary sequential probability ratio test (SPRT), and are referred to as MSPRTs. The first test is motivated by Bayesian optimality arguments, while the second corresponds to a generalized likelihood ratio test. It is shown ... View full abstract»

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  • Multicast-based inference of network-internal loss characteristics

    Publication Year: 1999, Page(s):2462 - 2480
    Cited by:  Papers (180)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    Robust measurements of network dynamics are increasingly important to the design and operation of large internetworks like the Internet. However, administrative diversity makes it impractical to monitor every link on an end-to-end path. At the same time, it is difficult to determine the performance characteristics of individual links from end-to-end measurements of unicast traffic. In this paper, ... View full abstract»

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  • Coding theorem and strong converse for quantum channels

    Publication Year: 1999, Page(s):2481 - 2485
    Cited by:  Papers (163)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (214 KB)

    We present a new proof of Holevo's (1973, 1977) coding theorem for transmitting classical information through quantum channels, and its strong converse. The technique is largely inspired by Wolfwitz's (1964) combinatorial approach using types of sequences. As a byproduct of our approach which is independent of previous ones, both in the coding theorem and the converse, we can give a new proof of H... View full abstract»

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  • Strong converse to the quantum channel coding theorem

    Publication Year: 1999, Page(s):2486 - 2489
    Cited by:  Papers (73)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (149 KB)

    A lower bound on the probability of decoding error for a quantum communication channel is presented, from which the strong converse to the quantum channel coding theorem is immediately shown. The results and their derivations are mostly straightforward extensions of the classical counterparts which were established by Arimoto (1973), except that more careful treatment is necessary here due to the ... View full abstract»

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  • Monotonicity of the quantum linear programming bound

    Publication Year: 1999, Page(s):2489 - 2492
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (147 KB)

    The most powerful technique known at present for bounding the size of quantum codes of prescribed minimum distance is the quantum linear programming bound. Unlike the classical linear programming bound, it is not immediately obvious that if the quantum linear programming constraints are satisfiable for dimension K, then the constraints can be satisfied for all lower dimensions. We show that the qu... View full abstract»

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  • Enlargement of Calderbank-Shor-Steane quantum codes

    Publication Year: 1999, Page(s):2492 - 2495
    Cited by:  Papers (119)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (163 KB)

    It is shown that a classical error correcting code C=[n,k,d] which contains its dual, C/sup /spl perp///spl sube/C, and which can be enlarged to C'=[n,k'>k+1,d'], can be converted into a quantum code of parameters [[n,k+k'-n,min(d,[3d'/2])]]. This is a generalization of a previous construction, it enables many new codes of good efficiency to be discovered. Examples based on classical Bose-Chaud... View full abstract»

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  • On binary constructions of quantum codes

    Publication Year: 1999, Page(s):2495 - 2498
    Cited by:  Papers (35)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (125 KB)

    We improve estimates on the parameters of quantum codes obtained by Steane's (see ibid., vol.45, no.7, p.2492-5, 1999) construction from binary codes. This yields several new families of quantum codes. 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
Alexander Barg

Department of Electrical and Computer Engineering and the Institute for Systems Research, University of Maryland

email: abarg-ittrans@ece.umd.edu