IEEE Transactions on Information Theory

Volume 45 Issue 7 • Nov. 1999

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Displaying Results 1 - 25 of 63
  • Multicast-based inference of network-internal loss characteristics

    Publication Year: 1999, Page(s):2462 - 2480
    Cited by:  Papers (172)  |  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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  • A multilevel approach to constructing trellis-matched codes for binary-input partial-response channels

    Publication Year: 1999, Page(s):2582 - 2591
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    The multilevel coding approach of Imai and Hirakawa (1977) is used to construct trellis-matched codes for binary-input partial-response channels. For the codes to be trellis matched, the signal constellations are selected according to certain constraints, but no conditions are imposed on the component codes. New codes for the (1-D)(1+D)/sup n/ channel compare favorably to existing codes. View full abstract»

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  • Addendum and correction to "Optimal phases for a family of quadriphase CDMA sequences"

    Publication Year: 1999, Page(s):2672 - 2673
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (56 KB)

    This correspondence presents several corrections and an addendum to the original article by Feng-Wen Sun and H. Leib (see ibid., vol.43, no.4, p.1205-17, July 1997). View full abstract»

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  • 1997-1999 Index IEEE Transactions on Information Theory Vols. 43-45

    Publication Year: 1999, Page(s):1 - 72
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    Freely Available from IEEE
  • Quantum shadow enumerators

    Publication Year: 1999, Page(s):2361 - 2366
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (152 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 thei... 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 (444 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 Z4 and F2+uF2 for reasonable lengths. We also construct a number of optimal Type TV codes 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 (144 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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  • The probability of undetected error can have several local maxima

    Publication Year: 1999, Page(s):2537 - 2539
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (136 KB)

    We show that for a code used for error detection in the binary-symmetric channel (BSC), the probability of an undetected error can have several local maxima. In particular, we construct a code with three local maxima in (0, 1/2), a code with five local maxima in (0, 1); and a linear code with two local maxima in (0, 1/2) and a linear code with three local maxima in (0, 1) 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 (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    Let a q-ary linear (n, k) code C be used over a memoryless channel. We design a decoding algorithm ΨN that splits the received block into two halves in n different ways. First, about √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√N ... View full abstract»

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  • On the Newton and covering radii of linear codes

    Publication Year: 1999, Page(s):2534 - 2536
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    The Newton radius of a code is the largest weight of a uniquely correctable error. The covering radius is the largest distance between a vector and the code. Two relations between the Newton radius and the covering radius are given 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 (296 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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  • Improved lower bounds for multicovering codes

    Publication Year: 1999, Page(s):2532 - 2534
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (112 KB)

    The m-covering radius of a code is a generalization of the covering radius of a code. It is the smallest t such that every m-tuple of vectors is contained in a ball of Hamming radius t centered at some codeword. We derive new lower bounds for the size of the smallest code that has a given length and m-covering radius 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 (472 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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  • Peak-to-mean power control in OFDM, Golay complementary sequences, and Reed-Muller codes

    Publication Year: 1999, Page(s):2397 - 2417
    Cited by:  Papers (466)  |  Patents (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (620 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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  • Negacyclic and cyclic codes over Z4

    Publication Year: 1999, Page(s):2527 - 2532
    Cited by:  Papers (62)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    The negashift ν of Z4n is defined as the permutation of Z4n such that ν(a0, a 1, ···, ai, ···, an-1)=(-an-1, a0 , ···, ai, ···, an-2) and a negacyclic code of length n over Z 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 (340 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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  • The structure of single-track Gray codes

    Publication Year: 1999, Page(s):2383 - 2396
    Cited by:  Papers (17)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (356 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 2n codewords when n is a power of 2. This implies that the known codes with 2n-2n co... View full abstract»

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  • On Z4- and Z9-linear lifts of the Golay codes

    Publication Year: 1999, Page(s):2524 - 2527
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    We analyze Z4S- and Z9-linear lifts of the binary [24, 12] and ternary [12, 6]-Golay code under different weight functions on the underlying ring, and present algebraic decoding schemes for these codes View full abstract»

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  • On Weierstrass semigroups and the redundancy of improved geometric Goppa codes

    Publication Year: 1999, Page(s):2512 - 2519
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    Improved geometric Goppa codes have a smaller redundancy and the same bound on the minimum distance as ordinary algebraic-geometry codes. For an asymptotically good sequence of function fields we give a formula for the redundancy View full abstract»

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  • A generalization of algebraic-geometry codes

    Publication Year: 1999, Page(s):2498 - 2501
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (132 KB)

    A generalization of algebraic-geometry codes based on function fields over finite fields with many places of small degree is presented. It turns out that many good linear codes can be obtained from these generalized algebraic-geometry codes. In particular, we calculate some examples of q-ary linear codes for q=2,3, 5. These examples show that many best possible linear codes can be found from our c... View full abstract»

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  • Shaping and nonequiprobable signaling for intensity-modulated signals

    Publication Year: 1999, Page(s):2661 - 2668
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    Theory of shaping and nonequiprobable signaling, which has been developed for conventional electrical signals, must be modified to treat intensity-modulated (IM) signals. We show that for IM signals, the optimum shape of the constellation bounding region in N-dimensional (N-D) space is an N-D simplex. As N→∞, the maximum achievable shape gain is 1.33 dB (in terms of transmitted power), ... 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 (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 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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  • Error propagation assessment of enumerative coding schemes

    Publication Year: 1999, Page(s):2591 - 2594
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    Enumerative coding is an attractive algorithmic procedure for translating long source words into codewords and vice versa. The usage of long codewords makes it possible to approach a code rate which is as close as desired to Shannon's noiseless capacity of the constrained channel. Enumerative encoding is prone to massive error propagation as a single bit error could ruin entire decoded words. This... View full abstract»

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  • Linear-time binary codes correcting localized erasures

    Publication Year: 1999, Page(s):2547 - 2552
    Cited by:  Papers (1)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    We consider a communication model over a binary channel in which the transmitter knows which bits of the n-bit transmission are prone to loss in the channel. We call this model channel with localized erasures in analogy with localized errors studied earlier in the literature. We present two constructions of binary codes with t(1+ε) check bits, where t=αn is the maximal possible number o... View full abstract»

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  • On denoising and best signal representation

    Publication Year: 1999, Page(s):2225 - 2238
    Cited by:  Papers (114)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (444 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 estim... 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
Prakash Narayan 

Department of Electrical and Computer Engineering