IEEE Transactions on Information Theory

Volume 46 Issue 2 • March 2000

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Displaying Results 1 - 25 of 41
  • Ideals, varieties, and algorithms [Book Review]

    Publication Year: 2000, Page(s):724 - 734
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    Freely Available from IEEE
  • On a conjectured ideal autocorrelation sequence and a related triple-error correcting cyclic code

    Publication Year: 2000, Page(s):680 - 687
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    In a previous paper, No, Golomb, Gong, Lee and Gaal (see ibid., vol.44, p.814-17, 1998) conjectured that certain binary sequences having a simple trace description possess the ideal autocorrelation property. In the present paper it is shown that each such sequence is balanced and, moreover, that the dual of the linear cyclic code generated by the sequence and its cyclic shifts, is a triple-error c... View full abstract»

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  • Constacyclic codes, cocycles and a u+v|u-v construction

    Publication Year: 2000, Page(s):674 - 680
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    A connection between cohomology, cocycles and constacyclic codes is explored. It suggests an isomorphism between cyclic codes of length mn and a direct sum of m constacyclic codes of length n. The isomorphism is used (i) to study the discrete Fourier transforms and the decomposition of group ring codes; (ii) to give a u+v|u-v construction over GF(q) when q is odd. The u+v|u-v construction gives so... View full abstract»

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  • On a sequence of cyclic codes with minimum distance six

    Publication Year: 2000, Page(s):673 - 674
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    A sequence of q-ary cyclic codes is considered. For each finite field GF(q), q⩾4, there is a code with parameters [n, k, d; q]=[q(q-1)+1, q(q-1)-6, 6; q]. We show that all these codes are n-, k-, and d-optimal, with only one exception. Also the dual codes are considered. Their true minimum distances are calculated in the range 4⩽q⩽32 View full abstract»

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  • Optimal transmit-receiver design in the presence of signal-dependent interference and channel noise

    Publication Year: 2000, Page(s):577 - 584
    Cited by:  Papers (159)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    Optimal detection of a target return contaminated by signal-dependent interference, as well as additive channel noise, requires the design of a transmit pulse f(t) and a receiver impulse response h(t) jointly maximizing the output signal to interference plus noise ratio (SINR). Despite the highly nonlinear nature of this problem, it has been possible to show that f(t) may always be chosen minimum-... View full abstract»

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  • On systematic single asymmetric error-correcting codes

    Publication Year: 2000, Page(s):669 - 672
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    It is proved that for all values of code length n, except when n=2, 4, and 8 and possibly when n=2r and n=2r+1, where r⩾1, the Hamming codes are also optimal systematic single asymmetric error-correcting codes. For the cases n=2r and n=2 r+1, r⩾4, when not all information words are used, two efficient systematic 1-asymmetric codes are described View full abstract»

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  • Optimizing the transmit power for slow fading channels

    Publication Year: 2000, Page(s):565 - 576
    Cited by:  Papers (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    We consider the design of power-adaptive systems for minimizing the average bit-error rate over flat fading channels. Channel state information, obtained through estimation at the receiver, is sent to the transmitter over a feedback channel, where it is used to optimally adapt the transmit power. We consider finite-state optimal policies to reflect the limitations of the feedback channel. We devel... View full abstract»

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  • On classes of convolutional codes that are not asymptotically catastrophic

    Publication Year: 2000, Page(s):663 - 669
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    The author denotes by w0 the minimum average weight per edge over all nonzero cycles in the state diagram for a convolutional code, and assumes that a technique is available for generating canonical parity-check matrices for codes with increasing degree m. The obtained class of codes is asymptotically catastrophic if w0 approaches zero for large m. We prove the existence of c... View full abstract»

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  • On the theory of space-time codes for PSK modulation

    Publication Year: 2000, Page(s):524 - 542
    Cited by:  Papers (269)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (452 KB)

    The design of space-time codes to achieve full spatial diversity over fading channels has largely been addressed by handcrafting example codes using computer search methods and only for small numbers of antennas. The lack of more general designs is in part due to the fact that the diversity advantage of a code is the minimum rank among the complex baseband differences between modulated codewords, ... View full abstract»

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  • An upper bound on the minimum Euclidean distance for block-coded phase-shift keying

    Publication Year: 2000, Page(s):656 - 662
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    We present an upper bound on the minimum Euclidean distance dEmin(C) for block-coded PSK. The bound is an analytic expression depending on the alphabet size q, the block length n, and the number of codewords |C| of the code C. The bound is valid for all block codes with q⩾4 and with medium or high rate-codes where |C|>(q/3) n. There are several well-known block codes w... View full abstract»

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  • Enumeration and criteria for cyclically shift-distinct GMW sequences

    Publication Year: 2000, Page(s):474 - 484
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (388 KB)

    Gordon-Mills-Welch (GMW) sequences (also called cascaded GMW sequences) have two-level autocorrelations. This property makes them widely used in various communication and cryptographic systems. The generation of q-ary GMW sequences of period qn-1 involves three types of parameters. To determine whether GMW sequences are cyclically shift-distinct for differing parameters has remained an ... View full abstract»

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  • Ellipsoidal lists and maximum-likelihood decoding

    Publication Year: 2000, Page(s):649 - 656
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (364 KB)

    We study an interrelation between the coverings generated by linear (n,k)-codes and complexity of their maximum-likelihood (ML) decoding. First , discrete ellipsoids in the Hamming spaces E1n are introduced. These ellipsoids represent the sets of most probable error patterns that need to be tested in soft-decision ML decoding. We show that long linear (n,k)-codes surrounded b... View full abstract»

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  • Sequential decoding for the exponential server timing channel

    Publication Year: 2000, Page(s):705 - 709
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    We show the existence of a good tree code with a sequential decoder for the exponential server timing channel. The expected number of computations before moving one step ahead is upper-bounded by a finite number. The rate of information transfer for this code is μ/(2e) nats per second i.e., one half of the capacity. The cutoff rate for the exponential server queue is therefore at least μ/(2u... View full abstract»

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  • Minimum description length induction, Bayesianism, and Kolmogorov complexity

    Publication Year: 2000, Page(s):446 - 464
    Cited by:  Papers (95)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    The relationship between the Bayesian approach and the minimum description length approach is established. We sharpen and clarify the general modeling principles minimum description length (MDL) and minimum message length (MML), abstracted as the ideal MDL principle and defined from Bayes's rule by means of Kolmogorov complexity. The basic condition under which the ideal principle should be applie... View full abstract»

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  • The capacity of wireless networks

    Publication Year: 2000, Page(s):388 - 404
    Cited by:  Papers (4816)  |  Patents (71)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    When n identical randomly located nodes, each capable of transmitting at W bits per second and using a fixed range, form a wireless network, the throughput λ(n) obtainable by each node for a randomly chosen destination is Θ(W/√(nlogn)) bits per second under a noninterference protocol. If the nodes are optimally placed in a disk of unit area, traffic patterns are optimally assign... View full abstract»

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  • Decoding of Hermitian codes: the key equation and efficient error evaluation

    Publication Year: 2000, Page(s):512 - 523
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    This paper presents a generalization of the key equation to Hermitian codes. The syndrome is interpreted as a power series and the product of this power series with a locator polynomial gives the error evaluator polynomial. The computation of the evaluator polynomial may be done iteratively using a modified version of a previously published computationally efficient algorithm for computing locator... View full abstract»

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  • Decoding real block codes: activity detection Wiener estimation

    Publication Year: 2000, Page(s):609 - 623
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    New decoding procedures for real-number block codes which are constructed by imposing constraints in the discrete Fourier transform (DFT) domain are examined. The codewords are corrupted by small levels of roundoff noise and possibly occasionally by a few large excursions of random disturbances. The error-correcting procedure is separated into two parts, large activity detection followed by error ... View full abstract»

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  • A lower bound on the linear span of an FCSR

    Publication Year: 2000, Page(s):691 - 693
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (112 KB)

    We have derived a lower bound on the linear span of a binary sequence generated by a feedback with carry shift register (FCSR) under the following condition: q is a power of a prime such that q=re (e⩾2) and r(=2p+1), where both r and p are 2-prime. This allows us to design FCSR stream ciphers similar to previously proposed linear feedback shift register (LFSR) stream ciphers View full abstract»

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  • Unitary space-time modulation for multiple-antenna communications in Rayleigh flat fading

    Publication Year: 2000, Page(s):543 - 564
    Cited by:  Papers (648)  |  Patents (44)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (724 KB)

    Motivated by information-theoretic considerations, we propose a signaling scheme, unitary space-time modulation, for multiple-antenna communication links. This modulation is ideally suited for Rayleigh fast-fading environments, since it does not require the receiver to know or learn the propagation coefficients. Unitary space-time modulation uses constellations of T×M space-time signals (&Ph... View full abstract»

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  • Transform coding with integer-to-integer transforms

    Publication Year: 2000, Page(s):465 - 473
    Cited by:  Papers (19)  |  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (220 KB)

    A new interpretation of transform coding is developed that downplays quantization and emphasizes entropy coding, allowing a comparison of entropy coding methods with different memory requirements. With conventional transform coding, based on computing Karhunen-Loeve transform coefficients and then quantizing them, vector entropy coding can be replaced by scalar entropy coding without an increase i... View full abstract»

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  • On random coding error exponents of watermarking systems

    Publication Year: 2000, Page(s):420 - 430
    Cited by:  Papers (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    Watermarking codes are analyzed from an information-theoretic viewpoint as a game between an information hider and an active attacker. While the information hider embeds a secret message (watermark) in a covertext message (typically: text, image, sound, or video stream) within a certain distortion level, the attacker processes the resulting watermarked message, within limited additional distortion... View full abstract»

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  • DC-free codes of rate (n-1)/n, n odd

    Publication Year: 2000, Page(s):633 - 634
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (84 KB)

    We report on a new class of DC-free codes of rate (n-1)/n, odd. The spectral and runlength properties of the new codes have been evaluated by computer simulation View full abstract»

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  • About priority encoding transmission

    Publication Year: 2000, Page(s):699 - 705
    Cited by:  Papers (32)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (276 KB)

    Albanese et al. (see ibid. vol.42, p.1737-44, 1996) introduced priority encoding transmission (PET) for sending hierarchically organized messages over lossy packet-based computer networks. In a PET system, each symbol in the message is assigned a priority which determines the minimal number of codeword symbols that is required to recover that symbol. This article revisits the PET approach using to... View full abstract»

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  • Footprints or generalized Bezout's theorem

    Publication Year: 2000, Page(s):635 - 641
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (312 KB)

    In two previous papers, the first by Feng, Rao, Berg, and Zhu (see ibid., vol.43, p.1799-810, 1997) and the second by Feng, Zhu, Shi, and Rao (see Proc. 35th. Afferton Conf. Communication, Control and Computing, p.205-14, 1997), the authors use a generalization of Bezout's theorem to estimate the minimum distance and generalized Hamming weights for a class of error correcting codes obtained by eva... View full abstract»

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  • An analysis of Chen's construction of minimum-distance five codes

    Publication Year: 2000, Page(s):505 - 511
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    In 1991, C.L. Chen used the inverted construction Y1 on binary linear codes of minimum Hamming distance five to construct a new [47, 36, 5] code. We examine this construction in depth and show that no such codes are obtained unless the fields GF(8) or GF(32) are used. Using MAGMA, we prove that the binary [11, 4, 5] code and the binary [15, 7, 5] extension found by Chen are the only pos... 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
Alexander Barg

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

email: abarg-ittrans@ece.umd.edu