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IEEE Transactions on Information Theory

Issue 5 • Sept. 1995

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Displaying Results 1 - 25 of 33
  • Comments on "A lower bound on the minimum Euclidean distance of trellis-coded modulation schemes"

    Publication Year: 1995, Page(s):1531 - 1535
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (363 KB)

    Commentson a paper by Rouanne and Costello Jr. (IEEE Trans. Inform. Theory, vol.34, p.1011-20, 1988). It is shown that the derivation in the above paper is incorrect and hence the lower bound obtained is not valid for general trellis-coded modulation schemes. A corrected bound is presented to remedy this flaw. Also shown is a similar lower bound derived from the average distance structure. Both bo... View full abstract»

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  • Generalized partial spreads

    Publication Year: 1995, Page(s):1482 - 1487
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (414 KB)

    We exhibit a simple condition under which the sum (modulo 2) of characteristic functions of (n/2)-dimensional vector subspaces of (GF(2))n (n even) is a Bent function. The “Fourier” transform of such a Bent function is the sum of the characteristic functions of the duals of these spaces. The class of Bent functions that we obtain contains the whole partial spreads class. Any... View full abstract»

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  • Generating random bits from an arbitrary source: fundamental limits

    Publication Year: 1995, Page(s):1322 - 1332
    Cited by:  Papers (45)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (718 KB)

    Suppose we are given a random source and want to use it as a random number generator; at what rate can we generate fair bits from it? We address this question in an information-theoretic setting by allowing for some arbitrarily small but nonzero deviation from “ideal” random bits. We prove our results with three different measures of approximation between the ideal and the obtained pro... View full abstract»

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  • On the minimum bit-error rate of linear codes

    Publication Year: 1995, Page(s):1457 - 1466
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (590 KB)

    We investigate the bit-error rate (BER) of linear block codes. The BER is a function of the encoder realization of the code. We express the BER in terms of the weight profiles of the subspaces of the code. We also discuss the relation between the Hadamard transform and the BER View full abstract»

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  • Good error-detection codes satisfying the expurgated bound

    Publication Year: 1995, Page(s):1347 - 1353
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (467 KB)

    A q-ary (n, k) linear code is said to be proper if, as an error-detection code, the probability of undetectable error Pud satisfies Pud⩽q-(n-k) for completely symmetric channels. We show that a proper code, as an error-correction code, satisfies the expurgated bound on the decoding error probability for a class of channels with the associated Bhattacharyya dis... View full abstract»

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  • Soft-decision decoding of linear block codes based on ordered statistics

    Publication Year: 1995, Page(s):1379 - 1396
    Cited by:  Papers (220)  |  Patents (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1367 KB)

    Presents a novel approach to soft decision decoding for binary linear block codes. The basic idea is to achieve a desired error performance progressively in a number of stages. For each decoding stage, the error performance is tightly bounded and the decoding is terminated at the stage where either near-optimum error performance or a desired level of error performance is achieved. As a result, mor... View full abstract»

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  • Multilevel construction of block and trellis group codes

    Publication Year: 1995, Page(s):1257 - 1264
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (684 KB)

    The theory of group codes has been shown to be a useful starting point for the construction of good geometrically uniform codes. In this paper we study the problem of building multilevel group codes, i.e., codes obtained combining separate coding at different levels in such a way that the resulting code is a group code. A construction leading to multilevel group codes for semi-direct and direct pr... View full abstract»

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  • Trellis group codes for the Gaussian channel

    Publication Year: 1995, Page(s):1217 - 1245
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2578 KB)

    In this paper, trellis group codes are introduced as an extension of Slepian group codes to codes over sequence spaces. A trellis group code is defined over Rn as the orbit of a bi-infinite “seed sequence”, x0∈(R n)Z, under an infinite, defining group of transformations. This group of transformations is generated by a s... View full abstract»

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  • On the capacity of M-ary runlength-limited codes

    Publication Year: 1995, Page(s):1508 - 1511
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    Presents two results on the Shannon capacity of M-ary (d,k) codes. First the authors show that 100% efficient fixed-rate codes are impossible for all values of (M,d,k), 0⩽d<k<∞, M<∞, thereby extending a result of Ashley and Siegel (1987) to M-ary channels. Second, they show that for k=∞, there exist an infinite number of 100% efficient M-ary (d,k) codes, and they con... View full abstract»

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  • Computing the weight distribution of a set of points obtained by scaling, shifting, and truncating a lattice

    Publication Year: 1995, Page(s):1480 - 1482
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (221 KB)

    A method is developed to compute the weight distribution of a set of points obtained from a lattice. The lattice is scaled (with possibly nonequal factors) along different dimensions, is shifted to an arbitrary point, and its lower dimensional subspaces are truncated within given shaping regions. Each branch in the lattice trellis diagram is labeled by the weight distribution of the corresponding ... View full abstract»

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  • A new approach to the design of codes for synchronous-CDMA systems

    Publication Year: 1995, Page(s):1503 - 1506
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (282 KB)

    A new approach to increase the sum rate for conventional synchronous code-division multiple-access (S-CDMA) systems is presented. It is shown that it can be done by joint processing of the outputs of matched filters, when one considers the system of codes for S-CDMA to be the codes for the usual adder channel. An example of construction and decoding of such a system is also given View full abstract»

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  • Krawtchouk polynomials and universal bounds for codes and designs in Hamming spaces

    Publication Year: 1995, Page(s):1303 - 1321
    Cited by:  Papers (50)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1201 KB)

    Universal bounds for the cardinality of codes in the Hamming space Frn with a given minimum distance d and/or dual distance d' are stated. A self-contained proof of optimality of these bounds in the framework of the linear programming method is given. The necessary and sufficient conditions for attainability of the bounds are found. The parameters of codes satisfying these co... View full abstract»

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  • The expansion factor of error-control codes

    Publication Year: 1995, Page(s):1452 - 1457
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (402 KB)

    We investigate the expansion factor Δ(C) of an (n, k, d) linear block code. Δ(C) indicates how well the code preserves and expands the distance relations of the input. We relate Δ(C) to n, k, d, the total weight, and the weight distribution, and we find bounds on Δ(C) View full abstract»

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  • On Z4-duality

    Publication Year: 1995, Page(s):1487 - 1494
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (502 KB)

    Recently the notion on binary codes called Z4-linearity was introduced. This notion explains why Kerdock codes and Delsarte-Goethals codes admit formal duals in spite of their nonlinearity. The “Z4-duals” of these codes (called “Preparata” and “Goethals” codes) are new nonlinear codes which admit simpler decoding algorithms than the previou... View full abstract»

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  • On the generalized symmetric cutoff rate for finite-state channels

    Publication Year: 1995, Page(s):1333 - 1346
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (833 KB)

    Finite-state discrete-time channels with equiprobable M-ary inputs are considered. The generating function bound, which is ubiquitously applied to upper-bound the error probability of uncoded signaling over these channels, is used here to lower-bound the corresponding generalized symmetric cutoff rate, which lower-bounds the practically achievable rates and error exponents in these channels with s... View full abstract»

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  • On the accuracy of the binomial approximation to the distance distribution of codes

    Publication Year: 1995, Page(s):1472 - 1474
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (149 KB)

    The binomial distribution is a well-known approximation to the distance spectra of many classes of codes. We derive a lower estimate for the deviation from the binomial approximation View full abstract»

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  • On the construction of bounded-delay encodable codes for constrained systems

    Publication Year: 1995, Page(s):1354 - 1378
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2213 KB)

    We present a new technique to construct sliding-block modulation codes with a small decoding window. Our method, which involves both state splitting and look-ahead encoding, crucially depends on a new “local” construction method for bounded-delay codes. We apply our method to construct several new codes, all with a smaller decoding window than previously known codes for the same constr... View full abstract»

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  • Efficiency of data-aided timing recovery techniques

    Publication Year: 1995, Page(s):1397 - 1408
    Cited by:  Papers (8)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (912 KB)

    This paper assesses the tracking capabilities of data-aided timing recovery schemes in terms of an efficiency that characterizes, coarsely speaking, the amount of timing information that the scheme manages to extract from the incoming signal per unit of time and signal-to-noise ratio. Efficiencies of maximum-likelihood and various baud-rate timing recovery schemes are determined as a function of t... View full abstract»

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  • Decomposition of M-ary CPM signals into PAM waveforms

    Publication Year: 1995, Page(s):1265 - 1275
    Cited by:  Papers (116)  |  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (620 KB)

    It is widely known that minimum shift keying (MSK) may be seen as a PAM signaling scheme and that the same is true, albeit approximately, with MSK-like modulations. It is also known (perhaps not so widely) that any binary continuous phase-modulated (CPM) signal may be exactly decomposed into the sum of a few PAM waveforms. In this paper we show that this property extends to multilevel CPM signalin... View full abstract»

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  • Linear block codes over cyclic groups

    Publication Year: 1995, Page(s):1246 - 1256
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (833 KB)

    The main building block for the construction of a geometrically uniform coded modulation scheme is a subgroup of GI, where G is a group generating a low-dimensional signal constellation and I is an index set. In this paper we study the properties of these subgroups when G is cyclic. We exploit the fact that any cyclic group of q elements is isomorphic to the additive group of Z... View full abstract»

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  • On the odd and the aperiodic correlation properties of the Kasami sequences

    Publication Year: 1995, Page(s):1506 - 1508
    Cited by:  Papers (32)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (217 KB)

    Derives a new upper bound for the odd and the aperiodic correlations of binary sequences in the small Kasami family. The approach is based on a technique described in S. Litsyn and A. Tietavainen (1994) that is originally due to I.M. Vinogradov (1954). An essential ingredient in this method is a good upper bound on the discrete Fourier coefficients of a shifted product of a pair of sequences. The ... View full abstract»

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  • On the distance distribution of codes

    Publication Year: 1995, Page(s):1467 - 1472
    Cited by:  Papers (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (398 KB)

    The distinct distribution of a binary code C is the sequence (B i)i=0n defined as follows: let Bi (w) be the number of codewords at distance i from the codeword w, and let Bi be the average of Bi(w) over all w in C. In this correspondence we study the distance distribution for codes of length n and minimal distance δn, with &d... View full abstract»

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  • Even more efficient bounded-distance decoding of the hexacode, the Golay code, and the Leech lattice

    Publication Year: 1995, Page(s):1495 - 1499
    Cited by:  Papers (18)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (405 KB)

    We present a new bounded-distance decoding algorithm for the hexacode, which requires at most 34 real operations in the worst case, as compared to 57 such operations in the best previously known decoder. The new algorithm is then employed for bounded-distance decoding of the Leech lattice and the Golay code. The error-correction radius of the resulting decoders is equal to that of a maximum-likeli... View full abstract»

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  • Weight hierarchy of a product code

    Publication Year: 1995, Page(s):1475 - 1479
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    Formulas to compute the first members of the weight hierarchy of a product code are given and proved. Basic patterns for the supports of subcodes in which the minimum cardinalities can be found are presented. Hence, formulas for every term of the hierarchy can be given, and the proof for each case will be a generalization of the proofs shown here View full abstract»

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  • Simultaneous estimation of echo path and channel responses using full-duplex transmitted training data sequences

    Publication Year: 1995, Page(s):1409 - 1417
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (654 KB)

    To reduce the system initialization time in high-speed full-duplex data transmission over two-wire lines, we propose an efficient full-duplex fast training algorithm which can simultaneously estimate the impulse responses of echo paths and channels at both ends. Two mutually orthogonal periodic sequences are designed and used to co-estimate the near echo, the far echo with bulk delay, and the chan... 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
Prakash Narayan 

Department of Electrical and Computer Engineering