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IEEE Transactions on Information Theory

Issue 5 • Date Sept. 1996

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Displaying Results 1 - 25 of 44
  • A geometric construction procedure for geometrically uniform trellis codes

    Publication Year: 1996, Page(s):1498 - 1513
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1500 KB)

    The problem of maximizing the minimum free squared Euclidean distance of a trellis code is developed from a geometric point of view. This approach provides a new way of constructing constellations for trellis coding. A decomposition of the trellis topology leads to a systematic construction of signal sets and generators for geometrically uniform trellis codes. An algorithm is proposed to construct... View full abstract»

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  • Two-Dimensional Imaging [Book Reviews]

    Publication Year: 1996
    Request permission for commercial reuse | PDF file iconPDF (234 KB)
    Freely Available from IEEE
  • Contributors

    Publication Year: 1996
    Request permission for commercial reuse | PDF file iconPDF (527 KB)
    Freely Available from IEEE
  • Cyclic codes and quadratic residue codes over Z4

    Publication Year: 1996, Page(s):1594 - 1600
    Cited by:  Papers (71)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB)

    A set of n-tuples over Z4 is called a code over Z4 or a Z4 code if it is a Z4 module. We prove that any Z4-cyclic code C has generators of the form (fh, 2fg) where fgh=xn-1 over Z4 and |C|=4deg g 2deg h. We also show that C has generators of the form (g*h*, 2f... View full abstract»

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  • Bounds on the weight hierarchy of generalized concatenated codes

    Publication Year: 1996, Page(s):1635 - 1640
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    We determine upper and lower bounds to the generalized Hamming weights of generalized concatenated codes. They are derived from the generalized Hamming weights of the outer codes and certain properties of the inner code and its partitions View full abstract»

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  • On the weight hierarchy of Kerdock codes over Z4

    Publication Year: 1996, Page(s):1587 - 1593
    Cited by:  Papers (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    The rth generalized Hamming weight dr of the Kerdock code of length 2m over Z4 is considered. A lower bound on dr is derived for any r, and dr is exactly determined for r=0.5, 1, 1.5, 2, 2.5. In the case of length 2 2m, dr is determined for any r, where 0⩽r⩽m and 2r is an integer. In addition, it is shown that it ... View full abstract»

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  • On the minimum distance of a q-ary image of a qm-ary cyclic code

    Publication Year: 1996, Page(s):1631 - 1635
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    We discuss a lower bound on the minimum distance of a q-ary image of qm-ary cyclic code, based on its concatenated structure due to Jensen (see ibid., vol.31, no.6, p.788-93, 1985) and Seguin (see ibid., vol.41, no.2, p.387-99, 1995). An explicit estimate for the minimum distance of the outer codes, which is analogous to the BCH bound, is derived. Complete lists of the values obtained f... View full abstract»

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  • Single-track Gray codes

    Publication Year: 1996, Page(s):1555 - 1561
    Cited by:  Papers (14)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    A particular class of Gray codes, called single-track Gray codes, is introduced. These codes have advantages over conventional Gray codes in certain practical applications. A simple construction for single-track Gray codes is given and it is shown how to obtain such codes for a large range of parameters of practical interest View full abstract»

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  • Improved binary codes and sequence families from Z4-linear codes

    Publication Year: 1996, Page(s):1582 - 1587
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB)

    A bound on exponential sums over Galois rings is used to construct a nested chain of Z4-linear binary codes and binary sequences. When compared with the chain of Delsarte-Goethals'(1975) codes, the codes in the new chain offer a larger minimum distance for the same code size. The binary sequence families constructed also make use of Nechaev's (1991) construction of a cyclic version of t... View full abstract»

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  • The existence of certain extremal [54,27,10] self-dual codes

    Publication Year: 1996, Page(s):1628 - 1631
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (324 KB)

    Some new extremal binary [54,27,10] self-dual codes are constructed using automorphisms of order 7 View full abstract»

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  • The intersymbol interference channel: lower bounds on capacity and channel precoding loss

    Publication Year: 1996, Page(s):1388 - 1404
    Cited by:  Papers (78)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1368 KB)

    The discrete-time additive Gaussian intersymbol interference (ISI) channel with i.i.d. (not necessarily Gaussian) input signals is considered. Several new and old lower bounds on the capacity are derived in a unified manner by assuming different front-end receiver filters, in particular the sampled whitened matched filter (SWMF) and the minimum mean-squared error-decision feedback equalizer (MMSE-... View full abstract»

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  • On the search for good aperiodic binary invertible sequences

    Publication Year: 1996, Page(s):1604 - 1612
    Cited by:  Papers (38)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (840 KB)

    For an aperiodic invertible sequence of length L, the optimality criterion is chosen to be the minimum noise enhancement factor of the corresponding aperiodic inverse filter. The noise enhancement factor is defined as the ratio of the noise energies at the outputs of the aperiodic inverse and the normalized matched filters of the sequence due to white noise at the filter inputs. Optimal binary seq... View full abstract»

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  • Recovering band-limited signals under noise

    Publication Year: 1996, Page(s):1425 - 1438
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (912 KB)

    We consider the problem of recovering a band-limited signal f(t) from noisy data yk=f(kτ)+≫epsilon/k, where τ is the sampling rate. Starting from the truncated Whittaker-Shannon cardinal expansion with or without sampling windows (both cases yield inconsistent estimates of f(t)) we propose estimators that are convergent to f(t) in the pointwise and uniform sense. The basic id... View full abstract»

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  • Information rates of pre/post-filtered dithered quantizers

    Publication Year: 1996, Page(s):1340 - 1353
    Cited by:  Papers (60)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1128 KB)

    We consider encoding of a source with pre-specified second-order statistics, but otherwise arbitrary, by entropy-coded dithered (lattice) quantization (ECDQ) incorporating linear pre- and post-filters. In the design and analysis of this scheme we utilize the equivalent additive-noise channel model of the ECDQ. For Gaussian sources and a square error distortion measure, the coding performance of th... View full abstract»

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  • Encoding of dklr-sequences using one weight set

    Publication Year: 1996, Page(s):1553 - 1554
    Cited by:  Papers (12)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB)

    Traditional schemes for encoding and decoding runlength-constrained sequences using the enumeration principle require two sets of weighting coefficients. A new enumeration is presented requiring only one set of coefficients View full abstract»

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  • Sample complexity for learning recurrent perceptron mappings

    Publication Year: 1996, Page(s):1479 - 1487
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (804 KB)

    Recurrent perceptron classifiers generalize the usual perceptron model. They correspond to linear transformations of input vectors obtained by means of “autoregressive moving-average schemes”, or infinite impulse response filters, and take into account those correlations and dependences among input coordinates which arise from linear digital filtering. This paper provides tight bounds ... View full abstract»

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  • On weak convergence of probability measures, channel capacity and code error probabilities

    Publication Year: 1996, Page(s):1549 - 1551
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (292 KB)

    The relationship between weak convergence of channel probability measures, channel capacity, and error probability of block codes is examined for memoryless channels with general input and output alphabets. It is shown that channel capacity is a lower semi-continuous function and that every block code with maximal probability of error δ for a nominal channel for any ε>0 can be modifi... View full abstract»

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  • Upper bounds on the minimum distance of spherical codes

    Publication Year: 1996, Page(s):1576 - 1581
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (484 KB)

    We use linear programming techniques to obtain new upper bounds on the maximal squared minimum distance of spherical codes with fixed cardinality. Functions Qj(n,s) are introduced with the property that Qj(n,s)<0 for some j>m if and only if the Levenshtein bound Lm(n,s) on A(n,s)=max{|W|:W is an (n,|W|,s) code} can be improved by a polynomial of degree at lea... View full abstract»

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  • Crosspoint complexity of sparse crossbar concentrators

    Publication Year: 1996, Page(s):1466 - 1471
    Cited by:  Papers (16)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (892 KB)

    A sparse crossbar (n,m,c)-concentrator is a bipartite graph with n inputs and m outputs in which any c or fewer inputs can be matched with an equal number of outputs, where c is called its capacity. We present a number of new results on the crosspoint complexity of such concentrators. First, we describe a sparse crossbar (n, m, m)-concentrator whose crosspoint complexity matches Nakamura-Masson's ... View full abstract»

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  • New ternary and quaternary linear block codes

    Publication Year: 1996, Page(s):1625 - 1628
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    We present several new ternary and quaternary codes found with a heuristic search procedure, originally proposed by the authors to find good binary codes, and which is based on combinatorial optimization View full abstract»

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  • First-order approximation of the ordered binary-symmetric channel

    Publication Year: 1996, Page(s):1381 - 1387
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (488 KB)

    Soft-decision decoding algorithms of binary linear block codes require reordering of the received symbols within each block in decreasing reliability. Efficient decoding algorithms based on reordering have been devised. This paper presents different results related to the ordering of a sequence of N received symbols with respect to their reliability measure, for BPSK transmission over the AWGN cha... View full abstract»

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  • Generation of discrete distributions from biased coins

    Publication Year: 1996, Page(s):1541 - 1546
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (556 KB)

    The procedure of Knuth and Yao (1976) to simulate random numbers with specified distribution by parsing sequences of fair coin tosses is generalized to employ discrete distributions of particular form instead of fair coins. Each probability in these distributions is an integral power of some fixed value t. The parse tree for the simulation procedure is closely related to the code trees arising in ... View full abstract»

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  • Codes spanned by quadratic and Hermitian forms

    Publication Year: 1996, Page(s):1600 - 1604
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (428 KB)

    We study the parameters of codes spanned by quadratic and Hermitian forms in projective space. The resulting codes have high minimum distance and few distinct weights. An example is a new ternary [91.9,54] code View full abstract»

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  • A note on bounds for q-ary covering codes

    Publication Year: 1996, Page(s):1640 - 1642
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    Two strongly seminormal codes over Z5 are constructed to prove a conjecture of Ostergard (see ibid., vol.37, no.3, p.660-4, 1991). It is shown that a result of Honkala (see ibid., vol.37, no.4, p.1203-6, 1991) on (k,t)-subnormal codes holds also under weaker assumptions. A lower bound and an upper bound on Kq(n, R), the minimal cardinality of a q-ary code of length n with cov... View full abstract»

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  • On the probability of error of convolutional codes

    Publication Year: 1996, Page(s):1562 - 1568
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (620 KB)

    New upper and lower bounds and approximations on the sequence, event, first event, and bit-error probabilities of convolutional codes are presented. Each of these probabilities are precisely defined and the relationship between them described. Some of the new bounds and approximations are found to be very close to computer simulations at very high error ratios. Simple modifications to the traditio... 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
Frank R. Kschischang

Department of Electrical and Computer Engineering