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IEEE Transactions on Information Theory

Issue 4 • Jul 1995

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Displaying Results 1 - 25 of 38
  • Trellis-oriented decomposition and trellis complexity of composite-length cyclic codes

    Publication Year: 1995, Page(s):1185 - 1191
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    The trellis complexity of composite-length cyclic codes (CLCC's) is addressed. We first investigate the trellis properties of concatenated and product codes in general. Known factoring of CLCC's into concatenated subcodes is thereby employed to derive upper bounds on the minimal trellis size and state-space profile. New decomposition of CLCC's into product subcodes is established and utilized to d... View full abstract»

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  • New optimal ternary linear codes

    Publication Year: 1995, Page(s):1182 - 1185
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    The class of quasi-twisted (QT) codes is a generalization of the class of quasi-cyclic codes, similar to the way constacyclic codes are a generalization of cyclic codes. In this paper, rate 1/p QT codes over GF(3) are presented which have been constructed using integer linear programming and heuristic combinatorial optimization. Many of these attain the maximum possible minimum distance for any li... View full abstract»

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  • Cosets of convolutional codes with short maximum zero-run lengths

    Publication Year: 1995, Page(s):1145 - 1150
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (496 KB)

    Communication systems and storage systems derive symbol synchronization from the received symbol stream. To facilitate symbol synchronization, the channel sequences must have a short maximum zero-run length. One way to achieve this is to use a coset of an (n, k) convolutional code to generate the channel inputs. For k⩽n-2, it is shown that there exist cosets with short maximum zero-run length ... View full abstract»

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  • A new construction for n-track (d, k) codes with redundancy

    Publication Year: 1995, Page(s):1107 - 1115
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    A new construction for n-track (d, k) codes with redundancy r, referred to as (d, k; n, r) codes, is presented. This construction applies single-track (d, k+Δk) codes (with certain extra constraints and appropriate amounts of delay) on each of the n tracks. This construction achieves a large part of the capacity increases possible when using (d, k; n, r) codes, has simple encoders and decode... View full abstract»

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  • Superimposed codes for the multiaccess binary adder channel

    Publication Year: 1995, Page(s):1178 - 1182
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    Superimposed codes for multiple-access communication in a binary adder channel are analyzed. The superposition mechanism used in this correspondence is ordinary addition. Each user is assigned a codeword from a superimposed code. It is proved that every constant-weight code C of weight w and maximal correlation c corresponds to a subclass of a disjunctive code D of order m<w/c. Therefore, any m... View full abstract»

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  • Statistics of the binary quantizer error in single-loop sigma-delta modulation with white Gaussian input

    Publication Year: 1995, Page(s):931 - 943
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (928 KB)

    Representations and statistical properties of the process e¯ defined by e¯n+1=λ(e¯n+ξn ), are given. Here λ(u):=u-b·sign(u)+m and {ξn}n=0+∞ is Gaussian white noise. The process e¯ represents the binary quantizer error in a model for single-loop sigma-delta modulation. The innovati... View full abstract»

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  • Proof of a conjecture of Sarwate and Pursley regarding pairs of binary m-sequences

    Publication Year: 1995, Page(s):1153 - 1155
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    Binary m-sequences are maximal length sequences generated by shift registers of length m, that are employed in navigation, radar, and spread-spectrum communications systems, because of their crosscorrelation properties. It is well known that given a pair of distinct m-sequences, the crosscorrelation function must take on at least three values. The article considers crosscorrelation functions that ... View full abstract»

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  • MMSE decision-feedback equalizers: finite-length results

    Publication Year: 1995, Page(s):961 - 975
    Cited by:  Papers (214)  |  Patents (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1020 KB)

    This paper extends a number of results on the infinite-length minimum-mean-square-error decision Feedback equalizer (MMSE-DFE) reported by Cioffi, Dudevoir, Eyuboglu and Forney (see IEEE Trans. Commun., 1995) to the finite-length case. Cholesky factorization and displacement structure theory are demonstrated to be two powerful analytical tools for analyzing the finite-length MMSE-DFE. Our objectiv... View full abstract»

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  • Threshold detection in correlated non-Gaussian noise fields

    Publication Year: 1995, Page(s):976 - 1000
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1728 KB)

    Classical threshold detection theory for arbitrary noise and signals, based on independent noise samples, i.e., using only the first-order probability density of the noise, is generalized to include the critical additional statistical information contained in the (first-order) covariances of the noise. This is accomplished by replacing the actual, generalized noise by a “quasi-equivalent&rdq... View full abstract»

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  • Upper bounds and Hamming spheres under the DC constraint

    Publication Year: 1995, Page(s):1138 - 1145
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    Upper bounds on the rate of codes in DC-constrained spaces are derived for imbalances 3, 4, and 5. The new bounds are based on the identification and size calculation of the minimal Hamming spheres. A new combination of the Hamming and Plotkin (1960) bounds for constrained spaces is obtained View full abstract»

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  • Rates of convergence of nearest neighbor estimation under arbitrary sampling

    Publication Year: 1995, Page(s):1028 - 1039
    Cited by:  Papers (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (808 KB)

    Rates of convergence for nearest neighbor estimation are established in a general framework in terms of metric covering numbers of the underlying space. The first result is to find explicit finite sample upper bounds for the classical independent and identically distributed (i.i.d.) random sampling problem in a separable metric space setting. The convergence rate is a function of the covering numb... View full abstract»

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  • The Leech lattice, the octacode, and decoding algorithms

    Publication Year: 1995, Page(s):1097 - 1106
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (836 KB)

    New multilevel constructions of the Golay code and the Leech lattice are presented. These are derived from the Turyn construction and the “holy construction” with the octacode as the glue code. Further, we show that the “holy construction” of the Leech lattice with the octacode as the glue code is essentially different from the permuted Turyn construction, although both con... View full abstract»

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  • Multiuser signaling in the symbol-synchronous AWGN channel

    Publication Year: 1995, Page(s):1174 - 1178
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (424 KB)

    Multiuser signal set design for the energy-constrained linear real-additive symbol-synchronous additive white Gaussian noise channel is investigated in this correspondence. An argument is presented showing the suboptimality of binary alphabets which, in turn, uncovers a rule for the formation of multiuser signal sets. This simple rule leads to a theorem stating the dimensionality at which addition... View full abstract»

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  • Variable-rate tree-structured vector quantizers

    Publication Year: 1995, Page(s):917 - 930
    Cited by:  Papers (17)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (884 KB)

    In general, growth algorithms for optimal tree-structured vector quantizers do not exist. In this paper we show that if the source satisfies certain conditions; namely, that of diminishing marginal returns; optimal growth algorithms do exist. We present such an algorithm and compare its performance with that of other tree growth algorithms. Even for sources that do not meet the necessary condition... View full abstract»

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  • Constructing a better cyclic code than cyclic Reed-Solomon code

    Publication Year: 1995, Page(s):1191 - 1194
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB)

    Problems of computing the generator polynomial for a (q+1, q-d+2) reversible cyclic BCH code over GF(q), q=pm, having the minimum Hamming distance d, are presented. The considered code is almost as short as a Reed-Solomon (RS) code but it generates codewords with two information symbols more than the codewords of RS code with the same minimum Hamming distance View full abstract»

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  • A coset correlation for sequences with two-valued periodic autocorrelation

    Publication Year: 1995, Page(s):1150 - 1153
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    Defines a new coset correlation that generalizes previous coset correlation results for m-sequences. This new correlation can be computed in terms of the coset sizes for any sequence that has a two-valued periodic autocorrelation function and that is constant on cosets. Thus the results apply to a larger family of periodic sequences than just m-sequences View full abstract»

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  • Error-correcting two-dimensional modulation codes

    Publication Year: 1995, Page(s):1116 - 1126
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1032 KB)

    Modulation coding, to limit the number of consecutive zeros in a data stream, is essential in digital magnetic recording/playback systems. Additionally, such systems require error-correction coding to ensure that the decoded output matches the recorder input, even if noise is present. Typically, these two coding steps have been performed independently, although various methods of combining them in... View full abstract»

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  • Blind adaptive multiuser detection

    Publication Year: 1995, Page(s):944 - 960
    Cited by:  Papers (1047)  |  Patents (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1440 KB)

    The decorrelating detector and the linear minimum mean-square error (MMSE) detector are known to be effective strategies to counter the presence of multiuser interference in code-division multiple-access channels; in particular, those multiuser detectors provide optimum near-far resistance. When training data sequences are available, the MMSE multiuser detector can be implemented adaptively withou... View full abstract»

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  • Properties of the x2 mod N pseudorandom number generator

    Publication Year: 1995, Page(s):1155 - 1159
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB)

    In 1986, L. Blum, R.I. Blum, and M. Shub introduced the x2 mod N generator of pseudorandom bit strings and showed, given certain plausible but unproved hypotheses, that it has the desirable cryptographic property of unpredictability. They also studied the period length of the sequences produced by this generator and proposed a way to guarantee that these sequences will have maximum pos... View full abstract»

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  • The capacity of average and peak-power-limited quadrature Gaussian channels

    Publication Year: 1995, Page(s):1060 - 1071
    Cited by:  Papers (102)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1068 KB)

    The capacity C(ρa, ρp) of the discrete-time quadrature additive Gaussian channel (QAGC) with inputs subjected to (normalized) average and peak power constraints, ρa and ρp respectively, is considered. By generalizing Smith's results for the scalar average and peak-power-constrained Gaussian channel, it is shown that the capacity achieving... View full abstract»

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  • Nonlinear filters for linear models (a robust approach)

    Publication Year: 1995, Page(s):1001 - 1009
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    We consider the altering problem for linear models where the driving noises may be quite general, nonwhite and non-Gaussian, and where the observation noise may only be known to belong to a finite family of possible disturbances. Using diffusion approximation methods, we show that a certain nonlinear filter minimizes the asymptotic filter variance. This nonlinear filter is obtained by choosing at ... View full abstract»

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  • Fast parallel algorithms for decoding Reed-Solomon codes based on remainder polynomials

    Publication Year: 1995, Page(s):873 - 885
    Cited by:  Papers (18)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (848 KB)

    The problem of decoding cyclic error correcting codes is one of solving a constrained polynomial congruence, often achieved using the Berlekamp-Massey or the extended Euclidean algorithm on a key equation involving the syndrome polynomial. A module-theoretic approach to the solution of polynomial congruences is developed here using the notion of exact sequences. This technique is applied to the We... View full abstract»

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  • New directions in the theory of identification via channels

    Publication Year: 1995, Page(s):1040 - 1050
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (728 KB)

    Studies two problems in the theory of identification via channels. The first problem concerns the identification via channels with noisy feedback. Whereas for Shannon's transmission problem the capacity of a discrete memoryless channel does not change with feedback, it is known that the identification capacity is affected by feedback. The authors study its dependence on the feedback channel. They ... View full abstract»

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  • A counterexample to a Voronoi region conjecture

    Publication Year: 1995, Page(s):1195 - 1196
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    Given a 2D-symmetric lattice Λ, it was conjectured by Forney (1989) that the projection of the Voronoi region R(Λ) onto two coordinates equals the Voronoi region of the constituent 2D-sublattice Λν2. We present a three-dimensional counterexample View full abstract»

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  • Decoding algorithms with input quantization and maximum error correction capability

    Publication Year: 1995, Page(s):1126 - 1133
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (604 KB)

    Decoding that uses soft-decision information but with multiple low-complexity decoders are investigated. These decoders correct only errors and erasures. The structure of the receiver consists of a bank of z demodulators followed by errors- and erasures-correcting decoders operating in parallel. Each demodulator has a threshold for determining when to erase a given symbol. We assign a cost f(&thet... 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