IEEE Transactions on Information Theory

Volume 43 Issue 5 • Sept. 1997

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Displaying Results 1 - 25 of 46
  • A practical method for approaching the channel capacity of constrained channels

    Publication Year: 1997, Page(s):1389 - 1399
    Cited by:  Papers (65)  |  Patents (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (336 KB)

    A new coding technique is proposed that translates user information into a constrained sequence using very long codewords. Huge error propagation resulting from the use of long codewords is avoided by reversing the conventional hierarchy of the error control code and the constrained code. The new technique is exemplified by focusing on (d, k)-constrained codes. A storage-effective enumerative enco... View full abstract»

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  • On Diamond codes

    Publication Year: 1997, Page(s):1400 - 1411
    Cited by:  Papers (5)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (447 KB)

    A Diamond code is an error-correcting code obtained from two component codes. As in a product code, any symbol in a word of a Diamond code is checked by both component codes. However, the "code directions" for the component codes have been selected to minimize the memory that is required between successive decoding stages for the component codes. Diamond codes combine the error correcting power of... View full abstract»

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  • Tradeoff between source and channel coding

    Publication Year: 1997, Page(s):1412 - 1424
    Cited by:  Papers (99)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (630 KB)

    A fundamental problem in the transmission of analog information across a noisy discrete channel is the choice of channel code rate that optimally allocates the available transmission rate between lossy source coding and block channel coding. We establish tight bounds on the channel code rate that minimizes the average distortion of a vector quantizer cascaded with a channel coder and a binary-symm... View full abstract»

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  • Probabilistic crisscross error correction

    Publication Year: 1997, Page(s):1425 - 1438
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (769 KB)

    The crisscross error model in data arrays is considered, where the corrupted symbols are confined to a prescribed number of rows or columns (or both). Under the additional assumption that the corrupted entries are uniformly distributed over the channel alphabet, and by allowing a small decoding error probability, a coding scheme is presented where the redundancy can get close to one half the redun... View full abstract»

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  • A suboptimal lossy data compression based on approximate pattern matching

    Publication Year: 1997, Page(s):1439 - 1451
    Cited by:  Papers (54)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (699 KB)

    A practical suboptimal (variable source coding) algorithm for lossy data compression is presented. This scheme is based on approximate string matching, and it naturally extends the lossless Lempel-Ziv (1977) data compression scheme. Among others we consider the typical length of an approximately repeated pattern within the first n positions of a stationary mixing sequence where D percent of mismat... View full abstract»

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  • The redundancy and distribution of the phrase lengths of the fixed-database Lempel-Ziv algorithm

    Publication Year: 1997, Page(s):1452 - 1464
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (753 KB)

    The fixed-database version of the Lempel-Ziv algorithm closely resembles many versions that appear in practice. We ascertain several key asymptotic properties of the algorithm as applied to sources with finite memory. First, we determine that for a dictionary of size n, the algorithm achieves a redundancy /spl rho//sub n/=Hlog log n/log n+0(log log n/log n) where H is the entropy of the process. T... View full abstract»

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  • Fixed-slope universal lossy data compression

    Publication Year: 1997, Page(s):1465 - 1476
    Cited by:  Papers (44)  |  Patents (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (623 KB)

    Corresponding to any lossless codeword length function l, three universal lossy data compression schemes are presented: one is with a fixed rate, another is with a fixed distortion, and a third is with a fixed slope. The former two universal lossy data compression schemes are the generalization of Yang-Kieffer's (see ibid., vol.42, no.1, p.239-45, 1995) results to the general case of any lossless ... View full abstract»

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  • On acceptance criterion for efficient successive errors-and-erasures decoding of Reed-Solomon and BCH codes

    Publication Year: 1997, Page(s):1477 - 1488
    Cited by:  Papers (7)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (720 KB)

    We describe an efficient algorithm for successive errors-and-erasures decoding of BCH codes. The decoding algorithm consists of finding all necessary error locator polynomials and errata evaluator polynomials, choosing the most appropriate error locator polynomial and errata evaluator polynomial, using these two polynomials to compute a candidate codeword for the decoder output, and testing the ca... View full abstract»

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  • A lower bound on the undetected error probability and strictly optimal codes

    Publication Year: 1997, Page(s):1489 - 1502
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (818 KB)

    Error detection is a simple technique used in various communication and memory systems to enhance reliability. We study the probability that a q-ary (linear or nonlinear) block code of length n and size M fails to detect an error. A lower bound on this undetected error probability is derived in terms of q, n, and M. The new bound improves upon other bounds mentioned in the literature, even those t... View full abstract»

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  • A multiuser approach to narrowband cellular communications

    Publication Year: 1997, Page(s):1503 - 1517
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (679 KB)

    We compare three receivers for coded narrowband transmission affected by fading and co-channel interference. The baseline receiver is based on conventional diversity reception with maximal-ratio combining. A multiuser approach allows us to derive a maximum-likelihood multiuser receiver and its reduced-complexity suboptimal version. Finally, a decorrelating diversity receiver, which seeks a tradeof... View full abstract»

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  • Optimal multiplexing on a single link: delay and buffer requirements

    Publication Year: 1997, Page(s):1518 - 1535
    Cited by:  Papers (89)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (734 KB)

    This paper is motivated by the need to provide per-session quality of service guarantees in fast packet-switched networks. We address the problem of characterizing and designing scheduling policies that are optimal in the sense of minimizing buffer and/or delay requirements under the assumption of commonly accepted traffic constraints. We investigate buffer requirements under three typical memory ... View full abstract»

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  • A hyperplane-based algorithm for the digital co-channel communications problem

    Publication Year: 1997, Page(s):1536 - 1548
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (643 KB)

    The relationship between the blind digital co-channel communications problem and the problem of finding a separating hyperplane in IR/sup d/ is explored. A simple model for the blind digital co-channel communications problem is X=AS, where X is a known IR/sup d/spl times/N/ matrix. A is an unknown full-rank IR/sup d/spl times/d/ matrix, and S is an unknown full-rank d/spl times/N matrix with eleme... View full abstract»

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  • The quadratic Gaussian CEO problem

    Publication Year: 1997, Page(s):1549 - 1559
    Cited by:  Papers (158)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (582 KB)

    A firm's CEO employs a team of L agents who observe independently corrupted versions of a data sequence {X(t)}/sub t=1//sup /spl infin//. Let R be the total data rate at which the agents may communicate information about their observations to the CEO. The agents are not allowed to convene. Berger, Zhang and Viswanathan (see ibid., vol.42, no.5, p.887-902, 1996) determined the asymptotic behavior o... View full abstract»

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  • Gauss-Markov random fields (CMrf) with continuous indices

    Publication Year: 1997, Page(s):1560 - 1573
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (668 KB)

    Gauss-Markov random fields (GMrfs) play an important role in the modeling of physical phenomena. The paper addresses the second-order characterization and the sample path description of GMrf's when the indexing parameters take values in bounded subsets of /spl Rfr//sup d/, d/spl ges/1. Using results of Pitt (1994), we give conditions for the covariance of a GMrf to be the Green's function of a par... View full abstract»

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  • Stochastic iterative algorithms for signal set design for Gaussian channels and optimality of the L2 signal set

    Publication Year: 1997, Page(s):1574 - 1587
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (757 KB)

    We propose a stochastic iteration approach to signal set design. Four practical stochastic iterative algorithms are proposed with respect to equal and average energy constraints and sequential and batch modes. By simulation, a new optimal signal set, the L2 signal set (consisting of a regular simplex set of three signals and some zero signals), is found under the strong simplex conjecture (SSC) co... View full abstract»

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  • The Nordstrom-Robinson code is algebraic-geometric

    Publication Year: 1997, Page(s):1588 - 1593
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (255 KB)

    The techniques of algebraic geometry have been widely and successfully applied to the study of linear codes over finite fields since the early 1980s. There has also been an increased interest in the study of linear codes over finite rings. In a previous paper, we combined these two approaches to coding theory by introducing and studying algebraic-geometric codes over rings. We show that the Nordst... View full abstract»

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  • On the aperiodic and odd correlations of the binary Shanbhag-Kumar-Helleseth sequences

    Publication Year: 1997, Page(s):1593 - 1596
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    A previously derived upper bound on hybrid sums over Galois rings is combined with a method due to Vinogradov (1954) to obtain an upper bound for the maximum aperiodic and odd correlations of the binary sequences constructed by Shanbhag, Kumar, and Helleseth (see Proc. 1995 IEEE Int. Symp. on Information Theory, 1995). View full abstract»

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  • New construction for families of binary sequences with optimal correlation properties

    Publication Year: 1997, Page(s):1596 - 1602
    Cited by:  Papers (15)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (319 KB)

    We present a construction, in a closed form, for an optimal family of 2/sup m/ binary sequences of period 2/sup 2m/-1 with respect to Welch's (1974) bound, whenever there exists a balanced binary sequence of period 2/sup m/-1 with ideal autocorrelation property using the trace function. This construction enables us to reinterpret a small set of Kasami and No (1988) sequences as a family constructe... View full abstract»

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  • Is code equivalence easy to decide?

    Publication Year: 1997, Page(s):1602 - 1604
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (100 KB)

    We study the computational difficulty of deciding whether two matrices generate equivalent linear codes, i.e., codes that consist of the same codewords up to a fixed permutation on the codeword coordinates. We call this problem code equivalence. Using techniques from the area of interactive proofs, we show on the one hand, that under the assumption that the polynomial-time hierarchy does not colla... View full abstract»

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  • The generalized Gilbert-Varshamov bound is implied by Turan's theorem [code construction]

    Publication Year: 1997, Page(s):1605 - 1606
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (68 KB)

    The generalization of the Gilbert-Varshamov bound due to Gu and Fuja (1993) is a direct consequence of Turan's theorem on the existence of a clique in a graph with many edges. Turan's theorem allows a slight improvement of Gu and Fuja's result. This improved generalized Gilbert-Varshamov bound is in fact equivalent to Turan's theorem. View full abstract»

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  • New extremal self-dual codes of lengths 42 and 44

    Publication Year: 1997, Page(s):1607 - 1612
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    All extremal binary self-dual codes of lengths 42 and 44 which have an automorphism of order 5 with eight independent cycles are obtained up to equivalence. There are 109 inequivalent [42, 21, 8] codes with such an automorphism. All [44, 22, 8] codes that are obtained have 29 different weight enumerators. View full abstract»

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  • Characterization of quaternary extremal codes of lengths 18 and 20

    Publication Year: 1997, Page(s):1613 - 1616
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (182 KB)

    We prove that, up to equivalence, there is a unique extremal quaternary Hermitian self-dual code of length 18, and that there are two inequivalent extremal quaternary Hermitian self-dual codes of length 20. View full abstract»

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  • Long packing and covering codes

    Publication Year: 1997, Page(s):1617 - 1619
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (174 KB)

    We study geometrically the domain of linear binary codes and of unrestricted binary codes in the plane (normalized covering radius, normalized minimal distance). View full abstract»

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  • New single asymmetric error-correcting codes

    Publication Year: 1997, Page(s):1619 - 1623
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (234 KB)

    New single asymmetric error-correcting codes are proposed. These codes are better than existing codes when the code length n is greater than 10, except for n=12 and n=15. In many cases one can construct a code C containing at least [2/sup n//n] codewords. It is known that a code with |C|/spl ges/[2/sup n//(n+1)] can be easily obtained. It should be noted that the proposed codes for n=12 and n=15 a... View full abstract»

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  • New constant weight codes from linear permutation groups

    Publication Year: 1997, Page(s):1623 - 1630
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (313 KB)

    New constant weight codes are found by considering certain linear permutation groups. A code is obtained as a collection of orbits of words under such a group. This leads to a difficult optimization problem, where a stochastic search heuristic, tabu search, is used to find good solutions in a feasible amount of time. Nearly 40 new codes of length at most 28 are presented. 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