IEEE Transactions on Information Theory

Volume 41 Issue 2 • March 1995

Filter Results

Displaying Results 1 - 25 of 38
  • Multiple description source coding with no excess marginal rate

    Publication Year: 1995, Page(s):349 - 357
    Cited by:  Papers (27)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (941 KB)

    Multiple description source coding concerns situations in which the transmission of the source information is distributed over two data streams at rates R/sub 1/ and R/sub 2/, respectively. When both data streams are received, the decoder uses the combined data at rate R/sub 1/+R/sub 2/ to reconstruct the source information with average distortion d/sub 0/. If a communication breakdown prevents on... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Scheduling nonuniform traffic in a packet switching system with large propagation delay

    Publication Year: 1995, Page(s):358 - 365
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (793 KB)

    Transmission algorithms are introduced for use in a single-hop packet switching system with nonuniform traffic and with propagation delay that Is large relative to the packet transmission time. The traffic model allows arbitrary traffic streams subject only to a constraint on the number of data packets which can arrive at any individual source in the system or for any individual destination in the... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Quaternary quadratic residue codes and unimodular lattices

    Publication Year: 1995, Page(s):366 - 377
    Cited by:  Papers (85)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1351 KB)

    We construct new self-dual and isodual codes over the integers module 4. The binary images of these codes under the Gray map are nonlinear, but formally self-dual. The construction involves Hensel lifting of binary cyclic codes. Quaternary quadratic residue codes are obtained by Hensel lifting of the classical binary quadratic residue codes. Repeated Hensel lifting produces a universal code define... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The automorphism groups of the generalized quadratic residue codes

    Publication Year: 1995, Page(s):378 - 386
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1221 KB)

    We give the full automorphism groups as groups of semiaffine transformations, of the extended generalized quadratic residue codes. We also present a proof of the Gleason-Prange theorem for the extended generalized quadratic residue codes that relies only on their definition and elementary theory of linear characters.<<ETX>> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The q-ary image of a q/sup m/-ary cyclic code

    Publication Year: 1995, Page(s):387 - 399
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1618 KB)

    For (n, q)=1 V a q/sup m/-ary cyclic code of length n and with generator polynomial g(x), we show that there exists a basis for F(q/sup m/) over F/sub q/ with respect to which the q-ary image of V is cyclic, if and only if: (i) g(x) is over F/sub q/; or (ii) g(x)=g/sub 0/(x)(x-/spl gammasup -q(/spl mu/)/), g/sub 0/(x) is over F/sub q/, F/sub qspl ne/F(q/sup k/)=F/sub q/(/spl gamma/)/spl sub/F(q/su... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Theory and applications of q-ary interleaved sequences

    Publication Year: 1995, Page(s):400 - 411
    Cited by:  Papers (102)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1440 KB)

    A new class of q-ary sequences, called interleaved sequence, is introduced. Their periods, shift equivalence, linear spans, and autocorrelation functions are derived. The interleaved sequences include a large number of popular sequences, such as multiplexed sequences, clock-controlled sequences, Kasami (1966) sequences, GMW sequences, geometric sequences, and No (1989) sequences. A special class o... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multilevel diversity coding with distortion

    Publication Year: 1995, Page(s):412 - 422
    Cited by:  Papers (84)  |  Patents (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1198 KB)

    In a Diversity Coding System, an information source is encoded by a number of encoders. There are a number of decoders, each of which can access a certain subset of the encoders. We study a diversity coding problem in which there are two levels of decoders. The reconstructions of the source by decoders within the same level are identical, and are subject to the same distortion criterion. Our resul... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • d-form sequences: families of sequences with low correlation values and large linear spans

    Publication Year: 1995, Page(s):423 - 431
    Cited by:  Papers (57)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1026 KB)

    Large families of binary sequences with low correlation values and large linear span are critical for spread-spectrum communication systems. The author describes a method for constructing such families from families of homogeneous functions over finite fields, satisfying certain properties. He then uses this general method to construct specific families of sequences with optimal correlations and e... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Bounds on the minimum support weights

    Publication Year: 1995, Page(s):432 - 440
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (999 KB)

    The minimum support weight, d/sub r/(C), of a linear code C over GF(q) is the minimal size of the support of an r-dimensional subcode of C. A number of bounds on d/sub r/(C) are derived, generalizing the Plotkin bound and the Griesmer bound, as well as giving two new existential bounds. As the main result, it is shown that there exist codes of any given rate R whose ratio d/sub rd/sub 1/ is lower ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On a technique to calculate the exact performance of a convolutional code

    Publication Year: 1995, Page(s):441 - 447
    Cited by:  Papers (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (732 KB)

    A Markovian technique is described to calculate the exact performance of the Viterbi algorithm used as either a channel decoder or a source encoder for a convolutional code. The probability of information bit error and the expected Hamming distortion are computed for codes of various rates and constraint lengths. The concept of tie-breaking rules is introduced and its influence on decoder performa... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • New constructions of optimal cyclically permutable constant weight codes

    Publication Year: 1995, Page(s):448 - 455
    Cited by:  Papers (57)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (852 KB)

    Three new constructions for families of cyclic constant weight codes are presented. All are asymptotically optimum in the sense that in each case, as the length of the sequences within the family approaches infinity, the ratio of family size to the maximum possible under the Johnson upper bound, approaches unity.<<ETX>> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An upper bound for Weil exponential sums over Galois rings and applications

    Publication Year: 1995, Page(s):456 - 468
    Cited by:  Papers (78)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1400 KB)

    We present an analog of the well-known Weil-Carlitz-Uchiyama (1948, 1957) upper bound for exponential sums over finite fields for exponential sums over Galois rings. Some examples are given where the bound is tight. The bound has immediate application to the design of large families of phase-shift-keying sequences having low correlation and an alphabet of size p/sup e/. p, prime, e/spl ges/2. Some... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The threshold probability of a code

    Publication Year: 1995, Page(s):469 - 477
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (949 KB)

    We define and estimate the threshold probability /spl theta/ of a linear code, using a theorem of Margulis (1974) originally conceived for the study of the probability of disconnecting a graph. We then apply this concept to the study of the erasure and Z-channels, for which we propose linear coding schemes that admit simple decoding. We show that /spl theta/ is particularly relevant to the erasure... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Average profile and limiting distribution for a phrase size in the Lempel-Ziv parsing algorithm

    Publication Year: 1995, Page(s):478 - 488
    Cited by:  Papers (29)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1314 KB)

    Consider the parsing algorithm developed by Lempel and Ziv (1978) that partitions a sequence of length n into variable phrases (blocks) such that a new block is the shortest substring not seen in the past as a phrase. In practice, the following parameters are of interest: number of phrases, the size of a phrase, the number of phrases of given size, and so forth. In this paper, we focus on the size... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Convergence analysis of the sign algorithm for adaptive filtering

    Publication Year: 1995, Page(s):489 - 495
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (729 KB)

    We consider the convergence analysis of the sign algorithm for adaptive filtering when the input processes are uncorrelated and Gaussian and a fixed step size /spl mu/>0 is used. Exact recursive equations for the covariance matrix of the deviation error are established for any step size /spl mu/>0. Asymptotic time-averaged convergence for the mean-absolute deviation error, mean-square deviat... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Interference suppression by biased nonlinearities

    Publication Year: 1995, Page(s):496 - 507
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1215 KB)

    It is shown that, when the input signal-to-interference ratio (SIR) is small, a biased nonlinearity that has a dead zone below some threshold value can provide a large enhancement in output SIR and signal-to-interference-plus-intermodulation ratio (SIIMR) if the threshold is set equal or close to the amplitude of the strong interference. In the absence of noise, the output SIR and SIIMIR are virtu... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Balanced nonbinary sequences with good periodic correlation properties obtained from modified Kumar-Moreno sequences

    Publication Year: 1995, Page(s):572 - 576
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (897 KB)

    Kumar and Moreno (see ibid., vol.37, no.3, p.603, 1991) presented a new family of nonbinary sequences which has not only good periodic correlation properties but also the largest family size. First, the unbalanced properties for Kumar-Moreno sequences are pointed out. Second, a new family of balanced nonbinary sequences obtained from modified Kumar-Moreno sequences is proposed, and it is shown tha... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • QPSK block-modulation codes for unequal error protection

    Publication Year: 1995, Page(s):576 - 581
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (980 KB)

    Unequal error protection (UEP) codes find applications in broadcast channels, as well as in other digital communication systems, where messages have different degrees of importance. Binary linear UEP (LUEP) codes combined with a Gray mapped QPSK signal set are used to obtain new efficient QPSK block-modulation codes for unequal error protection. Several examples of QPSK modulation codes that have ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The nonexistence of some five-dimensional quaternary linear codes

    Publication Year: 1995, Page(s):581 - 583
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    Let n/sub 4/(k, d) be the smallest integer n, such that a quaternary linear [n, k, d; 4]-code exists. It is proved that n/sub 4/(5, 20)=30, n/sub 4/(5, 42)/spl ges/59, n/sub 4/(5, 45)/spl ges/63, n/sub 4/(5, 64)/spl ges/88, n/sub 4/(5, 80)=109, n/sub 4/(5, 140)/spl ges/189, n/sub 4/(5, 143)/spl ges/193, n/sub 4/(5, 168)/spl ges/226, n/sub 4/(5, 180)/spl ges/242, n/sub 4/(5, 183)/spl ges/246, n/sub... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Universal redundancy rates for the class of B-processes do not exist

    Publication Year: 1995, Page(s):508 - 512
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (925 KB)

    Shows that for any sequence /spl rho/(n)=o(n) and any sequence of prefix codes, there is a B-process of entropy arbitrarily close to the maximum possible entropy for which the expected redundancy is at least as large as /spl rho/(n) for infinitely many n. This extends work of Shields (1993), whose examples had O entropy. The class of B-processes, that is, stationary codings of independent and iden... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Distributed cell-averaging CFAR detection in dependent sensors

    Publication Year: 1995, Page(s):513 - 518
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (834 KB)

    Constant false alarm rate detection is considered in a decentralized, two-sensor context. Cases with observations which are dependent from sensor to sensor are investigated, for which results have been lacking. The in-phase and quadrature components of the received narrowband observation at each sensor consist of a common weak random signal in additive Gaussian combined clutter and noise. The sens... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Distributed detection of narrowband signals

    Publication Year: 1995, Page(s):519 - 523
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (752 KB)

    Distributed signal detection schemes have received significant attention, but most research has focused on cases with independent observations at the different sensors. Cases with dependent narrowband signals, which are of practical interest in communication, radar, and sonar problems, are studied. The focus is on applications where the observations consist of a weak common signal in possibly non-... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Construction techniques for systematic SEC-DED codes with single byte error detection and partial correction capability for computer memory systems

    Publication Year: 1995, Page(s):584 - 591
    Cited by:  Papers (6)  |  Patents (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1171 KB)

    Three new techniques are proposed for constructing a class of codes that extends the protection provided by previous single error correcting (SEC)-double error detecting (DED)-single byte error detecting (SBD) codes. The proposed codes are systematic odd-weight-column SEC-DED-SBD codes providing also the correction of any odd number of erroneous bits per byte, where a byte represents a cluster of ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Bounded minimum distance decoding of unit memory codes

    Publication Year: 1995, Page(s):591 - 596
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (972 KB)

    We propose an algorithm for bounded minimum distance decoding of (partial) unit memory codes up to half the "designed" extended row distance. It makes use of a reduced trellis with the nodes found by bounded minimum distance decoding of the block codes used in the unit memory code. The results can be extended to general multimemory codes. The complexity of this algorithm is upper bounded by 2(d~/s... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Coding with digits of unequal cost

    Publication Year: 1995, Page(s):596 - 600
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (920 KB)

    At present, optimal coding for a noiseless digital channel with digits of unequal cost requires solving a large linear programming problem. Much simpler procedures give codes, resembling Shannon's (1948) and Huffman's, that are found close to optimal in tests with typical sources and channels.<<ETX>> View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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