IEEE Transactions on Information Theory

Volume 45 Issue 5 • July 1999

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Displaying Results 1 - 25 of 45
  • Multilevel codes: theoretical concepts and practical design rules

    Publication Year: 1999, Page(s):1361 - 1391
    Cited by:  Papers (507)  |  Patents (59)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (713 KB)

    This paper deals with 2/sup l/-ary transmission using multilevel coding (MLC) and multistage decoding (MSD). The known result that MLC and MSD suffice to approach capacity if the rates at each level are appropriately chosen is reviewed. Using multiuser information theory, it is shown that there is a large space of rate combinations such that MLC and full maximum-likelihood decoding (MLD) can appro... View full abstract»

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  • On the complexity of minimum distance decoding of long linear codes

    Publication Year: 1999, Page(s):1392 - 1405
    Cited by:  Papers (14)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (315 KB)

    We suggest a decoding algorithm of q-ary linear codes, which we call supercode decoding. It ensures the error probability that approaches the error probability of minimum-distance decoding as the length of the code grows. For n/spl rarr//spl infin/ the algorithm has the maximum-likelihood performance. The asymptotic complexity of supercode decoding is exponentially smaller than the complexity of a... View full abstract»

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  • Geometrical and performance analysis of GMD and Chase decoding algorithms

    Publication Year: 1999, Page(s):1406 - 1422
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    The overall number of nearest neighbors in bounded distance decoding (BDD) algorithms is given by N/sub 0,eff/=N/sub 0/+N/sub BDD/. Where NBDD denotes the number of additional, non-codeword, neighbors that are generated during the (suboptimal) decoding process. We identify and enumerate the nearest neighbors associated with the original generalized minimum distance (GMD) and Chase (1972) decoding ... View full abstract»

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  • On algebraic decoding of the Z/sub 4/-linear Calderbank-McGuire code

    Publication Year: 1999, Page(s):1423 - 1434
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (354 KB)

    The quaternary Calderbank-McGuire (see Des., Codes Cryptogr., vol.10, no.2, 1997) code is a Z/sub 4/-linear code of length 32 which has 2/sup 37/ codewords and a minimum Lee distance of 12. The Gray map of this code is known to be a nonlinear binary (64, 2/sup 37/,12) code. The Z/sub 4/-linear Calderbank-McGuire code can correct all errors with Lee weight /spl les/5. An algebraic decoding algorith... View full abstract»

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  • Minimal tail-biting trellises: the Golay code and more

    Publication Year: 1999, Page(s):1435 - 1455
    Cited by:  Papers (85)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (551 KB)

    Tail-biting trellis representations of block codes are investigated. We develop some elementary theory, and present several intriguing examples, which we hope will stimulate further developments in this field. In particular, we construct a 16-state 12-section structurally invariant tail-biting trellis for the (24, 12, 8) binary Golay code. This tail-biting trellis representation is minimal: it sim... View full abstract»

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  • Space-time block codes from orthogonal designs

    Publication Year: 1999, Page(s):1456 - 1467
    Cited by:  Papers (4737)  |  Patents (246)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (241 KB)

    We introduce space-time block coding, a new paradigm for communication over Rayleigh fading channels using multiple transmit antennas. Data is encoded using a space-time block code and the encoded data is split into n streams which are simultaneously transmitted using n transmit antennas. The received signal at each receive antenna is a linear superposition of the n transmitted signals perturbed b... View full abstract»

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  • Optimum power control over fading channels

    Publication Year: 1999, Page(s):1468 - 1489
    Cited by:  Papers (527)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (626 KB)

    We study optimal constant-rate coding schemes for a block-fading channel with strict transmission delay constraint, under the assumption that both the transmitter and the receiver have perfect channel-state information. We show that the information outage probability is minimized by concatenating a standard "Gaussian" code with an optimal power controller, which allocates the transmitted power dyn... View full abstract»

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  • Design of successively refinable trellis-coded quantizers

    Publication Year: 1999, Page(s):1490 - 1497
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (178 KB)

    We propose successively refinable trellis-coded quantizers for progressive transmission. (Progressive transmission is an essential component of image and multimedia browsing systems.) A new trellis structure which is scalable is used in the design of our trellis-coded quantizers. A hierarchical set partitioning is developed to preserve successive refinability. Two algorithms for designing trellis-... View full abstract»

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  • Low-complexity sequential lossless coding for piecewise-stationary memoryless sources

    Publication Year: 1999, Page(s):1498 - 1519
    Cited by:  Papers (41)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (580 KB)

    Three strongly sequential, lossless compression schemes, one with linearly growing per-letter computational complexity, and two with fixed per-letter complexity, are presented and analyzed for memoryless sources with abruptly changing statistics. The first method, which improves on Willems' (1994) weighting approach, asymptotically achieves a lower bound on the redundancy, and hence is optimal. Th... View full abstract»

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  • A semi-continuous version of the Berger-Yeung problem

    Publication Year: 1999, Page(s):1520 - 1526
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (197 KB)

    We present a continuous dual of multiterminal source encoding with one distortion criterion (the "Berger-Yeung (1989) problem"). A continuous source X is encoded with "high resolution" (D/sub x//spl rarr/0), with the aid of a "helper," i.e., a correlated discrete or continuous source Y, that is encoded separately subject to some arbitrary distortion criterion D/sub y/. We find the asymptotic form ... View full abstract»

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  • On the capacity of two-dimensional run-length constrained channels

    Publication Year: 1999, Page(s):1527 - 1540
    Cited by:  Papers (76)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (792 KB)

    Two-dimensional binary patterns that satisfy one-dimensional (d, k) run-length constraints both horizontally and vertically are considered. For a given d and k, the capacity C/sub d,k/ is defined as C/sub d,k/=lim/sub m,n/spl rarr//spl infin//log/sub 2/N/sub m,n//sup d,k//mn, where N/sub m,n//sup d,k/ denotes the number of m/spl times/n rectangular patterns that satisfy the two-dimensional (d,k) r... View full abstract»

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  • Efficient estimation of neural weights by polynomial approximation

    Publication Year: 1999, Page(s):1541 - 1550
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (235 KB)

    It has been known for some years that the uniform-density problem for forward neural networks has a positive answer: any real-valued, continuous function on a compact subset of R/sup d/ can be uniformly approximated by a sigmoidal neural network with one hidden layer. We design here algorithms for efficient uniform approximation by a certain class of neural networks with one hidden layer which we ... View full abstract»

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  • Efficient digital-to-analog encoding

    Publication Year: 1999, Page(s):1551 - 1554
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (82 KB)

    An important issue in analog circuit design is the problem of digital-to-analog conversion, i.e., the encoding of Boolean variables into a single analog value which contains enough information to reconstruct the values of the Boolean variables. A natural question is: what is the complexity of implementing the digital-to-analog encoding function? That question was answered by Wegener (see Inform. P... View full abstract»

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  • Minimum rate sampling and reconstruction of signals with arbitrary frequency support

    Publication Year: 1999, Page(s):1555 - 1564
    Cited by:  Papers (63)  |  Patents (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (205 KB)

    We examine the question of reconstruction of signals from periodic nonuniform samples. This involves discarding samples from a uniformly sampled signal in some periodic fashion. We give a characterization of the signals that can be reconstructed at exactly the minimum rate once a nonuniform sampling pattern has been fixed. We give an implicit characterization of the reconstruction system, and a de... View full abstract»

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  • A new look at entropy for solving linear inverse problems

    Publication Year: 1999, Page(s):1565 - 1578
    Cited by:  Papers (26)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (461 KB)

    Entropy-based methods are widely used for solving inverse problems, particularly when the solution is known to be positive. Here, we address linear ill-posed and noisy inverse problems of the form z=Ax+n with a general convex constraint x/spl isin/X, where X is a convex set. Although projective methods are well adapted to this context, we study alternative methods which rely highly on some "inform... View full abstract»

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  • Stability of N interacting queues in random-access systems

    Publication Year: 1999, Page(s):1579 - 1587
    Cited by:  Papers (145)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (219 KB)

    We revisit the stability problem of systems consisting of N buffered terminals accessing a common receiver over the collision channel by means of the standard ALOHA protocol. We find that in the slotted ALOHA system queues have "instability rank" based on their individual average arrival rates and transmission probabilities. If a queue is stable, then the queue with lower instability rank is stabl... View full abstract»

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  • Time-driven fluid simulation for high-speed networks

    Publication Year: 1999, Page(s):1588 - 1599
    Cited by:  Papers (45)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (257 KB)

    We propose to use time-driven fluid simulation to simulate high-speed networks. In this simulation scheme, network elements are modeled as fluid servers yet the traffic source can be of arbitrary type, including a discrete-event source and fluid source. We prove that for single class fluid, the discretization error is within a deterministic bound proportional to the discretization interval length ... View full abstract»

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  • Efficient generation of fair dice with few biased coins

    Publication Year: 1999, Page(s):1600 - 1606
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (237 KB)

    Given a random variable X which takes n equiprobable values, we consider several algorithmic questions related to the classical problem of simulating the outcomes of X by using a limited number of biased coins. View full abstract»

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  • The entropy of traces in parallel computation

    Publication Year: 1999, Page(s):1606 - 1608
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (113 KB)

    The following problem arises in the context of parallel computation: how many bits of information are required to specify any one element from an arbitrary (non-empty) k-subset of a set? We characterize optimal coding techniques for this problem. We calculate the asymptotic behavior of the amount of information necessary, and construct an algorithm that specifies an element from a subset in an opt... View full abstract»

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  • On the composition of Tunstall messages

    Publication Year: 1999, Page(s):1608 - 1612
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (168 KB)

    We study the composition of messages in an encoding tree for a Tunstall code, and, more generally, in a tree whose skewness is bounded. For such trees a sort of "law of large numbers" holds true; actually, we provide a direct and converse coding theorem for variable-length to block length source codes, when a vanishing error probability is allowed. View full abstract»

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  • Variable-to-fixed length codes and the conservation of entropy

    Publication Year: 1999, Page(s):1612 - 1620
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (337 KB)

    For a large class of parsing rules, we introduce a "conservation of entropy" theorem for the output of a unifilar Markov source. Using this theorem and renewal theory, we find a procedure to generate asymptotically optimal generalized variable-to-fixed length codes. View full abstract»

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  • Distortion bounds for vector quantizers with finite codebook size

    Publication Year: 1999, Page(s):1621 - 1631
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (442 KB)

    Upper and lower bounds are presented for the distortion of the optimal N-point vector quantizer applied to k-dimensional signals. Under certain smoothness conditions on the source distribution, the bounds are shown to hold for each and every value of N, the codebook size. These results extend bounds derived in the high-resolution limit, which assume that the number of code vectors is arbitrarily l... View full abstract»

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  • Calculation of shell frequency distributions obtained with shell-mapping schemes

    Publication Year: 1999, Page(s):1631 - 1639
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (278 KB)

    In order to calculate the transmit power in shell-mapping-based transmission schemes, the frequencies of the shells are required. In this correspondence, a simple but general method for the calculation of these frequencies is derived. The method has approximately the same complexity as the shell-mapping encoder. As an example, the method is shown in detail for the shell-mapping scheme specified fo... View full abstract»

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  • Evaluating the performance of convolutional codes over block fading channels

    Publication Year: 1999, Page(s):1643 - 1646
    Cited by:  Papers (166)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    This correspondence considers union upper bound techniques for error control codes with limited interleaving over block fading Rician channels. A modified bounding technique is presented that relies on limiting the conditional union bound before averaging over the fading process. This technique, although analytically not very attractive, provides tight and hence useful numerical results. View full abstract»

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  • On the weight distribution of terminated convolutional codes

    Publication Year: 1999, Page(s):1646 - 1648
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (98 KB)

    In this correspondence, the low-weight terms of the weight distribution of the block code obtained by terminating a convolutional code after x information blocks are expressed as a function of x. It is shown that this function is linear in x for codes with noncatastrophic encoders, but quadratic in x for codes with catastrophic encoders. These results are useful to explain the poor performance of ... 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