1998 Information Theory Workshop (Cat. No.98EX131)

22-26 June 1998

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  • 1998 Information Theory Workshop (Cat. No.98EX131)

    Publication Year: 1998
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  • Mixture models achieving optimal coding regret

    Publication Year: 1998
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (63 KB)

    Summary form only given. The relative entropy between the Jeffreys mixture and Shtarkov's normalized maximum likelihood distribution tends to zero as the sample size gets large for smooth parametric families of distributions, and equivalently, the Jeffreys mixture is asymptotically maximin for the coding regret problem. Implications of this fact reveal lower bounds, including explicit constants, t... View full abstract»

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  • MMD codes in a more general sense

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (73 KB)

    Summary form only given. The author deals with the characterisation of maximum minimum distance (MMD) codes in a more general sense, which has been completed in a joint work with Olsson. As in the m=1 case the weight distribution of an MMD code /spl Cscr/ is uniquely determined by its parameters [n,k,d]/sub q/. View full abstract»

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  • On the frame error rate of turbo-codes

    Publication Year: 1998, Page(s):118 - 119
    Cited by:  Papers (3)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (262 KB)

    In spite of the excellent bit error rate performance of the original turbo-code, simulations indicate that this code yields relatively poor frame error rate performance. In this paper we show that "primitive" turbo-codes and "asymmetric" turbo-codes provides both good bit error rate and frame error rate performance. View full abstract»

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  • Congestion control and routing in multicasting

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (83 KB)

    Summary form only given. The author addresses the problems of congestion control and routing of multicast traffic in communication networks. The network is modeled by an arbitrary topology directed graph G=(V,E) and the capacity of edge e is C/sub e/. A multicast session is identified by the pair (v,S) where v is the source node of the session and S is the group of intended destination nodes. Ther... View full abstract»

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  • Author index

    Publication Year: 1998, Page(s):161 - 162
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    Freely Available from IEEE
  • Spectral efficiency of direct-sequence spread-spectrum multiaccess with random spreading

    Publication Year: 1998, Page(s):64 - 65
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    Information theoretic aspects of code division multiple access (CDMA) random direct-sequence spread-spectrum (DSSS) are investigated. The CDMA-DSSS channel with randomly and independently chosen spreading sequences accurately models the situation where pseudo-noise sequences span many symbol periods. We analyze the spectral efficiency (total capacity per chip) as a function of the number of users,... View full abstract»

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  • A new unconditional information inequality

    Publication Year: 1998, Page(s):62 - 63
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (212 KB)

    In this paper, we report an unconditional inequality of Shannon's information measures which is not implied by the nonnegativity of such measures. To our knowledge, this is the first such inequality ever discovered View full abstract»

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  • The zero-error capacity region of the 2-user synchronous BAC is strictly smaller than its Shannon capacity region

    Publication Year: 1998
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (84 KB)

    New upper and lower bounds on the zero-error capacity region of the synchronous 2-user binary adder channel are given. The lower bound is in the form of a new uniquely decodable code with a sum rate higher than any previously reported such code. To derive the upper bound, we combine Van Tilborg's (1978) bound with Harper's (1966) isoperimetric inequality and a general information theoretic inequal... View full abstract»

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  • Covering radius: applications and generalizations

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (88 KB)

    We survey the last developments in the area of covering radius and illustrate the concept with applications to telecommunication problems. We discuss a few generalizations and open problems. We deal mostly with binary linear codes View full abstract»

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  • Exponential bounds for list size moments and error probability

    Publication Year: 1998
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (100 KB)

    We consider list decoding with a variable list size for discrete memoryless channels. We obtain simultaneous upper bounds on the error probability and the moments of list size View full abstract»

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  • On the effective free distance of turbo codes

    Publication Year: 1998, Page(s):120 - 121
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (148 KB)

    An expression for the Hamming weight of the (L+1)th order output of a constituent encoder is derived. This expression enables the determination of the inputs that produce outputs of finite weight. It also facilitates the calculation of the (L+1)th order effective free distance (i.e., minimum output weight) dL+1 of the encoder. Expressions and bounds for dL+1 and in particular... View full abstract»

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  • Trinomial curves with many rational points

    Publication Year: 1998, Page(s):38 - 39
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (144 KB)

    The authors discuss a method to get plane curves with many rational points and a construction to get asymptotically good codes and curves, that is closely related to finding bivariate polynomials representing designs. The number of rational points and the genus is computed for plane curves that have a defining equation with three monomials View full abstract»

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  • Perfect binary codes with trivial automorphism group

    Publication Year: 1998, Page(s):114 - 115
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    We present a class of perfect binary codes with trivial automorphism group for all admissible lengths n⩾255. The codes are nonsystematic and have full rank View full abstract»

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  • On the optimality of generalized time-sharing for M-ary multiple-access channels

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (96 KB)

    This paper addresses the problem of approaching any rate in the capacity region of an asynchronous M-user multiple-access channel via a sequence of at most 2M-1 encoding/decoding operations for point-to-point channels. The focus is on discrete-time memoryless multiple-access channels although the absence of memory does not seems to be crucial. This work was motivated by Grant and Rasmussen (1995) View full abstract»

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  • On epicyclic Hermitian codes

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (76 KB)

    The class of Hermitian codes is a popular and well-studied class of codes on planar curves over GF(2m). These codes have large blocklength, and may soon find engineering importance. In contrast to Reed-Solomon codes, which were discovered by engineers, Hermitian codes were introduced by mathematicians as an example of algebraic geometry codes. We re-introduce Hermitian codes as if they ... View full abstract»

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  • The Newton radius of MDS codes

    Publication Year: 1998, Page(s):50 - 51
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (136 KB)

    The Newton radius of a code is the maximal Hamming weight of a correctable error. The Newton radius of MDS codes is studied View full abstract»

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  • Bounds on the asymptotic buffer overflow probabilities of a parallel processing system

    Publication Year: 1998, Page(s):145 - 146
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    In queueing systems with heterogeneous processors and multiclass job flows, weighted queue length policies are known to achieve maximal throughput, that is, stabilize the system under the maximum possible arrival rates, when the buffers are of infinite capacity. However, very little is known regarding the delay or buffer overflow performance of weighted queue length policies in such queueing syste... View full abstract»

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  • Universal sequential decoding

    Publication Year: 1998
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (108 KB)

    An algorithm is proposed for universal decoding of convolutional/trellis codes employed over unknown channels. On discrete memoryless channels and at rates below the computational cut-off rate (corresponding to a uniform input distribution), the algorithm achieves an asymptotic complexity-vs.-performance tradeoff similar to the tradeoff achieved by the Viterbi (1979) algorithm, but with the benefi... View full abstract»

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  • Turbo codes for high order constellations

    Publication Year: 1998, Page(s):6 - 7
    Cited by:  Papers (2)  |  Patents (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (212 KB)

    The feasibility of the extension of the original turbo codes to higher rate systems is investigated. Extension to the 8-PSK constellation is given as an example. The theoretical critical SNR to achieve one and two bits per 2-D symbol is calculated for 8-PSK with the Blahut-Arimoto algorithm, thus taking into consideration the additional loss due to selecting a finite signaling set. Codes for 8-PSK... View full abstract»

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  • Information-set soft-decision decoding

    Publication Year: 1998, Page(s):77 - 78
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (180 KB)

    Information-set decoding is considered for soft decision channels. The sets of most plausible error patterns are represented as ellipsoids in Hamming spaces, and their minimum coverings are designed by random search. For general linear codes, maximum likelihood decoding with the lowest known complexity is obtained View full abstract»

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  • Interpolation and approximation in decoding

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (100 KB)

    Recently Sudan (see J. Complexity, vol.13, no.1, p.180-93, 1997) formulated a decoding procedure for decoding Reed-Solomon codes beyond the packing radius. The potential of the method for algebraic-geometric codes was recognized by Shokrollahi and Wasserman. We discuss similarities and differences with some previous algebraic decoding procedures View full abstract»

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  • Minimality and canonicity tests for rational generator matrices for convolutional codes

    Publication Year: 1998, Page(s):112 - 113
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (156 KB)

    We derive computationally efficient minimality and canonicity tests for rational generator matrices for convolutional codes. The first set of tests are given in terms of easily obtained equivalent polynomial generator matrices and are suitable for small k and n. New tests are derived based on the scalar generator matrix G which are computationally more efficient for large k and n and small v. The ... View full abstract»

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  • Relationships between different error-correcting capabilities of a code

    Publication Year: 1998, Page(s):122 - 123
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    SID channels are discrete channels represented by expressions that involve combinations of the error types substitution, insertion, and deletion. Based on the SID channel model, a simple distance is defined that generalizes the Hamming and Levenshtein distances. For a certain class of SID channels, the distance is used to obtain a unifying necessary and sufficient condition for the error correctin... View full abstract»

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  • On the missing functions of Hermitian-like codes over GF(22 )

    Publication Year: 1998, Page(s):29 - 30
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (196 KB)

    The authors study the explicit construction of asymptotically good improved algebraic geometric codes that exceed the Gilbert-Varshamov bound. The also find missing functions in improved well-behaving sequences View full abstract»

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