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Proceedings. 1998 IEEE International Symposium on Information Theory (Cat. No.98CH36252)

16-21 Aug. 1998

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  • Proceedings. 1998 IEEE International Symposium on Information Theory (Cat. No.98CH36252)

    Publication Year: 1998
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    Freely Available from IEEE
  • Codes and lattices

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (33 KB)

    Summary form only given. The author reports on the progress on Shannon's old problem of finding the best way to pack billiard balls in n=2WT dimensions. Thanks to the efforts of a number of people, we now have reasonably good packings in perhaps the first 64 dimensions. Many-but not all-of the new constructions make use of codes, although we now have to allow codes over rings as well as fields. View full abstract»

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  • From matched filters to martingales

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (60 KB)

    Summary form only given. The famous matched filter solution for maximizing the output SNR of a known signal in additive white noise was independently discovered by several investigators in the mid-forties. Since then it has appeared as a key component of optimal detectors in a variety of scenarios. Its first appearance was perhaps in D.O. North's 1943 RCA report, which is remarkable for the facili... View full abstract»

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  • Variations on the theme of "twenty questions"

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (68 KB)

    Summary form only given. One of the aims of computational complexity theory is to derive lower and upper bounds on the complexity of particular computational problems within particular models of computation. In many of these models computation can be viewed as the acquisition of information about an unknown object and elementary concepts from information theory, such as entropy and Kolmogorov comp... View full abstract»

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  • Surviving in a fast, nomadic world [mobile computing and communication]

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (95 KB)

    Summary form only given, as follows. Most of us are nomads in that we travel from place to place with a wild array of laptops, PDA's, cellular telephones, pagers, etc. We desire to have the same computing environment, services and system support in those locations as we have in our corporate offices. Indeed we desire "anywhere, anytime" connectivity. Unfortunately, as soon as we leave the comfort ... View full abstract»

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  • A fast modular multiplication method using Yacobi's algorithm

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (33 KB)

    Summary form only given. A fast modular multiplication method is presented. The known fastest modular multiplication method by Su and Hwang requires n+11 additions on average for an n-bit modulus. In Su and Hwang's method, the computed values are not stored for use again. In our method, the computed values can be stored by Yacobi's algorithm. According to our analysis, our method is faster than Su... View full abstract»

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  • Coding theorems of quantum information theory

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (54 KB)

    Summary form only given. Shannon's original proof of the channel coding theorem via typical input/output sequences is presented in a sphere-packing form to determine the minimum quantum source coding rate. Let S(/spl rho/)/spl equiv/-tr/spl rho/log/spl rho/ be the Von Neumann entropy of a density operator p on a finite-dimensional space H, i/spl rarr//spl rho//sub i/ the state modulation map on an... View full abstract»

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  • Investigation of binary sequences with the "trinomial property"

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (38 KB)

    Summary form only given, as follows. It is well-known that if {a/sub k/} is an m-sequence of period p=2/sup n/-1, then for every /spl tau/, 1/spl les//spl tau//spl les/p-1, {a/sub k/}+{a/sub k+/spl tau//}={a/sub k+/spl tau/'/} for some /spl tau/', 1/spl les//spl tau/'/spl les/p-1. We say that a binary sequence (b/sub k/) of period p has the trinomial property if there exists a pair (/spl tau/,/spl... View full abstract»

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  • Asymmetric turbo-codes

    Publication Year: 1998
    Cited by:  Papers (3)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (131 KB)

    This paper examines the performance of turbo-codes with non-identical component codes. We show that asymmetric turbo-codes provide good performance with respect to both the "error-floor" and the "pre-error-floor" regions of the bit error rate curve. View full abstract»

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  • On systematic single asymmetric error correcting codes

    Publication Year: 1998
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (115 KB)

    Summary form only given. In the asymmetric channel it is assumed that the transmitted binary sequence may suffer errors of one type only, say 1/spl rarr/0; the 0/spl rarr/1 errors are rare. Since errors are of one type they are called asymmetric errors as opposed to symmetric errors in which both 1/spl rarr/0 and 0/spl rarr/1 are expectable. Obviously, any symmetric error correcting code is also a... View full abstract»

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  • Investigation of the error performance of Tunstall coding

    Publication Year: 1998
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (119 KB)

    The error performance of the Tunstall code is analysed, and a relevant metric defined. Several parameters in the encoding process are considered, with the objective of minimising the effect of errors without sacrificing compression. The results obtained show that the error performance may be significantly improved without loss of compression. View full abstract»

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  • New classes of algebraic interleavers for turbo-codes

    Publication Year: 1998
    Cited by:  Papers (28)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    In this paper we present classes of algebraic interleavers that permute a sequence of bits with nearly the same statistical distribution as a randomly chosen interleaver. When these interleavers are used in turbo-coding, they perform equal to or better than the average of a set of randomly chosen interleavers. They are based on a property of quadratic congruences over the ring of integers modulo p... View full abstract»

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  • Author index

    Publication Year: 1998, Page(s):479 - 484
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    Freely Available from IEEE
  • Iterative decoding of generalized low-density parity-check codes

    Publication Year: 1998
    Cited by:  Papers (25)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (100 KB)

    A generalization of Gallager's low-density parity-check codes is introduced, where as component codes single-error correcting Hamming codes are used instead of single-error detecting parity-check codes. Low-density (LD) parity-check codes were first introduced by Gallager in 1963. These codes are, in combination with iterative decoding, very promising for achieving low error probabilities at a rea... View full abstract»

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  • Performance of FFH-GMSK signals with centre sampling single and double differential detection in frequency-selective Rayleigh channels with CCI

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

    It is well known that classical (single) differential detection systems yield poor performance for channels that introduce into the carrier a random frequency shift, such as mobile radio (MR) channels. In such situations, one must resort to a form of differential detection (DD) that has the capability to remove the effect of frequency variations. The object of this paper is to study the performanc... View full abstract»

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  • On the capacity of two dimensional run length limited codes

    Publication Year: 1998
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (56 KB)

    The capacity of two dimensional run length limited codes are studied. Zero capacities are characterized, bounds on nonzero capacities are given, and encoding algorithms are also discussed View full abstract»

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  • Random sequence analysis of optimum near-far resistance in a variable chipping rate dual-rate CDMA system

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

    Direct-sequence code-division multiple-access (DS/CDMA) provides natural implementations for multi-rate communications systems. In this work, we will extend prior results on multi-rate systems with constant chipping rates to the case of variable chipping rate access (VCR) where chipping rates are proportional to user data rates. We use optimum near-far resistance as the performance measure of inte... View full abstract»

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  • An algorithm to construct strongly controllable group codes from an abstract group

    Publication Year: 1998
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (92 KB)

    In this paper we present a computationally implementable algorithm, based on the Schreier product theory (extension of groups), to construct a time-invariant and strongly controllable group code 𝒴, from a given abstract group G, such that the trellis section group T of 𝒴 is isomorphic to G View full abstract»

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  • Multiuser decision-feedback detection: performance bounds and adaptive algorithms

    Publication Year: 1998
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (92 KB)

    Multiuser decision-feedback detection has been previously considered for DS-CDMA. Here we evaluate asymptotic MSE and capacity (averaged over the users) of the multiuser decision-feedback detector (DFD) in the absence of error propagation. Asymptotic means that the number of users K→∞ and the processing gain N→∞ with K/N fixed. The resulting capacity is the same as that achie... View full abstract»

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  • Skewness and pseudocodewords in iterative decoding

    Publication Year: 1998
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (112 KB)

    Impressive performances by low-density parity-check codes and turbo codes have inspired researchers to determine how their iterative decoders depart from optimal decoding. Iterative decoding can be viewed as the application of the sum-product or min-sum algorithm in a graph that describes the constraints on a system of variables. The authors discuss here how iterative decoding maximizes correlatio... View full abstract»

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  • Nonlinear blind channel equalization via ring decision feedback

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

    A novel nonlinear blind equalizer for linearly modulated digital communication is proposed. The equalizer employs a ring decision device that feeds back a weighted sum of past ring decisions to approximately cancel intersymbol interference (ISI) in the present signalling interval. Simple adaptive algorithms for blindly adapting the coefficients of the equalizer are presented View full abstract»

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  • Type for hierarchical probability model class and universal coding

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

    The authors discuss type and sufficient statistics for hierarchical probability models. They go on to consider multistage codes using hierarchical sufficient statistics View full abstract»

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  • An exploration of the relationship between the Baum-Welch algorithm and turbo decoding

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

    It is shown that the problem of APP decoding of single and parallel concatenated codes can be recast in terms of parameter estimation for one or more nonstationary hidden Markov processes. It is then shown that simple extensions of the Baum-Welch algorithm provide solutions to these problems, including solutions that provide channel-matching turbo decoding algorithms View full abstract»

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  • Joint source channel decoding using bit-reliability information and source statistics

    Publication Year: 1998
    Cited by:  Papers (9)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (88 KB)

    A new joint source channel decoding technique called channel coded optimal estimation (CCOE) is introduced. Bit-reliability information of the received source-encoder bits and the redundant bits of a systematic channel code are combined with the source-signal statistics to calculate the a-posteriori probabilities for all possibly transmitted codewords. The probabilities are used to estimate the tr... View full abstract»

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  • Minimal syndrome formers for group codes

    Publication Year: 1998
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (100 KB)

    The purpose of this summary is to present a syndrome former for group codes which satisfies some nice properties. This syndrome former admits a state realization with state space coinciding with the canonical state space of the group code View full abstract»

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