IEEE Transactions on Information Theory

Issue 3 • May 1997

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Displaying Results 1 - 25 of 36
  • Correction to "On the existence of positive-definite maximum-likelihood estimates of structured covariance matrices"

    Publication Year: 1997, Page(s):1094 - 1096
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (113 KB)

    A correction to, and a more complete proof of, Theorem 1 of Fuhrmann and Miller (see ibid., vol.34, no.7, p.722-29, 1988) is given. We consider the existence of solutions to the maximum-likelihood (ML) structured covariance estimation problem. In particular, we are interested in determining the circumstances under which the log likelihood is unbounded above for a given covariance constraint set R ... View full abstract»

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  • Contributors

    Publication Year: 1997, Page(s):1097 - 1100
    Request permission for commercial reuse | PDF file iconPDF (37 KB)
    Freely Available from IEEE
  • A Barankin-type lower bound on the estimation error of a hybrid parameter vector

    Publication Year: 1997, Page(s):1084 - 1093
    Cited by:  Papers (60)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    The Barankin (1949) bound is a realizable lower bound on the mean-square error (MSE) of any unbiased estimator of a (nonrandom) parameter vector. We present a Barankin-type bound which is useful in problems where there is a prior knowledge on some of the parameters to be estimated. That is, the parameter vector is a hybrid vector in the sense that some of its entries are deterministic while other ... View full abstract»

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  • Improved bounds on maximum size binary radar arrays

    Publication Year: 1997, Page(s):997 - 1000
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (184 KB)

    The maximum size of binary radar arrays (matrices) with only eight or fewer rows has previously been determined. We determine the maximum size of radar arrays containing 9-16 rows, and for those containing 17 rows we narrow the maximum size down to two values. We also give improved upper and lower asymptotic bounds on the maximum size of radar arrays, which narrow the gap between the existing uppe... View full abstract»

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  • Stability analysis of quota allocation access protocols in ring networks with spatial reuse

    Publication Year: 1997, Page(s):923 - 937
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (692 KB)

    We consider a slotted ring that allows simultaneous transmissions of messages by different nodes, known as ring with spatial reuse. To alleviate fairness problems that arise in such networks, policies have been proposed that operate in cycles and guarantee that a certain number of packets, not exceeding a given number called a quota, will be transmitted by every node in every cycle. We provide suf... View full abstract»

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  • The role of the asymptotic equipartition property in noiseless source coding

    Publication Year: 1997, Page(s):847 - 857
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (448 KB)

    The (noiseless) fixed-length source coding theorem states that, except for outcomes in a set of vanishing probability, a source can be encoded at its entropy but not more efficiently. It is well known that the asymptotic equipartition property (AEP) is a sufficient condition for a source to be encodable at its entropy. This paper shows that the AEP is necessary for the source coding theorem to hol... View full abstract»

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  • Symmetrical multilevel diversity coding

    Publication Year: 1997, Page(s):1059 - 1064
    Cited by:  Papers (43)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (216 KB)

    Multilevel diversity coding was introduced in recent work by Roche (1992) and Yeung (1995). In a multilevel diversity coding system, an information source is encoded by a number of encoders. There is a set of decoders, partitioned into multiple levels, with each decoder having access to a certain subset of the encoders. The reconstructions of the source by decoders within the same level are identi... View full abstract»

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  • Adaptive de-noising of signals satisfying differential inequalities

    Publication Year: 1997, Page(s):872 - 889
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1144 KB)

    The paper is devoted to spatial adaptive estimation of signals satisfying linear differential inequalities with an unknown differential operator of a given order. The classes of signals under consideration cover a wide variety of classes common to nonparametric regression. In particular, they contain the signals whose parameters of smoothness are not uniformly bounded, even locally. We develop an ... View full abstract»

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  • Scheduling and performance limits of networks with constantly changing topology

    Publication Year: 1997, Page(s):1067 - 1073
    Cited by:  Papers (101)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (280 KB)

    A communication network with tine-varying topology is considered. The network consists of M receivers and N transmitters that, in principle, may access every receiver. An underlying network state process with Markovian statistics is considered that reflects the physical characteristics of the network affecting the link service capacity. The transmissions are scheduled dynamically, based on informa... View full abstract»

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  • Information and entropy of continuous random variables

    Publication Year: 1997, Page(s):1080 - 1084
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (200 KB)

    The mean value of the square of a generalized score function is shown to be interpretable as information associated with a continuous random variable. This information is in particular cases equal to the Fisher information of the corresponding distribution View full abstract»

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  • A construction of codes with exponential error bounds on arbitrary discrete memoryless channels

    Publication Year: 1997, Page(s):992 - 996
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB)

    This correspondence proposes an explicit construction of codes achieving capacity for arbitrary discrete memoryless channels. The proposed code is obtained by concatenating variable inner codes and an algebraic geometry code. Further, we clarify that the proposed code achieves the error exponent obtained by Forney for concatenated codes View full abstract»

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  • Estimates for the range of binomiality in codes' spectra

    Publication Year: 1997, Page(s):987 - 991
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (204 KB)

    We derive new estimates for the range of binomiality in a code's spectra, where the distance distribution of a code is upperbounded by the corresponding normalized binomial distribution. The estimates depend on the code's dual distance View full abstract»

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  • Type II codes over Z4

    Publication Year: 1997, Page(s):969 - 976
    Cited by:  Papers (56)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    Type II Z4-codes are introduced as self-dual codes over the integers modulo 4 containing the all-one vector and with Euclidean weights multiple of 8. Their weight enumerators are characterized by means of invariant theory. A notion of extremality for the Euclidean weight is introduced. Their binary images under the Gray map are formally self-dual with even weights. Extended qua... View full abstract»

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  • Bounds on the accuracy of estimating the parameters of discrete homogeneous random fields with mixed spectral distributions

    Publication Year: 1997, Page(s):908 - 922
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (776 KB)

    This paper considers the achievable accuracy in jointly estimating the parameters of a real-valued two-dimensional (2-D) homogeneous random field with mixed spectral distribution, from a single observed realization of it. On the basis of a 2-D Wold-like decomposition, the field is represented as a sum of mutually orthogonal components of three types: purely indeterministic, harmonic, and evanescen... View full abstract»

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  • Binary codes derived from the Hoffman-Singleton and Higman-Sims graphs

    Publication Year: 1997, Page(s):1021 - 1025
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (248 KB)

    Some binary linear codes of length 50 and 100 are constructed using the adjacency matrices of the Hoffman-Singleton graph and the Higman-Sims graph, Some of the codes are optimal or nearly optimal for the given length and dimension. The dual codes admit majority logic decoding View full abstract»

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  • The empirical distribution of good codes

    Publication Year: 1997, Page(s):836 - 846
    Cited by:  Papers (53)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    Let the kth-order empirical distribution of a code be defined as the proportion of k-strings anywhere in the codebook equal to every given k-string. We show that for any fixed k, the kth-order empirical distribution of any good code (i.e., a code approaching capacity with vanishing probability of error) converges in the sense of divergence to the set of input distributions that maximize the input/... View full abstract»

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  • Low-complexity decoding of partial unit memory codes on precoded partial-response channels

    Publication Year: 1997, Page(s):1052 - 1058
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    Cosets of convolutional codes can be used to obtain large free Euclidean distances and short maximum zero-run lengths at the output of the 1-D partial-response channel (PRC). We present a new soft-decision decoding technique for cosets of convolutional codes on the preceded 1-D PRC. The decoding technique is especially well suited for cosets of partial unit memory (PUM) convolutional codes. A conn... View full abstract»

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  • Aperiodic autocorrelation and crosscorrelation of polyphase sequences

    Publication Year: 1997, Page(s):1000 - 1007
    Cited by:  Papers (15)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (332 KB)

    A detailed analysis of the maximum aperiodic autocorrelation of the original Chu sequences (equivalently, P3/P4 pulse compression codes) is presented. The result implies the best known upper bound on the minimax aperiodic autocorrelation for polyphase sequences except when the length is very small or a perfect square. It is well known that determining the minimax aperiodic correlation for polyphas... View full abstract»

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  • Algebraic tools to build modulation schemes for fading channels

    Publication Year: 1997, Page(s):938 - 952
    Cited by:  Papers (233)  |  Patents (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (760 KB)

    A unified framework is presented in order to build lattice constellations matched to both the Rayleigh fading channel and the Gaussian channel. The method encompasses the situations where the interleaving is done on the real components or on two-dimensional signals. In the latter case, a simple construction of lattices congruent to the densest binary lattices with respect to the Euclidean distance... View full abstract»

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  • The smallest list for the arbitrarily varying channel

    Publication Year: 1997, Page(s):803 - 815
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (928 KB)

    The capacity of the discrete memoryless arbitrarily varying channel (AVC) is investigated for deterministic list codes with fixed list size L. For every AVC with positive random code capacity Cr , a nonnegative integer M called the symmetrizability is defined. For the average probability of error criterion, it is shown that the list capacity is given by C(L)=Cr for L>M and... View full abstract»

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  • Probability of error in MMSE multiuser detection

    Publication Year: 1997, Page(s):858 - 871
    Cited by:  Papers (569)  |  Patents (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (596 KB)

    The performance analysis of the minimum-mean-square-error (MMSE) linear multiuser detector is considered in an environment of nonorthogonal signaling and additive white Gaussian noise. In particular, the behavior of the multiple-access interference (MAI) at the output of the MMSE detector is examined under various asymptotic conditions, including: large signal-to-noise ratio; large near-far ratios... View full abstract»

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  • Coding scheme for synchronous-CDMA systems

    Publication Year: 1997, Page(s):1064 - 1067
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (164 KB)

    This correspondence presents a new coding scheme based on a combinatory detecting set for synchronous code-division multiple-access (S-CDMA) systems, which can support a number of users far exceeding current S-CDMA approaches. Examples of code construction and decoding are also given View full abstract»

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  • Improved bounds for error recovery times of decision feedback equalization

    Publication Year: 1997, Page(s):890 - 902
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (452 KB)

    New upper and lower bounds on the mean recovery time of decision feedback equalization (DFE) are derived. The recovery time is defined as the time it takes the decision feedback equalizer (DFEQ) to reach the error-free state after an error has corrupted an error-free DFEQ. The derivations of the bounds assume a causal channel response, independent data symbols, and independent noise samples. The b... View full abstract»

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  • Displacement structure and maximum entropy

    Publication Year: 1997, Page(s):1074 - 1080
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (284 KB)

    The study of matrices with a displacement structure is mainly concerned with recursions for the so-called generator matrices. The recursion usually involves free parameters, which can be chosen in several ways so as to simplify the resulting algorithm. In this correspondence we present a choice for the parameters that is motivated by a maximum-entropy formulation, This choice further motivates the... View full abstract»

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  • Lengthening and the Gilbert-Varshamov bound

    Publication Year: 1997, Page(s):991 - 992
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (72 KB)

    We use lengthening and an enhanced version of the Gilbert-Varshamov lower bound for linear codes to construct a large number of record-breaking codes. Our main theorem may be seen as a closure operation on databases 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.

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Meet Our Editors

Editor-in-Chief
Prakash Narayan 

Department of Electrical and Computer Engineering