IEEE Transactions on Information Theory

Issue 2 • March 1996

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Displaying Results 1 - 25 of 37
  • Algebraic Function Fields and Codes [Book Reviews]

    Publication Year: 1996
    Request permission for commercial reuse | |PDF file iconPDF (402 KB)
    Freely Available from IEEE
  • Generation of canonical M-sequences and dual bases

    Publication Year: 1996, Page(s):638 - 641
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (316 KB)

    An expression for the shift necessary to obtain a canonical M-sequence is obtained in terms of the coefficients of the primitive polynomial that generates this m-sequence. This shift for obtaining a canonical M-sequence is also directly related to the shift for obtaining the location of the span “100...0” in the M-sequence. In addition, a recursion is developed for obtaining the dual b... View full abstract»

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  • Complex Hadamard matrices related to Bent sequences

    Publication Year: 1996
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (96 KB)

    Hadamard matrices are often used for some applications, such as error-correcting codes and spread sequences. This article gives the construction of complex Hadamard matrices of order pn, where p is prime and n is even. The complex Hadamard matrices include bi-phase Hadamard matrices whose elements take {-1, +1}, and four-phase Hadamard matrices whose elements take {±1, ±j}... View full abstract»

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  • The ternary Golay code, the integers mod 9, and the Coxeter-Todd lattice

    Publication Year: 1996, Page(s):636 - 637
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (208 KB)

    The 12-dimensional Coxeter-Todd lattice can be obtained by lifting the ternary Golay code to a code over the integers mod 9 and applying Construction A View full abstract»

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  • A new universal random coding bound for the multiple-access channel

    Publication Year: 1996, Page(s):376 - 386
    Cited by:  Papers (45)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (780 KB)

    The minimum average error probability achievable by block codes on the two-user multiple-access channel is investigated. A new exponential upper bound is found which can be achieved universally for all discrete memoryless multiple-access channels with given input and output alphabets. It is shown that the exponent of this bound is greater than or equal to those of previously known bounds. Moreover... View full abstract»

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  • Location-correcting codes

    Publication Year: 1996, Page(s):554 - 565
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1144 KB)

    We study codes over GF(q) that can correct t channel errors assuming the error values are known. This is a counterpart to the well-known problem of erasure correction, where error values are found assuming the locations are known. The correction capabilities of these so-called t-location correcting codes (t-LCCs) are characterized by a new metric, the decomposability distance, which plays a role a... View full abstract»

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  • Asymptotic distribution of the errors in scalar and vector quantizers

    Publication Year: 1996, Page(s):446 - 460
    Cited by:  Papers (32)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1268 KB)

    High-rate (or asymptotic) quantization theory has found formulas for the average squared length (more generally, the qth moment of the length) of the error produced by various scalar and vector quantizers with many quantization points. In contrast, this paper finds an asymptotic formula for the probability density of the length of the error and, in certain special cases, for the probability densit... View full abstract»

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  • On punctured trellis-coded modulation

    Publication Year: 1996, Page(s):627 - 636
    Cited by:  Papers (10)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (924 KB)

    Punctured convolutional codes result in some savings in the complexity of Viterbi decoders, compared to other codes of the same rate. However, in general use of the punctured structure in the decoder results in a performance loss for trellis codes, due to difficulties in assigning metrics, We provide constructions for punctured rate-2/3 codes based on decomposition of the metric into orthogonal co... View full abstract»

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  • A rate-splitting approach to the Gaussian multiple-access channel

    Publication Year: 1996, Page(s):364 - 375
    Cited by:  Papers (183)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1236 KB)

    It is shown that any point in the capacity region of a Gaussian multiple-access channel is achievable by single-user coding without requiring synchronization among users, provided that each user “splits” data and signal into two parts. Based on this result, a new multiple-access technique called rate-splitting multiple accessing (RSMA) is proposed. RSMA is a code-division multiple-acce... View full abstract»

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  • A soft-output decoding algorithm for concatenated systems

    Publication Year: 1996, Page(s):543 - 553
    Cited by:  Papers (15)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1016 KB)

    In order to fully utilize the SDD (soft-decision decoding) capacity of the outer codes in a concatenated system, reliability information on the inner decoder outputs (called soft outputs) needs to be provided to the outer decoder. This paper shows that a modified MAP algorithm can be effectively and accurately used to generate such information. In the course of the presentation, a metric based on ... View full abstract»

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  • Iterative decoding of binary block and convolutional codes

    Publication Year: 1996, Page(s):429 - 445
    Cited by:  Papers (1471)  |  Patents (205)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1420 KB)

    Iterative decoding of two-dimensional systematic convolutional codes has been termed “turbo” (de)coding. Using log-likelihood algebra, we show that any decoder can be used which accepts soft inputs-including a priori values-and delivers soft outputs that can be split into three terms: the soft channel and a priori inputs, and the extrinsic value. The extrinsic value is used as an a pri... View full abstract»

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  • Irregular sampling for spline wavelet subspaces

    Publication Year: 1996, Page(s):623 - 627
    Cited by:  Papers (35)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (332 KB)

    Spline wavelets ψm(t) are important in time-frequency localization due to (i) ψm can be arbitrarily close to the optimal case as m is sufficiently large, (ii) ψm has compact support and simple analytic expression, which lead to effective computation. Although the spline wavelet subspaces are so simple, Walter's well-known sampling theorem does not hold ... View full abstract»

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  • Universal portfolios with side information

    Publication Year: 1996, Page(s):348 - 363
    Cited by:  Papers (117)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1228 KB)

    We present a sequential investment algorithm, the μ-weighted universal portfolio with side information, which achieves, to first order in the exponent, the same wealth as the best side-information dependent investment strategy (the best state-constant rebalanced portfolio) determined in hindsight from observed market and side-information outcomes. This is an individual sequence result which sho... View full abstract»

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  • A simple analysis of average queueing delay in tree networks

    Publication Year: 1996, Page(s):660 - 664
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (520 KB)

    We develop an approach to the analysis of average queueing delay in a tree network of discrete-time queues with constant service time. The analysis of such systems is pertinent to packet-switched data networks with fixed-length packets. Our solution is based on considering an equivalent network, in which at each node packets in transit are given priority over exogenous arrivals. The solution to th... View full abstract»

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  • MDS array codes with independent parity symbols

    Publication Year: 1996, Page(s):529 - 542
    Cited by:  Papers (100)  |  Patents (13)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1188 KB)

    A new family of maximum distance separable (MDS) array codes is presented. The code arrays contain p information columns and r independent parity columns, each column consisting of p-1 bits, where p is a prime. We extend a previously known construction for the case r=2 to three and more parity columns. It is shown that when r=3 such extension is possible for any prime p. For larger values of r, we... View full abstract»

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  • Approaching capacity of a continuous channel by discrete input distributions

    Publication Year: 1996, Page(s):671 - 675
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (524 KB)

    In this paper memoryless channels with general alphabets and input constraint are considered. Sufficient conditions are given that channel capacity can be approached by discrete input distributions or by uniform input distributions with finite support. As an example, the additive white Gaussian noise channel is considered View full abstract»

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  • Unveiling turbo codes: some results on parallel concatenated coding schemes

    Publication Year: 1996, Page(s):409 - 428
    Cited by:  Papers (758)  |  Patents (59)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1516 KB)

    A parallel concatenated coding scheme consists of two simple constituent systematic encoders linked by an interleaver. The input bits to the first encoder are scrambled by the interleaver before entering the second encoder. The codeword of the parallel concatenated code consists of the input bits to the first encoder followed by the parity check bits of both encoders. This construction can be gene... View full abstract»

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  • Time discretization of continuous-time filters and smoothers for HMM parameter estimation

    Publication Year: 1996, Page(s):593 - 605
    Cited by:  Papers (37)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (980 KB)

    In this paper we propose algorithms for parameter estimation of fast-sampled homogeneous Markov chains observed in white Gaussian noise. Our algorithms are obtained by the robust discretization of stochastic differential equations involved in the estimation of continuous-time hidden Markov models (HMM's) via the EM algorithm. We present two algorithms: the first is based on the robust discretizati... View full abstract»

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  • Some counterexamples in the theory of Weyl-Heisenberg frames

    Publication Year: 1996, Page(s):621 - 623
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (228 KB)

    We present an example of a positive function g with a positive Fourier transform gˆ and reasonable smoothness and decay properties such that (-1)nmexp(πitm)g(t-n), n, m∈Z does not constitute a frame for L2(R). We also give counterexamples for the statement that one can tell (in)definiteness of a Weyl-Heisenberg frame operator from (in)definitene... View full abstract»

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  • Classification with finite memory

    Publication Year: 1996, Page(s):337 - 347
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (760 KB)

    Consider the following situation. A device called a classifier observes a probability law P on l-vectors from an alphabet of size A. Its task is to observe a second probability law Q and decide whether P≡Q or P and Q are sufficiently different according to some appropriate criterion. If the classifier has available an unlimited memory (so that it can remember P(z) exactly for all z), this is... View full abstract»

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  • Weight enumerators of extremal singly-even [60,30,12] codes

    Publication Year: 1996, Page(s):658 - 659
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (168 KB)

    Conway and Sloane (1990) have listed the possible weight enumerators for extremal self-dual codes up to length 72. In this correspondence, we construct extremal singly-even self-dual [60,30,12] codes whose weight enumerator does not appear in this list. In addition, we present the possible weight enumerators for extremal self-dual codes of length 60 View full abstract»

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  • Group codes generated by finite reflection groups

    Publication Year: 1996, Page(s):519 - 528
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (916 KB)

    Slepian-type group codes generated by finite Coxeter groups are considered. The resulting class of group codes is a generalization of the well-known permutation modulation codes of Slepian (1965), it is shown that a restricted initial-point problem for these codes has a canonical solution that can easily be computed. This allows one to enumerate all optimal group codes in this restricted sense and... View full abstract»

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  • On generalizations of repeated-root cyclic codes

    Publication Year: 1996, Page(s):641 - 649
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (768 KB)

    We first consider repeated-root cyclic codes, i.e., cyclic codes whose block length is divisible by the characteristic of the underlying field. It is well known that the formula for the minimum distance of repeated-root cyclic codes is similar to that for generalized concatenated codes. We show that indecomposable repeated-root cyclic codes are product codes and that the minimum weight of each rep... View full abstract»

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  • Nearly optimal multiuser codes for the binary adder channel

    Publication Year: 1996, Page(s):387 - 398
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1028 KB)

    Coding schemes for the T-user binary adder channel are investigated. Recursive constructions are given for two families of mixed-rate, multiuser codes. It is shown that these basic codes can be combined by time-sharing to yield codes approaching most rates in the T-user capacity region. In particular, the best codes constructed herein achieve a sum-rate, R1+...+RT, which is h... View full abstract»

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  • On the cardinality of systematic authentication codes via error-correcting codes

    Publication Year: 1996, Page(s):566 - 578
    Cited by:  Papers (12)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract |PDF file iconPDF (1084 KB)

    In both open and private communication the participants face potential threats from a malicious enemy who has access to the communication channel and can insert messages (impersonation attack) or alter already transmitted messages (substitution attack). Authentication codes (A-codes) have been developed to provide protection against these threats. In this paper we introduce a new distance, called ... 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