IEEE Transactions on Information Theory

Volume 40 Issue 6 • Nov. 1994

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Displaying Results 1 - 25 of 40
  • Shannon-theoretic approach to a Gaussian cellular multiple-access channel

    Publication Year: 1994, Page(s):1713 - 1727
    Cited by:  Papers (477)  |  Patents (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1151 KB)

    We obtain Shannon-theoretic limits for a very simple cellular multiple-access system. In our model the received signal at a given cell site is the sum of the signals transmitted from within that cell plus a factor /spl alpha/ (0/spl les//spl alpha//spl les/1) times the sum of the signals transmitted from the adjacent cells plus ambient Gaussian noise. Although this simple model is scarcely realist... View full abstract»

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  • Rates of convergence in the source coding theorem, in empirical quantizer design, and in universal lossy source coding

    Publication Year: 1994, Page(s):1728 - 1740
    Cited by:  Papers (55)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1220 KB)

    Rate of convergence results are established for vector quantization. Convergence rates are given for an increasing vector dimension and/or an increasing training set size. In particular, the following results are shown for memoryless real-valued sources with bounded support at transmission rate R. (1) If a vector quantizer with fixed dimension k is designed to minimize the empirical mean-square er... View full abstract»

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  • Dimension/length profiles and trellis complexity of linear block codes

    Publication Year: 1994, Page(s):1741 - 1752
    Cited by:  Papers (152)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1058 KB)

    This semi-tutorial paper discusses the connections between the dimension/length profile (DLP) of a linear code, which is essentially the same as its "generalized Hamming weight hierarchy", and the complexity of its minimal trellis diagram. These connections are close and deep. DLP duality is closely related to trellis duality. The DLP of a code gives tight bounds on its state and branch complexity... View full abstract»

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  • Density/length profiles and trellis complexity of lattices

    Publication Year: 1994, Page(s):1753 - 1772
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1522 KB)

    The density/length profile (DCP) of a lattice /spl Lambda/ is analogous to the dimension/length profile of a linear code. The DLP is a geometrical invariant of /spl Lambda/ that includes the coding gain of /spl Lambda/. Duality results analogous to those of linear block codes are derived for lattices. Bounds on the DLP may be derived from bounds on Hermite's constants; these hold with equality for... View full abstract»

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  • Rotationally invariant nonlinear trellis codes for two-dimensional modulation

    Publication Year: 1994, Page(s):1773 - 1791
    Cited by:  Papers (15)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1616 KB)

    A general parity-check equation is presented that defines rotationally invariant trellis codes of rate k/(k+1) for two-dimensional signal sets. This parity-check equation is used to find rate k/(k+1) codes for 4PSK, 8PSK, 16PSK, and QAM signal sets by systematic code searches. The MPSK codes exhibit smaller free Euclidean distances than nonrotationally invariant linear codes with the same number o... View full abstract»

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  • Trellis-coded quantization designed for noisy channels

    Publication Year: 1994, Page(s):1792 - 1802
    Cited by:  Papers (72)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1050 KB)

    Trellis-coded quantization (TCQ) of memoryless sources is developed for transmission over a binary symmetric channel. The optimized TCQ coder can achieve essentially the same performance as Ayanoglu and Gray's (1987) unconstrained trellis coding optimized for the binary symmetric channel, but with a much lower implementation complexity for transmission rates above 1 b/sample. In most cases, the op... View full abstract»

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  • Erasure-free sequential decoding of trellis codes

    Publication Year: 1994, Page(s):1803 - 1817
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1418 KB)

    An erasure-free sequential decoding algorithm for trellis codes, called the buffer looking algorithm (BLA), is introduced. Several versions of the algorithm can be obtained by choosing certain parameters and selecting a resynchronization scheme. These can be categorized as block decoding or continuous decoding, depending on the resynchronization scheme. Block decoding is guaranteed to resynchroniz... View full abstract»

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  • Minimal presentations for irreducible sofic shifts

    Publication Year: 1994, Page(s):1818 - 1825
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (864 KB)

    We re-cast a theorem of Willems (1989) in terms of symbolic dynamics. We then present a new result which characterizes when an irreducible sofic shift (i.e., constrained system) has a unique minimal irreducible presentation.<<ETX>> View full abstract»

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  • High-order spectral-null codes-constructions and bounds

    Publication Year: 1994, Page(s):1826 - 1840
    Cited by:  Papers (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1355 KB)

    Let /spl Sscr/(n.k) denote the set of all words of length n over the alphabet {+1,-1}, having a k th order spectral-null at zero frequency. A subset of /spl Sscr/(n,k) is a spectral-null code of length n and order k. Upper and lower bounds on the cardinality of /spl Sscr/(n,k) are derived. In particular we prove that (k-1) log/sub 2/ (n/k)/spl les/n-log/sub 2/|/spl Sscr/(n,k)|/spl les/O(2/sup k/lo... View full abstract»

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  • Construction of fixed-length insertion/deletion correcting runlength-limited codes

    Publication Year: 1994, Page(s):1841 - 1856
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1450 KB)

    An algorithm is presented for the construction of fixed-length insertion/deletion correcting runlength-limited (RLL) codes. In this construction binary (d,k)-constrained codewords are generated by codewords of a q-ary Lee metric based code. It is shown that this new construction always yields better codes than known constructions. The use of a q-ary Lee (1987) metric code (q odd) is based on the a... View full abstract»

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  • A class of error-locating codes for byte-organized memory systems

    Publication Year: 1994, Page(s):1857 - 1865
    Cited by:  Papers (4)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (778 KB)

    Error-locating codes (EL codes), first proposed by J.K. Wolf and B. Elspas in 1963, have the potential to be used to identify the faulty module for fault isolation and reconfiguration in fault-tolerant computer systems. This paper proposes a new class of EL codes suitable for memory systems organized with b-bit (b/spl ges/2) byte-organized semiconductor memory chips that are mounted on memory card... View full abstract»

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  • On the general defective channel with informed encoder and capacities of some constrained memories

    Publication Year: 1994, Page(s):1866 - 1871
    Cited by:  Papers (21)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (643 KB)

    From an information-theoretical point of view the write once memory (WOM), the unidirectional memory (WUM), the write isolated memory (WIM), the memory with address faults (MAF), Blackwell's broadcast channel, and some other constrained memories and channels with an informed encoder can be considered as particular cases of the general defective channel (GDC) introduced by Kuznetsov (1983) as a gen... View full abstract»

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  • Intersecting codes and independent families

    Publication Year: 1994, Page(s):1872 - 1881
    Cited by:  Papers (37)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1005 KB)

    A binary intersecting code is a linear code with the property that any two nonzero codewords have intersecting supports. These codes appear in a wide variety of contexts and applications, e.g., multiple access, cryptography, and information theory. This paper is devoted partly to the study of intersecting codes, and partly to their use in constructing large t-independent families of binary vectors... View full abstract»

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  • Superimposed codes in the Hamming space

    Publication Year: 1994, Page(s):1882 - 1893
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1045 KB)

    We consider the problem of simultaneous identification and transmission of information by means of superimposed codes. It is assumed that a total population of T users share a common channel. At each time at most in of the T users are active. The output from the channel is the modulo-2 sum of the binary codewords transmitted by the active users, possibly disturbed by errors. A superimposed code is... View full abstract»

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  • The MacWilliams-Sloane conjecture on the tightness of the Carlitz-Uchiyama bound and the weights of duals of BCH codes

    Publication Year: 1994, Page(s):1894 - 1907
    Cited by:  Papers (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1141 KB)

    Research Problem 9.5 of MacWilliams and Sloane's book, The Theory of Error Correcting Codes (Amsterdam: North-Holland, 1977), asks for an improvement of the minimum distance bound of the duals of BCH codes, defined over F/sub 2/m with m odd. The objective of the present article is to give a solution to the above problem by with (i) obtaining an improvement to the Ax (1964) theorem, which we prove ... View full abstract»

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  • Universal coding for the Slepian-Wolf data compression system and the strong converse theorem

    Publication Year: 1994, Page(s):1908 - 1919
    Cited by:  Papers (41)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (845 KB)

    Universal coding for the Slepian-Wolf (1973) data compression system is considered. We shall demonstrate based on a simple observation that the error exponent given by Csiszar and Korner (1980) for the universal coding system can strictly be sharpened in general for a region of relatively higher rates. This kind of observation can be carried over also to the case of lower rates outside the Slepian... View full abstract»

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  • Variable-rate source coding theorems for stationary nonergodic sources

    Publication Year: 1994, Page(s):1920 - 1925
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (495 KB)

    For a stationary ergodic source, the source coding theorem and its converse imply that the optimal performance theoretically achievable by a fixed-rate or variable-rate block quantizer is equal to the distortion-rate function, which is defined as the infimum of an expected distortion subject to a mutual information constraint. For a stationary nonergodic source, however, the. Distortion-rate funct... View full abstract»

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  • Asymptotic bounds on optimal noisy channel quantization via random coding

    Publication Year: 1994, Page(s):1926 - 1938
    Cited by:  Papers (33)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1162 KB)

    Asymptotically optimal zero-delay vector quantization in the presence of channel noise is studied using random coding techniques. First, an upper bound is derived for the average rth-power distortion of channel optimized k-dimensional vector quantization at transmission rate R on a binary symmetric channel with bit error probability /spl epsiv/. The upper bound asymptotically equals 2/sup -rRg(/sp... View full abstract»

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  • A mapping approach to rate-distortion computation and analysis

    Publication Year: 1994, Page(s):1939 - 1952
    Cited by:  Papers (66)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1330 KB)

    In rate-distortion theory, results are often derived and stated in terms of the optimizing density over the reproduction space. In this paper, the problem is reformulated in terms of the optimal mapping from the unit interval with Lebesgue measure that would induce the desired reproduction probability density. This results in optimality conditions that are "random relatives" of the known Lloyd (19... View full abstract»

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  • On information rates for mismatched decoders

    Publication Year: 1994, Page(s):1953 - 1967
    Cited by:  Papers (206)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1473 KB)

    Reliable transmission over a discrete-time memoryless channel with a decoding metric that is not necessarily matched to the channel (mismatched decoding) is considered. It is assumed that the encoder knows both the true channel and the decoding metric. The lower bound on the highest achievable rate found by Csiszar and Korner (1981) and by Hui (1983) for DMC's, hereafter denoted C/sub LM/, is show... View full abstract»

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  • M-ary phase coding for the noncoherent AWGN channel

    Publication Year: 1994, Page(s):1968 - 1984
    Cited by:  Papers (40)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1437 KB)

    This work considers coded M-ary phase-shift keying (MPSK) schemes with noncoherent detection. A class of block codes called module-phase codes is described. The algebraic framework used for describing these codes relies on elements from module theory which are discussed along with a method for constructing such codes for noncoherent detection. It is shown that differential encoding may be viewed a... View full abstract»

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  • Quickest detection of an abrupt change in a random sequence with finite change-time

    Publication Year: 1994, Page(s):1985 - 1993
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (836 KB)

    This paper proposes a new procedure for quickest detection of an abrupt change in a random sequence, where a change is known to occur with probability one. Applications include on-line speech segmentation, edge detection in image processing, and communications channel monitoring. In contrast to Shiryayev's (1963) problem formulation, prior knowledge of a change-time distribution is not required. T... View full abstract»

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  • A sequential procedure for multihypothesis testing

    Publication Year: 1994, Page(s):1994 - 2007
    Cited by:  Papers (142)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1152 KB)

    The sequential testing of more than two hypotheses has important applications in direct-sequence spread spectrum signal acquisition, multiple-resolution-element radar, and other areas. A useful sequential test which we term the MSPRT is studied in this paper. The test is shown to be a generalization of the sequential probability ratio test. Under Bayesian assumptions, it is argued that the MSPRT a... View full abstract»

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  • Asymptotic analysis of adaptive rate control for diverse sources with delayed feedback

    Publication Year: 1994, Page(s):2008 - 2025
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1801 KB)

    This paper analyzes the effectiveness of a class of adaptive algorithms for rate control in a data network with the following two elements: many sources with diverse characteristics (e.g., nonadaptive and adaptive sources with different feedback delays, different constraints on transmission rates) and a switch, based on ATM or cell-relay technology, with finite buffers. Several adaptive sources co... View full abstract»

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  • On the asymptotic tightness of the Shannon lower bound

    Publication Year: 1994, Page(s):2026 - 2031
    Cited by:  Papers (74)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (623 KB)

    New results are proved on the convergence of the Shannon (1959) lower bound to the rate distortion function as the distortion decreases to zero. The key convergence result is proved using a fundamental property of informational divergence. As a corollary, it is shown that the Shannon lower bound is asymptotically tight for norm-based distortions, when the source vector has a finite differential en... 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