IEEE Transactions on Information Theory

Volume 48 Issue 9 • Sept. 2002

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Displaying Results 1 - 21 of 21
  • Upper bounds on the rate of LDPC codes

    Publication Year: 2002, Page(s):2437 - 2449
    Cited by:  Papers (37)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (454 KB) | HTML iconHTML

    We derive upper bounds on the rate of low-density parity-check (LDPC) codes for which reliable communication is achievable. We first generalize Gallager's (1963) bound to a general binary-input symmetric-output channel. We then proceed to derive tighter bounds. We also derive upper bounds on the rate as a function of the minimum distance of the code. We consider both individual codes and ensembles... View full abstract»

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  • Bounds on packings of spheres in the Grassmann manifold

    Publication Year: 2002, Page(s):2450 - 2454
    Cited by:  Papers (115)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (265 KB) | HTML iconHTML

    We derive the Gilbert-Varshamov and Hamming bounds for packings of spheres (codes) in the Grassmann manifolds over R and C. Asymptotic expressions are obtained for the geodesic metric and projection Frobenius (chordal) metric on the manifold. View full abstract»

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  • An information-theoretic and game-theoretic study of timing channels

    Publication Year: 2002, Page(s):2455 - 2477
    Cited by:  Papers (65)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (750 KB) | HTML iconHTML

    This paper focuses on jammed timing channels. Pure delay jammers with a maximum delay constraint, an average delay constraint, or a maximum buffer size constraint are explored, for continuous-time or discrete-time packet waveforms. Fluid waveform approximations of each of these classes of waveforms are employed to aid in analysis. Channel capacity is defined and an information-theoretic game based... View full abstract»

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  • Delay-constrained capacity with causal feedback

    Publication Year: 2002, Page(s):2478 - 2494
    Cited by:  Papers (90)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (633 KB) | HTML iconHTML

    A block-fading channel model is considered, and a K-block delay constraint is imposed on data transmission. The key consideration is that the channel state information is fed back to the transmitter in a causal manner. A general cost function /spl mu/(x) is considered in solving the delay-constrained transmission problem, under the short-term and the long-term power constraints. A causal power ada... View full abstract»

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  • A random matrix model of communication via antenna arrays

    Publication Year: 2002, Page(s):2495 - 2506
    Cited by:  Papers (119)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (578 KB) | HTML iconHTML

    A random matrix model is introduced that probabilistically describes the spatial and temporal multipath propagation between a transmitting and receiving antenna array with a limited number of scatterers for mobile radio and indoor environments. The model characterizes the channel by its richness delay profile which gives the number of scattering objects as a function of the path delay. Each delay ... View full abstract»

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  • Large-system performance analysis of blind and group-blind multiuser receivers

    Publication Year: 2002, Page(s):2507 - 2523
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (636 KB) | HTML iconHTML

    We present a large-system performance analysis of blind and group-blind multiuser detection methods. In these methods, the receivers are estimated based on the received signal samples. In particular, we assume binary random spreading, and let the spreading gain N, the number of users K, and the number of received signal samples M all go to infinity, while keeping the ratios K/N and M/N fixed. We c... View full abstract»

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  • Construction of secure and fast hash functions using nonbinary error-correcting codes

    Publication Year: 2002, Page(s):2524 - 2539
    Cited by:  Papers (5)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (456 KB) | HTML iconHTML

    This paper considers iterated hash functions. It proposes new constructions of fast and secure compression functions with nl-bit outputs for integers n>1 based on error-correcting codes and secure compression functions with l-bit outputs. This leads to simple and practical hash function constructions based on block ciphers such as the Data Encryption Standard (DES), where the key size is slight... View full abstract»

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  • p-ary unified sequences: p-ary extended d-form sequences with the ideal autocorrelation property

    Publication Year: 2002, Page(s):2540 - 2546
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (341 KB) | HTML iconHTML

    In this paper, for a prime number p, a construction method to generate p-ary d-form sequences with the ideal autocorrelation property is proposed and using the ternary sequences found by Helleseth, Kumar, and Martinsen (2000), ternary d-form sequences with the ideal autocorrelation property are constructed. By combining the methods for generating p-ary extended sequences (a special case of geometr... View full abstract»

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  • Lower bounds on the quantum capacity and highest error exponent of general memoryless channels

    Publication Year: 2002, Page(s):2547 - 2557
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (501 KB) | HTML iconHTML

    Tradeoffs between the information rate and fidelity of quantum error-correcting codes are discussed. Quantum channels to be considered are those subject to independent errors and modeled as tensor products of copies of a general completely positive (CP) linear map, where the dimension of the underlying Hilbert space is a prime number. On such a quantum channel, the highest fidelity of a quantum er... View full abstract»

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  • A generalized uncertainty principle and sparse representation in pairs of bases

    Publication Year: 2002, Page(s):2558 - 2567
    Cited by:  Papers (287)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (369 KB) | HTML iconHTML

    An elementary proof of a basic uncertainty principle concerning pairs of representations of R/sup N/ vectors in different orthonormal bases is provided. The result, slightly stronger than stated before, has a direct impact on the uniqueness property of the sparse representation of such vectors using pairs of orthonormal bases as overcomplete dictionaries. The main contribution in this paper is the... View full abstract»

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  • Random codes: minimum distances and error exponents

    Publication Year: 2002, Page(s):2568 - 2573
    Cited by:  Papers (87)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB) | HTML iconHTML

    Minimum distances, distance distributions, and error exponents on a binary-symmetric channel (BSC) are given for typical codes from Shannon's random code ensemble and for typical codes from a random linear code ensemble. A typical random code of length N and rate R is shown to have minimum distance N/spl delta//sub GV/(2R), where /spl delta//sub GV/(R) is the Gilbert-Varshamov (GV) relative distan... View full abstract»

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  • More results on the weight enumerator of product codes

    Publication Year: 2002, Page(s):2573 - 2577
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (316 KB) | HTML iconHTML

    We consider the product code C/sub p/ of q-ary linear codes with minimum distances d/sub c/ and d/sub r/. The words in C/sub p/ of weight less than d/sub r/d/sub c/+max(d/sub r//spl lceil/(d/sub c//g)/spl rceil/,d/sub c//spl lceil/(d/sub r//q)/spl rceil/) are characterized, and their number is expressed in the number of low-weight words of the constituent codes. For binary product codes, we give a... View full abstract»

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  • Tailbiting codes obtained via convolutional codes with large active distance-slopes

    Publication Year: 2002, Page(s):2577 - 2587
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (563 KB) | HTML iconHTML

    The slope of the active distances is an important parameter when investigating the error-correcting capability of convolutional codes and the distance behavior of concatenated convolutional codes. The slope of the active distances is equal to the minimum average weight cycle in the state-transition diagram of the encoder. A general upper bound on the slope depending on the free distance of the con... View full abstract»

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  • On binary 1-perfect additive codes: some structural properties

    Publication Year: 2002, Page(s):2587 - 2592
    Cited by:  Papers (21)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (375 KB) | HTML iconHTML

    The rank and kernel of 1-perfect additive codes is determined. Additive codes could be seen as translation-invariant propelinear codes and, in this correspondence, a characterization of propelinear codes as codes having a regular subgroup of the full group of isometrics of the code is established. A characterization of the automorphism group of a 1-perfect additive code is given and also the cardi... View full abstract»

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  • Z(p/sup k+1/)-linear codes

    Publication Year: 2002, Page(s):2592 - 2605
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (675 KB) | HTML iconHTML

    We characterize codes over Z/sub p/ which are the Gray images of (1-p/sup k/)-cyclic codes or cyclic codes over Z(p/sup k+l/) (k/spl ges/1). A necessary and sufficient condition for the Gray image of a Z(p/sup 2/)-linear (1-p)-cyclic code to be linear is given. In many cases, this yields an explicit description of the Gray image of a linear (1-p)-cyclic code over Z(p/sup 2/), of length relatively ... View full abstract»

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  • More on (2,2)-separating systems

    Publication Year: 2002, Page(s):2606 - 2609
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (305 KB) | HTML iconHTML

    The theory of separating systems has been applied in different areas of science and technology such as automata synthesis, technical diagnosis, and authenticating ownership claims. Constructions of (2,2)-separating systems derived from error-correcting codes are given, together with bounds on their parameters based on distance considerations. View full abstract»

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  • On the equivalence of three reduced rank linear estimators with applications to DS-CDMA

    Publication Year: 2002, Page(s):2609 - 2614
    Cited by:  Papers (41)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB) | HTML iconHTML

    This correspondence shows the equivalence of three previously proposed reduced-rank detection schemes for direct-sequence code-division multiple-access (DS-CDMA) communication systems. The auxiliary vector filtering (AVF) algorithm is simplified through a key observation on the construction of the auxiliary vectors. After simplification, it is shown that the AVF algorithm is equivalent to the mult... View full abstract»

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  • Optimal versus randomized search of fixed length binary words

    Publication Year: 2002, Page(s):2614 - 2621
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (421 KB) | HTML iconHTML

    We consider the search problem in which one finds a binary word among m words chosen randomly from the set of all words of fixed length n. It is well known that the optimal search is equivalent to the Huffman coding that requires on average log/sub 2/ m bits to be checked plus a small additional cost called the average redundancy. The latter is an oscillating function of m and is bounded between z... View full abstract»

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  • On the performance of recency-rank and block-sorting universal lossless data compression algorithms

    Publication Year: 2002, Page(s):2621 - 2625
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB) | HTML iconHTML

    Bounds on the redundancy of the recency-rank and block-sorting universal lossless data compression algorithms for finite-length sequences are presented. These algorithms are asymptotically optimal for infinite-length sequences, stationary ergodic sources in the almost-sure sense, and asymptotically mean stationary sources in the average and almost-sure sense. View full abstract»

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  • Maximum nonlinearity of symmetric Boolean functions on odd number of variables

    Publication Year: 2002, Page(s):2626 - 2630
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (309 KB) | HTML iconHTML

    In this correspondence, we establish that for odd n, the maximum nonlinearity achievable by an n-variable symmetric Boolean function is 2/sup n-1/-2/sup (n-1)///sup 2/ and characterize the set of functions which achieve this value of nonlinearity. In particular, we show that for each odd n/spl ges/3, there are exactly four possible symmetric Boolean functions achieving the nonlinearity 2/sup n-1/-... View full abstract»

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  • Contributors

    Publication Year: 2002, Page(s):2631 - 2634
    Request permission for commercial reuse | PDF file iconPDF (170 KB)
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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
Alexander Barg

Department of Electrical and Computer Engineering and the Institute for Systems Research, University of Maryland

email: abarg-ittrans@ece.umd.edu