IEEE Transactions on Information Theory

Issue 12 • Dec. 2004

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Displaying Results 1 - 25 of 48
  • Table of contents

    Publication Year: 2004, Page(s):c1 - c4
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  • IEEE Transactions on Information Theory publication information

    Publication Year: 2004, Page(s): c2
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  • The dynamics of group codes: Dual abelian group codes and systems

    Publication Year: 2004, Page(s):2935 - 2965
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (752 KB) | HTML iconHTML

    Fundamental results concerning the dynamics of abelian group codes (behaviors) and their duals are developed. Duals of sequence spaces over locally compact abelian (LCA) groups may be defined via Pontryagin duality; dual group codes are orthogonal subgroups of dual sequence spaces. The dual of a complete code or system is finite, and the dual of a Laurent code or system is (anti-)Laurent. If C and... View full abstract»

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  • LDPC block and convolutional codes based on circulant matrices

    Publication Year: 2004, Page(s):2966 - 2984
    Cited by:  Papers (298)  |  Patents (80)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1088 KB) | HTML iconHTML

    A class of algebraically structured quasi-cyclic (QC) low-density parity-check (LDPC) codes and their convolutional counterparts is presented. The QC codes are described by sparse parity-check matrices comprised of blocks of circulant matrices. The sparse parity-check representation allows for practical graph-based iterative message-passing decoding. Based on the algebraic structure, bounds on the... View full abstract»

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  • A new upper bound on the minimum distance of turbo codes

    Publication Year: 2004, Page(s):2985 - 2997
    Cited by:  Papers (17)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (568 KB) | HTML iconHTML

    In this paper, a new upper bound on the minimum distance of turbo codes is derived. The new bound is obtained by construction of an undirected graph which reflects the characteristics of the constituent codes and the interleaver. The resulting expression shows that the minimum distance of a turbo code grows approximately with the base-3 logarithm of the information word length. The new bound is ea... View full abstract»

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  • Sphere-packing bounds revisited for moderate block lengths

    Publication Year: 2004, Page(s):2998 - 3014
    Cited by:  Papers (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB) | HTML iconHTML

    The main reference of this paper is the sphere-packing bound of 1967 (SP67) derived by Shannon, Gallager, and Berlekamp. It offers a lower bound on the decoding error probability over a very large variety of channels. If it has failed so far to provide any usable material in practical implementation of telecommunication systems, it is due to an original focus on asymptotic results (making it inapp... View full abstract»

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  • Extractor codes

    Publication Year: 2004, Page(s):3015 - 3025
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB) | HTML iconHTML

    We study error-correcting codes for highly noisy channels. For example, every received signal in the channel may originate from some half of the symbols in the alphabet. Our main conceptual contribution is an equivalence between error-correcting codes for such channels and extractors. Our main technical contribution is a new explicit error-correcting code based on Trevisan's extractor that can han... View full abstract»

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  • A new upper bound on the ML decoding error probability of linear binary block codes in AWGN interference

    Publication Year: 2004, Page(s):3026 - 3036
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (376 KB) | HTML iconHTML

    Performance evaluation of maximum-likelihood (ML) soft-decision-decoded binary block codes is usually carried out using bounding techniques. Many tight upper bounds on the error probability of binary codes are based on the so-called Gallager's first bounding technique (GFBT). The tangential sphere bound (TSB) of Poltyrev which has been believed for many years to offer the tightest bound developed ... View full abstract»

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  • Degraded Gaussian multirelay channel: capacity and optimal power allocation

    Publication Year: 2004, Page(s):3037 - 3046
    Cited by:  Papers (90)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB) | HTML iconHTML

    We determine the capacity region of a degraded Gaussian relay channel with multiple relay stages. This is done by building an inductive argument based on the single-relay capacity theorem of Cover and El Gamal. For an arbitrary distribution of noise powers, we derive the optimal power distribution strategy among the transmitter and the relays and the best possible improvement in signal-to-noise ra... View full abstract»

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  • Secrecy capacities for multiple terminals

    Publication Year: 2004, Page(s):3047 - 3061
    Cited by:  Papers (192)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB) | HTML iconHTML

    We derive single-letter characterizations of (strong) secrecy capacities for models with an arbitrary number of terminals, each of which observes a distinct component of a discrete memoryless multiple source, with unrestricted and interactive public communication permitted between the terminals. A subset of these terminals can serve as helpers for the remaining terminals in generating secrecy. Acc... View full abstract»

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  • Cooperative diversity in wireless networks: Efficient protocols and outage behavior

    Publication Year: 2004, Page(s):3062 - 3080
    Cited by:  Papers (8104)  |  Patents (60)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB) | HTML iconHTML

    We develop and analyze low-complexity cooperative diversity protocols that combat fading induced by multipath propagation in wireless networks. The underlying techniques exploit space diversity available through cooperating terminals' relaying signals for one another. We outline several strategies employed by the cooperating radios, including fixed relaying schemes such as amplify-and-forward and ... View full abstract»

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  • On adaptive transmission for energy efficiency in wireless data networks

    Publication Year: 2004, Page(s):3081 - 3094
    Cited by:  Papers (102)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (390 KB) | HTML iconHTML

    This paper investigates the problem of energy-efficient transmission of data packets in a wireless network by jointly adapting to backlog and channel condition. Specifically, we consider minimum-energy scheduling problems over multiple-access channels, broadcast channels, and channels with fading, when packets of all users need to be transmitted before a deadline T. Earlier work has considered a s... View full abstract»

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  • Capacity of noncoherent time-selective Rayleigh-fading channels

    Publication Year: 2004, Page(s):3095 - 3110
    Cited by:  Papers (74)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (408 KB) | HTML iconHTML

    The capacity of noncoherent time-selective Rayleigh-fading channels is studied under various models for the variations in time. The study includes both single-input and single-output (SISO) and multiple-input and multiple-output (MIMO) systems. A block-fading model is first considered where the channel changes correlatively over each block period of length T, and independently across blocks. The p... View full abstract»

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  • Space-time communication for OFDM with implicit channel feedback

    Publication Year: 2004, Page(s):3111 - 3129
    Cited by:  Papers (47)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (568 KB) | HTML iconHTML

    We consider wideband communication (e.g., using orthogonal frequency-division multiplexed (OFDM) systems) over a typical cellular "downlink," in which both the base station and the mobile may have multiple antennas, but the number of antennas at the mobile is assumed to be small. Implicit channel feedback can play a powerful role in such systems, especially for outdoor channels, which typically ex... View full abstract»

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  • Multiresolution vector quantization

    Publication Year: 2004, Page(s):3130 - 3145
    Cited by:  Papers (16)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1024 KB) | HTML iconHTML

    Multiresolution source codes are data compression algorithms yielding embedded source descriptions. The decoder of a multiresolution code can build a source reproduction by decoding the embedded bit stream in part or in whole. All decoding procedures start at the beginning of the binary source description and decode some fraction of that string. Decoding a small portion of the binary string gives ... View full abstract»

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  • Bit-stuffing algorithms and analysis for run-length constrained channels in two and three dimensions

    Publication Year: 2004, Page(s):3146 - 3169
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1168 KB) | HTML iconHTML

    A rigorous derivation is given of the coding rate of a variable-to-variable length bit-stuffing coder for a two-dimensional (1,∞)-constrained channel. The coder studied is "nearly" a fixed-to-fixed length algorithm. Then an analogous variable-to-variable length bit-stuffing algorithm for the three-dimensional (1,∞)-constrained channel is presented, and its coding rate is analyzed using... View full abstract»

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  • On the optimality of the binary reflected Gray code

    Publication Year: 2004, Page(s):3170 - 3182
    Cited by:  Papers (76)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB) | HTML iconHTML

    This paper concerns the problem of selecting a binary labeling for the signal constellation in M-PSK, M-PAM, and M-QAM communication systems. Gray labelings are discussed and the original work by Frank Gray is analyzed. As is noted, the number of distinct Gray labelings that result in different bit-error probability grows rapidly with increasing constellation size. By introducing a recursive Gray ... View full abstract»

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  • Distilling common randomness from bipartite quantum states

    Publication Year: 2004, Page(s):3183 - 3196
    Cited by:  Papers (57)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (432 KB) | HTML iconHTML

    The problem of converting noisy quantum correlations between two parties into noiseless classical ones using a limited amount of one-way classical communication is addressed. A single-letter formula for the optimal tradeoff between the extracted common randomness and classical communication rate is obtained for the special case of classical-quantum correlations. The resulting curve is intimately r... View full abstract»

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  • Optimum scheduling and memory management in input queued switches with finite buffer space

    Publication Year: 2004, Page(s):3197 - 3220
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB) | HTML iconHTML

    The goal of this paper is to design optimal scheduling and memory management so as to minimize packet loss in input queued switches with finite input buffers. The contribution is to obtain closed-form optimal strategies that minimize packet loss in 2×2 switches with equal arrival rates for all streams. For arbitrary arrival rates, the contribution is to identify certain characteristics of th... View full abstract»

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  • Recursive construction of FIFO optical multiplexers with switched delay lines

    Publication Year: 2004, Page(s):3221 - 3233
    Cited by:  Papers (37)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB) | HTML iconHTML

    In this paper, we develop mathematical theory for recursive construction of first-in first-out (FIFO) optical multiplexers by the combination of (bufferless) crossbar switches and fiber delay lines (SDLs). We show that by cascading multistage SDL units, 2-to-1 multiplexers with a large buffer can be emulated exactly for both the departure process and the loss process from the multiplexer. Such res... View full abstract»

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  • Binary sequences with merit factor greater than 6.34

    Publication Year: 2004, Page(s):3234 - 3249
    Cited by:  Papers (25)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (2376 KB) | HTML iconHTML

    The maximum known asymptotic merit factor for binary sequences has been stuck at a value of 6 since the 1980s. Several authors have suggested that this value cannot be improved. In this paper, we construct an infinite family of binary sequences whose asymptotic merit factor we conjecture to be greater than 6.34. We present what we believe to be compelling evidence in support of this conjecture. Th... View full abstract»

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  • The similarity metric

    Publication Year: 2004, Page(s):3250 - 3264
    Cited by:  Papers (319)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (416 KB) | HTML iconHTML

    A new class of distances appropriate for measuring similarity relations between sequences, say one type of similarity per distance, is studied. We propose a new "normalized information distance," based on the noncomputable notion of Kolmogorov complexity, and show that it is in this class and it minorizes every computable distance in the class (that is, it is universal in that it discovers all com... View full abstract»

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  • Kolmogorov's structure functions and model selection

    Publication Year: 2004, Page(s):3265 - 3290
    Cited by:  Papers (47)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (648 KB) | HTML iconHTML

    In 1974, Kolmogorov proposed a nonprobabilistic approach to statistics and model selection. Let data be finite binary strings and models be finite sets of binary strings. Consider model classes consisting of models of given maximal (Kolmogorov) complexity. The "structure function" of the given data expresses the relation between the complexity level constraint on a model class and the least log-ca... View full abstract»

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  • Linear subcodes of turbo codes with improved distance spectra

    Publication Year: 2004, Page(s):3291 - 3294
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (192 KB) | HTML iconHTML

    In this correspondence, we present a technique for generation of linear subcodes of a given turbo code with better distance spectrum than the original mother turbo code, via an iterative process of trace-bit injection which minimally reduces code rate, followed by selective puncturing that allows recovery of the rate loss incurred during the trace-bit injection. The technique allows for asymptotic... View full abstract»

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  • Near-optimal depth-constrained codes

    Publication Year: 2004, Page(s):3294 - 3298
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (208 KB) | HTML iconHTML

    This note considers an n-letter alphabet in which the ith letter is accessed with probability pi. The problem is to design efficient algorithms for constructing near-optimal, depth-constrained Huffman and alphabetic codes. We recast the problem as one of determining a probability vector q*=(q*1,...,q*n) in an appropriate convex set,... 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