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IEEE Transactions on Information Theory

Issue 4 • Date April 2003

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Displaying Results 1 - 25 of 27
  • Contributors

    Publication Year: 2003, Page(s):1064 - 1069
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  • Alternative structure for computing APPs of the Markov source

    Publication Year: 2003, Page(s):1027 - 1029
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (225 KB) | HTML iconHTML

    We introduce an alternative structure for computing the a posteriori probabilities (APPs) for state and transition sequences of a Markov source observed through a noisy output sequence. Compared to the well-established forward-backward recursion algorithm of Bahl et al. (1974), the proposed structure allows a reduction in computational complexity at the expense of increased memory requirements. Al... View full abstract»

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  • Linear authentication codes: bounds and constructions

    Publication Year: 2003, Page(s):866 - 872
    Cited by:  Papers (42)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (576 KB) | HTML iconHTML

    In this paper, we consider a new class of unconditionally secure authentication codes, called linear authentication codes (or linear A-codes). We show that a linear A-code can be characterized by a family of subspaces of a vector space over a finite field. We then derive an upper bound on the size of the source space when other parameters of the system, that is, the sizes of the key space and the ... View full abstract»

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  • Optimum receivers and low-dimensional spreaded modulation for multiuser space-time communications

    Publication Year: 2003, Page(s):901 - 918
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1029 KB) | HTML iconHTML

    The jointly optimum receiver is obtained for multi- user communications in a frequency nonselective Rayleigh-fading channel with NT transmit antennas per user and NR receive antennas. Based on a general analysis of quadratic receivers in zero-mean complex Gaussian vectors, asymptotically tight expressions (for high signal-to-noise ratio (SNR)) for the pairwise error probabili... View full abstract»

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  • Distance-preserving mappings from binary vectors to permutations

    Publication Year: 2003, Page(s):1054 - 1059
    Cited by:  Papers (38)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (373 KB) | HTML iconHTML

    Mappings of the set of binary vectors of a fixed length to the set of permutations of the same length are useful for the construction of permutation codes. In this article, several explicit constructions of such mappings preserving or increasing the Hamming distance are given. Some applications are given to illustrate the usefulness of the construction. In particular, a new lower bound on the maxi... View full abstract»

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  • Reduced GMD decoding

    Publication Year: 2003, Page(s):1013 - 1027
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (818 KB) | HTML iconHTML

    A framework is presented for generalized minimum distance (GMD) decoding with a limited number of decoding trials and a restricted set of reliability values. In GMD decoding, symbols received from the channel may be erased before being fed into an algebraic error-erasure decoder for error correction, in subsequent or simultaneous trials with different erasing patterns. The decision whether or not ... View full abstract»

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  • Digital fingerprinting codes: problem statements, constructions, identification of traitors

    Publication Year: 2003, Page(s):852 - 865
    Cited by:  Papers (83)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1021 KB) | HTML iconHTML

    We consider a general fingerprinting problem of digital data under which coalitions of users can alter or erase some bits in their copies in order to create an illegal copy. Each user is assigned a fingerprint which is a word in a fingerprinting code of size M (the total number of users) and length n. We present binary fingerprinting codes secure against size-t coalitions which enable the distribu... View full abstract»

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  • Optimal sequences for CDMA with decision-feedback receivers

    Publication Year: 2003, Page(s):886 - 900
    Cited by:  Papers (45)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (775 KB) | HTML iconHTML

    We consider a symbol-synchronous code-division multiple-access (CDMA) system that is equipped with a multiuser decision-feedback receiver and for which power control is available. The users are each assigned a quality-of-service (QoS) threshold to be guaranteed by the system, and to cover scenarios for which there are multiple classes of users, these are not required to be equal to each other. For... View full abstract»

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  • Good self-dual quasi-cyclic codes exist

    Publication Year: 2003, Page(s):1052 - 1053
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (224 KB) | HTML iconHTML

    We show that there are long binary quasi-cyclic self-dual (either Type I or Type II) codes satisfying the Gilbert-Varshamov bound. View full abstract»

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  • Designing optimal quantum detectors via semidefinite programming

    Publication Year: 2003, Page(s):1007 - 1012
    Cited by:  Papers (73)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (345 KB) | HTML iconHTML

    We consider the problem of designing an optimal quantum detector to minimize the probability of a detection error when distinguishing among a collection of quantum states, represented by a set of density operators. We show that the design of the optimal detector can be formulated as a semidefinite programming problem. Based on this formulation, we derive a set of necessary and sufficient condition... View full abstract»

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  • Secret-key agreement over unauthenticated public channels .II. Privacy amplification

    Publication Year: 2003, Page(s):839 - 851
    Cited by:  Papers (48)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (917 KB) | HTML iconHTML

    For pt. II see ibid., vol.49, no.4, p.832-38 (2003). Here, we consider the special case where the legitimate partners already share a mutual string which might, however, be partially known to the adversary. The problem of generating a secret key in this case has been well studied in the passive-adversary model - for instance, in the context of quantum key agreement - under the name of privacy ampl... View full abstract»

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  • Lattice decoding for joint detection in direct-sequence CDMA systems

    Publication Year: 2003, Page(s):1030 - 1037
    Cited by:  Papers (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (548 KB) | HTML iconHTML

    A new joint detection method based on sphere packing lattice decoding is presented in this paper. The algorithm is suitable for both synchronous and asynchronous multiple access direct-sequence code-division multiple-access (DS-CDMA) systems, and it may jointly detect up to 64 users with a reasonable complexity. The detection complexity is independent of the modulation size and large M-PAM or M-QA... View full abstract»

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  • Ensuring convergence of the MMSE iteration for interference avoidance to the global optimum

    Publication Year: 2003, Page(s):873 - 885
    Cited by:  Papers (59)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1281 KB) | HTML iconHTML

    Viswanath and Anantharam (1999) characterize the sum capacity of multiaccess vector channels. For a given number of users, received powers, spreading gain, and noise covariance matrix in a code-division multiple-access (CDMA) system, Viswanath and Anantharam present a combinatorial algorithm to generate a set of signature sequences that achieves the maximum sum capacity. These sets also minimize a... View full abstract»

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  • Improving the generalized likelihood ratio test for unknown linear Gaussian channels

    Publication Year: 2003, Page(s):919 - 936
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (3112 KB) | HTML iconHTML

    In this work, we consider the decoding problem for unknown Gaussian linear channels. Important examples of linear channels are the intersymbol interference (ISI) channel and the diversity channel with multiple transmit and receive antennas employing space-time codes (STC). An important class of decoders is based on the generalized likelihood ratio test (GLRT). Our work deals primarily with a decod... View full abstract»

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  • On two high-rate algebraic space-time codes

    Publication Year: 2003, Page(s):1059 - 1063
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB) | HTML iconHTML

    We examine some algebraic properties of two high-rate linear space-time block codes over M=2,3 transmit antennas. Although these high-rate codes have positive coding gain, the gain decreases when increasing the constellation size. We give tight upper and lower bounds on the achieved coding gains as functions of the size of the constellations used. We show that when using the irrational numbers &ra... View full abstract»

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  • Upper bounds on empirically optimal quantizers

    Publication Year: 2003, Page(s):1037 - 1046
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (704 KB) | HTML iconHTML

    In designing a vector quantizer using a training sequence (TS), the training algorithm tries to find an empirically optimal quantizer that minimizes the selected distortion criteria using the sequence. In order to evaluate the performance of the trained quantizer, we can use the empirically minimized distortion that we obtain when designing the quantizer. Several upper bounds on the empirically mi... View full abstract»

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  • Super-orthogonal space-time trellis codes

    Publication Year: 2003, Page(s):937 - 950
    Cited by:  Papers (163)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (710 KB) | HTML iconHTML

    We introduce a new class of space-time codes called super-orthogonal space-time trellis codes. These codes combine set partitioning and a super set of orthogonal space-time block codes in a systematic way to provide full diversity and improved coding gain over earlier space-time trellis code constructions. We also study the optimality of our set partitioning and provide coding gain analysis. Codes... View full abstract»

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  • Pattern matching and lossy data compression on random fields

    Publication Year: 2003, Page(s):1047 - 1051
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (343 KB) | HTML iconHTML

    We consider the problem of lossy data compression for data arranged on two-dimensional arrays (such as images), or more generally on higher dimensional arrays (such as video sequences). Several of the most commonly used algorithms are based on pattern matching: Given a distortion level D and a block of data to be compressed, the encoder first finds a D-close match of this block into some database,... View full abstract»

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  • How much training is needed in multiple-antenna wireless links?

    Publication Year: 2003, Page(s):951 - 963
    Cited by:  Papers (1026)  |  Patents (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (832 KB) | HTML iconHTML

    Multiple-antenna wireless communication links promise very high data rates with low error probabilities, especially when the wireless channel response is known at the receiver. In practice, knowledge of the channel is often obtained by sending known training symbols to the receiver. We show how training affects the capacity of a fading channel-too little training and the channel is improperly lear... View full abstract»

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  • The inequalities of quantum information theory

    Publication Year: 2003, Page(s):773 - 789
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1293 KB) | HTML iconHTML

    Let ρ denote the density matrix of a quantum state having n parts 1, ..., n. For I⊆N={1, ..., n}, let ρI=TrNI/(ρ) denote the density matrix of the state comprising those parts i such that i∈I, and let S(ρI) denote the von Neumann (1927) entropy of the state ρI. The collection of ν=2n numbers {S(ρ... View full abstract»

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  • Optimal error exponents in hidden Markov models order estimation

    Publication Year: 2003, Page(s):964 - 980
    Cited by:  Papers (18)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1257 KB) | HTML iconHTML

    We consider the estimation of the number of hidden states (the order) of a discrete-time finite-alphabet hidden Markov model (HMM). The estimators we investigate are related to code-based order estimators: penalized maximum-likelihood (ML) estimators and penalized versions of the mixture estimator introduced by Liu and Narayan (1994). We prove strong consistency of those estimators without assumin... View full abstract»

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  • Energy reduction in VLSI computation modules: an information-theoretic approach

    Publication Year: 2003, Page(s):790 - 808
    Cited by:  Papers (9)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1200 KB) | HTML iconHTML

    We consider the problem of reduction of computation cost by introducing redundancy in the number of ports as well as in the input and output sequences of computation modules. Using our formulation, the classical "communication scenario" is the case when a computation module has to recompute the input sequence at a different location or time with high fidelity and low bit-error rates. We then consi... View full abstract»

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  • Maximum minimal distance partitioning of the Z2 lattice

    Publication Year: 2003, Page(s):981 - 992
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1297 KB) | HTML iconHTML

    We study the problem of dividing the Z2 lattice into partitions so that minimal intra-partition distance between the points is maximized. We show that this problem is analogous to the problem of sphere packing. An upper bound on the achievable intra-partition distances for a given number of partitions follows naturally from this observation, since the optimal sphere packing in two dimen... View full abstract»

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  • Improved bounds for the rate loss of multiresolution source codes

    Publication Year: 2003, Page(s):809 - 821
    Cited by:  Papers (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1669 KB) | HTML iconHTML

    We present new bounds for the rate loss of multiresolution source codes (MRSCs). Considering an M-resolution code, the rate loss at the ith resolution with distortion Di is defined as Li=Ri-R(Di), where Ri is the rate achievable by the MRSC at stage i. This rate loss describes the performance degradation of the MRSC compared to the best single... View full abstract»

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  • Geometrically uniform frames

    Publication Year: 2003, Page(s):993 - 1006
    Cited by:  Papers (41)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (919 KB) | HTML iconHTML

    We introduce a new class of finite-dimensional frames with strong symmetry properties, called geometrically uniform (GU) frames, that are defined over a finite Abelian group of unitary matrices and are generated by a single generating vector. The notion of GU frames is then extended to compound GU (CGU) frames which are generated by a finite Abelian group of unitary matrices using multiple generat... 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
Frank R. Kschischang

Department of Electrical and Computer Engineering