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IEEE Transactions on Information Theory

Issue 9 • Sept. 2005

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Displaying Results 1 - 25 of 38
  • Table of contents

    Publication Year: 2005, Page(s):c1 - c4
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  • IEEE Transactions on Information Theory publication information

    Publication Year: 2005, Page(s): c2
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  • On mutual information, likelihood ratios, and estimation error for the additive Gaussian channel

    Publication Year: 2005, Page(s):3017 - 3024
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (240 KB) | HTML iconHTML

    This paper considers the model of an arbitrarily distributed signal x observed through an added independent white Gaussian noise w, y=x+w. New relations between the minimal mean-square error of the noncausal estimator and the likelihood ratio between y and w are derived. This is followed by an extended version of a recently derived relation between the mutual information I(x;y) and the minimal mea... View full abstract»

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  • On the high-SNR capacity of noncoherent networks

    Publication Year: 2005, Page(s):3025 - 3036
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (303 KB) | HTML iconHTML

    We obtain the first term in the high signal-to-noise ratio (SNR) asymptotic expansion of the sum-rate capacity of noncoherent fading networks, i.e., networks where the transmitters and receivers-while fully cognizant of the fading law-have no access to the fading realization. This term is an integer multiple of log log SNR with the coefficient having a simple combinatorial characterization. It can... View full abstract»

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  • Cooperative Strategies and Capacity Theorems for Relay Networks

    Publication Year: 2005, Page(s):3037 - 3063
    Cited by:  Papers (1649)  |  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (912 KB) | HTML iconHTML

    Coding strategies that exploit node cooperation are developed for relay networks. Two basic schemes are studied: the relays decode-and-forward the source message to the destination, or they compress-and-forward their channel outputs to the destination. The decode-and-forward scheme is a variant of multihopping, but in addition to having the relays successively decode the message, the transmitters ... View full abstract»

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  • Divergence estimation of continuous distributions based on data-dependent partitions

    Publication Year: 2005, Page(s):3064 - 3074
    Cited by:  Papers (51)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (449 KB) | HTML iconHTML

    We present a universal estimator of the divergence D(P/spl par/Q) for two arbitrary continuous distributions P and Q satisfying certain regularity conditions. This algorithm, which observes independent and identically distributed (i.i.d.) samples from both P and Q, is based on the estimation of the Radon-Nikodym derivative dP/dQ via a data-dependent partition of the observation space. Strong conve... View full abstract»

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  • Capacity Analysis for Continuous-Alphabet Channels With Side Information, Part I: A General Framework

    Publication Year: 2005, Page(s):3075 - 3085
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB) | HTML iconHTML

    Capacity analysis for channels with side information at the receiver has been an active area of interest. This problem is well investigated for the case of finite-alphabet channels. However, the results are not easily generalizable to the case of continuous-alphabet channels due to analytical difficulties inherent with continuous alphabets. In the first part of this two-part paper, we address an a... View full abstract»

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  • Capacity Analysis for Continuous Alphabet Channels With Side Information, Part II: MIMO Channels

    Publication Year: 2005, Page(s):3086 - 3101
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (440 KB) | HTML iconHTML

    In this second part of our two-part paper, we consider the capacity analysis for wireless mobile systems with multiple-antenna architectures. We apply the results of the first part to a commonly known baseband, discrete-time multiple-antenna system where both the transmitter and receiver know the channel's statistical law. We analyze the capacity for additive white Gaussian noise (AWGN) channels, ... View full abstract»

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  • Capacity Per Unit Energy of Fading Channels With a Peak Constraint

    Publication Year: 2005, Page(s):3102 - 3120
    Cited by:  Papers (32)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (560 KB) | HTML iconHTML

    A discrete-time single-user scalar channel with temporally correlated Rayleigh fading is analyzed. There is no side information at the transmitter or the receiver. A simple expression is given for the capacity per unit energy, in the presence of a peak constraint. The simple formula of VerdÚ for capacity per unit cost is adapted to a channel with memory, and is used in the proof. In addition ... View full abstract»

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  • General capacity bounds for spatially correlated Rician MIMO channels

    Publication Year: 2005, Page(s):3121 - 3145
    Cited by:  Papers (134)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (765 KB) | HTML iconHTML

    This paper considers the capacity of spatially correlated Rician multiple-input multiple-output (MIMO) channels. We consider the general case with double-sided correlation and arbitrary rank channel means. We derive tight upper and lower bounds on the ergodic capacity. In the particular cases when the numbers of transmit and receive antennas are equal, or when the correlation is single sided, we d... View full abstract»

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  • A Systematic Approach to Multistage Detectors in Multipath Fading Channels

    Publication Year: 2005, Page(s):3146 - 3158
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (464 KB) | HTML iconHTML

    We consider linear multistage detectors with universal (large system) weighting for synchronous code-division multiple access (CDMA) in multipath fading channels with many users. A convenient choice of the basis of the projection subspace allows a joint projection of all users. Taking advantage of this property, the complexity per bit of multistage detectors with universal weights scales linearly ... View full abstract»

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  • Uncertainty, monogamy, and locking of quantum correlations

    Publication Year: 2005, Page(s):3159 - 3165
    Cited by:  Papers (38)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (201 KB) | HTML iconHTML

    Squashed entanglement and entanglement of purification are quantum-mechanical correlation measures and are defined as certain minimizations of entropic quantities. In this paper, we present the first nontrivial calculations of both quantities. Our results lead to the conclusion that both measures can drop by an arbitrary amount when only a single qubit of a local system is lost. This property is k... View full abstract»

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  • On joint information embedding and lossy compression in the presence of a stationary memoryless attack channel

    Publication Year: 2005, Page(s):3166 - 3175
    Cited by:  Papers (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (282 KB) | HTML iconHTML

    We consider the problem of optimum joint public information embedding and lossy compression with respect to a fidelity criterion. The decompressed composite sequence (stegotext) is distorted by a stationary memoryless attack, resulting in a forgery which in turn is fed into the decoder, whose task is to retrieve the embedded information. The goal of this paper is to characterize the maximum achiev... View full abstract»

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  • Continuous-Time Equivalents of Welch Bound Equality Sequences

    Publication Year: 2005, Page(s):3176 - 3185
    Cited by:  Papers (13)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (288 KB) | HTML iconHTML

    The theory developed on the sequence optimization for equal-power code-division multiple-access (CDMA) systems is generalized in this paper. Unlike previous works, where discrete-time or vector channel models are predominantly employed, the overloaded channels are modeled as strictly band-limited, continuous-time multiple-access channels corrupted by additive white Gaussian noise (AWGN). After bei... View full abstract»

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  • Zero/positive capacities of two-dimensional runlength-constrained arrays

    Publication Year: 2005, Page(s):3186 - 3199
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (390 KB) | HTML iconHTML

    A binary sequence satisfies a one-dimensional (d/sub 1/,k/sub 1/,d/sub 2/,k/sub 2/) runlength constraint if every run of zeros has length at least d/sub 1/ and at most k/sub 1/ and every run of ones has length at least d/sub 2/ and at most k/sub 2/. A two-dimensional binary array is (d/sub 1/,k/sub 1/,d/sub 2/,k/sub 2/;d/sub 3/,k/sub 3/,d/sub 4/,k/sub 4/)-constrained if it satisfies the one-dimens... View full abstract»

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  • Improving the Gilbert-Varshamov bound for q-ary codes

    Publication Year: 2005, Page(s):3200 - 3208
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB) | HTML iconHTML

    Given positive integers q,n, and d, denote by Aq(n,d) the maximum size of a q-ary code of length n and minimum distance d. The famous Gilbert-Varshamov bound asserts that Aq(n,d+1)≥qn/Vq(n,d) where Vq(n,d)=Σi=0d (in)(q-1)i is the volume of a q-ary sphere of radius d. Extending a r... View full abstract»

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  • LDPC codes over rings for PSK modulation

    Publication Year: 2005, Page(s):3209 - 3220
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (389 KB) | HTML iconHTML

    This paper describes the design and analysis of low-density parity-check (LDPC) codes over rings and shows how these codes, when mapped onto appropriate signal constellations, can be used to effect bandwidth-efficient modulation. Specifically, LDPC codes are constructed over the integer rings /spl Zopf//sub m/ and G/sub m//sup 2/ and mapped onto phase-shift keying (PSK)-type signal sets to yield g... View full abstract»

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  • Tight bounds for LDPC and LDGM codes under MAP decoding

    Publication Year: 2005, Page(s):3221 - 3246
    Cited by:  Papers (48)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (753 KB) | HTML iconHTML

    A new method for analyzing low-density parity-check (LDPC) codes and low-density generator-matrix (LDGM) codes under bit maximum a posteriori probability (MAP) decoding is introduced. The method is based on a rigorous approach to spin glasses developed by Francesco Guerra. It allows one to construct lower bounds on the entropy of the transmitted message conditional to the received one. Based on he... View full abstract»

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  • An analysis of the orthogonality structures of convolutional codes for iterative decoding

    Publication Year: 2005, Page(s):3247 - 3261
    Cited by:  Papers (20)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (624 KB) | HTML iconHTML

    The structures of convolutional self-orthogonal codes and convolutional self-doubly-orthogonal codes for both belief propagation and threshold iterative decoding algorithms are analyzed on the basis of difference sets and computation tree. It is shown that the double orthogonality property of convolutional self-doubly-orthogonal codes improves the code structure by maximizing the number of indepen... View full abstract»

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  • An analysis on optimal rates of BDB encoders for RLL and MTR systems

    Publication Year: 2005, Page(s):3262 - 3283
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (694 KB) | HTML iconHTML

    In most recording channels, modulation codes are employed to transform user data to sequences that satisfy some desirable constraint. Run-length-limited (RLL(d,k)) and maximum transition run (MTR(j,k)) systems are examples of constraints that improve timing and detection performance. A modulation encoder typically takes the form of a finite-state machine. Alternatively, a look-ahead encoder can be... View full abstract»

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  • Gaussian orthogonal relay channels: optimal resource allocation and capacity

    Publication Year: 2005, Page(s):3284 - 3289
    Cited by:  Papers (152)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (236 KB) | HTML iconHTML

    A Gaussian orthogonal relay model is investigated, where the source transmits to the relay and destination in channel 1, and the relay transmits to the destination in channel 2, with channels 1 and 2 being orthogonalized in the time-frequency plane in order to satisfy practical constraints. The total available channel resource (time and bandwidth) is split into the two orthogonal channels, and the... View full abstract»

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  • A new bound for the zero-error capacity region of the two-user binary adder channel

    Publication Year: 2005, Page(s):3289 - 3291
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (102 KB) | HTML iconHTML

    A new uniquely decodable (UD) code pair for the two-user binary adder channel (BAC) is presented. This code pair leads to an improved bound for the zero-error capacity region of such a channel. The highest known rate for a UD code pair for the two-user BAC is thereby improved to (log/sub 2/240)/6/spl ap/1.3178. It is also demonstrated that the problem of finding UD code pairs for the closely relat... View full abstract»

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  • Design and analysis of password-based key derivation functions

    Publication Year: 2005, Page(s):3292 - 3297
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (239 KB) | HTML iconHTML

    A password-based key derivation function (KDF)-a function that derives cryptographic keys from a password-is necessary in many security applications. Like any password-based schemes, such KDFs are subject to key search attacks (often called dictionary attacks). Salt and iteration count are used in practice to significantly increase the workload of such attacks. These techniques have also been spec... View full abstract»

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  • Toward a general correlation theorem

    Publication Year: 2005, Page(s):3297 - 3302
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (260 KB) | HTML iconHTML

    In 2001, Nyberg proved three important correlation theorems and applied them to several cryptanalytic contexts. We continue the work of Nyberg in a more theoretical direction. We consider a general functional form and obtain its Walsh transform. Two of Nyberg's correlation theorems are seen to be special cases of our general functional form. S-box lookup, addition modulo 2/sup 2k/, and X-OR are th... View full abstract»

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  • On the autocorrelation distributions of Sidel'nikov sequences

    Publication Year: 2005, Page(s):3303 - 3307
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (213 KB) | HTML iconHTML

    For a prime p and positive integers M and n such that M|p/sup n/-1, Sidel'nikov introduced M-ary sequences (called Sidel'nikov sequences) of period p/sup n/-1, the out-of-phase autocorrelation magnitude of which is upper bounded by 4. In this correspondence, we derived the autocorrelation distributions, i.e., the values and the number of occurrences of each value of the autocorrelation function of... 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