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Signal Processing Letters, IEEE

Issue 4 • Date April 2009

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Displaying Results 1 - 25 of 30
  • [Front cover]

    Publication Year: 2009 , Page(s): C1
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    Freely Available from IEEE
  • IEEE Signal Processing Letters publication information

    Publication Year: 2009 , Page(s): C2
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    Freely Available from IEEE
  • Table of contents

    Publication Year: 2009 , Page(s): 235 - 236
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  • Outage Performance of Cooperative Communication Systems Using Opportunistic Relaying and Selection Combining Receiver

    Publication Year: 2009 , Page(s): 237 - 240
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (175 KB) |  | HTML iconHTML  

    We analyze the performance of cooperative communication systems with opportunistic decode-and-forward for relaying and selection combining receiver at the destination. We derive an exact closed-form expression for the outage of the system over dissimilar Nakagami fading channels. Also, we study its asymptotic outage performance, based on which the optimum power allocations for the source and the r... View full abstract»

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  • Missing Data Recovery Via a Nonparametric Iterative Adaptive Approach

    Publication Year: 2009 , Page(s): 241 - 244
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (555 KB) |  | HTML iconHTML  

    We introduce a missing data recovery methodology based on a weighted least squares iterative adaptive approach (IAA). The proposed method is referred to as the missing-data IAA (MIAA) and it can be used for uniform or nonuniform sampling as well as for arbitrary data missing patterns. MIAA uses the IAA spectrum estimates to retrieve the missing data, by means of either a frequency domain or a time... View full abstract»

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  • Multistage Spread Spectrum Watermark Detection Technique Using Fuzzy Logic

    Publication Year: 2009 , Page(s): 245 - 248
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (343 KB) |  | HTML iconHTML  

    In this letter, a new model of spread spectrum (SS) watermarking is proposed where each watermark bit is spread using a distinct code pattern over N-mutually orthogonal signal points. Decision variable for each bit of watermark decoding is formed from the weighted average of N-decision statistics. Multiple detection stages are applied where the detected bit patterns of one stage are used in the im... View full abstract»

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  • On Convergence of the Auxiliary-Vector Beamformer With Rank-Deficient Covariance Matrices

    Publication Year: 2009 , Page(s): 249 - 252
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (245 KB) |  | HTML iconHTML  

    The auxiliary-vector beamformer is an algorithm that generates iteratively a sequence of beamformers which, under the assumption of a positive definite covariance matrix R, converges to the minimum variance distortionless response beamformer, without resorting to any matrix inversion. In the case where R is rank-deficient, e.g., when R is substituted for the sample covariance ... View full abstract»

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  • Enhancing Two-Stage Multiple Description Scalar Quantization

    Publication Year: 2009 , Page(s): 253 - 256
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (144 KB) |  | HTML iconHTML  

    In this letter we consider enhancing coding performance of two-stage multiple description scalar quantization. An enhancement scheme is proposed to make the product of central and side distortions closer to the rate-distortion bound of multiple description coding under the high-resolution assumption. We show analytically that the second stage refinement information, i.e., the quantized residual er... View full abstract»

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  • Collaborative-Relay Beamforming With Perfect CSI: Optimum and Distributed Implementation

    Publication Year: 2009 , Page(s): 257 - 260
    Cited by:  Papers (47)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (294 KB) |  | HTML iconHTML  

    This letter studies the collaborative use of amplify-and-forward (AF) relays to form a virtual multiple-input single-output (MISO) beamforming system with the aid of perfect channel state information (CSI) in a flat-fading channel. In particular, we optimize the relay weights jointly to maximize the received signal-to-noise ratio (SNR) at the destination terminal with both individual and total pow... View full abstract»

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  • State-Information-Assisting EREC

    Publication Year: 2009 , Page(s): 260 - 263
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (392 KB) |  | HTML iconHTML  

    This paper proposes an improved algorithm of the error-resilient entropy coding (EREC). The idea is to record and transmit the states of variable-length data blocks (VLBs) and fixed-length data slots (FLSs) during EREC encoding process. The state information (SI) of VLBs and FLSs is used at the receiver to resynchronize VLBs during EREC decoding process. It is proved that the cost of SI is fewer t... View full abstract»

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  • Environmental Model Adaptation Based on Histogram Equalization

    Publication Year: 2009 , Page(s): 264 - 267
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (120 KB) |  | HTML iconHTML  

    In this letter, a new environmental model adaptation method is proposed for robust speech recognition under noisy environments. The proposed method adapts initial acoustic models of a speech recognizer into environmentally matched models by utilizing the histogram equalization technique. Experiments performed on the Aurora noisy environment showed that the proposed technique provides substantial i... View full abstract»

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  • Cross Layer Design and Analysis of Multiuser Wireless Video Streaming Over 802.11e EDCA

    Publication Year: 2009 , Page(s): 268 - 271
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (266 KB) |  | HTML iconHTML  

    We propose a novel cross layer solution for optimizing the performance of multiple users, which are concurrently transmitting their delay-sensitive video streams over the same shared contention-based wireless LAN. To improve the performance of their applications, they dynamically adapt their medium access control (MAC) strategies (i.e., retry limits). Higher retry limits will benefit the user, but... View full abstract»

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  • Computing Transformation Matrices for Arbitrary Polynomial Transformation

    Publication Year: 2009 , Page(s): 272 - 274
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (86 KB) |  | HTML iconHTML  

    In many engineering applications it is required to convert a polynomial into another polynomial through a transformation. This letter presents a simple algorithm by which one can successively compute transformation matrices of various order for arbitrary polynomial transformation. View full abstract»

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  • A Novel Representation Approach to DNA Sequence and Its Application

    Publication Year: 2009 , Page(s): 275 - 278
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (143 KB) |  | HTML iconHTML  

    The representation of a DNA sequence is the first stage of genome analysis. A wide variety of approaches has been proposed for different applications in bioinformatics. In this letter, based on the principle of symbolic dynamics, a novel representation approach is proposed, which maps DNA sequence into 3-D chaotic sequences of sawtooth function and completely conserve its biological information. W... View full abstract»

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  • Reduced-Complexity Reed–Solomon Decoders Based on Cyclotomic FFTs

    Publication Year: 2009 , Page(s): 279 - 282
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (299 KB) |  | HTML iconHTML  

    In this paper, we reduce the computational complexities of partial and dual partial cyclotomic FFTs (CFFTs), which are discrete Fourier transforms where spectral and temporal components are constrained, based on their properties as well as a common subexpression elimination algorithm. Our partial CFFTs achieve smaller computational complexities than previously proposed partial CFFTs. Utilizing our... View full abstract»

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  • Quantization of Log-Likelihood Ratios to Maximize Mutual Information

    Publication Year: 2009 , Page(s): 283 - 286
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (627 KB) |  | HTML iconHTML  

    We propose a quantization scheme for log-likelihood ratios which optimizes the trade-off between rate and accuracy in the sense of rate distortion theory: as distortion measure we use mutual information to determine quantization and decision levels maximizing mutual information for a given rate over a Gaussian channel. This approach is slightly superior to the previously proposed idea of applying ... View full abstract»

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  • Robust Signal Detection Under Model Uncertainty

    Publication Year: 2009 , Page(s): 287 - 290
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (191 KB) |  | HTML iconHTML  

    In detecting a deterministic signal in the presence of Gaussian noise, the receiver operating characteristic (ROC) curve determined by a linear detector with slope maximizing the signal-to-noise ratio (SNR) and with varying threshold characterizes limits of detection performance. In this note, we consider the problem of detecting a signal in the presence of uncertainty in the signal itself and the... View full abstract»

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  • Sphere Packing Modulation in the SDMA Uplink Using K -Best Sphere Detection

    Publication Year: 2009 , Page(s): 291 - 294
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (224 KB) |  | HTML iconHTML  

    Recently, the turbo-detected sphere packing (SP) aided space-time block-coding (STBC) STBC-SP scheme was demonstrated to provide useful performance improvements over conventionally-modulated orthogonal design-based STBC schemes in the context of single-user multiple-input multiple-output (SU-MIMO) systems. Hence, in this letter, we extend its employment to the multiuser MIMO (MU-MIMO) scenario. Fo... View full abstract»

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  • Impulse Noise Removal Using Directional Difference Based Noise Detector and Adaptive Weighted Mean Filter

    Publication Year: 2009 , Page(s): 295 - 298
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (616 KB) |  | HTML iconHTML  

    A two-stage algorithm, called switching-based adaptive weighted mean filter, is proposed to remove salt-and-pepper noise from the corrupted images. First, the directional difference based noise detector is used to identify the noisy pixels by comparing the minimum absolute value of four mean differences between the current pixel and its neighbors in four directional windows with a predefined thres... View full abstract»

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  • Blind Channel Estimation for Non-CP OFDM Systems Using Multiple Receive Antennas

    Publication Year: 2009 , Page(s): 299 - 302
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (254 KB) |  | HTML iconHTML  

    The orthogonal frequency division multiplexing (OFDM) transmission scheme equipped with multiple receive antennas increases robustness against frequency-selective fading and combats loss in SNR. Based on the multichannel signaling property, this letter develops a frequency-domain blind channel estimator for OFDM systems without cyclic prefix (CP). With high data efficiency and low computational co... View full abstract»

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  • Learning an Orthogonal and Smooth Subspace for Image Classification

    Publication Year: 2009 , Page(s): 303 - 306
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (286 KB) |  | HTML iconHTML  

    The recent years have witnessed a surge of interests of learning a subspace for image classification, which has aroused considerable researches from the pattern recognition and signal processing fields. However, for image classification, the accuracies of previous methods are not so high since they neglect some particular characters of the image data. In this paper, we propose a new subspace learn... View full abstract»

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  • A Best Lag Size of Minimum Variance FIR Smoothers

    Publication Year: 2009 , Page(s): 307 - 310
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (132 KB) |  | HTML iconHTML  

    In this paper, we argue that the lag size of half a moving horizon of the minimum variance finite impulse response (MVFIR) smoother is not generally best in the sense of the estimation error variance even though it has been believed to be optimal for a simple input/output (I/O) model with correlated data. For a more general analysis, a state space model is considered in this paper. It is shown via... View full abstract»

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  • A New Mura Defect Inspection Way for TFT-LCD Using Level Set Method

    Publication Year: 2009 , Page(s): 311 - 314
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1013 KB) |  | HTML iconHTML  

    Mura is a typical vision defect of LCD panel, appearing as local lightness variation with low contrast and blurry contour. This letter presents a new machine vision inspection way for Mura defect based on the level set method. First, a set of real Gabor filters are applied to eliminating the global textured backgrounds. Then, the level set method is employed for image segmentation with a new regio... View full abstract»

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  • Blind Equalization Method Based on Sparse Bayesian Learning

    Publication Year: 2009 , Page(s): 315 - 318
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (249 KB) |  | HTML iconHTML  

    A novel adaptive blind equalization method based on sparse Bayesian learning (blind relevance vector machine (RVM) equalizer) is proposed. This letter incorporates a Godard or constant modulus algorithm (CMA)-like error function into a general Bayesian framework. This Bayesian framework can obtain sparse solutions to regression tasks utilizing models linear in the parameters. By exploiting a proba... View full abstract»

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  • Speech-Signal-Based Frequency Warping

    Publication Year: 2009 , Page(s): 319 - 322
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (249 KB) |  | HTML iconHTML  

    The speech signal is used for transmission of linguistic information. High energy portions of the speech spectrum have higher signal-to-noise ratios than the low energy portions. As a result, these regions are more robust to noise. Since the speech signal is known to be very robust to noise, it is expected that the high energy regions of the speech spectrum carry the majority of the linguistic inf... View full abstract»

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Aims & Scope

The IEEE Signal Processing Letters is a monthly, archival publication designed to provide rapid dissemination of original, cutting-edge ideas and timely, significant contributions in signal, image, speech, language and audio processing.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Peter Willett
University of Connecticut
Storrs, CT 06269
peter.willett@uconn.edu