By Topic

Sensor Array and Multichannel Signal Processing Workshop Proceedings, 2002

Date 6-6 Aug. 2002

Filter Results

Displaying Results 1 - 25 of 126
  • 2002 IEEE Sensor Array and Multichannel Signal Processing Workshop Proceedings (Cat. No.02EX593)

    Publication Year: 2002
    Save to Project icon | Request Permissions | PDF file iconPDF (520 KB)  
    Freely Available from IEEE
  • Author index

    Publication Year: 2002 , Page(s): 605 - 607
    Save to Project icon | Request Permissions | PDF file iconPDF (171 KB)  
    Freely Available from IEEE
  • Finite sample identifiability of multiple constant modulus sources

    Publication Year: 2002 , Page(s): 408 - 412
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (503 KB) |  | HTML iconHTML  

    We prove that mixtures of continuous constant modulus sources can be identified with probability 1 with a finite number of samples (under noise-free conditions). This strengthens earlier results which only considered an infinite number of samples. The proof is based on the linearization technique of the Analytical Constant Modulus Algorithm, together with a simple inductive argument. We then study... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Frequency-domain penalized least-squares beamformer design for early detection of breast cancer via microwave imaging

    Publication Year: 2002 , Page(s): 120 - 124
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (609 KB) |  | HTML iconHTML  

    Microwave imaging has been proposed as an alternative to X-ray mammography for early-stage breast cancer detection. We investigate a method of microwave imaging via space-time (MIST) beamforming for detecting backscattered energy from small malignant breast tumors. The beamformer weights are designed to optimally compensate for frequency-dependent propagation effects and minimize clutter by solvin... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Most reliable space vector and its application to direction finding

    Publication Year: 2002 , Page(s): 342 - 345
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (408 KB) |  | HTML iconHTML  

    Given a data matrix, we desire a space vector that is the most robust against correlated Gaussian noise perturbations. A closed-form calculation of the most reliable space vector is presented. An attempt to modify the min-norm direction finding algorithm for use in spatio-temporal colored noise is investigated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Blind multichannel image restoration using oblique projections

    Publication Year: 2002 , Page(s): 125 - 129
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (391 KB) |  | HTML iconHTML  

    We address the problem of image restoration in a multichannel system degraded by unknown blurs and additive noise. Instead of estimating first the channels or the restoration filters, we propose to estimate directly the input image by using a linear estimator in the form of oblique projections (OP) operator. In our OP method, the restoration is achieved by projecting the observed data onto the sub... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multichannel stochastic gradient method for adaptive equalization in uplink asynchronous DS/CDMA

    Publication Year: 2002 , Page(s): 303 - 307
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (441 KB) |  | HTML iconHTML  

    The paper addresses the problem of channel equalization in asynchronous uplink DS/CDMA systems. An MMSE equalizer is derived based on our proposed channel estimation algorithm (Sirbu, M. and Koivunen, V., Proc. IEEE Int. Conf. on DSP, 2002). For channel estimation, there is no need for knowledge of the propagation delays, whereas for despreading purposes only the chip period multiple of the propag... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Pruned multi-angle resolution fast beamforming

    Publication Year: 2002 , Page(s): 490 - 494
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (517 KB) |  | HTML iconHTML  

    Delay-and-sum (DS) beamforming is one of the basic beamforming methods, and it is effective for both narrowband and wideband sources. However, DS beamforming exhibits high computational complexity. Recently, a fast multistage approximation of DS beamforming was introduced (Oh, S.-M. and McClellan, J.H., Proc. ICASSP-2002, p.2937-40, 2002). In order to improve the computational efficiency of the fa... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A pragmatic approach to multi-user spatial multiplexing

    Publication Year: 2002 , Page(s): 130 - 134
    Cited by:  Papers (29)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (491 KB) |  | HTML iconHTML  

    We suggest a new approach for spatial multiplexing in a narrowband system with several access points serving a number of mobile terminals. In contrast to previously suggested algorithms, this approach is formulated based on a systems perspective, generalizing earlier algorithms for jointly optimal beamforming and power control. Since global channel knowledge is required, the algorithm is mainly in... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Information theoretic bounds on source localization performance

    Publication Year: 2002 , Page(s): 184 - 188
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (570 KB) |  | HTML iconHTML  

    This paper examines the underwater acoustic source localization problem as an unorthodox communication problem. This perspective produces novel bounds on the performance of any source localization algorithm. The search space is divided into a grid whose cell size is determined by operational constraints. The message transmitted by the source is the cell it is located within. The receiver uses pres... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Channel equalization in the presence of strong interference sources

    Publication Year: 2002 , Page(s): 308 - 312
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (430 KB) |  | HTML iconHTML  

    Space-time channel estimation is essential for communication systems which separate sources in the space domain in addition to time/frequency/code domains. We first develop a maximum likelihood (ML) estimator for the spatial channel transfer function in the presence of strong interference sources, for 3 different channel scenarios: no multipath, locally scattered multipath, and general multipath c... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • OFDM channel estimation in the presence of interference

    Publication Year: 2002 , Page(s): 154 - 158
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (519 KB) |  | HTML iconHTML  

    We develop a frequency-domain channel estimation algorithm for single-user orthogonal frequency division multiplex (OFDM) wireless systems in the presence of interference. The received measurement is correlated in space with a covariance matrix dependent on frequency. Hence, the commonly used least-squares algorithm is suboptimal. On the other hand, accurate estimation of the spatial covariance ma... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Robust TDE-based DOA estimation for compact audio arrays

    Publication Year: 2002 , Page(s): 214 - 218
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (529 KB) |  | HTML iconHTML  

    Cross-correlation based time delay estimates (TDE) can be used for direction-of-arrival (DOA) estimation with an acoustic array in not-too-reverberant environments. In order to benefit from the computational efficiency of TDE-based DOA estimation, and concentrating on applications that use a compact microphone array and low sampling frequency, we use a combination of approaches to make TDE-based D... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Array configuration design for space-time adaptive processing systems

    Publication Year: 2002 , Page(s): 145 - 148
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (428 KB) |  | HTML iconHTML  

    It is known that the design of antenna array configuration is an important issue to the antenna array applications. We present a method to design antenna array configurations for space-time adaptive processing (STAP) applied to mobile communication systems. We first derive an upper bound of the residual error power of STAP systems under the minimum mean square error (MMSE) criterion. Then, the rel... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Eigenstructure-based azimuth and elevation estimation in sparse uniform rectangular arrays

    Publication Year: 2002 , Page(s): 327 - 331
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (510 KB) |  | HTML iconHTML  

    A new method for 2D direction of arrival (DOA) estimation in uniform rectangular arrays (URAs) is proposed. Unlike previous methods, which usually require fully loaded arrays, the proposed method can also be applied in the case of sparse URAs. The algorithm is based on an new formulation of the rank reduction estimator (RARE) which originally was derived for 1D DOA estimation in partly calibrated ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Asymptotic performance of contrast-based blind source separation algorithms

    Publication Year: 2002 , Page(s): 244 - 248
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (442 KB) |  | HTML iconHTML  

    For several years, contrast-based blind source separation (BSS) has been successfully used in several areas, including radiocommunications. A functional approach relying on differential calculus theory is proposed, aiming at analyzing asymptotic performances of BSS contrast criteria: the variance of the estimated separating matrix is expressed as a function of that of estimated cumulants. As an ex... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Superresolution source localization through data-adaptive regularization

    Publication Year: 2002 , Page(s): 194 - 198
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (542 KB) |  | HTML iconHTML  

    We address the task of source localization using a novel non-parametric data-adaptive approach based on regularized linear inverse problems with sparsity constraints. The class of penalty functions that we use for regularization favors sparsity of the reconstructions, thus producing superb resolution of the sources. We present a computationally efficient technique to carry out the numerical optimi... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Improvement of high frequency ocean surveillance radar using subspace methods based on sea clutter suppression

    Publication Year: 2002 , Page(s): 557 - 560
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (439 KB) |  | HTML iconHTML  

    We present a new direction finding scheme for slow targets embedded in sea clutter that combines subspace methods (MUSIC and Root-MUSIC) and time domain sea clutter and noise suppression. The ocean surface behaves as a distributed source in contrast to ships that are point sources. By mapping data to eigenspaces, the sea clutter level decreases due to its non-deterministic behavior while point tar... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Adaptive antenna arrays for the co-channel interference cancellation in OFDM communication systems with virtual carriers

    Publication Year: 2002 , Page(s): 393 - 397
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (491 KB) |  | HTML iconHTML  

    We propose a blind beamforming algorithm for OFDM based communication systems. After applying the DFT operation to the output of each antenna, one estimates the signal plus interference spatial correlation matrix by selecting the samples at the "non-zero valued" subcarriers, and the interference-alone spatial correlation matrix by choosing those samples at the "zero valued" subcarriers (also known... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Detection-estimation of distributed Gaussian sources

    Publication Year: 2002 , Page(s): 513 - 517
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (499 KB) |  | HTML iconHTML  

    The problem of estimating the number of independent homogeneously distributed (spread) Gaussian sources and their parameters impinging upon a uniform linear antenna array is considered for scenarios with a priori known angular spreading. This new method adopts the generalised likelihood ratio test (GLRT) methodology, based on LR maximisation, supported by a statistical nonasymptotic scenario-free ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • From academe to industry or from writing papers to making chips: experiences and conclusions

    Publication Year: 2002 , Page(s): 8 - 12
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (500 KB) |  | HTML iconHTML  

    In recent years, the author has been involved in starting up a high-tech company and bringing both the product and the company itself to a successful fruition. The paper describes the author's experiences from this venture. The product in question was a VDSL modem, delivering about 15 megabits-per-second over unshielded telephone wires in full duplex. The paper reviews VDSL technology, its capabil... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Suppression of moving interference with SIS-based projections, in shallow water environments

    Publication Year: 2002 , Page(s): 96 - 99
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (718 KB) |  | HTML iconHTML  

    We present an approach for suppressing moving interference in shallow water environments. Adaptive beamforming techniques are based upon applying a covariance matrix inverse or projection operator to the data, in order to suppress noise and interference. Their performance typically degrades in the presence of moving interference, since more adaptive degrees of freedom are needed to suppress it. In... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A simple soft-detector for the BLAST system

    Publication Year: 2002 , Page(s): 159 - 163
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (524 KB) |  | HTML iconHTML  

    The BLAST (Bell-Labs' layered space-time) system is a multi-input multi-output (MIMO) system that can be used to increase the wireless transmission data rate without increasing the total transmission power or bandwidth. In practice, forward error correction (FEC) codes, such as the convolutional code, are often used to lower the bit-error-rate (BER) drastically. We propose a simple soft-detector f... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Voice activity detector for microphone array processing in hand-free systems

    Publication Year: 2002 , Page(s): 224 - 228
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (405 KB) |  | HTML iconHTML  

    This paper describes the use of voice activity detector (VAD) in microphone array processing for hand-free systems. Two different types of VAD are proposed using conventional and adaptive beamforming. Taking into account the fact that the speech signal is not present at all time in human conversations, both signal of interest and noise can be better estimated. Simulation results show that the VAD ... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Estimating statistical properties of MIMO Rician fading channels

    Publication Year: 2002 , Page(s): 149 - 153
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (488 KB) |  | HTML iconHTML  

    We propose maximum likelihood (ML) methods for estimating the mean and covariance parameters of multi-input multi-output (MIMO) Rician fading channels. We consider both correlated and independent fading scenarios, and derive computationally efficient algorithms for a practically important special case in which the covariance matrix of the transmitted signal is constant. Numerical simulations demon... View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.