This paper describes the use of voice activity defector (VAD) in microphone arrayprocessing for hand-free systems. Two different types of VAD are proposed using conventional and adaptive beamforming. Taking into acco...
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ISBN:
(纸本)0780375513
This paper describes the use of voice activity defector (VAD) in microphone arrayprocessing 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 significantly improves the performance of the arrayprocessing algorithms. The performances of the two types of VAD are also compared in the paper.
We consider the problem of estimating the parameters of linear chirp signals when received at a multi-sensor antenna. Exploiting the negligible variation of the parameters of interest over the coherence time of the ch...
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ISBN:
(纸本)0780385454
We consider the problem of estimating the parameters of linear chirp signals when received at a multi-sensor antenna. Exploiting the negligible variation of the parameters of interest over the coherence time of the channel, we derive a new data model that Outlines the space-time relation between the parameters. In the case of multiple chirps and single-path channels, the derived model allows the estimation of more signals than antennas. The model is directly employed in the case of a single chirp in multipath, where angles of arrival can be retrieved if more antennas than paths are available. We use a MUSIC-based estimator to recover the unknown parameters and compare its performance through simulations against the Cramer-Rao Bound.
Compressive sensing (CS) has successfully been applied to reconstruct sparse signals and images from few observations. For multi-component nonstationary signals characterized by instantaneous frequency laws, the spars...
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ISBN:
(纸本)9781467310710
Compressive sensing (CS) has successfully been applied to reconstruct sparse signals and images from few observations. For multi-component nonstationary signals characterized by instantaneous frequency laws, the sparsity exhibits itself in the time-frequency domain as well as the ambiguity domain. In this paper, we examine CS in the context of nonstationary arrayprocessing. We show that the spatial averaging of the ambiguity function across the array improves the CS performance by reducing both noise and cross-terms. The corresponding time-frequency distribution which is reconstructed through L-1 minimizations yields significant improvement in time-frequency signature localizations and characterizations.
This paper presents a statistical analysis of two schemes for intelligent STAP training data selection in Gaussian and non-Gaussian interference backgrounds. Performance analysis of the two methods is carried out usin...
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ISBN:
(纸本)0780375513
This paper presents a statistical analysis of two schemes for intelligent STAP training data selection in Gaussian and non-Gaussian interference backgrounds. Performance analysis of the two methods is carried out using simulated as well as measured radar data.
In this paper, we devise a sparse array design algorithm for adaptive beamforming. Our strategy is based on finding a sparse beamformer weight to maximize the output signal-tointerference-plus-noise ratio (SINR). The ...
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ISBN:
(纸本)9781665406338
In this paper, we devise a sparse array design algorithm for adaptive beamforming. Our strategy is based on finding a sparse beamformer weight to maximize the output signal-tointerference-plus-noise ratio (SINR). The proposed method uses the alternating direction method of multipliers (ADMM), and admits closed-form solutions at each ADMM iteration. Numerical results exhibit excellent performance of the proposed method, which is comparable to that of the exhaustive search approach.
We consider gridless direction-of-arrival (DOA) estimation of much more targets than the number of physical sensors through the exploitation of multi-frequency sparse array design and processing which increase the deg...
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ISBN:
(纸本)9781728119465
We consider gridless direction-of-arrival (DOA) estimation of much more targets than the number of physical sensors through the exploitation of multi-frequency sparse array design and processing which increase the degrees of freedom as more frequency components are used. A modified sensor interpolation technique is developed to accurately estimate the signal covariance matrix using very few snapshots, thereby eliminating the requirement of a large number of snapshots as in conventional different coarray-based DOA estimation. Simulation results demonstrate high-resolution gridless DOA estimation capability of more targets than the number of physical sensors.
In this paper, a new spatial filter bank design method for speech enhancement beamforming applications is presented. The aim of this design is to construct a set of different filter banks that would include the constr...
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ISBN:
(纸本)0780385454
In this paper, a new spatial filter bank design method for speech enhancement beamforming applications is presented. The aim of this design is to construct a set of different filter banks that would include the constraint of signal passage at one position (and closing in other positions corresponding to known disturbing, sources). By performing the directional opening towards the desired location in the fixed filter bank structure, the beamformer is left with the task of tracking and suppressing the continuously emerging noise sources. This algorithm has been implemented in MATLAB and tested on real speech recordings conducted in a car hands-free communication situation. Results show that a reduction of the total complexity can be achieved while maintaining the noise suppression performance and reducing the speech distorsion.
The fact that most of high-accuracy positioning and distributed timing services, including safety-critical operations, rely on Global Navigation Satellite Systems (GNSS) has raised the concern of possible denial-of-se...
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ISBN:
(纸本)9781479914814
The fact that most of high-accuracy positioning and distributed timing services, including safety-critical operations, rely on Global Navigation Satellite Systems (GNSS) has raised the concern of possible denial-of-service situations. Complementary to time-and frequency-domain mitigation techniques, it is well known that antenna-array based receivers can benefit from spatial domain processing and effectively mitigate unintentional and intentional Radio Frequency Interferences (RFIs). In this work, we propose a software-based GNSS receiver architecture that implements a real-time, array-based signal acquisition algorithm based on the Generalized Likelihood Ratio Test, combined with a null-steering spatial filter for signal tracking, showing its RFI rejection capabilities.
作者:
Zatman, MMIT
Lincoln Lab Lexington MA 02420 USA
Most adaptive arrayprocessing schemes assume that the interference is 'wide sense stationary'. However, in practice this assumption is often violated. For example there may be motion of either the array and/o...
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ISBN:
(纸本)0780363396
Most adaptive arrayprocessing schemes assume that the interference is 'wide sense stationary'. However, in practice this assumption is often violated. For example there may be motion of either the array and/or the interference during the processing interval. The asymptotic performance of two adaptive beamforming algorithms which compensate for this type of changing interference scenario are analyzed in this paper.
Integrated wireless communications and radar detections have so far mainly relied on phased-array (PA) antennas with only considering the beampatterns in angle domain. By applying the frequency diverse array (FDA) int...
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ISBN:
(纸本)9781728119465
Integrated wireless communications and radar detections have so far mainly relied on phased-array (PA) antennas with only considering the beampatterns in angle domain. By applying the frequency diverse array (FDA) into radar and communications (RadComm) systems, a compact dual-functional structure of joint PA and FDA is designed. Based on the built joint PA and FDA channel models, different beamformer designs are proposed by jointly optimizing the signal-to-interference-noises of the communications and radar. Numerical simulations demonstrate the performances of both communications and the radar with the proposed approaches are over than that of the conventional PA RadComm systems.
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