This paper presents an analysis of different alternatives for the realization of a VLSI cell in a nonlinear neuronal array, based on a simplicial piecewise linear (PWL) operation. Depending on the type of existing des...
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ISBN:
(纸本)9781424453092
This paper presents an analysis of different alternatives for the realization of a VLSI cell in a nonlinear neuronal array, based on a simplicial piecewise linear (PWL) operation. Depending on the type of existing design constraints, namely, speed or density, different bus sizes can be used to broadcast the parameters stored in the memory, and in addition, row and column operations can be serialized. Based on a 90nm technology process, the different options will be analyzed and compared using simulations.
We address the problem of pilot decontamination for massive MIMO systems for finite dimensional channels, wherein the channel vectors between the users and the base station are composed of a finite number of discrete ...
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ISBN:
(纸本)9781479919635
We address the problem of pilot decontamination for massive MIMO systems for finite dimensional channels, wherein the channel vectors between the users and the base station are composed of a finite number of discrete paths. The pilot decontamination problem is addressed using high-resolution parametric spectral estimation methods, such as root multiple-signal classification (root-MUSIC), for resolving paths based on their angle-of-arrivals. The paths corresponding to the desired user are identified based on their amplitudes and then the paths are used to form the channel estimate. Our simulations show an improved performance in terms of bit-error rate compared to the existing approaches in certain critical scenarios.
In many signal processing applications, signals are received on an array of sensors, and the problem consists in estimating the Directions Of Arrival (DOA) of the signals, and/or in estimating the sources. Basically, ...
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ISBN:
(纸本)0780309111
In many signal processing applications, signals are received on an array of sensors, and the problem consists in estimating the Directions Of Arrival (DOA) of the signals, and/or in estimating the sources. Basically, the techniques proposed for its solution use either information about the geometry of the array, or information about the statistics of the sources. Efficient neural-based approaches for both kinds of situations are proposed in this paper. When geometrical knowledge is available, the weights and structure of the neural networks are constrained according to the geometry of the array. When statistical information is available, neural networks which optimize a statistical criterion (namely the measure of dependence) are developed. Furthermore, neural networks provide the opportunity to fuse both approaches in a unified framework, and to take profit simultaneously of both kind of information.
In this paper, we propose a sampling architecture for the efficient acquisition of multiple signals lying in a subspace. We show that without the knowledge of the signal subspace, the proposed sampling architecture ac...
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ISBN:
(纸本)9781467331463;9781467331449
In this paper, we propose a sampling architecture for the efficient acquisition of multiple signals lying in a subspace. We show that without the knowledge of the signal subspace, the proposed sampling architecture acquires the signals at a sub-Nyquist rate. Prior to sampling at a sub-Nyquist rate, the analog signals are diversified using analog preprocessing. The preprocessing step is carried out using implementable components that inject "structured" randomness into the signals. We recast the signal reconstruction from fewer samples as a low-rank matrix recovery problem from generalized linear measurements. Our results also include a sampling theorem that provides the sufficient sampling rate for the exact reconstruction of the signals. We also discuss an application of this sampling architecture in the estimation of the covariance matrix, required for parameter estimation in several important array processing applications, from much fewer samples.
We propose an approach to achieve high-performance localization of multiple sources using a small aperture array of spatially-distributed electric and magnetic component sensors. The approach is based on exploiting of...
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ISBN:
(纸本)0780379462
We propose an approach to achieve high-performance localization of multiple sources using a small aperture array of spatially-distributed electric and magnetic component sensors. The approach is based on exploiting of all available electromagnetic information along with the time delay information. Using simulated data. we demonstrate that this approach outperforms both a single vector-sensor anti scalar-sensor arrays in accuracy of direction-of-arrival (DOA) estimation.
In this paper, a novel positioning approach for wireless sensor networks (WSNs) is proposed. The approach locates a given target node by using a number of surrounding anchor nodes as an array of large aperture with kn...
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ISBN:
(纸本)9781424423248
In this paper, a novel positioning approach for wireless sensor networks (WSNs) is proposed. The approach locates a given target node by using a number of surrounding anchor nodes as an array of large aperture with known geometry. The approach uses the concept of the array manifold vector based on spherical wave propagation. The position of the target is estimated as the intersection point of three circular loci, the centres and radii of which are calculated from the signal eigenvalues of the covariance matrices corresponding to a number of reference points. A number of simulation results show that the proposed approach can estimate a target location with exceptional accuracy even for low SNRin x (observation-interval). Analytical expressions are also provided for the estimation error due to the finite averaging effects, as a function of the locations of the anchor nodes and the SNRin.
This paper presents a novel algorithm for designing beam-space transformation with robust interference suppression, reducing the computation complexity, and improving the performance of applied signal processing algor...
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ISBN:
(纸本)9781728116792
This paper presents a novel algorithm for designing beam-space transformation with robust interference suppression, reducing the computation complexity, and improving the performance of applied signal processing algorithms. This approach constructs an objective function that addresses multiple performance criteria simultaneously including the in-sector estimation accuracy and the out-of-sector interference rejection capability, and then utilizes a numerical optimization paradigm to search for the solution. The algorithm is flexible, robust and data independent, which performs well in harsh environment involving a small number of snapshots and highly correlated/coherent sources. Simulation results confirm its effectiveness in the presence of strong moving interference.
This paper examines the use of arrays of seismic sensors to enhance signals where multiple sources and an inhomogeneous medium complicate the received signal. array processing is useful because it offers the opportuni...
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ISBN:
(纸本)0819440884
This paper examines the use of arrays of seismic sensors to enhance signals where multiple sources and an inhomogeneous medium complicate the received signal. array processing is useful because it offers the opportunity to enhance SNR of the target signal while attenuating noise sources via spatiotemporal filtering. We used an adaptive beamforming algorithm to isolate the particular signal of interest from ambient noise and an interferer. The unpredictable nature of the noise and interferer environment was addressed by having the beamformer adapt to the environment. We present the results of using the beamformer on data from a thirty-geophone array. Initial results indicate inhomogeneities in the vacinity of the seismic sensors caused the significant perturbations to the wavefront. The adaptive algorithm was able to compensate for this and thereby performed better than the traditional delay-and-sum algorithm at isolating the target signal from the interfering signals.
This paper describes the use of voice activity defector (VAD) in microphone array processing 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 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 significantly improves the performance of the array processing algorithms. The performances of the two types of VAD are also compared in the paper.
Rule-based thinning and element placement methods are first discussed. This includes random arrays, binned random arrays, periodic thinning, element shadowing properties, and fractal arrays. The algorithmic optimizati...
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ISBN:
(纸本)0780362934
Rule-based thinning and element placement methods are first discussed. This includes random arrays, binned random arrays, periodic thinning, element shadowing properties, and fractal arrays. The algorithmic optimization of layouts of I-D and 2-D sparse arrays is presented and it is empirically derived that the peak sidelobe level for an array with K active elements is proportional to I/K for a 1-D array and 2/K for a 2-D array. The constant of proportionality depends strongly on the width of the mainlobe relative to that of the full array. With an increase of 50%. the constant is 1..5.
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