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Signal processing on graphs becomes popular nowadays due to its great potential in processing the large amount of high dimensional data which exhibit irregular structures. As a signal propagates on a graph, the signal at a later time slot can be thought of as the graph-filtered version of the previous one. Therefore, estimation of the graph filter is important and serves as the building block for...
The conventional algorithm of channel estimation based on IEEE802.11ac is Least Square (LS) algorithm, which uses the Very High Throughput-Long Training Field (VHTLTF) of frame header as training sequence. While the conventional algorithm does not take into account the effects of noise and the varying characteristics of channel in time domain. In order to describe the slow change of channel in time...
As a first step to Antarctic Blue Whale monitoring, a new method based on a passive application of the Stochastic Matched Filter (SMF) is developed. To perform Z-call detection in noisy environment, improvements on the classical SMF requirements are proposed. The signal's reference is adjusted, the background noise estimation is reevaluated to avoid operator's selection, and the time-dependent Signal...
Estimating the direction of arrival (DOA) in sensor arrays is a crucial task in array signal processing systems. This task becomes more difficult when the sensors have gain/phase uncertainty. We have addressed this issue by modeling the problem as a combination of two sparse components, the DOA vector and the gain/phase uncertainty vector. Therefore, a sparse decomposition technique is suggested to...
A joint timing offset (TO) and frequency offset (FO) estimation method based on Radon-Wigner transform (RWT) is first proposed for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems. The result shows that the timing and frequency synchronization performance of the proposed method are both better than the Schmidl & Cox method and fractional Fourier transform (FrFT) algorithm...
We propose an accurate laser linewidth estimation technique based on the decision-aided maximum likelihood carrier phase estimator (DA-ML). Its performance is verified in M-ary quadrature amplitude modulation (MQAM) within a wide range of the laser linewidths and SNR values.
The cognitive radio (CR) have been proposed to improve spectral efficiency and to meet growing demands for higher data rates in mobile communications and satellite communications. In this paper, we propose a blind estimation algorithm for a secondary user to estimate transmission parameters of the primary signal in an OFDM overlay system, using only the available fast Fourier transform (FFT) component...
A constant modulus algorithm-(CMA) based carrier frequency offset estimation method for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system is proposed. Theoretical analysis and simulation results indicate that the frequency offset estimation range of the proposed algorithm can achieve [−5.9, +5.9] GHz, and the mean normalized estimation error can be kept under 0.001 even...
Due to the attenuation effects of walls, the signal to noise ratio (SNR) for targets indoor is unavoidably decreased, which seriously influences the quality of through-the-wall imaging (TWI) results. To suppress the deterioration of noise and clutters yield by walls, an adaptive noise power spectrum estimation method is put forward in this paper to enhance the performance of TWI. Through a combination...
Mobile devices are widely used today for speech communication. The environments in which these devices are used are widely varied and often the level of background noise in the speaker's environment can be significant. The purpose of speech enhancement is to reduce the level of background noise, ideally to such a level that it is not noticed by the listener. While speech enhancement algorithms can...
A method of blind signal separation based on second order statistic analytic equations is provided for a single sensor. This method takes second order statistics equations as restrictive conditions to construct blind separation criterion, then traditional blind separation methods are used to separate source signals through iterative optimization of genetic algorithm. In theory, not only can the coherent...
The accurate and fast estimation of multifrequency signal parameters has a great importance in many applications. This paper presents a comparison of five (three IpDFT, Prony, TLS) estimation methods in respect of accuracy in the measurement time below two cycles of the tested signal which contains AWGN noise and harmonic components. A new IpDFT method is discussed and presented. It is based on the...
In the channel blind estimation algorithm which exploits the first-order cyclostationarity in the received signal and performs circular deconvolution for Ultra Wide-Band (UWB) systems, there has a limitation that the duration of the channel must be less than the symbol duration. The problem can be effectively solved by using the channel shortening technique which compresses the length of the combined...
This paper presents a novel method for joint frequency and angle estimation of incoming signals. Two-layers compressed sensing method is used to obtain direction wave number and frequency parameters respectively. The algorithm provides high resolution and accuracy in both frequency and direction of arrival (DOA) estimation over the frequency range under the condition of small signal to noise ratio...
Aiming at the problem that the signal-to-noise ratio of the cumulative pulse contour is low and the accu racy of the pulsar navigation and positioning is affected, a fast pulse time delay estimation algorithm based on va riable step size iteration is proposed.Firstly,the algorith m calculated one-dimensional slice of standard pulse pro file signal and pulse profile signal by using the third-cum ulant...
The paper considers periodogram maximization-based frequency estimation of a single complex sinusoid. We propose to improve the accuracy of recently proposed methods based on three discrete Fourier transform (DFT) samples around the DFT maximum. For that purpose, a three-point parabolic interpolation of the periodogram peak is used. The proposed method requires the calculation of only two additional...
We proposed a novel blind polarization de-multiplexing technique for higher order modulation signals based on unscented Kalman filter (UKF) in 3D Stokes space. Simulation results show that UKF has better performance of de-multiplexing and convergence speed compared to extended Kalman filters (EKF).
Sparse unmixing of hyperspectral data is an important technique which aims at estimating the fractional abundances of endmembers (pure spectral components). It is well known that enforcing sparseness becomes a necessary process in sparse unmixing methods. To better exploit the sparsity in hyperspectral imagery, a double reweighted sparse unmixing algorithm has been proposed. However, it focusses on...
In this paper, a new synthetic frequency estimator of sinusoid signal based on discrete Fourier transform (DFT) amplitudes is proposed. Compared with the existing methods, the proposed method has the advantages of low computational complexity and high precision. The method has two main stages. Firstly, N-point sampled data in the time domain DFT is performed and the coarse estimation is completed...
Algorithms for estimating the symbol rate of signals with modulation types M-PSK and M-FSK are presented. The algorithm for estimating the symbol rate of the M-PSK signals is based on the Fourier transform of the squares of the modules of the complex envelope of the signal. The algorithm for estimating the symbol rate of M-FSK signals is based on the separation of the spectrum of the original signal...
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