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In this paper, a joint synchronization and Doppler scaling factor estimation algorithm has been proposed for underwater acoustic communications. The training sequence, which consists of two Zadoff-Chu (ZC) sequences being conjugate with each other, is utilized to synchronize and estimate Doppler scaling factor, time delay and carrier frequency offsets (CFOs). ZC sequences are well designed to show...
The quasi-likelihood algorithm detection of rectangle ultra-wideband quasi-radiosignal with unknown amplitude, initial phase and duration has been synthesized. The statistical characteristics of the efficiency synthesized detection algorithm — false alarm probability and probability of missing a signal, have been found.
Time Difference Of Arrival (TDOA) method is very often used inside electronic intelligence systems. TDOA method requires the high signal to noise ratio at the output of the intermediate frequency amplifier for target localization, usually around 12 dB or more. At low signal-to-noise ratio TDOA is inaccurate and especially in case of the active jamming it is nearly impossible. The multilateral TDOA...
In this paper, we investigate the cryptanalysis of stream ciphers, and evaluate the enhancement to security that can be gained when the ciphertext is error prone by analyzing specific attack algorithm. The stream ciphers that we investigate here have a keystream generator that is based on linear-feedback shift registers (LFSRs). In particular, we characterize the security of these ciphers when the...
We present an optimal frame timing estimator for OFDM signals that utilizes both cyclic prefix (CP) and pilot-carrier-aided channel estimation. Combining the periodic nature of the embedded pilot signal information with the correlation present in the cyclic prefix allows improved frame timing estimates relative to use of either one. Following a derivation of the ML estimator, a processor diagram is...
Cognitive radio (CR) is an intelligent system for designing modern wireless communication systems. Spectrum sensing is one of the most important issues in CR. This paper presents a semi blind spectrum sensing method which exploits the combination of comb filter and autocorrelator. The proposed method improves the detection performance of blind spectrum sensing in severe noise environments where an...
The use of the Electrohysterogram (EHG) for imaging the sources of the uterine electrical activity is a new and powerful diagnosis technique. However, its performance is limited as the uterus often demonstrates several simultaneously active regions and as EHGs present low signal-to-noise ratios. To overcome these problems, tensor-based preprocessing can be applied, which consists in constructing a...
The article presents an analysis of correlation-based clustering procedure in cooperative spectrum sensing. The motivation is to assess if it is more beneficial in terms of energy efficiency to group nodes according to the received signal-to-noise ratio (SNR) on the link between Primary User and node or according to the distance between nodes. To this end, a merged clustering measure is introduced...
In this paper, a waveform design method utilizing the low maximum side-lobe in the synthetic range profile as the criterion for the random hopping frequency radar is proposed. Firstly, the center range ambiguity function which represents matched filtering output of transmitted signal is derived. And the output signal to noise ratios (SNR) of it and the synthetic range profile based on correlation...
In this paper the power requirements of deception jamming in the signal acquisition phase of BeiDou navigation receiver are discussed in two cases. In the first case, the deception jamming signal is released before the start of the receiver, with the method of analyzing the signal acquisition probability model and the acquisition correlation peak, the conclusion is obtained that the effective power...
Dense false target jamming is suppressive and deceptive. Traditional anti-jamming measures, such as side-lobe canceller, are invalid. In this paper, a method based on jamming sample selection is presented to counter dense false target jamming. The method first judges the correlation between the signal in the main channel and that in the auxiliary channel, then selects jamming samples through correlation...
This paper considers the identification of impulse responses of systems with multiple inputs. An existing technique utilizing signal sets which are correlated with one another is modified to improve its convergence properties. A detailed example is presented to compare the performance between identification using a set of correlated signals and identification using a set of uncorrelated signals. In...
Distributed coherent aperture radar (DCAR) can be applied to improve the target tracking and identification performance through adjusting transmitting/receiving timing and phase of spatial distributed radars via the coherent parameters (CPs). Therefore, estimating high precision of CPs is the core and prerequisite for DCAR to realize coherent synthesis. In this paper, we introduce the workflow of...
A novel two dimension direction-of-arrival (2D-DOA) estimation method for L-shaped array using atomic norm minimization based on the cross-correlation matrix is proposed in this paper. We first reconstruct the autocorrelation matrix of observed signals in the Toeplitz structure by cross-correlation matrix-based atomic norm minimization (CCMANM), and then employ the reconstructed autocorrelation matrix...
The Delay-Multiply-And-Sum (DMAS) beamformer has recently been presented in the context of medical ultrasound image formation. Images obtained with the DMAS beamformer present improved contrast resolution and noise rejection when compared to images obtained with the standard Delay-And-Sum (DAS) beamformer. We study here the signal statistics for a homogeneous medium using both the DAS and DMAS beamformers...
Stroke is commonly caused by thromboembolic events originating from a ruptured carotid plaque. Histological studies have shown that plaque rupture potential is related to plaque composition rather than degree of stenosis. The use of Acoustic Radiation Force Impulse (ARFI) ultrasound imaging has enabled assessment of carotid plaque composition and structure. In particular, a previous study has shown...
Nowadays the Massive MIMO system is one of the keys for obtaining high quality and reliability of data transmission. One of the main characteristics influencing the MIMO system performance is the channel (system) correlation matrix (CM). The proposed research assumes an exponential-type banded CM structure, which is bridging the gap between fully correlated and uncorrelated/weakly correlated (tridiagonal...
Recently, cognitive radio based sensor network (CRSN) has been introduced into Smart Grids (SG) in order to address the problems of spectrum inefficiency and interferences. CRSN has the capability of opportunistic spectrum access (OSA) to dynamically allocate radio resources to the sensor nodes. However, one of the CRSN challenges is the problem of dual/multi correlation fading channels due to dual/multi...
Plane wave methods for ultrafast ultrasound imaging suffer from a low signal to noise ratio (SNR) and a limited field of view at greater imaging depths. Imaging using multiple focused coded beams in parallel is one strategy for high speed imaging that may improve on these limitations. However, the SNR and resolution of this strategy are degraded by the interference between the beams transmitted in...
Received Signal Strength Indicator (RSSI) is simplest among various indoor localization methods. The main drawback is requiring a training phase to build fingerprints database, which is time consuming and sensitive to changes of test environment. Time based approaches such as Time of Arrival (ToA) and Time Difference of Arrival (TDoA) achieve better performance with some hardware expenditure, while...
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