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Speech enhancement using adaptive filtering methods are known to give good signal recovery from the noisy speech signal. Among these, Least Mean Square (LMS) and Recursive Least Squares (RLS) algorithms are more popular. These algorithms have a constraint that correlating noise should be given as the reference signal for denoising. Therefore in all the adaptive algorithms, two microphones are used,...
Next generation 5G wireless networks pose several important security challenges. One fundamental challenge is key management between the two communicating parties. The goal is to establish a common secret key through an unsecured wireless medium. In this paper, we introduce a new physical layer paradigm for secure key exchange between the legitimate communication parties in the presence of a passive...
For cooperative received Paired Carrier Multiple Access (PCMA) signals, a new algorithm for frequency offset estimation is proposed. The local sample sequence is used as auxiliary data, and frequency offset is estimated based on the discrete Fourier transform (DFT) of the autocorrelation of the sequence, which obtained by multiplying the auxiliary data and mixed signal. The modified Cramer-Rao Bound...
Direct Sequence Spread Spectrum (DSSS) signal has been widely used because of its low signal-to-noise ratio, strong anti-interference, low interception rate and multi-path effect. It is gradually replacing the traditional communications, and widely used in modern military and commercial communications systems. Therefore, the corresponding direct-communication communication reconnaissance technology...
Present day distributed inference systems consist of sensors with different modalities working as a system to perform specific tasks. With multiple sensors sensing heterogeneous data over multiple time instants, diversity is an inherent aspect of such systems. In this work, we take the first step to characterize the diversity of a general heterogeneous sensing system performing inference tasks. We...
In this work, the inter-dependency of TCM signals is studied. Using this inter-dependency, correlation-based detectors are proposed for spectrum sensing of TCM signals in white Gaussian noise. In particular, a constant false alarm rate (CFAR) detector is presented and its performance is evaluated using simulations. We also describe an application of our detector for the classification of uncoded modulation...
The existence of complementary information across multiple sensors has driven the proliferation of multivariate datasets. Exploitation of this common information, while minimizing the assumptions imposed on the data has led to the popularity of data-driven methods. Independent vector analysis (IVA), in particular, provides a flexible and effective approach for the fusion of multivariate data. In many...
Cognitive Radio requires both efficient and reliable spectrum sensing of wideband signals. In order to cope with the sampling rate bottleneck when dealing with such signals, sub-Nyquist methods have been proposed. However, these techniques decrease the signal to noise ratio (SNR) due to aliasing effects. Cyclostationary detection, which exploits the periodic property of communication signal statistics,...
We propose computationally efficient carrier frequency offset estimators for multicarrier underwater acoustic communication using identical pilot tones equi-spaced in the frequency domain. The first estimator uses the phase of the maximal eigenvector of a channel-dependent correlation matrix. Next, the phase of the minimal eigenvector of a channel-independent correlation matrix is combined with the...
We address the problem of sound source localization with a microphone array mounted on a micro aerial vehicle (MAV). Due to the noise generated by motors and propellers, this scenario is characterized by extremely low signal-to-noise ratios (SNR). Based on the observation that the energy of MAV sound recordings is usually concentrated at isolated time-frequency bins, we propose a time-frequency processing...
This paper deals with the problem of single-channel noise reduction. Thanks to the eigenvalue decomposition, we arrange the eigenvalues of the speech correlation matrix in such a way that all the spectral mode signal-to-noise ratios (SNRs) of the noisy speech are ordered in a descending manner. By maintaining no speech distortion in the spectral modes with high input SNRs while allowing some degree...
A binary communication channel under the action of additive Gaussian and non-Gaussian broadband and narrow-band interferences is considered in order to identify the possibilities of using the method of bispectral analysis for the detection and recovery of the useful signal. The discrete random process with SL Johnson distribution is taken as non-Gaussian noise. The estimation of periodic signal detection...
Geological processes such tornados, avalanches or earthquakes can unleash adverse effects especially life losses, when we miss detect the presence of victims in devastated area. Statistics prove that death toll caused by natural hazards is becoming more prevalent from year to another. Meanwhile, telecommunications are booming with arising broadband networks. Besides, new wireless applications lead...
Security is one of the crucial requirements of the multimedia communication which can be achieved by using encryption. Encryption algorithms based on chaos generally satisfy the basic requirements of the cryptosystem such as simplicity, high sensitivity, fast speed, high security etc. In this paper, chaos based speech encryption algorithm is proposed which employs modified Henon map and sine map....
Digital Pulse compression is a technique to achieve better range resolution that of corresponding short pulse by transmitted power of a reasonably long pulse. Compare to other radar waveform codes, Polyphase codes have the ability to achieve better side lobe levels without applying weighting functions. More importantly, Polyphase wave forms have the advantages of low main lobe width, high peak side...
This paper deals with the near-field DOA-Matrix method for source localization using a uniform linear array antenna. In general, the mutual coupling between array elements degrades the DOA estimation accuracy. In this paper, we investigate the influence of mutual coupling in source localization using the near-field DOA-Matrix method and the improved method.
The cyclic method performs the direction-of-arrival (DOA) estimation of the desired signals by using cyclic correlations of digital-modulation signals. This paper proposes a cyclic method which uses in-phase combining of multiple cyclic correlations (MCC) and the forward and backward spatial smoothing processing (FB-SSP). Also, the way of reducing the computation load in FB-SSP is provided. Computer...
We suggest several techniques for demodulation of frequency-modulated signals. The techniques are compared using the criterion of error rate of a demodulated signal relative to the signal before modulation. The experimental research is conducted for different signal-to-noise ratios.
the paper presents a cognitive radio networks which proposes a novel method of channel assessment analysis with dynamic channel allocation with the help of priority scheduling and improvement in data transmission. The paper first deals with the selection of a novel approach to sense the available spectrum in the area and then simulate a co-operative spectrum sensing system. The co-operative spectrum...
Noise is omnipresent in almost all acoustical environments. The investigation presents here seeks to quantify the impact of noise on mel-frequency cepstral coefficients (MFCC) of speech signal. MFCC is one of the most commonly used features for speech recognition systems. However, it has been observed that performance of MFCC based system degrades drastically with changing noise levels and noise types...
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