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Interference measurements in an infrastructure 802.11n Wireless Mesh Network (WMN) testbed are described. Each wireless router consists of a Linux processor with multiple dual-band 802.11a/b/g/n transceivers. The 5 GHz band can be used for backhauling, and the 2.4 GHz band can be used for end-user service. The backhaul links use sectorized 3×3 MIMO directional antenna, to support directional parallel...
This work addresses the problem of speaker verification where additive noise is present in the enrollment and testing utterances. We show how the current state-of-the-art framework can be effectively used to mitigate this effect. We first look at the degradation a standard speaker verification system is subjected to when presented with noisy speech waveforms. We designed and generated a corpus with...
In this paper a dynamic stochastic resonance (DSR)-based watermark extraction technique from audio signal in discrete wavelet transform domain has been presented. The watermark embedding has been done in detail coefficient of DWT transformed audio signal. DSR improves the authenticity of the extraction process by utilizing noise or degradation introduced during different signal processing attacks...
In this paper, a nonlinear non-dynamic stochastic resonance-based technique has been proposed for enhancement of dark and low contrast images. A low contrast image is treated as a subthreshold signal and noise-enhanced signal processing is applied to improve its contrast. The proposed technique uniquely utilizes addition of external noise to neutralize the effect of internal noise (due to insufficient...
Hybrid NEMS interfaces are the key to systems combining the benefits of highly sensitive miniaturized mechanical sensors with the vast functionalities available in electronics. In this context, we analyze diverse RF front-ends meant for interfacing high-impedance carbon nanotube based NEMS. Given the feeble signals from the NEMS, their high output impedance and non-negligible interconnect parasitics,...
The proposed resource allocation scheme can boost the spectral efficiency of multi-user OFDMA wireless systems with heterogeneous delay requirements. The existing designs usually have two important assumptions that the users are delay insensitive and Channel State Information at the Transmitter (CSI) is perfect. In practice, users have heterogeneous delay requirements and CSI usually becomes outdated...
In this paper, we investigate the enhancement of speech by applying kernel adaptive filter. Noise removal is very important in many applications like telephone conversation, speech recognition, etc. Kernel methods have shown good results for other applications like handwriting recognition, inverse distance weightings, etc. To improve the speech quality and intelligibility, we can process the signals...
PLL, DLL and data demodulator are key components in a GNSS receiver. Basing on the parameters of widely-used hardware, this paper calculates the noise performance of data demodulator and input SNRs of PLL and DLL. The phase models of GNSS receiver's carrier-tracking loop and code-tracking loop with thermal noise are also established. Then the loop SNRs(Signal to Noise Ratio)of carrier-tracking loop...
To get robust results under varied noise, an adaptive super-resolution (SR) method is proposed. The method runs in frame of regularization, and there will be an iteration process, the signal to noise ratio(SNR) is estimated by the local varicance of image in every iteration step, and be used as the regularization parameter to control the iteration, as the SNR is a reflection of image noise, and varied...
Cognitive radio (CR) is a critical issue to solve the spectrum scarcity and to improve frequency spectrum utilization in wireless communication. Spectrum sensing is the first step for cognitive radio and it needs to detect signals presence under strict requirement such that secondary users (unlicensed users) can use the licensed spectral band without interfering primary users (licensed users). In...
This paper presents a method for detection of sinusoidal signals corrupted by an additive noise in the short-time Fourier domain. The proposed method is based on probabilistic modelling of the spectral magnitude shape and phase continuity around spectral peaks and can deal with both stationary and non-stationary sinusoidal signals. Experimental results are presented for both sinusoidal signals of...
Clock timing jitter refers to random perturbations in the sampling time in analog-to-digital converters (ADCs). The perturbations are caused by circuit imperfections in the sampling clock. This paper analyzes the effect of sampling clock jitter on the acquired samples in the midst of quantization noise and random Gaussian noise. The paper proposes a method for estimating the jitter for cognitive radio...
Power Line Communications (PLC) technologies and systems use state-of-the-art technical solutions to provide communication means for Smart Grid applications. PRIME is one of those systems, with a comprehensive Physical and Media Access Control (MAC) Layer specification for CENELEC A-band, used today in Smart Metering deployments. PRIME systems have demonstrated to be capable of working in normal scenarios...
A novel method has been introduced to provide a clear endpoint signal for copper CMP barrier polish with minimal time delay as compared to conventional endpoint. A modified power sensor is installed on a 300mm polisher to measure the torque generated by the platen motor with an improved signal to noise ratio. An Extended Kalman filter (EKF) is integrated to the software to extract the friction signals...
This survey examines the bandwidth efficiency of wireless signals, beginning with a review of the Shannon capacity and of the important differences between signal to noise ratio (snr) and individual bit energy to noise density (IBEND = Eb/N0). Recognizing that communication systems are successful only if they are profitable, value propositions that have been realized along the evolution of adopted...
A system for the real-time and fully automated detection, classification and localisation of acoustic sources in the marine environment has been developed at the Laboratory of Applied Bioacoustics (LAB) of the Technical University of Catalonia (UPC). The system features modules for the detection, the classification and localisation of short tonal sounds and impulsive sounds and the quantification...
Although a significant amount of research has been given to wavelet transform as a denoising technique, little has been done to apply new approach to chaotic noisy signal and most of them have a lack of details and they do not discuss the results on a complete chaotic communication system. In this paper a comprehensive study for a new approach to denoise chaotic signals by using wavelet transform...
The paper, we put forward a new piecewise hybrid system, and study the behavior of the stochastic resonance. Through the method of numerical simulation, we studied the influence of noise and parameters variation to the output of the system, and also calculated the behavior of error rate against system parameters. The result showed that with the appropriate system parameters, the system can restore...
In the last decades, Global Positioning System (GPS) receivers have become more popular and are now incorporated in mobile phone electronics and also in navigation systems, namely in automotive, marine and aerospace equipment. This paper presents the design of various digital signal processing (DSP) and communication blocks which form an integral part of a typical L1-band Coarse/Acquisition (C/A)-code...
In this paper an improved method of speech enhancement using Power Spectral Density (PSD) codebooks of clean speech and several types of noise, is proposed. The proposed algorithm estimates the PSDs of speech and noise of unknown nature and evaluates the input Signal-to-Noise Ratio (SNR) by solving an over-determined set of equations as in the previous version. However, the search method used for...
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