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Recent advances in interference exploitation showed that exploiting knowledge of interference constructively can improve the receive signal-to-interference and noise ratio (SINR) at the destination. This paper exploits this concept to design artificial noise (AN) beamformers constructive to the intended receiver (IR) yet keeping AN disruptive to possible eavesdroppers (Eves). A multiple-input single-output...
With the multi-antenna design of WiFi interfaces, phased array has become a promising mechanism for accurateWiFi localization. State-of-the-art WiFi-based solutions using AoA (Angle-of-Arrival), however, face a number of critical challenges. First, their localization accuracy degrades dramatically when the Signal-to-Noise Ratio (SNR) becomes low. Second, they do not fully utilize coherent processing...
This paper analyzes and studies the influence of different adjustment factor upon the algorithm property in Gerschgorin Criterion for Source Number Estimation. Then a new design method of adjustment factor is proposed, which is irrelevant to sampling points. This adjustable factor-designed don't need be chose subjectively, and it is determined completely by centre information of Gerschgorin circle...
This paper investigates the robustness of the optimized link state routing (OLSR) protocol when used for unicast traffic in a highly dynamic military tactical scenario. The importance of the channel model in ad hoc network simulations is shown, as a radio channel model considering terrain effects and real radio transmission behaviour is employed. Results show, among other things, that using an advanced...
In body sensor networks, the need to brace sensing devices firmly to the body raises a fundamental barrier to usability. In this paper, we examine the effects of sensing from devices that do not face this mounting limitation. With sensors integrated into common pieces of clothing, we demonstrate that signals in such free-mode body sensor networks are contaminated heavily with motion artifacts leading...
We discuss the threat that hardware Trojans (HTs) impose on wireless networks, along with possible remedies for mitigating the risk. We first present an HT attack on an 802.11a/g transmitter (TX), which exploits Forward Error Correction (FEC) encoding. While FEC seeks to protect the transmitted signal against channel noise, it often offers more protection than needed by the actual channel. This margin...
This paper compares the performance of various beamforming techniques using convex optimization. A new robust beamforming technique is formulated, and its performance is compared with the diagonal loading, robust SOCP techniques and the standard sample matrix inversion technique in different scenarios. The robustness of the proposed technique to errors in the array steering vector is demonstrated...
Mobile communications are greatly influenced by environmental noise that may cause a significant deterioration in automatic speech recognition (ASR) systems performance. In this paper, we present a new framework integrating a noise-robust front-end in distributed speech recognition (DSR) systems. Using the Aurora-2 speech database, the authors evaluate the development of an additional feature set...
This paper compares the use of signal to noise ratio (SNR)-dependent and SNR-independent mixtures of probabilistic linear discriminant analysis (PLDA) versus conventional PLDA, under multi-noise and multi-SNR conditions for a small-set speaker verification system. Results indicate that conventional PLDA is more robust under multi-SNR conditions. The effect of the testing speech length is also examined...
Based on the tapped delay-lines (TDL) wideband model, the response variation (RV) constraint is applied to improve the frequency response consistency of the wideband beamforming. The optimization criterion of the proposed algorithm is minimizing the designed sidelobe level utmost and the constraints of the sidelobe level, interference suppression and the response variation while making the direction...
The audio watermarking systems are more challenge due to the lack of publicly available reference algorithms. It includes the robustness against acoustic path transmission is only evaluated. So this systems will gives the chance of digital watermarking to be used in many applications where such as e.g., second screen applications, audience measurement, and so on. In this paper introducing a simple...
This paper focuses on an average robust transmit beamforming optimization problem for the multiuser multiple-input-single-output (MISO) downlink scenario. In this problem, the channels are modeled as Gaussian variables with mean zero and with known covariance at the transmitter. The design criterion is to maximize the sum of the users' average rates with respect to the channels, subject to the total...
This paper presents a novel noise suppression method to enhance soft speech recorded with a special body-conductive microphone called nonaudible murmur (NAM) microphone. NAM microphone is capable of detecting extremely soft speech, but the recorded soft speech easily suffers from external noise due to its faint volume. To effectively suppress noise on the body-conducted signals, an external noise...
In the era of deep learning, although beam-forming multi-channel signal processing is still very helpful, it was reported that single-channel robust front-ends usually cannot benefit deep learning models because the layer-by-layer structure of deep learning models provides a feature extraction strategy that automatically derives powerful noise-resistant features from primitive raw data for senone...
An effective method is proposed to estimate the desired-signal (S) subspace by the intersection between the signal-plus-interference (SI) subspace and a reference space covering the angular region where the desired signal is located. The estimated S subspace is robust to steering vector mismatch and overestimation of the SI subspace, capable of detecting the relative strength of the desired signal...
In this work, we extend the popular sparse iterative covariance-based estimator (SPICE) by generalizing the formulation to allow for different norm constraint on the signal and noise parameters in the covariance model. For any choice of norms, the resulting generalized SPICE method enjoys the same benefits as the regular SPICE method, including being hyperparameter free, although the choice of norm...
In this work, we consider the robust beamforming design for secondary downlink multicasting channels, where primary users are present with norm-bounded channel errors. In particular, the max-min-fair formulation is considered and the resulting design problem is a quadratically constrained quadratic program (QCQP) with a set of semi-infinite constraints, which is NP-hard in general. As a remedy, we...
Adaptive beamformers (ABF) are used when estimating the direction of arrival of a narrowband planewave with a uniform line array in an environment with loud, unwanted signals. Capon's minimum variance distortionless response (MVDR) suppresses interferers by steering beampattern nulls in their directions but maintains unity gain in the look direction. In practical situations, ABFs replace the ensemble...
This paper addresses the task of Automatic Speech Recognition (ASR) with music in the background, where the accuracy of recognition may deteriorate significantly. To improve the robustness of ASR in this task, e.g. for broadcast news transcription or subtitles creation, we adopt two approaches: 1) multi-condition training of the acoustic models and 2) denoising autoencoders followed by acoustic model...
The regularization parameter is required in most (if not all) adaptive algorithms, while its role becomes very critical in the presence of additive noise. In this paper, we focus on the regularized recursive least-squares (RLS) algorithm and present a method to find its regularization parameter, which is related to the signal-to-noise ratio (SNR). Also, using a proper estimation of the SNR, we further...
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