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The methods of dynamic access to spectrum developed in Cognitive Radio require efficient and robust spectrum detectors. Most of these detectors suffer from four main limits: the computational cost required for the detection procedure; the need of prior knowledge of Primary User's (PU) signal features; the poor performances obtained in low SNR (Signal to Noise Ratio) environment; finding an optimal...
In this paper the impact of exponential correlation model on massive multiple input multiple output (MIMO) channel estimation is analyzed using a large number of antennas in the base station (BS) and a user terminal. We consider pilot-based channel estimation in the UL channel. The Linear minimum mean square error (LMMSE) estimator is used to investigate the effect of correlation factor on the average...
In this paper, two methods are showed to identify the seismic source using an array signal processing technique. One method is applicable when there are multiple sources, and it identifies the directions of the sources, and the other one estimates the distance and angular position of a single seismic source. Both the methods uses MUltiple SIgnal Classifier (MUSIC) for array signal processing. In case...
A large part of unoccupied licensed spectrum can be vital for many applications and can be accessed opportunistically by Cognitive Radio. Cognitive Radio serves to be a framework for forthcoming 5G communication systems and therefore, extensive research is being carried out in its different domains. The task of sensing spectrum should be efficient and reliable to avoid interference between licensed...
This paper analyzes the performance of energy beamforming in spatially correlated multiple-input multiple-output (MIMO) relaying systems, where the source and destination nodes are equipped with multiple spatially correlated antennas and communicating via a dual-hop amplify-and-forward (AF) single antenna energy-constrained relay. To maximize the overall harvested energy so as to enable long-distance...
Correlation-based algorithms are low-complexity spectrum sensing methods requiring little knowledge on primary signals or noise signals. However, their detection performance severely degrades in the low signal-to-noise ratio (SNR) regime with low signal correlation, which happens to be quite common in practice. In this paper, a weighted correlation- based spectrum sensing scheme and its simplified...
In cognitive radio networks, multichannel spectrum sensing yield accurate results compared to single channel sensing schemes. However, often realistic correlation among multiple sensing channels is ignored. In this paper, we investigate the performance of a cognitive radio spectrum sensing systems considering more realistic exponential correlation among multiple sensing channels. Closed-form expressions...
Abstract-In this article, the authors focus on a correlated channel model for secure relay beamforming in the relayeavesdropper network. In this network, a single-antenna sourcedestination pair transmits secure information with the help of a amplify-and-forward (AF) relay equipped with multiple antennas. The relay cannot obtain the instantaneous channel state information (CSI) of the eavesdropper...
This paper investigates the impact of antenna correlation on wireless powered dual-hop multi-antenna relaying systems with instantaneous channel state information (CSI) or statistical CSI at the relay. Considering the power-splitting architecture, we study the outage probability as well as the achievable diversity order of the system for amplify-and-forward protocol. Our results show that, antenna...
The problem of carrier frequency and phase synchronization exists in most wireless digital communication systems. These offsets are generally results from the Doppler effect, oscillator instabilities, and unknown transmission delays between receiver and transmitter. In this paper, we propose a joint synchronization algorithm applicable for short-burst PSK modulation systems. In the coarse estimation,...
In this paper, a computationally efficient direction of arrival (DOA) estimation algorithm without subspace decomposition is presented with a uniform linear array (ULA). The ULA is divided into two sub-arrays and two noise-free cross-correlation matrices are computed using the data vectors received by the two sub-arrays. By rearranging the elements of a vector formed from the new constructed cross-correlation...
An approach was developed using maximum eigenvalue principal components analysis(PCA) neural network for direct sequence spread spectrum (DSSS) signals to reconstruct the pseudo noise(PN) sequence blindly in low SNR conditions. Firstly, the received signals were divided into column vectors to form an observation matrix according to a temporal window, whose duration is one period of PN sequence. Then,...
In this paper, a target sound enhancement method using two microphones under a nonstationary noise environment is described. In the method, a linear filter is connected to each microphone, and filter coefficients of linear filter are determined adaptively to enhance a target sound. Then, a supervised signal is required for learning the filter. However, the supervised signal is generally unknown. According...
This paper proposes a new signal-to-noise ratio (SNR) estimation technique on scanning electron microscope (SEM) image, using linear regression. The method is based on the single image approach. Four good quality images are used to compare the proposed method and the existing methods: nearest neighborhood, first order interpolation and piecewise cubic Hermite interpolation. The results are compared...
We present a scheme for determining the number of signals common to or correlated across multiple data sets. Handling multiple data sets is challenging due to the different possible correlation structures. For two data sets, the signals are either correlated or uncorrelated between the data sets. For multiple data sets, however, there are numerous combinations how the signals can be correlated. Prior...
This paper presents a simple and robust algorithm for determining a leader node in a cooperative network based on MDL (Minimum Description Length) subspace algorithm. The algorithm aims to improve the performance of the cooperating network in a spectrum sensing problem for cognitive radio. The outline of the communication and selection process is described and the SNR (signal to noise ratio) estimation...
Consider a two-user MIMO Gaussian Broadcast Channel with two antennas at the transmitter and two single-antenna receivers. While Dirty Paper Coding (DPC) achieves capacity, its practical adoption needs a precise comparison with the popular method of Zero Forcing Beam Forming (ZFBF). In this work, we obtain a simplified expression for the exact difference in sum rate between DPC and ZFBF at all SNRs...
This paper deals with carrier frequency offset (CFO) estimation for interleaved orthogonal frequency division multiple access (OFDMA) uplink systems. Firstly, gravitational search algorithm (GSA) with center-symmetric trimmed correlation matrix and multiple signal classification criterion is presented for the purpose of efficient estimation. It has been shown that the estimate accuracy of the searching-based...
This paper considers the problems of efficiency estimation of using different types of modulation of hydroacoustic signals of AUV communication, navigation and control systems. The types of signal were investigated: simple signal, linear frequency modulation signal and direct sequence spread spectrum. The signals were compared by the noise immunity, time resolution and detection probability with usage...
In a low signal / noise ratio, shape deviation of detected signals causes them pass. The task of neutralization of this effect is classified as actual one. In active control systems it is proposed to solve the task through result tracing operation of reactions comparison for controlled and reference objects on sounding effects. The most probable one is selected according to similarity degree of possible...
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