scholarly journals Cognitive Spectrum Sensing with Multiple Primary Users in Rayleigh Fading Channels

2021 ◽  
Author(s):  
Salam Al-Juboori ◽  
Sattar J. Hussain ◽  
Xavier N. Fernando
Keyword(s):  
Fading Channels ◽  
Spectrum Sensing ◽  
Multipath Fading ◽  
Primary User ◽  
Multipath Fading Channels ◽  
Primary Users ◽  
Accurate Detection ◽  
Multiple Primary ◽  
Spherical Detector ◽  
Multiple Primary Users

Accurate detection of white spaces is crucial in cognitive radio networks. Initial investigations show that the accurate detection in a multiple primary users environment is challenging, especially under severe multipath conditions. Among many techniques, recently proposed eigenvalue-based detectors that use random matrix theories to eliminate the need of prior knowledge of the signals proved to be a solid approach. In this work, we study the effect of Rayleigh multipath fading channels on spectrum sensing in a multiple primary user environment for a pre-proposed detector called the spherical detector using the eigenvalue approach. Simulation results show interesting outcomes.

scholarly journals Cognitive Spectrum Sensing with Multiple Primary Users in Rayleigh Fading Channels

2021 ◽  
Author(s):  
Salam Al-Juboori ◽  
Sattar J. Hussain ◽  
Xavier N. Fernando
Keyword(s):  
Fading Channels ◽  
Spectrum Sensing ◽  
Multipath Fading ◽  
Primary User ◽  
Multipath Fading Channels ◽  
Primary Users ◽  
Accurate Detection ◽  
Multiple Primary ◽  
Spherical Detector ◽  
Multiple Primary Users

Accurate detection of white spaces is crucial in cognitive radio networks. Initial investigations show that the accurate detection in a multiple primary users environment is challenging, especially under severe multipath conditions. Among many techniques, recently proposed eigenvalue-based detectors that use random matrix theories to eliminate the need of prior knowledge of the signals proved to be a solid approach. In this work, we study the effect of Rayleigh multipath fading channels on spectrum sensing in a multiple primary user environment for a pre-proposed detector called the spherical detector using the eigenvalue approach. Simulation results show interesting outcomes.

scholarly journals A Novel Multiband Spectrum Sensing Method Based on Wavelets and the Higuchi Fractal Dimension

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1322 ◽  
Author(s):  
Yanqueleth Molina-Tenorio ◽  
Alfonso Prieto-Guerrero ◽  
Rafael Aguilar-Gonzalez
Keyword(s):  
Fractal Dimension ◽  
Spectrum Sensing ◽  
Cognitive Radios ◽  
Primary User ◽  
Linear Measure ◽  
Signal To Noise ◽  
Primary Users ◽  
Multiple Primary ◽  
Higuchi Fractal Dimension ◽  
Multiple Primary Users

In this work, two novel methodologies for the multiband spectrum sensing in cognitive radios are implemented. Methods are based on the continuous wavelet transform (CWT) and the multiresolution analysis (MRA) to detect the edges of available holes in the considered wideband spectrum. Besides, MRA is also combined with the Higuchi fractal dimension (a non-linear measure) to establish the decision rule permitting the detection of the absence or presence of one or multiple primary users in the studied wideband spectrum. Methods were tested on simulated and real signals showing a good performance. The results present these two methods as effective options for detecting primary user activity on the multiband spectrum. The first methodology works for 95% of cases, while the second one presents 98% of effectivity under simulated signals of signal-to-noise ratios (SNR) higher than 0 dB.

scholarly journals Spectrum Sensing with Multiple Primary Users over Fading Channels

2016 ◽  
pp. 1-1 ◽  
Author(s):  
Alexandros-Apostolos A. Boulogeorgos ◽  
Nestor D. Chatzidiamantis ◽  
George K. Karagiannidis
Keyword(s):  
Fading Channels ◽  
Spectrum Sensing ◽  
Primary Users ◽  
Multiple Primary ◽  
Multiple Primary Users

scholarly journals Multichannel spectrum sensing over correlated fading channels with diversity reception

2021 ◽  
Author(s):  
Salam Al-Juboori ◽  
Xavier Fernando
Keyword(s):  
Closed Form ◽  
Fading Channels ◽  
Spectrum Sensing ◽  
Detection Probability ◽  
Multipath Fading ◽  
Primary User ◽  
Secondary User ◽  
Selection Combining ◽  
Standard Normal Distribution ◽  
Correlated Fading

Accurate detection of white spaces is crucial to protect primary user against interference with secondary user. Multipath fading and correlation among diversity branches represent essential challenges in Cognitive Radio Network Spectrum Sensing (CRNSS). This dissertation investigates the problem of correlation among multiple diversity receivers in wireless communications in the presence of multipath fading. The work of this dissertation falls into two folds, analysis and solution. In the analysis fold, this dissertation implements a unified approach of performance analysis for cognitive spectrum sensing. It considers a more realistic sensing scenario where non-independent multipath fading channels with diversity combining technique are assumed. Maximum Ratio Combining (MRC), Equal Gain Combining (EGC), Selection Combining (SC) and Selection and Stay Combining (SSC) techniques are employed. Arbitrarily, constant and exponentially dual, triple and L number of Nakagami-m correlated fading branches are investigated. We derive novel closed-form expressions for the average detection probability for each sensing scenario with simpler and more general alternative expressions. Our numerical analysis reveals the deterioration in detection probability due to correlation especially in deep fading. Consequently, an increase in the interference rate between the primary user and secondary user is observed by three times its rate when independent fading branches is assumed. However, results also show that this effect could be compensated for, through employing the appropriate diversity technique and by increasing the diversity branches. Therefore, we say that the correlation cannot be overlooked in deep fading, however in low fading can be ignored so as to reduce complexity and computation. Furthermore, at low fading, low false alarm probability and highly correlated environments, EGC which is simpler scheme performs as good as MRC which is a more complex scheme. Similar result are observed for SC and SSC. For the solution fold and towards combatting the correlation impact on the wireless systems, a decorrelator implementation at the receiver will be very beneficial. We propose such decorrelator scheme which would significantly alleviate the correlation effect. We derive closed-form expressions for the decorrelator receiver detection statistics including the Probability Density Function (PDF) from fundamental principles, considering dual antenna SC receiver in Nakagami-m fading channels. Numerical results show that the PDF of the bivariate difference could be perfectly represented by a semi-standard normal distribution with zero mean and constant variance depending on the bivariate's parameters. This observation would significantly help simplifying the design of decorrelator receiver. The derived statistics can be used in the problem of self-interference for multicarrier systems. Results also show the outage probability has been improved by double, due to the decorrelator.

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