In this work, three specific machine learning techniques (neural networks, expectation maximization and -means) are applied to a multiband spectrum sensing technique for cognitive radios. All of them have been used as a classifier using the approximation coefficients from a Multiresolution Analysis in order to detect presence of one or multiple primary users in a wideband spectrum. Methods were tested on simulated and real signals showing a good performance. The results presented of these three methods are effective options for detecting primary user transmission on the multiband spectrum. These methodologies work for 99% of cases under simulated signals of SNR higher than 0 dB and are feasible in the case of real signals.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6864763 | PMC |
http://dx.doi.org/10.3390/s19214715 | DOI Listing |
Microsyst Nanoeng
January 2025
Sichuan University, 610207, Chengdu, China.
In conventional nondispersive infrared (NDIR) gas sensors, a wide-spectrum IR source or detector must be combined with a narrowband filter to eliminate the interference of nontarget gases. Therefore, the multiplexed NDIR gas sensor requires multiple pairs of narrowband filters, which is not conducive to miniaturization and integration. Although plasmonic metamaterials or multilayer thin-film structures are widely applied in spectral absorption filters, realizing high-performance, large-area, multiband, and compact filters is rather challenging.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Advanced Broadband Communications Center (CCABA), Universitat Politècnica de Catalunya (UPC), 08034 Barcelona, Spain.
Multiband (MB) optical transmission targets increasing the capacity of operators' optical transport networks. However, nonlinear impairments (NLI) affect each optical channel in the C+L+S bands differently, and, therefore, the routing and spectrum assignment (RSA) problem needs to be complemented with fast and accurate tools to consider the quality of transmission (QoT) within the provisioning process. This paper proposes a digital twin-assisted approach for lightpath provisioning to provide a complete solution for the RSA problem that ensures the required QoT in MB optical networks.
View Article and Find Full Text PDFSci Rep
January 2025
Electrical Engineering Department, King Saud University, 11421, Riyadh, Saudi Arabia.
A multipurpose antenna system that can handle a broad area of frequencies is crucial in the effort to build up widespread 5G Internet-of-Things (IoT) networks. For fifth-generation Internet-of-things applications, this research introduces a new multi-band antenna that can operate in the sub-6 GHz band (2-7 GHz), Ku-band (13-17.5 GHz), and millimeter wave band (25-39 GHz).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
School of Materials Science and Engineering, Tianjin University, Tianjin, 300350, P. R. China.
Multispectral camouflage materials that provide adaptable features across a wide spectrum, from visible light to radar frequencies, play a vital role in sophisticated multi-band electromagnetic (EM) applications. However, conventional single-band stealth is difficult to align with the growing demand for multi-band compatibility and intelligent adaptation. Herein, we report the design and synthesis of cephalopod-inspired MXene-integrated cholesteric liquid crystal elastomers (MXene-CLCEs) with multispectral camouflage capability, which was fabricated through in situ thiol-acrylate Michael addition and free-radical photopolymerization of CLCE precursor and isocyanate-mediated robust covalent chemical bonding of MXene nanocoating at the interface.
View Article and Find Full Text PDFJ Pharm Biomed Anal
February 2025
Medical School of Tianjin University, Tianjin University, China. Electronic address:
The signal-to-noise ratio of the spectrum is a critical determinant of detection accuracy in compositional analysis utilizing spectroscopy. The spectral data acquired by the spectrometer, while intended to capture essential sample characteristics, is often interspersed with various noise interferences. This contamination can severely disrupt the integrity of measurement outcomes.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!