Etude comparative entre les performances des séquences binaires à bonne corrélation avec les séquences GOUTELARD Q-aire. Application à la technique DS/CDMA

- Les séquences complexes, comparées aux séquences binaires présentent de bonnes performances en terme d'étalement spectral et réduction du facteur d'interférence entre utilisateurs dans une chaîne de transmission utilisant la technique DS/CDMA. Dans cet article nous avons effectué une comparaison entre les différents types de séquences binaires les plus utilisées : les séquences de Gold, l'ensemble petit de séquences de Kasami et l'ensemble large de séquences de Kasami. L'ensemble large de séquences de Kasami constitue le meilleur compromis pour les séquences binaires. On a introduit ensuite une nouvelle famille de séquences complexes qui constitue un nouveau formalisme : les séquences GOUTELARD Q-aire (GQ) ; elles présentent une autocorrélation presque parfaite et une intercorrélation nulle, pouvant ainsi augmenter la capacité du canal, en minimisant le facteur d'interférence

Photonic hydrogel sensors

Analyte-sensitive hydrogels that incorporate optical structures have emerged as sensing platforms for point-of-care diagnostics. The optical properties of the hydrogel sensors can be rationally designed and fabricated through self-assembly, microfabrication or laser writing. The advantages of photonic hydrogel sensors over conventional assay formats include label-free, quantitative, reusable, and continuous measurement capability that can be integrated with equipment-free text or image display. This Review explains the operation principles of photonic hydrogel sensors, presents syntheses of stimuli-responsive polymers, and provides an overview of qualitative and quantitative readout technologies. Applications in clinical samples are discussed, and potential future directions are identified

Kullback–Leibler Divergence Between Multivariate Generalized Gaussian Distributions

International audienceThe Kullback-Leibler divergence (KLD) between two multivariate generalized Gaussian distributions (MGGDs) is a fundamental tool in many signal and image processing applications. Until now, the KLD of MGGDs has no known explicit form, and it is in practice either estimated using expensive Monte-Carlo stochastic integration or approximated. The main contribution of this letter is to present a closed-form expression of the KLD between two zero-mean MGGDs. Depending on the Lauricella series, a simple way of calculating numerically the KLD is exposed. Finally, we show that the approximation of the KLD by Monte-Carlo sampling converges to its theoretical value when the number of samples goes to the infinity

Maximal function and fractional integral associated with Laplace-Bessel differential operators on generalized Morrey spaces

In this work we study the boundedness of the maximal and fractional integral operators associated with Laplace-Bessel differential operators on generalized Morrey spaces. © 2022, Institute of Mathematics and Mechanics, National Academy of Sciences of Azerbaijan. All rights reserved

Performance analysis of MIMO cooperative relays for wireless sensor networks

International audienc

Performance Analysis of Decode and Forward Cooperative Relaying over the Generalized-K Channel

permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In this paper, we analyze the performance of cooperative diversity using adaptive Decode and Forward (DF) relaying over independent but non-necessarily identical flat composite fading channels which include multipath fading and shadowing simultaneously. We have considered the transmission of M-QAM modulated signals over Generalized-K channel model which is very versatile and accurately approximates many of the commonly used channel models as Nakagami-m, Log-Normal distributions and the mixture of the two distributions for the composite fading. Using an approximation of the Generalized-K pdf by a Gamma pdf, we derive analytical expressions for the outage probability and the Average Symbol Error Probability (ASEP) of the proposed scenario and analyze their dependence on the channel parameters. We assume in our context that the relay decides independently whether or not to forward the signal to the destination based on the received signal quality. Simulations are provided for 16-QAM modulation for both the outage and the ASEP. The obtained results are discussed and proved to be in good agreement with our theoretical analysis

Compressed Sensing-based Centralized Multiple Targets Localization

Compressed Sensing-based Centralized Multiple Targets Localizatio

A New Theoretical Approach of Wavelet-Based Multifractal Characterization of HF Channel Scattering Function: Theoretical and Physical Interpretations

In high-frequency (HF) ionospheric communications, the dynamic nature of the high-latitude ionosphere creates small-scale ionospheric irregularities capable of scattering HF radio waves. In addition, there are large-scale irregularities which may be identified using some specific methods. However, small-scale irregularities cannot be easily identified and characterized. The aim of this paper is to introduce a new wavelet-based multifractal dimension mapping approach for the identification and the quantification of the small-scale irregularities. Numerical results show the improvement of the proposed methods compared to those obtained by the classical Legendre multifractal analysis. In our analysis, we have used the scattering function as a tool for the HF channel characterization. Our analysis deals with experimental scattering functions measured during the solar eclipse on August 11, 1999