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Sofwan A.,King Saud University | Barkat M.,Valencia College | AlQahtani S.A.,King Saud University
Wireless Networks | Year: 2015

In this paper, we consider a pseudo-noise (PN) code acquisition for direct sequence spread spectrum communication in a Rayleigh fading multipath channel environment using smart antenna and adaptive thresholding automatic trimmed-mean constant false alarm rate (ATM-CFAR) processing. A smart antenna is an array of antenna elements that can modify the array pattern adaptively to minimize the effect of multiple access interference (MAI) from other users and multipath. PN code acquisition using a fixed threshold may lead to an excessive number of false alarms, and thus, adaptive thresholding ATM-CFAR processing is considered. In addition, since the interference (MAI and multipath) can be considered as outliers, an outlier determiner is embedded to the proposed system based on the interquartile range. This novel approach of combining smart antennas and adaptive thresholding ATM-CFAR detection with an outlier determiner proved to be very robust since it resulted in a serious enhancement of the probability of detection. © 2015 Springer Science+Business Media New York Source


Colebunders E.,Vrije Universiteit Brussel | Boustique H.,Valencia College | Mikusinski P.,University of Central Florida | Richardson G.,University of Central Florida
Applied Categorical Structures | Year: 2015

Properties of continuous actions and pseudoquotients are studied in the category of convergence approach spaces. Invariance properties of continuous actions on convergence approach spaces are given. It is shown that the formation of pseudoquotient spaces is idempotent. Function space actions are also investigated. © 2015 Springer Science+Business Media Dordrecht Source


Berbra K.,Blida University | Barkat M.,Valencia College | Gini F.,University of Pisa | Greco M.,University of Pisa | Stinco P.,University of Pisa
Signal Processing | Year: 2016

Recently, cyclostationarity (CS) based detection methods exploiting the autocorrelation periodicity property of the orthogonal frequency division multiplexing (OFDM) signals attracted a lot of attention. These detection methods are more complex than energy detection but they have better detection performance in low-SNR regimes. The drawback, however, is their extensive computational complexity. In this paper, we propose a computationally efficient spectrum sensing method for detecting unsynchronized OFDM signals in additive white Gaussian noise (AWGN). The proposed method exploits the second-order CS property of OFDM signals to set an adaptive threshold, which achieves the desired constant false alarm rate (CFAR) property. The complexity of the proposed method is significantly reduced compared with the scheme proposed in [22]. Monte-Carlo simulations illustrate that the performance of the proposed detector outperforms the classical energy detector (ED), the sliding window detector (SW) and Axell's detector in addition to guaranteeing a low sensing time. © 2016 Elsevier B.V. Source


Bradman M.,Valencia College
IEEE Potentials | Year: 2016

I got involved with laser and photonics engineering because I thought it would be where I wanted my life to go. I'd work in some lab, improving fiber optics or something. Maybe I'd work for NASA and build something that would travel to Mars. These were the thoughts of a student with no concept of what was really out there. John Lennon wrote in his song «Beautiful Boy» that «Life is what happens when you're making other plans.» These words could not be more true. © 2016 IEEE. Source


Boustique H.,Valencia College | Richardson G.,University of Central Florida
Applied Categorical Structures | Year: 2016

Convergence approach spaces, defined by E. Lowen and R. Lowen, possess both quantitative and topological properties. These spaces are equipped with a structure which provides information as to whether or not a sequence or filter approximately converges. P. Brock and D. Kent showed that the category of convergence approach spaces with contractions as morphisms is isomorphic to the category of limit tower spaces. It is shown below that every limit tower space has a compactification. Moreover, a characterization of the limit tower spaces which possess a strongly regular compactification is given here. Further, a strongly regular S-compactification of a limit tower space is studied, where S is a limit tower monoid acting on the limit tower space. © 2016 Springer Science+Business Media Dordrecht Source

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