Spectrum Sensing Based on Cyclostationary Detector with the Use of Transmission Period in Cognitive Radio Networks

, M.Sc. Thesis Sharif University of Technology Khorramshahi, Pirazh (Author) ; Salehi, Javad (Supervisor)

Abstract

The different methods of spectrum sensing to identify the presence of signal transmission are as follows: Energy detectors, Cyclostationary detectors and Matched-filter detectors. Energy detectors are simple and easy to implement but they are unable to differentiate interference from primary users and noise. They also have a very poor performance in low SNR. Matched-filtering is the optimum method for detection of primary users and can achieve a certain detection performance in a short time but its implementation complexity is too high and requires perfect knowledge of primary user’s signaling features that makes its usage in cognitive radios infeasible. Among these detectors Cyclostationary...

Mining DNA sequences based on spatially coded technique using spatial light modulator

, Article IWCIT 2016 - Iran Workshop on Communication and Information Theory, 3 May 2016 through 4 May 2016 ; 2016 ; 9781509019229 (ISBN) Fazelian, M ; Abdollahramezani, S ; Bahrani, S ; Chizari, A ; Jamali, M. V ; Khorramshahi, P ; Tashakori, A ; Shahsavari, S ; Salehi, J. A ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2016

Abstract

In this paper, we present an optical computing method for string data alignment applicable to genome information analysis. By applying moire technique to spatial encoding patterns of deoxyribonucleic acid (DNA) sequences, association information of the genome and the expressed phenotypes could more effectively be extracted. Such moire fringes reveal occurrence of matching, deletion and insertion between DNA sequences providing useful visualized information for prediction of gene function and classification of species. Furthermore, by applying a cylindrical lens, a new technique is proposed to map two-dimensional (2D) association information to a one-dimensional (1D) column of pixels, where...

Statistical studies of fading in underwater wireless optical channels in the presence of air bubble, temperature, and salinity random variations

, Article IEEE Transactions on Communications ; Volume 66, Issue 10 , 2018 , Pages 4706-4723 ; 00906778 (ISSN) Jamali, M. V ; Mirani, A ; Parsay, A ; Abolhassani, B ; Nabavi, P ; Chizari, A ; Khorramshahi, P ; Abdollahramezani, S ; Salehi, J. A ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2018

Abstract

Optical signal propagation through underwater channels is affected by three main degrading phenomena, namely, absorption, scattering, and fading. In this paper, we experimentally study the statistical distribution of intensity fluctuations in underwater wireless optical channels with random temperature and salinity variations, as well as the presence of air bubbles. In particular, we define different scenarios to produce random fluctuations on the water refractive index across the propagation path and, then, examine the accuracy of various statistical distributions in terms of their goodness of fit to the experimental data. We also obtain the channel coherence time to address the average...