, Sharif University of Technology,
, Sharif University of Technology,
, Sharif University of Technology,
Paeiz Azmi was born in Tehran-Iran, on April 17, 1974. He received the B.Sc., M.Sc., and Ph.D. degrees in electrical engineering from Sharif University of Technology (SUT), Tehran-Iran, in 1996, 1998, and 2002, respectively. Since September 2002, he has been with the Electrical and Computer Engineering Department of Tarbiat Modares University, Tehran-Iran, where he became an associate professor on January 2006 and he is a full professor now. From 1999 to 2001, Prof. Azmi was with the Advanced Communication Science Research Laboratory, Iran Telecommunication Research Center (ITRC), and Tehran, Iran. From 2002 to 2005, he was with the Signal Processing Research Group at ITRC. Prof. Azmi is a senior member of IEEE now. His current research interests include modulation and coding techniques, digital signal processing, wireless communications, resource allocation, molecular communications, and estimation and detection theories.
In this study, an algorithm to blind and automatic modulation classification has been proposed. It well benefits combined machine leaning and signal feature extraction to recognize diverse range of modulation in low signal power to noise ratio (SNR). The presented algorithm contains four. First, it advantages spectrum analyzing to branching modulated signal based on regular and irregular spectrum character. Seconds, a nonlinear soft margin support vector (NS SVM) problem is applied to received signal, and its symbols are classified to correct and incorrect (support vectors) symbols. The NS SVM employment leads to discounting in physical layer noise effect on modulated signal. After that, a k-center clustering can find center of each class.
In this paper, we consider a cooperative multiple-input single-output (MISO) heterogeneous communication network based on the power domain non-orthogonal multiple access (PD-NOMA). We aim to investigate a resource allocation problem regarding the uncertainty of the channel state information at the transmitter (CSIT) and the imperfect SIC case. Since there is an essential need for low-complexity algorithms with reasonably good performance for the extremely complex access architectures, we propose two novel methods based on matching game with externalities and successive convex approximation (SCA) to realize the hybrid scheme where the number of the cooperative nodes is variable. Moreover, we propose a new matching utility function to manage
High spectral efficiency and low latency are required to provide ubiquitous communication for the emerging applications in 5G wireless communication networks. In this letter, we propose a novel framework that considers these requirements simultaneously by integrating the notion of effective capacity (EC) into orthogonal frequency division multiple access (OFDMA) cloud-radio access networks (C-RAN) where the users select the distributed radio remote heads (RRHs) based on their specific delay requirements to transmit over different subcarriers cooperatively. Consequently, an optimization problem is defined to maximize the EC under the average peak power constraint and the delay requirements. The problem is combinatorial and non-convex and an
The precision of Rayleigh distribution, as the simplest fading model in Non-Line-of-Sight (NLOS) channels, is low in high-resolution radars and long-distance communication receivers. Many currently-available statistical models with a higher precision, including Nakagami-m, Weibull and generalized hybrid Gamma models, are used to describe the radar clutter and the reflected signals in communication receivers. Although the mentioned models in NLOS channels have more accurate matching with the actual fading, a variety of models and the lack of a comprehensive model in different fading channels make it difficult to select an appropriate model. In this paper, the generalized Gamma model is analyzed and evaluated to demonstrate that it adapts to
Nonorthogonal multiple access (NOMA) and energy harvesting technologies are two promising approaches to increase spectral and energy efficiency, respectively. In this paper, a pattern division multiple access (PDMA) uplink transmission network in which users are able to harvest energy from the received radio frequency power is considered. In order to maximize the energy efficiency, we perform resource allocation in the power, subcarrier, and time domains. Also, for each time slot, the pattern matrix is determined dynamically. To enhance the detection reliability, successive interference cancellation and maximal ratio combining at each receiver are utilized. For resource allocation, the actual harvested and available energies of the users a
Covert communication is often limited in rate be- cause it is difficult to hide the signal in the background noise. Recent work has shown that jamming can significantly improve the rate at which covert communication can be conducted, but this jamming signal has a devastating effect on the receiver. To tackle this issue, we equip the jammer with multiple antennas so that it can employ beamforming to place the intended receiver in the null space of the jamming. Moreover, in order to increase rate in this network, we equip the transmitter with an antenna array to be able to perform 3-dimensional (3D) beamforming toward its intended recipient. To evaluate this design, we formulate an optimization problem and present an iterative algorithm to so
In this paper, we address the problem of joint covert communication and secure transmission in untrusted relaying networks when multiple wardens exist in the network. We first consider a system model consisting of one source, one untrusted amplify-and-forward relay, one destination, and one warden. For covert communications, our aim is to prevent the warden from detecting the presence of communications via the source-relay-destination link. For secure transmission, our aim is to prevent the untrusted relay from decoding the source signal. To satisfy these requirements, we propose that the destination and the source inject jamming signals during the source-to-relay and relay-to-destination transmission phases, respectively. For the considere
In this paper, we investigate joint information theoretic secrecy and covert communication in a single-input multi-output (SIMO) system where a transmitter (Alice) is communicating with two legitimate users (Bob and Carol). We consider that an untrusted user and a warden node are also present in the network attempting to attack the secure and covert communications to Bob and Carol, respectively. Specifically, Bob requires secure communications such that his messages from Alice are not decoded by the untrusted user, while Carol requires covert communications such that her messages from Alice are not detected by the warden.
5G and beyond wireless networks are the upcoming evolution for the current cellular networks to provide the essential requirement of future demands such as high data rate, low energy consumption, and low latency to provide seamless communication for the emerging applications. Heterogeneous cloud radio access network (H-CRAN) is envisioned as a new trend of 5G that uses the advantages of heterogeneous and cloud radio access networks to enhance both the spectral and energy efficiency. In this paper, building on the notion of effective capacity (EC), we propose a framework in non-orthogonal multiple access (NOMA)-based H-CRAN to meet these demands simultaneously. Our proposed approach is to maximize the effective energy efficiency (EEE) while
In this paper, an improved channel model of visible light communication (VLC) for ranging in presented. For indoor channel model of VLC, distance is estimated based on received signal strength. In this model, received shot noise as a distance-dependent parameter is considered in range estimation accuracy. Moreover, based on this model, the Cramer-Rao lower bound is computed as the theoretical limits on the performance and accuracy of any unbiased estimator. In this way, the effects of horizontal and vertical distances are investigated. In addition, the transmitted power effect on RSN and accordingly on CRLB is demonstrated.
Knowledge about ambient noise wavefield, through decomposition into different participant waves and determination of precise singularities in ellipticity curves, could be very beneficial to improve the obtained subsurface velocity structures. In this paper, two array processing methods; WaveDec and high-resolution Rayleigh three-component beamforming (RTBF) and four single-station methods; Horizontal-to-Vertical Spectral Ratio (HVSR) or H/V, HVTFA (H/V using time frequency analysis), RayDec (Random Decrement Technique) and DOP-E (Degree Of Polarization) are applied to decompose ambient noise wavefield and to extract dispersion and ellipticity curves of surface waves. Two sites with different geological and geophysical conditions are chosen
Statistical models are employed to characterize the clutter in the radar and the reflective signals of the telecommunication receivers. End to this, Rayliegh distribution is the simplest fading models in NLOS channels possessing low-accuracy in the high-resolution radars and distant telecommunication receivers. At present, high accuracy models such as the m-type Nakagami and hybrid GG distributions are utilized in order to model fading. However, despite the Non-Rayliegh models have better precision in the NLOS relative to the Rayliegh models, the accuracy of these models decreases when the radiation angle in the transmitter and the reflection angle in the receiver are different. In this paper, the K distribution function is analytically int
The study of the fundamental limits of covert communications, where a transmitter Alice wants to send information to a desired recipient Bob without detection of that transmission by an attentive and capable warden Willie, has emerged recently as a topic of great research interest. Critical to these analyses is a characterization of the detection problem that is presented to Willie. Previous work has assumed that the channel distribution information (CDI) is known to Alice, hence facilitating her characterization of Willie's capabilities to detect the signal. However, in practice, Willie tends to be passive and the environment heterogeneous, implying a lack of signaling interchange between the transmitter and Willie makes it difficult if no
In this paper, we propose a new practical power allocation technique based on bit error probability (BEP) for physical layer security systems. It is shown that the secrecy rate that is the most commonly used in physical layer security systems, cannot be a suitable criterion lonely. Large positive values are suitable for the secrecy rate in physical layer security, but it does not consider the performance of the legitimate and adversary users. In this paper, we consider and analyze BEP for physical layer security systems because based on it, the performance of the legitimate and adversary users are guaranteed and it is needed to use lower power. BEP is calculated for the legitimate and adversary users and it is shown that BEP can be better c
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