Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/11

Browse

Filters

Settings

Publisher: search.filters.publisher.Institute of Electrical and Electronics Engineers Inc.WoS Q: search.filters.wosQuartile.Q1

Search Results

Now showing 1 - 10 of 21
  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    The Resilience of Massive Mimo Pnc To Jamming Attacks in Vehicular Networks
    (Institute of Electrical and Electronics Engineers Inc., 2021) Okyere, Bismark; Musavian, Leila; Özbek, Berna; Busari, Sherif A.; Gonzalez, Jonathan
    In this article, we investigate the resilience of Massive MIMO Physical Layer Network Coding (PNC) to jamming attack in both sub-6 GHz and millimeter-Wave (mmWave) systems in vehicular networks. Massive MIMO generally is resilient to jamming attacks, and we investigate the impact that PNC has on this resilience, if combined with Massive MIMO. The combination of Massive MIMO and PNC has shown a significant improvement in the bit error rate (BER) in our previous investigation. The corresponding framework is analysed against a barraging attack from a jammer, where the jamming channel is not known to the base station (BS), and the jammer can use any number of transmit antennas. Over Rayleigh channel, our simulation results reveal that Massive MIMO PNC performs better in the lower signal-to-noise ratio (SNR) regions to jamming attacks and this is achieved at twice the spectral efficiency. A similar performance is observed over mmWave channel.
  • Article
    Citation - WoS: 5
    Citation - Scopus: 8
    Coverage Analysis of Physical Layer Network Coding in Massive Mimo Systems
    (Institute of Electrical and Electronics Engineers Inc., 2021) İlgüy, Mert; Özbek, Berna; Mumtaz, Rao; Busari, Sherif A.; Gonzalez, Jonathan
    Wireless networks are prone to interference due to their broadcast nature. In the design of most of the traditional networks, this broadcast nature is perceived as a performance-degrading factor. However, Physical Layer Network Coding (PNC) exploits this broadcast nature by enabling simultaneous transmissions from different sources and thereby enhances the performance of the wireless networks with respect to improvement in spectral efficiency, coverage, latency and security of the system. For fifth generation (5G) networks and beyond, massive multiple input multiple output (MIMO) is considered as a key physical layer technology. Thus, its combination with PNC can significantly enhance the performance of the network, facilitating capacity-coverage improvement, among other benefits. While the bit error rate performance of multiuser massive MIMO-PNC systems through linear detection has been investigated extensively, their coverage probability for a given target signal-to-noise ratio has not been explored yet. In this paper, we derive a closed form expression for coverage probability in PNC based multiuser massive MIMO systems employing zero-forcing equalization. Both theoretical and simulation results are provided for different number of users and antennas in the multiuser massive MIMO-PNC communications systems.
  • Article
    Citation - WoS: 10
    Citation - Scopus: 13
    User Selection for Noma Based Mimo With Physical Layer Network Coding in Internet of Things Applications
    (Institute of Electrical and Electronics Engineers Inc., 2022) Yılmaz, Saadet Simay; Özbek, Berna; İlgüy, Mert; Okyere, Bismark; Musavian, Leila; Gonzalez, Jonathan
    Non-orthogonal multiple access (NOMA) based multiple-input multiple-output (MIMO), which has the potential to provide both massive connectivity and high spectrum efficiency, is considered as one of the efficient techniques for sixth generation (6G) wireless systems. In massive Internet of Things (IoT) networks, user-set selection is crucial for enhancing the overall performance of NOMA based systems when compared with orthogonal multiple access (OMA) techniques. In this paper, we propose a user-set selection algorithm for IoT uplink transmission to improve the sum data rate of the NOMA based MIMO systems. In order to exchange data between the selected IoT pairs, we propose to employ wireless physical layer network coding (PNC) to further improve the spectral efficiency and reduce the delay to fulfill the requirements of future IoT applications. Performance evaluations are provided based on both sum data rate and bit error rate for the proposed NOMA based MIMO with PNC in the considered massive IoT scenarios. IEEE
  • Article
    Citation - WoS: 39
    Citation - Scopus: 43
    Self-Adjusting Fuzzy Logic Based Control of Robot Manipulators in Task Space
    (Institute of Electrical and Electronics Engineers Inc., 2021) Yılmaz, Bayram Melih; Tatlıcıoğlu, Enver; Savran, Aydoğan; Alcı, Musa
    End effector tracking control of robot manipulators subject to dynamical uncertainties is the main objective of this work. Direct task space control that aims minimizing the end effector tracking error directly is preferred. In the open loop error system, the vector that depends on uncertain dynamical terms is modeled via a fuzzy logic network and a self-adjusting adaptive fuzzy logic component is designed as part of the nonlinear proportional derivative based control input torque. The stability of the closed loop system is investigated via Lyapunov based arguments and practical tracking is proven. The viability of the proposed control strategy is shown with experimental results. Extensions to uncertain Jacobian case and kinematically redundant robots are also presented. IEEE
  • Article
    Citation - WoS: 18
    Citation - Scopus: 19
    Generalized Bayesian Model Selection for Speckle on Remote Sensing Images
    (Institute of Electrical and Electronics Engineers Inc., 2019) Karakuş, Oktay; Kuruoğlu, Ercan E.; Altınkaya, Mustafa Aziz
    Synthetic aperture radar (SAR) and ultrasound (US) are two important active imaging techniques for remote sensing, both of which are subject to speckle noise caused by coherent summation of back-scattered waves and subsequent nonlinear envelope transformations. Estimating the characteristics of this multiplicative noise is crucial to develop denoising methods and to improve statistical inference from remote sensing images. In this paper, reversible jump Markov chain Monte Carlo (RJMCMC) algorithm has been used with a wider interpretation and a recently proposed RJMCMC-based Bayesian approach, trans-space RJMCMC, has been utilized. The proposed method provides an automatic model class selection mechanism for remote sensing images of SAR and US where the model class space consists of popular envelope distribution families. The proposed method estimates the correct distribution family, as well as the shape and the scale parameters, avoiding performing an exhaustive search. For the experimental analysis, different SAR images of urban, forest and agricultural scenes, and two different US images of a human heart have been used. Simulation results show the efficiency of the proposed method in finding statistical models for speckle.
  • Article
    Citation - WoS: 16
    Citation - Scopus: 23
    Energy Efficient Resource Allocation for Underlaying Multi-D2d Enabled Multiple-Antennas Communications
    (Institute of Electrical and Electronics Engineers Inc., 2020) Özbek, Berna; Pischella, M.; Le Ruyet, Didier
    Energy efficiency has a significant importance to optimize the wireless communications systems by providing high data rates. In order to develop energy efficient systems, one of the promising methods is to use multiple device-to-device (D2D) underlaying multiple antenna cellular systems. The interference from cellular users to D2D pairs, the interference between D2D pairs and the interference at the base station (BS) caused by D2D pairs occur in these communications systems. In this article, we propose energy efficient resource allocation algorithms for underlaying multi-D2D enabled multiple-antennas communications by employing different multiple antenna processing techniques at the BS. A joint method based on Dinkelbach algorithm and Message Passing Algorithm (MPA) and an approach based on deep learning with multi-layer artificial neural network are proposed to maximize the global energy efficiency (GEE) while satisfying the data rate requirements of both cellular users and D2D pairs. In MPA, the factor graph of the D2D pairs is constructed by taking into account the interference among the D2D pairs and the interference level at the BS to avoid any interruption in the cellular transmission. By relying on the training based on the proposed joint algorithm, a deep neural network approach is presented for off-line implementation. The performance results of the proposed energy efficient resource allocation algorithms show the superiority of multi-D2D communications over conventional single-D2D communications. © 1967-2012 IEEE.
  • Article
    Citation - WoS: 20
    Citation - Scopus: 22
    Key Error Rates in Physical Layer Key Generation: Theoretical Analysis and Measurement-Based Verification
    (Institute of Electrical and Electronics Engineers Inc., 2017) Topal, Ozan Alp; Karabulut Kurt, Güneş; Özbek, Berna
    Channel gains are frequently used to obtain a secret key that can be used for encryption in physical layer security systems. However, the channel gains captured by the nodes may not always be the same due to channel estimation errors. This would result in a non-zero key error rate (KER). In this letter, we obtain theoretical expressions for KER in orthogonal frequency division multiplexing systems. Tight KER approximations are provided based on Gauss-Laguerre quadrature. A measurementbased study is conducted by using software defined radio nodes to demonstrate the validity and the practicality of the provided results.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 9
    Dynamic Shared Spectrum Allocation for Underlaying Device-To Communications
    (Institute of Electrical and Electronics Engineers Inc., 2017) Özbek, Berna; Pischella, Mylene; Le Ruyet, Didier
    This article provides an overview on spectrum sharing in D2D underlaying communications for 5G and beyond 5G applications. Various spectrum sharing algorithms are summarized within a framework of underlaying D2D communications in cellular networks to increase spectrum efficiency. Dynamic spectrum sharing algorithms in the frequency, power, and spatial dimensions are proposed for underlaying D2D communications with both single antenna and multiple antennas at the base station. Performance evaluations show the effectiveness of the proposed algorithms in terms of average data rate per D2D pair.
  • Article
    Citation - WoS: 32
    Citation - Scopus: 41
    Subsectional Tapered Fed Printed Lpda Antenna With a Feeding Point Patch
    (Institute of Electrical and Electronics Engineers Inc., 2016) Bozdağ, Göksenin; Kuştepeli, Alp
    In this letter, a log-periodic dipole array (LPDA) antenna operating between 1.1 and 13.8 GHz with VSWR < 2and an average peak realized gain of 5.2 dB is presented. It is suitable for GPS (L1-L5), PCS, IMT-2000, Bluetooth, WLAN, WiMAX, UWB, and X-band applications. The antenna is designed by introducing a subsectional tapered feedline instead of standard microstrip feeding, which leads to a remarkable lower-frequency performance. The upper-frequency performance of the antenna is improved by adding a feeding point patch. The group delay is also examined for the final design, and maximum 1.5 ns deviation is observed in UWB. By using ordinary and simple dipoles with this modified feedline approach, a superior antenna performance is obtained over a very wide frequency band, and it is validated by the comparison of three fabricated antennas. Additionally, the antenna size is also reduced without using complicated and/or top-loaded dipole structures.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 10
    Performance Analysis of Diffusion-Based Molecular Communications With Memory
    (Institute of Electrical and Electronics Engineers Inc., 2016) Galmes, Sebastia; Atakan, Barış
    In this paper, the comprehensive delay and performance analyses of the $M$-ary molecular communications with memory are presented. By taking into account any level of channel memory, the type-based and concentration-based modulation schemes are introduced and analyzed. In the type-based modulation, information symbols are encoded through different molecule types. In the concentration-based modulation, various concentration levels of one molecule type are used to encode information symbols. For both modulation schemes, the delay distributions of the molecular symbols are derived, and then, the symbol error probabilities are developed. The given distributions and the error probability expressions are validated through extensive simulation experiments. After showing that the derived expressions are valid, the performance of the modulation schemes is evaluated. The performance evaluations reveal that by properly selecting the parameters such as slot time and number of emitted molecules, the performance can be improved in both type and concentration-based molecular communication as the channel memory is increased. Furthermore, it is shown that the type-based molecular communication outperforms the concentration-based molecular communication.