WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7150

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Author: search.filters.author.Le Ruyet, DidierPublisher: search.filters.publisher.Institute of Electrical and Electronics Engineers Inc.

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Now showing 1 - 10 of 18
  • Conference Object
    Citation - Scopus: 2
    Genetik Algoritma ile Çok Kullanıcı Dfbç Sistemleri için Toplam Veri Hızı Enbüyüklemeli Uyarlanır Alttaşıyıcı ve Bit Yerleşimi
    (Institute of Electrical and Electronics Engineers Inc., 2008) Özbek, Berna; Le Ruyet, Didier
    In this work, we perform the adaptive subcarrier and bit allocation to maximize the sum data rate for multiuser OFDM systems using genetic algorithm. Since the convergence time of the genetic algorithm could be slow, we propose to use a different initial condition to accelerate it without increasing the complexity of genetic algorithm and sacrificing the performance of the system. We obtain the simulation results and compare them with the classical methods. We show that the genetic algorithm with proposed initial condition gives better performances than the classical ones for sum data rate maximized allocation.
  • Conference Object
    Transmit Beamforming Techniques for Multicast Wireless Communication Systems
    (Institute of Electrical and Electronics Engineers Inc., 2009) Özbek, Berna; Le Ruyet, Didier
    In this paperg transmit beamforming algorithm is designed for multicast wireless communication providing only one beam and multiple beams. The reduced complexity algorithms are imyproved the system performance with multiple transmit beamy forming techniques.
  • 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: 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.
  • Conference Object
    Heterojen Ağlarda Veri Katarı Seçimi Tabanlı Girişim Hizalama için Uyarlamalı Sınırlı Geri Besleme Yöntemi
    (Institute of Electrical and Electronics Engineers Inc., 2016) Aycan, Esra; Özbek, Berna; Le Ruyet, Didier
    Bu bildiride, sınırlı geri beslemeli heterojen ağlar için veri katarı seçimi tabanlı bir girişim hizalama yöntemi sunulmuştur. Sunulan veri katarı seçimi yöntemi, veri katarlarını ilk olarak piko kullanıcılarından seçmeye başlar, daha sonra veri hızını artıran en güçlü veri katarı ile seçim işlemi devam eder ve tüm kullanıcıların en az bir veri katarının olması sağlanır. Seçim işleminden sonra, seçilen veri katarı ile diğerleri arasında oluşan girişimler ortogonal projeksiyonlarla önlenir. Sınırlı geri beslemeli kanalda toplam kapasite, uyarlanır bit paylaşımıyla iyileştirilmektedir.
  • Conference Object
    Citation - Scopus: 3
    Improved Successive Stream Selection With Quantized Channel in Heterogeneous Networks
    (Institute of Electrical and Electronics Engineers Inc., 2015) Aycan, Esra; Özbek, Berna; Le Ruyet, Didier
    This paper focuses on different distortion metrics in order to analyze the influence of the imperfect channel state information (CSI) on the improved successive stream selection algorithm that manages the interference in a heterogeneous network. The presented approach initially selects the streams from the user of the pico cell, continuing with the strongest streams among the remaining streams that increase the sum rate and satisfy the constraint that at least one stream is selected from each user. In order to reduce the interference, the channel matrices of the remaining streams are projected orthogonally to the virtual transmit and receive channels of the selected stream. The impact of the quantization distortion on the precoding and postcoding design is examined. The performance of two distortion metrics which are the Chordal distance and the Euclidean distance are compared for different number of quantization bits. The performance evaluations are obtained by considering different locations of small cells with respect to the macro cell.
  • Conference Object
    Citation - Scopus: 2
    Sum Capacity Maximization in Distributed Multicell Miso-Ofdma Systems With Reduced Feedback Links
    (Institute of Electrical and Electronics Engineers Inc., 2014) Özbek, Berna; Le Ruyet, Didier; Pischella, Mylene
    In this paper, we examine distributed and fair resource allocation for weighted sum multicell capacity maximization in multi-input single-output (MISO)-Orthogonal Frequency-Division Multiple Access (OFDMA) multicell systems with reduced feedback links. We apply zero forcing (ZF) precoding to reduce interference between the users in the same cell and then propose iterative distributed power allocation algorithm for the users with high signal-to-interference-plus-noise ratio (SINR) to reduce the interference between BSs. In order to perform distributed RA for MISO-OFDMA multicell systems, the channel state information (CSI) of all required links are fed back to all base stations. However, the feedback load increases with the number of users, base stations, subcarriers and antennas. Therefore, we propose a user selection algorithm at the receiver side to reduce the feedback load while providing CSI of the users with high SINR at the BSs. The performance results of the proposed algorithms are illustrated for multicell MISO-OFDMA systems in wireless channels. © 2014 IEEE.
  • Conference Object
    Citation - WoS: 5
    Citation - Scopus: 3
    Hierarchical Successive Stream Selection for Heterogeneous Network Interference
    (Institute of Electrical and Electronics Engineers Inc., 2014) Aycan, Esra; Özbek, Berna; Le Ruyet, Didier
    This paper presents a hierarchical stream selection approach to deal with the interference in a heterogeneous network where different cell types are coexisting with each other to increase the sum capacity. Due to the variety of the transmit powers between the macro and small cells, interference levels are different. The proposed solution hierarchically selects the strongest streams of each cell with a contribution to the sum rate, while constructing the streams via singular value decomposition (SVD). In order to reduce the interference, the channel matrices of the remaining streams are projected orthogonally to the virtual transmit channel and virtual receive channel of the selected stream. The performance evaluations are obtained by considering different locations of small cells with respect to the macro cell. It is shown that the proposed method can dynamically select more streams in heterogeneous networks and achieve higher data rates compared to the existing algorithms. © 2014 IEEE.
  • Conference Object
    Citation - WoS: 5
    Citation - Scopus: 5
    On Precoding Mimo-Fbmc With Imperfect Channel State Information at the Transmitter
    (Institute of Electrical and Electronics Engineers Inc., 2014) Le Ruyet, Didier; Zakaria, Rostom; Özbek, Berna
    This paper studies the impact of imperfect channel state information (CSI) due to limited feedback link on the performance of multi-user MIMO system using filter bank based multicarrier (FBMC) modulation. The system is composed of a transmitter performing Zero Forcing (ZF) precoding and single antenna receivers applying decoding techniques. Simulation-based results show that except when the number of users is less than the number of transmit antennas, the BER performance and capacity of FBMC and OFDM modulation are the same. These results are theoretically justified due to the distribution of the interfering terms. As in OFDM, depending on the number of interferers, for a given BER performance target, the required number of feedback bits per channel vector can be rather high. FBMC becomes attractive not only because it relaxes the synchronization with respect to OFDM, but also because it achieves the same performance results as OFDM for multiuser MIMO precoding even in the case of imperfect CSI at the transmitter. © 2014 IEEE.
  • Conference Object
    Citation - Scopus: 2
    Adaptive Bit Partitioning Strategy for Cell-Edge Users in Multi-Antenna Multicell Networks
    (Institute of Electrical and Electronics Engineers Inc., 2011) Özbek, Berna; Le Ruyet, Didier
    In this paper, we improve the performance of cell-edge users by applying adaptive bit partitioning for intercell interference cancelation in cooperative downlink multicell systems. The strategy for partitioning quantization bits between serving and interfering base stations affects the performance of the cooperative networks which is quite sensitive to the quality of the channel state information. The existing transmission strategies are based on the maximization of average cell rate which results in a reduced rate for the users in the cell-edge regions. We propose an adaptive bit partitioning strategy to improve the rate of cell-edge users at the same average feedback link rate. We show the performance of the cell-edge users is significantly increased while keeping the same average cell rate. © 2011 IEEE.