Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

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

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Access Right: Open AccessAuthor: search.filters.author.Le Ruyet, Didier

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  • 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
    Citation - WoS: 2
    Citation - Scopus: 3
    Heterojen ağlarda iyileştirilmiş veri katarı seçimi ile girişim hizalama
    (IEEE, 2015) Le Ruyet, Didier; Aycan, Esra; Özbek, Berna
    In this article, interference that occurs in heterogeneous networks is studied and a new stream selection approach with an interference alignment solution is presented. In the proposed algorithm, stream selection starts with the streams that belongs to the pico cell users and continues to select the strongest streams that increase the total sum rate. The power of each stream with the precoding and the postcoding vectors are calculated by performing singular value decomposition (SVD). Virtual channels that belong to the selected stream are calculated by using precoding and postcoding vectors. After the selection procedure, the interferences between the selected stream and the remaining streams are mitigated by orthogonally projecting the channel matrices of the remaining streams to the virtual channels of the selected stream.
  • Conference Object
    Citation - Scopus: 1
    Interference Management for Multiuser Multiantenna Ofdma Underlaying Device-To Communications
    (IEEE, 2017) Özbek, Berna; Pischella, Mylene; Le Ruyet, Didier
    Underlaying device-to-device (D2D) transmission in cellular wireless systems is one of the promising transmission techniques for fifth generation (5G) and beyond 5G applications. Nevertheless, the interference between the D2D pairs, the interference from cellular users to D2D receivers and the interference that affects the cellular communications should be mitigated to increase the overall system performance. In this paper, we propose interference management techniques for D2D underlaying communications in multiuser multiantenna orthogonal frequency division multiple access (OFDMA) systems. Our goal is to increase the data rate of both the cellular users and D2D pairs by performing interference management in frequency, power and spatial dimensions. The performance evaluations illustrate the effectiveness of the proposed algorithm in terms of average data rate and average transmitted power for both cellular users and D2D pairs.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 1
    Interference-Based Clustering for Mimo D2d Underlay Communications
    (IEEE, 2018) Pischella, Mylene; Özbek, Berna; Le Ruyet, Didier
    Clustering of Device-to-Device (D2D) pairs with cellular transmissions is particularly challenging to manage interference in future fifth generation networks. D2D pairs should coexist with cellular users in underlay scenario, taking advantage of frequency and spatial dimensions. We consider a Multiple Input Multiple Output (MIMO) channel where all users (whether cellular or devices) are equipped with N > 1 antennas, and the Base Station (BS) has M >= N antennas. Interference between D2D pairs, between D2D transmitters and the BS and between cellular users and D2D receivers is then managed by determining clusters of D2D pairs and cellular users with very low relative interference levels. Clusters are obtained after graph-coloring on a pairwise interference-leakage based matrix. Then, several Resource Blocks (RB) allocation algorithms are proposed, with various fairness levels. A final orthogonalization step using Minimum Mean Square Error (MMSE) may be added at the BS in order to further reduce interference. Simulation results show very large D2D data rates improvements, while cellular data rates degradation due to interference can be controlled.
  • Conference Object
    Citation - Scopus: 2
    Message-Passing Algorithm for Sum-Rate Maximization in Multi-Antenna Underlay D2d Communications
    (IEEE, 2018) Özbek, Berna; Pischella, Mylene; Le Ruyet, Didier
    In this paper, we propose a resource allocation of device-to-device (D2D) communications underlaying multiantenna cellular systems by employing message-passing algorithm. It is possible to construct the factor graph of the D2D pairs by considering the interference power at the base station and among the D2D pairs. The goal is to avoid interfering the cellular transmission while increasing the sum data rate of D2D pairs. We show that the proposed resource allocation based on message passing algorithm allow us to almost reach the performance of the exhaustive search and outperforms the random allocation. Since the associated factor graph is not fully connected, the complexity of the algorithm is significantly reduced compared to the exhaustive search. © 2018 IEEE.
  • Conference Object
    Performance of Multicast Miso-Ofdm Systems
    (Ecole Nationale Superieure de Techniques Avancees, ENSTA, 2020) Le Ruyet, Didier; Özbek, Berna; Khanfir, Hajer
    In this paper, we evaluate the performance of multicast OFDM systems with single and multiple transmit antennas. We have shown that it is possible to increase the data rate of multicast OFDM systems by selecting the users with good channel for each subcarrier. For the single transmit antenna case, the resource allocation has been applied using the two-step algorithm where subcarrier allocation and bit loading are performed separately. For the multiple transmit antennas case, we have proposed a suboptimal algorithm using a set of precoding vectors. In this study, we present the simulation results of the complete transmission chain where we have associated the resource allocation algorithms with a powerful erasure code. The results show that the proposed algorithms outperform the classical worst case algorithm for both single and multiple transmit antennas. © EW 2007 - 13th European Wireless Conference: Enabling Technologies for Wireless Multimedia Communications. All rights reserved.
  • 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.
  • Other
    Erratum To: on Stream Selection for Interference Alignment in Heterogeneous Networks
    (Springer Verlag, 2016) Aycan, Esra; Özbek, Berna; Le Ruyet, Didier