WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

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

Browse

Filters

2004 - 200992010 - 2019142020 - 20212

Settings

Author: search.filters.author.Le Ruyet, DidierLanguage: search.filters.language.en

Search Results

Now showing 1 - 10 of 25
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Deep Learning Based Adaptive Bit Allocation for Heterogeneous Interference Channels
    (Elsevier, 2021) Aycan, Esra; Özbek, Berna; Le Ruyet, Didier
    This paper proposes an adaptive bit allocation scheme by using a fully connected (FC) deep neural network (DNN) considering imperfect channel state information (CSI) for heterogeneous networks. Achieving an accurate CSI has a crucial role on the system performance of the heterogeneous networks. Different quantization techniques have been employed to reduce the feedback overhead. However, the system performance cannot increase linearly with the number of bits increasing exponentially. Since optimizing the total number of bits is too complex for the entire network, an initial step is performed to distribute the bits to each cell in the conventional method. Then, the distributed bits are further allocated to each channel optimally. In order to enable direct allocation for the entire network, a FC-DNN based method is presented in this study. The optimized number of bits can be directly obtained for a different number of bits and scenarios by the proposed approach. The simulations are performed by using various scenarios with different allocation schemes. The performance results show that the DNN based method achieves a closer performance to the conventional approach. (C) 2021 Elsevier B.V. All rights reserved.
  • Book Part
    Citation - WoS: 1
    Resource management techniques for OFDMA
    (Taylor and Francis Ltd., 2010) Le Ruyet, Didier; Özbek, Berna
    [No abstract available]
  • 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.
  • 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
    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
  • Article
    Citation - Scopus: 1
    On Stream Selection for Interference Alignment With Limited Feedback in Heterogeneous Networks
    (John Wiley and Sons Inc., 2016) Aycan, Esra; Özbek, Berna; Le Ruyet, Didier
    This paper presents a stream selection based interference alignment approach with imperfect channel state information for heterogeneous networks. The proposed solution constructs stream sequences by selecting only the strongest stream of each user where the first stream of the constructed stream sequences is associated to a pico user. While selecting the streams, the channel matrices of the unselected streams are projected orthogonally to the virtual transmit and receive channels of the selected stream in order to align the interference in the null space of these virtual channels. In addition, the influence of imperfect channel state information on the proposed algorithm is analysed. A bit allocation scheme is given by deriving an upper bound on the rate loss because of quantisation. The simulation results are carried out by considering various scenarios with different locations of pico cells at the cell edge regions of the macro cell. The performance results show that the proposed algorithm with the imperfect channel state information achieves higher performance than the existing algorithms.
  • Article
    Citation - WoS: 3
    Citation - Scopus: 5
    On stream selection for interference alignment in heterogeneous networks
    (Springer Verlag, 2016) Aycan, Esra; Özbek, Berna; Le Ruyet, Didier
    This paper proposes a stream selection algorithm to deal with the interference and increase the sum capacity in the context of heterogeneous networks where cells of different types coexist. Due to the different transmit powers between the macro and small cells, interference levels are also different. Since the small cells are densely deployed, fully connected interference network between small cells is considered in this paper. The proposed algorithm performs the selection of a stream sequence among a predetermined set of sequences. Those selected sequences are the ones that mostly contribute to the sum rate when performing the exhaustive search. As a consequence, since the search space is reduced, the complexity is significantly decreased. These stream sequences form a regular structure where the first stream is associated to a pico user. Another distinguishing property of the proposed approach is that the stream sequences include at least one stream for each user. When selecting the streams, the channel matrices of the unselected streams are projected orthogonally to the virtual transmit and virtual receive channels of the selected stream in order to align the interference in the null space of these virtual channels. The performance evaluations are carried out by considering different scenarios with different numbers and locations of pico cells. It is shown that the proposed method can significantly reduce the computational complexity while achieving a very close performance to the exhaustive search.