Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7755

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Author: search.filters.author.Özbek, BernaSubject: search.filters.subject.Wireless networks

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  • Conference Object
    Citation - Scopus: 2
    Resource Allocation for User-Relay Assisted Miso-Ofdma Networks
    (Institute of Electrical and Electronics Engineers Inc., 2015) Baştürk, İlhan; Özbek, Berna
    The next generation cellular networks request higher capacity and coverage that user-relay assisted Orthogonal Frequency Division Multiple Access (OFDMA) networks are costeffective solutions to meet these demands. These networks can be enriched with multiple antennas in order to obtain a diversity gain to combat signal fading and to achieve more capacity gain without increasing the bandwidth or transmit power. However, radio resource management (RRM) such as relay selection and resource allocation (RA) is important in such a multi-user, multirelay and multi-antenna environment to fully take advantage of multiple-input single-output (MISO)-OFDMA based user-relay assisted cellular networks. Thus, we propose a RA algorithm for these networks to reveal the benefits of the combination of userrelaying and multiple antennas technologies and compare the proposed scheme with existing schemes in terms of percentage of satisfied users and cell-edge users' data rate.
  • Master Thesis
    Interference Management Techniques for Femtocell Networks
    (Izmir Institute of Technology, 2015) Bayrak, Uğur; Özbek, Berna
    The need for high capacity and data rate increases with the growing demand for wireless communication. In order to meet this demand, one of the most effective ways of improving capacity and data rate is deployment of femtocell networks which are considered to be a promising technique for future wireless networks. However, mass deployment of these low-power base stations brings many challenges. Interference management will be one of the major challenges for the dense deployment scenarios of femtocells in coverage of the macro base stations. To cope with interference problem, there are many interference management techniques. In this thesis, power control and beamforming techniques are implemented separately and jointly in order to deal with cross-tier downlink interference which occurs between macro base station and users of femtocell. In this two-tier network system involving femtocell and macrocell layers, power control problem, first, is investigated. Feasible transmission power region for femtocell is determined with respect to the user locations so that targeted signal-to-interference-plus-noise-ratio (SINR) values are satisfied. Secondly, beamforming technique is applied using partial zero-forcing method. In this method, beamforming vectors are designed to remove cross-tier interference. It is observed that SINR of macro base station’s user does not undergoes any degradation in the nearfield region of femtocell. Finally, we apply these two techniques jointly. Since both interference suppression and power-efficiency is provided, joint technique seems to be a viable and environment-friendly solution for femtocell networks.