WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection

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

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Language: search.filters.language.enSubject: search.filters.subject.Communication systems

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  • Conference Object
    Semi-Orthogonal User Selection for Miso Systems With Quantized Feedback
    (Institute of Electrical and Electronics Engineers Inc., 2008) Khanfir, Hajer; Özbek, Berna; Khanfir, Hajer; 03.05. Department of Electrical and Electronics Engineering; 01. Izmir Institute of Technology; 03. Faculty of Engineering
    For MISO multi-user downlink wireless communication system with precoding at the transmission, the channel state information at the transmitter can provide tremendous capacity gains. However, the amount of feedback data increases with the number of users in the cell and the number of transmit antennas. In this paper, we study on different algorithms and criteria in order to significantly reduce the amount of feedback data. We associate the classical norm criterion with a criterion based on the orthogonality between the user channels. Without cooperation between the users, we only allow users that are semi-orthogonal to feedback their channel information (CQI and CDI) to the base station. The feedback CDI is quantized using a local grassmanian packing. We show that the proposed combined criterion with a finite feedback rate gives better performance compared to the norm criterion. Furthermore we show that the performance is not affected by CQI quantization.
  • Conference Object
    Citation - WoS: 6
    Citation - Scopus: 6
    A Merging Clustering Algorithm for Mobile Ad Hoc Networks
    (Springer Verlag, 2006) Dağdeviren, Orhan; Erciyeş, Kayhan; Erciyeş, Kayhan; Çokuslu, Deniz; Dağdeviren, Orhan; 03.04. Department of Computer Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    Clustering is a widely used approach to ease implementation of various problems such as routing and resource management in mobile ad hoc networks (MANET)s. We propose a new fully distributed algorithm for clustering in MANETs that merges clusters to form higher level clusters by increasing their levels. We show the operation of the algorithm and analyze its time and message complexities and provide results in the simulation environment of ns2. Our results conform that the algorithm proposed is scalable and has a lower time and message complexities than the other algorithms