Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

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

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Author: search.filters.author.Le Ruyet, DidierSubject: search.filters.subject.OFDMA systems

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  • Conference Object
    Citation - Scopus: 3
    Reduced Feedback Designs for Sdma-Ofdma Systems
    (Institute of Electrical and Electronics Engineers Inc., 2009) Özbek, Berna; Le Ruyet, Didier
    In SDMA-OFDMA wireless communication systems, the feedback load increases with the number of users, subcarriers and antennas in the cell. In this paper, we propose two efficient reduced feedback algorithms by selecting the clusters at the user side. For each cluster, we select the users according to their norm and their orthogonality. We evaluate the performance of the user selection algorithms considering the quantization effect. We also design a specific codebook design to quantize CSI for the proposed criterion.
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 3
    Adaptive Resource Allocation for Sdma-Ofdma Systems With Genetic Algorithm
    (Institute of Electrical and Electronics Engineers Inc., 2009) Özbek, Berna; Le Ruyet, Didier
    In this paper, we propose an adaptive resource allocation algorithm to maximize the sum data rate for spatial division multiplexing access (SDMA) orthogonal division multiple access (OFDMA) systems using genetic algorithm. We perform Zero forcing (ZF) beamforming at the transmitter constructing single and multiple beams for OFDMA systems with multiple transmit antennas. In order to reduce the complexity and convergence time of genetic algorithm (GA), we present an initial condition obtained by allocating the user to the subcarrier with maximum precoding gain. The proposed algorithm reduces the complexity without sacrificing the performance. We obtain the simulation results and compare them with the classical static and adaptive allocation methods. We show that the GA with the proposed initial condition increases the sum data rate compared to classical GA and reduces the convergence time significantly for SDMA-OFDMA systems.