Browsing by Author "Demir, Muhammet Selim."

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    PhD DissertationPublicationMetadata only
    Mobility management and resource allocation strategies for visible light communication networks
    (2021-05-11) Demir, Muhammet Selim.; Uysal, Murat; Uysal, Murat; Uğurdağ, Hasan Fatih; Çöleri, S.; Altunbaş, İ.; Altunbaş, İ.; İlhan, H.; Department of Electrical and Electronics Engineering; Demir, Muhammet Selim.
    There has been a growing interest in Visible Light Communications (VLC) in recent years. The existing works in the literature on point-to-point VLC systems are well established, and especially the studies on physical layer aspects demonstrate the po tential of VLC. However, to transform VLC into a multi-user, multi-cell, scalable, and fully networked wireless technology, significant further efforts for upper layer issues are needed. This dissertation focuses on mobility management and resource allocation techniques for indoor and vehicular VLC systems. In the first part of this thesis, we consider a centralized Direct Current biased Optical Orthogonal Frequency Division Multiplexing (DCO-OFDM) based VLC network and formulate a subcarrier resource allocation problem to maximize the user satisfaction index. We have used the Particle Swarm Optimization (PSO) method for the solution to the resulting problem. The superiority of the proposed algorithm is demonstrated through an extensive simula tion study. In the second part of the thesis, we propose an energy-efficient dynamic resource management framework for indoor OFDM-based VLC networks. Specifi cally, we formulate and investigate a stochastic cross-layer optimization problem to optimize the network resources under the constraints of queue stability and power to maximize the average system throughput. In the last part of the thesis, we pro pose handover algorithms for indoor and outdoor VLC networks. First, we propose a handover algorithm for indoor VLC networks with Coordinated Multipoint (CoMP) transmission and evaluate its performance in physical channel settings based on ray tracing. Then, we present a novel dynamic handover algorithm for outdoor vehicular VLC networks. The proposed algorithm dynamically revises the handover parameters by considering the vehicle speed without requiring additional feedback information.