Yazar "Serpedin, Erchin" seçeneğine göre listele

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    The advances of fronthaul and backhaul communication for 5G and beyond
    (Elsevier B.V., 2019) Serpedin, Erchin; Ekti, Ali Rıza; Boyacı, Ali; Imran M.A.; Aydın, Muhammed Ali; Yarkan, Serkan
    [Abstract Not Available]
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    Analysis of mobility impact on interference in cognitive radio networks
    (Elsevier B.V., 2013) Ekti, Ali Rıza; Yarkan, Serkan; Qaraqe, Khalid A.; Serpedin, Erchin; Dobre, O.A.
    Cognitive radio (CR) technology seems to be a promising candidate for solving the radio frequency (RF) spectrum occupancy problem. CRs strive to utilize the white holes in the RF spectrum in an opportunistic manner. Because interference is an inherent and a very critical design parameter for all sorts of wireless communication systems, many of the recently emerging wireless technologies prefer smaller size coverage with reduced transmit power in order to decrease interference. Prominent examples of short-range communication systems trying to achieve low interference power levels are CR relays in CR networks and femtocells in next generation wireless networks (NGWNs). It is clear that a comprehensive interference model including mobility is essential especially in elaborating the performance of such short-range communication scenarios. Therefore, in this study, a physical layer interference model in a mobile radio communication environment is investigated by taking into account all of the basic propagation mechanisms such as large- and small-scale fading under a generic single primary user (PU) and single secondary user (SU) scenario. Both one-dimensional (1D) and two-dimensional (2D) random walk models are incorporated into the physical layer signal model. The analysis and corresponding numerical results are given along with the relevant discussions. © 2012 Elsevier B.V.
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    Effects of mobility on uplink interference for short-range cognitive radio networks
    (2012) Ekti, Ali Rıza; Yarkan, Serkan; Qaraqe, Khalid A.; Serpedin, Erchin
    Cognitive radio (CR) has attracted significant attention due to expected radio frequency (RF) spectrum scarcity with ever-increasing demands. CR networks, which strive to utilize opportunistically the RF spectrum, require new ways of looking at interference in wireless networks. Since a decrease in transmit power translates into an increase in energy efficiency and a decrease in RF interference, communication ranges have been shrinking dramatically in recently emerging wireless technologies. Prominent examples of decrease-in-transmit-power strategies are CR relays in CR networks and femtocells in next generation wireless networks (NGWNs). Therefore, the impact of mobility especially with respect to relatively small displacements needs to be investigated. In this study, a comprehensive interference model is considered and examined by taking into account all of the basic propagation mechanisms such as large- and small-scale fading under a generic single secondary user (SU) and single primary user (PU) scenario. The analysis and corresponding numerical results are given and discussed. © 2012 IEEE.
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    Hybrid RF-VLC Communication System: Performance Analysis and Deep Learning Detection in the Presence of Blockages
    (Institute of Electrical and Electronics Engineers Inc., 2024) Shaik, Parvez; Keçeci, Cihat; Garg, Kamal K.; Boyacı, Ali; Ismail, Muhammad; Serpedin, Erchin
    This paper analyzes the performance of a dual-hop hybrid radio frequency - visible light communications (VLCs) system. VLC exploits high frequencies for signal propagation for short-range and is highly susceptible to blockages. Hence, in this work, the sensitivity of the VLC toward the blockages is explored. This study examines outdoor-indoor communication for an urban scenario featuring an office environment. The VLC system is designed by considering multiple VLC access points serving the end users in the presence of human blockages. Selection combining is employed to select the access point which offers the maximum instantaneous signal-to-noise ratio at the user. To capture the outdoor scenario, path loss modeling is conducted to account for signal attenuation from outdoor to indoor spaces. The outdoor scenario is modeled using Nakagami-m fading channels while VLC is employed for the indoor scenario. System performance is assessed in closed-form expression for outage probability and the symbol error rate for binary phase shift keying and quadrature amplitude modulation. A deep learning-based approach detects the symbols by tracking dynamic changes in the channel. Simulation results corroborate the correctness of derived analytical expressions and reveal that blockages significantly impact both single and multiple LED based communication channels.
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    Performance of Deep Learning Assisted Visible Light Communications Impaired by Blockages
    (IEEE, 2023) Shaik, Parvez; Keçeci, Cihat; Garg, Kamal K.; Boyacı, Ali; Ismail, Muhammad; Serpedin, Erchin
    This study investigates the performance of visible light communications (VLCs) in the presence of blockages. An indoor office scenario with a single VLC access point serving the user nodes in the presence of human blockages is examined. System performance is assessed through closed-form expressions for outage probability and symbol error rate for binary phase shift keying and quadrature amplitude modulation. A deep neural network for symbol detection is deployed at the receiver. Performance metrics illustrate that the blockages cause significant impact on signal detection. Computer simulations corroborate the correctness of the obtained analytical expressions.