Browsing by Author "Hocaoglu, Kemal"

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Citation - WoS: 15
Citation - Scopus: 21
Characterization of Line-of-Sight Link Availability in Indoor Visible Light Communication Networks Based on the Behavior of Human Users
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2020) Volkan Rodoplu; Kemal Hocaoglu; Anil Adar; Rifat Orhan Cikmazel; Alper Saylam; Adar, Anil; Saylam, Alper; Cikmazel, Rifat Orhan; Rodoplu, Volkan; Hocaoglu, Kemal
We characterize the line-of-sight (LOS) link availability in indoor visible light communication (VLC) networks based on the behavior of human users. The VLC link availability is impacted by humans in three distinct ways: (1) Users turn the lights on or off in each room. (2) Users may carry mobile devices. (3) Users constitute mobile obstacles that block or shadow the channel between the transmitter and the receiver. First we develop a mathematical framework for VLC link availability and a probabilistic model of the VLC network with respect to human behavior in indoor environments. Second we design a realistic multi-user indoor VLC system simulation with static and mobile VLC devices that are expected to be found in smart home environments. We present the following four sets of results: (1) We report statistics on the blockage durations of VLC links and categorize the links with respect to these statistics. (2) We demonstrate the performance of Selection Diversity versus Maximal Ratio Combining for mobile VLC devices carried by humans in a smart home setting. (3) We show that optimal LED resource allocation policies for multiple users are impacted by the VLC link blockage events caused by humans. (4) We demonstrate that the link blockage events in different rooms become dependent due to humans who transition between rooms. Based on our results we provide new directions for the design of network architectures for indoor VLC systems.
Citation - WoS: 1
Citation - Scopus: 3
Design of a Low-Cost Visible Light Communication (VLC) System for Music and Video Streaming
(Institute of Electrical and Electronics Engineers Inc., 2019) Kemal Hocaoglu; Anil Adar; Yigit Ahmet Arıkök; Volkan Rodoplu; Adar, Anil; Hocaoglu, Kemal; Rodoplu, Volkan; Arikok, Yigit Ahmet
In this paper we describe our design of an end-to-end Visible Light Communication (VLC) system prototype that is able to stream music and video. Our system is able to transmit and receive video and audio signals and is capable of communicating at a data rate of 7.14 Mbps at a distance of 6.7 cm at a much lower cost for the transmitter and the receiver circuitry compared with existing VLC designs. The channel attenuation and SNR tests that we have conducted on our design demonstrate the VLC channel characteristics. In order to assess the design for deployment in more realistic settings we also compute the transmit power that will be required if our prototype system were scaled to transmit over the dimensions of a room and show that the required transmit power is reasonable. Furthermore our audio and video fidelity tests quantify the user experience via the Mean Opinion Score (MOS) metric. Finally alternative transmitter and receiver designs are discussed as possible improvements for future work. This prototype constitutes a first step towards wide-scale deployment of VLC technology for downlink video transmission in indoor spaces in the smart cities of the near future. © 2020 Elsevier B.V. All rights reserved.