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Konu: Visible light communication × WoS Q: N/A ×

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Listeleniyor 1 - 4 / 4
  • Küçük Resim
    Yayın
    Comparative performance evaluation of VLC, LTE and WLAN technologies in indoor environments
    (IEEE, 2021-05-24) Zeshan, Arooba; Karbalayghareh, Mehdi; Miramirkhani, Farshad; Uysal, Murat; Baykaş, Tunçer
    Recent years have seen an exponential rise in the demand for indoor wireless connections that have driven future generation networks to aim for higher data rates with extended coverage and affordable rates. The two most prominent technologies for providing indoor wireless connections, WLAN and LTE, have their limitations and they can not coexist in a single band to form heterogeneous networks (HetNets). Visible light communication (VLC) has seen rapid growth in recent years as it has the capability to seamlessly merge with the existing technologies and provide wireless connections with high data rates. VLC based hybrid indoor network effectively combines the preferences of an end-user with the practicality of implementation. In this work, we investigate specific VLC/WLAN and VLC/LTE hybrid scenarios to perform a detailed analysis on the effect of user mobility on the performance of the system and how the performance of the network (in terms of throughput) can be maximized. The study aims to show how different technologies complement each other in the best and even the worst-case scenarios.
  • Küçük Resim
    Yayın
    A path loss model for link budget analysis of indoor visible light communications
    (Istanbul Univ-Cerrahpasa, 2021-05) Miramirkhani, Farshad
    In the context of beyond 5G indoor communication systems, visible light communications (VLC) has emerged as a viable supplement for existing radio frequency based systems and as an enabler for high data rate communications. However, the existing indoor VLC systems are limited by detrimental outages caused by fluctuations in the VLC channel gain because of user mobility. In this study, we proposed a tractable path loss model for indoor VLC that reflects the effect of room size and coating material of surfaces. We performed an extensive advanced ray tracing simulation to obtain the channel impulse responses within a room and presented a path loss model as a function of distance, room size, and coating material through curve fitting. In addition, path loss parameters such as the path loss exponent and the standard deviation of the shadowing component were determined. The simulation results indicate that path loss is a linear function of distance, path loss exponent is a function of room size and coating material, and shadowing follows a log normal distribution.
  • Küçük Resim
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    Visible light communication with solar cell receiver for indoor IoT applications
    (Institute of Electrical and Electronics Engineers Inc., 2024) Bonakdar, Roozbeh; Edemen, Çağatay; Akbulut, Muhammed Emin; Keskin, Onur; Kaya, Onur; Uysal, Murat
    The rapid increase of Internet of Things (IoT) devices has ushered in a new era of connectivity, with an increasing reliance on efficient communication models. In this context, Optical Wireless Communications (OWC) presents a promising avenue for transmitting data at the speed of light, utilizing the optical spectrum to alleviate congestion in urban environments. Leveraging Light Emitting Diodes (LEDs) as transmitters and solar cells as receivers, this paper explores the feasibility of indoor OWC systems. Moreover, we present an experimental setup focusing on bandwidth measurement, data transmission, and energy harvesting. Our results indicate a maximum data rate of 19.2 Kbps using On-Off Keying (OOK) modulation at a 15 cm link distance. Notably, by avoiding the utilization of external circuitry for performance enhancement of the solar cell, we tried to maintain the system's suitability for IoT applications. Our findings contribute to understanding solar cell-based data reception from LEDs, offering simulation results for practical implementation and performance considerations for indoor IoT communication systems.
  • Küçük Resim
    Yayın
    IEEE 802.11BB reference channel models for light communications
    (IEEE, 2023-12-01) Miramirkhani, Farshad; Baykaş, Tunçer; Elamassie, Mohammed; Uysal, Murat
    Increasing industrial attention to visible light communications (VLC) technology led the IEEE 802.11 to establish the task group 802.11bb 'Light Communications' (LC) for the development of a VLC standard. As a part of the standard development process, the development of realistic channel models according to possible use cases is of critical importance for physical layer system design. This article presents the reference channel models for the mandatory usage models adopted by IEEE 802.11bb for the evaluation of system proposals. The use cases include industrial, medical, enterprise, and residential scenarios. Channel impulse responses and corresponding frequency responses are obtained for each use case using a ray tracing approach based on realistic specifications for transmitters and receivers, and optical characterization of the environment.