Browsing by Author "Zvanovec, S."

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Open Access
Coverage of a shopping mall with flexible OLED-based visible light communications
(The Optical Society, 2020-03-30) Chaleshtori, Z. N.; Zvanovec, S.; Ghassemlooy, Z.; Eldeeb, Hossıen Badr; Uysal, Murat; Electrical & Electronics Engineering; UYSAL, Murat; ELDEEB, Hossien Badr Hossien
Visible light communications (VLC) can utilize light-emitting diodes (LEDs) to provide illumination and a safe and low-cost broadcasting network simultaneously. In the past decade, there has been a growing interest in using organic LEDs (OLEDs) for soft lighting and display applications in public places. Organic electronics can be mechanically flexible, thus the potential of curved OLED panels/displays devices. This paper provides unique characteristics of a flexible OLED-based VLC link in a shopping mall. We show that, for curved OLED the radiation pattern displays a symmetry, which is wider than Lambertian. A number of scenarios of VLC system with flexible OLED are analyzed. Numerical models for the delay spread and optical path loss are derived, which followed a 2-term power series model for both empty and furnished rooms. We show that using a full-circular OLED for both empty and furnished rooms offers a uniform distribution of emitted power for the same transmission link spans. The link performance using full and half-circular OLED in an empty room shows that the average optical path losses are lower by 5 and 4 dB, compared with the furnished room.
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A flexible OLED VLC system for an office environment
(IEEE, 2020) Chaleshtori, Z. N.; Zvanovec, S.; Ghassemlooy, Z.; Eldeeb, Hossıen Badr; Uysal, Murat; Electrical & Electronics Engineering; ELDEEB, Hossien Badr Hossien; UYSAL, Murat
The potential use of flexible substrate-based organic light emitting diodes (OLEDs) as curved or rolled lighting sources offers news opportunities for the implementation of visible light communications (VLC) in indoor environments. This paper outlines the use of such a system in a furnished office and investigates the impact of the beam pattern of OLED, which is symmetrical and wider than Lambertian, on the VLC system. We present new results of the VLC system performance in terms of the root-mean-square delay spread and the bit error rate (BER) for the link using both flat and half-circular OLEDs. We demonstrate a data rate of 4 Mb/s using both the curved and flat OLEDs for the transmitter's half-angle within the range of ±90° and ±53°, respectively with a BER below the forward error correction BER limit.
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Practical implementation and performance study of a hard-switched hybrid FSO/RF link under controlled fog environment
(IEEE, 2014) Lee, I. E.; Ghassemlooy, Z.; Ng, W. P.; Gourdel, V.; Khalighi, M. A.; Zvanovec, S.; Uysal, Murat; Electrical & Electronics Engineering; UYSAL, Murat
The availability and performance of terrestrial free-space optical (FSO) communication systems are heavily deterred by the fluctuating conditions of the atmospheric channel, particularly in the presence of visibility-limiting fog effects. In this paper, we examine the viability of deploying hybrid FSO and radio frequency (RF) links through an experimental study, which takes advantage of a dedicated laboratory atmospheric chamber to emulate the fog scenarios encountered on outdoor environment. In particular, a root mean square power detector is developed and introduced in the system under study to monitor the signal quality of the primary FSO link. The quasi-linear output voltage characteristics of the power detector device is utilized as a useful decision metric to implement hard switching in a hybrid FSO/RF link based upon the changes in the visibility. Our measurement results reveal that the selection of a desirable threshold voltage is dependent upon the intended data rate and minimum achievable bit error rate, in order to enable effective switching between the FSO and RF links.
Open Access
Utilization of an oled-based vlc system in office, corridor, and semi-open corridor environments
(MDPI, 2020-12-01) Chaleshtori, Z. N.; Ghassemlooy, Z.; Eldeeb, Hossıen Badr; Uysal, Murat; Zvanovec, S.; Electrical & Electronics Engineering; UYSAL, Murat; ELDEEB, Hossien Badr Hossien
Organic light emitting diodes (OLEDs) have recently received growing interest for their merits as soft light and large panels at a low cost for the use in public places such as airports, shopping centers, offices, and train or bus stations. Moreover, the flexible substrate-based OLEDs provide an attractive feature of having curved or rolled lighting sources for the use in wearable devices and display panels. This technology can be implemented in visible light communications (VLC) for several applications such as visual display, data communications, and indoor localization. This article aims to investigate the use of flexible OLED-based VLC in indoor environments (i.e., office, corridor and semi-open corridor in shopping malls). We derive a two-term power series model to be match with the root-mean-square delay spread and optical path loss (OPL). We show that, for OLED positioned on outer-wall of shops, the channel gain is enhanced in contrast to them being positioned on the inner-wall. Moreover, the channel gain in empty environments is higher compare with the furnished rooms. We show that, the OPL for a 10 m link span are lower by 4.4 and 6.1 dB for the empty and semi-open corridors compared with the furnished rooms, when OLED is positioned on outer-wall of shops. Moreover, the channel gain in the corridor is higher compared with the semi-open corridor. We also show that, in furnished and semi-open corridors the OPL values are 55.6 and 57.2 dB at the center of corridor increasing to 87.6 and 90.7 dB at 20 m, respectively, when OLED is positioned on outer-wall of shops.
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Vehicular visible light communications: The impact of taillight radiation pattern
(IEEE, 2020-09) Eldeeb, Hossıen Badr; Eso, E.; Uysal, Murat; Ghassemlooy, Z.; Zvanovec, S.; Sathian, J.; Electrical & Electronics Engineering; UYSAL, Murat; ELDEEB, Hossien Badr Hossien
We investigate the path-loss of vehicular visible light communications based on the radiation pattern of a commercial car taillight. The measured pattern is incorporated into a ray-tracing model and simulation results indicate up to 4.2 dB variation in the path-loss compared with the Lambertian model.
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Vehicular VLC: A ray tracing study based on measured radiation patterns of commercial taillights
(IEEE, 2021-08-15) Eldeeb, Hossıen Badr; Eso, E.; Jarchlo, E. A.; Zvanovec, S.; Zvanovec, S.; Uysal, Murat; Ghassemlooy, Z.; Sathian, J.; Electrical & Electronics Engineering; ELDEEB, Hossien Badr Hossien; UYSAL, Murat
In this letter, we investigate the performance of vehicular visible light communications based on the radiation patterns of different commercial taillights (TLs) using non-sequential ray tracing simulations. Our simulation results indicate a significant variation in the path loss compared with Lambertian model. Based on the ray tracing results, we propose a new path loss model as a function of the propagation distance considering the asymmetrical radiation pattern of TLs. We use this model to derive the attainable transmission distance. We further present the delay spread for various vehicular communication scenarios to demonstrate the effect of neighboring vehicles.