Researcher:
Turan, Buğra

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Buğra

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Turan

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Turan, Buğra

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2016 - 2019192020 - 20228

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Now showing 1 - 10 of 27
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    Physical layer implementation of standard compliant vehicular VLC
    (Institute of Electrical and Electronics Engineers (IEEE), 2016) Narmanloğlu, Ömer; Uysal, Murat; N/A; Department of Electrical and Electronics Engineering; Turan, Buğra; Ergen, Sinem Çöleri; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 7211
    Visible light communication (VLC) has recently gained popularity as a complementary technology to radio frequency (RF) based alternatives for vehicular communications as a low-cost, secure and RF interference free technology. In this paper, we propose IEEE 802.15.7 standard-compliant physical layer (PHY) implementation and experimental evaluation, using commercial off-the-shelf (COTS) automotive light emitting diode (LED) fog light for the purpose of low-latency safety message dissemination. We first show that the standard is applicable to line of sight (LoS) vehicle-to-vehicle (V2V) VLC. We then demonstrate that the proper selection of modulation coding schemes (MCS) plays an important role in order to minimize bit-error-rate (BER) for the reliable transmission with varying inter-vehicle distances. We also addressed the angular limitations of COTS automotive LED light for viable vehicular VLC.
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    Developing trends in power and networking technologies for intelligent cities
    (IGI Global, 2020) Demir, Kadir Alpaslan; N/A; Turan, Buğra; PhD Student; Graduate School of Sciences and Engineering; N/A
    The introduction of Industry 4.0 has increased the focus on a number of technologies. These technologies also help realize the vision for intelligent cities. Furthermore, there are already discussions of Industry 5.0. One emerging aspect of Industry 5.0 is human-robot co-working. With the help of artificial intelligence, the internet of things paradigm, Industry 4.0, and Industry 5.0 visions, there will be two predominant types of systems interfacing with people in intelligent cities. These are robotic and ambient intelligence systems. The increasing deployment of these will help make cities even smarter. However, we need to see advancements in a number of relevant key technologies, including power and networking technologies. In this chapter, first, the authors briefly discuss Industry 4.0, Industry 5.0, and intelligent cities paradigm, as well as robotic and ambient intelligence systems. Then, they focus on developing trends in power and networking technologies.
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    Dimming support for visible light communication in intelligent transportation and traffic system
    (Institute of Electrical and Electronics Engineers (IEEE), 2016) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Uçar, Seyhan; Turan, Buğra; Ergen, Sinem Çöleri; Özkasap, Öznur; Ergen, Mustafa; PhD Student; PhD Student; Faculty Member; Faculty Member; Faculty Member; Department of Computer Engineering; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; College of Engineering; N/A; N/A; 7211; 113507; N/A
    The automotive industry is under a major change and new vehicles are being enriched by the recent advances in communication. Not only business plans are changing due to connected and urbanized lifestyle, but also transportation is becoming more intelligent with smart roads that connect smart cars. Technology coined as the vehicular ad-hoc network (VANET) is harmonizing with Intelligent Transportation System (ITS) and Intelligent Traffic System (ITF). However, ITS and ITF systems suffer from the scarcity of radio frequency spectrum. Visible light communication (VLC) that uses modulated optical radiation in the visible light spectrum is an alternative medium being researched. To date, the majority of research on vehicular VLC was aimed at achieving high data rates provided that high lighting quality is achieved without any concern on dimmable LED lights. Auto-dimmable headlights gain attention due to danger caused by sudden glare on drivers at night conditions which makes dimming in VLC necessary. In this paper, we first present the latest concept of vehicular VLC on ITS and ITF systems and address dimming utility. We then demonstrate experimentally that dimming is a key parameter in VLC which affects data dissemination and received power signal strength.
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    Cooperative MIMO-OFDM based inter-vehicular visible light communication using brake lights
    (Elsevier, 2018) Narmanlıoğlu, Omer; T; Uysal, Murat; N/A; Department of Electrical and Electronics Engineering; Turan, Buğra; Ergen, Sinem Çöleri; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 7211
    Inter-vehicular connectivity to enhance road safety and support highly autonomous driving is increasingly becoming popular. Despite the prevalent works on radio-frequency (RF) based vehicular communication schemes, visible light communication (VLC) is considered to be a promising candidate for vehicular communications due to its low complexity and RF interference-free nature. Deployment of multiple light emitting diodes (LEDs) enables multiple-input multiple-output (MIMO) transmission in the context of vehicular VLC. This paper investigates applicability of both point-to-point (direct) vehicular VLC and decode-and-forward relaying based cooperative vehicular VLC including relay terminals between source and destination terminals to enhance road safety based on real world measurements. We consider direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) based MIMO transmission scheme and evaluate the performances of different MIMO modes including repetition code (RC) and spatial multiplexing (SM), different modulation orders with different transmitter receiver selection mechanisms to support line-of-sight (LoS) and beyond LoS multi-hop vehicular VLC. The results reveal that the selection of the closest transmitters to the receivers provides better performance due to high signal-to-noise-ratio requirements for RC mode whereas SM suffers from channel correlation. Usage of all possible transmitters does not always yield better performance due to the power division at the transmitter side. on the other hand, the performance of RC shows more degradation on higher-order modulations that are required to yield the same throughput with SM. Therefore, considering the higher order modulation requirement for RC based VLC, SM is concluded to be a favorable MIMO scheme for cooperative vehicular VLC. We further demonstrate the benefits of multi-hop transmission over direct transmission with respect to different number of relay vehicles as a consequence of varying inter-vehicular distances between source and destination vehicles.
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    EEE 802.15.13-compliant visible light communications in vehicular networks
    (Taylor and Francis, 2018) Narmanloğlu, Ömer; Uysal, Murat; N/A; Department of Electrical and Electronics Engineering; Turan, Buğra; Ergen, Sinem Çöleri; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 7211
    Current research activities and standardization efforts in intelligent transportation systems (ITS) have mainly focused around the deployment of radio frequency (RF)-based communication techniques for vehicular networking. Considering the wide deployment of light emitting diodes (LEDs) both in automotive lighting and roadside infrastructure, visible light communication (VLC) has emerged as a potential complementary technology for both vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. VLC is based on the principle of modulating LEDs at very high frequencies that are not noticeable by the human eye. Recognizing the economic potential of VLC technology, the IEEE 802.15.13 Task Group has been preparing a new standard on VLC. In this chapter, we explore the potential usage of the IEEE 802.15.13 standard for vehicular networks and evaluate its performance for V2V communications through Monte Carlo simulations under the consideration of channel model obtained by experimental results.
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    Broadcasting brake lights with MIMO-OFDM based vehicular VLC
    (IEEE Computer Society, 2016) Narmanloğlu, Ömer; Uysal, Murat; N/A; Department of Electrical and Electronics Engineering; Turan, Buğra; Ergen, Sinem Çöleri; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 7211
    Inter-vehicular connectivity to enhance road safety and enable highly autonomous driving is increasingly becoming popular. Despite the prevalent works on radio-frequency (RF) based vehicular communication schemes, visible light communication (VLC) is considered to be a promising candidate for vehicular communications due to its low complexity and RF interference-free nature. This paper investigates applicability of VLC to enhance road safety based on real world measurements. Deployment of multiple light emitting diodes (LEDs) enables multiple-input multiple-output (MIMO) transmission in the context of vehicular VLC. We consider direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) based MIMO transmission scheme and evaluate the performances of different MIMO modes including repetition code (RC) and spatial multiplexing (SM), different modulation orders and different transmitter-receiver selection. The results reveal that selection of the closest transmitters to the receivers, provide better performance due to high signal-to-noise-ratio (SNR) requirements for RC mode. However, usage of all possible transmitters does not always yield better performance due to power division at the transmitter side. Moreover, SM suffers from channel correlation whereas the performance of RC shows more degradation on higher-order modulations that are required to yield the same throughput with SM.
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    Neural network based digital pre-distorter design for DCO-OFDM visible light communications
    (Institute of Electrical and Electronics Engineers Inc., 2022) Narmanlıoğlu, Ömer; Uysal, Murat; Department of Electrical and Electronics Engineering; N/A; Ergen, Sinem Çöleri; Turan, Buğra; Faculty Member; PhD Student; Department of Electrical and Electronics Engineering; College of Engineering; Graduate School of Sciences and Engineering; 7211; N/A
    Direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) is an appealing modulation scheme for reliable, high-speed optical transmissions and foreseen to be used in the upcoming IEEE 802.11bb visible light communication (VLC) standard. However, non-linear characteristics of light emitting diodes (LEDs) as VLC transmitters degrade the bit error rate (BER) performance of DCO-OFDM due to its high peak-to-average-power ratio. In this paper, we propose neural network based digital pre-distorter (DPD) to mitigate non-linear LED response for DCO-OFDM transmission. The proposed scheme extends the reliable transmission range by 1.75 m and 1.8 cm for non-compensated LED response and Memory Polynomial based DPD, respectively.
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    On the performance of MIMO OFDM-based intra-vehicular VLC networks
    (Institute of Electrical and Electronics Engineers (IEEE), 2016) Narmanloğlu, Ömer; Uysal, Murat; N/A; Department of Electrical and Electronics Engineering; Turan, Buğra; Ergen, Sinem Çöleri; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 7211
    Vehicular hotspots for on-board Internet access using Long Term Evolution (LTE) as the backhaul network has recently gained popularity. Currently, Wi-Fi is the most common technology to provide in-vehicle access, where data has been relayed through on board LTE receiver. Despite its wide acceptance, coexistence and contention based data rate limitations with Wi-Fi necessitates alternatives for in-vehicle data access schemes. This paper investigates the performance of hybrid LTE and visible light communication (VLC) networks using LTE as the backhaul and VLC as the on-board access network.Under the consideration of vehicle interior unique channel characteristics and light emitting diode (LED) deployment flexibility, best transmitter configuration using repetition coding (RC) and spatial multiplexing (SM) multiple input multiple output (MIMO)modes is determined. Proposed configurations based on direct current biased optical orthogonal frequency-division multiplexing(DCO-OFDM) are compared with respect to their bit-error-rate (BER) performances. Furthermore, the performance of intravehicular VLC networks for single and multi-user scenarios is investigated.
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    Poster: vehicular VLC experimental modulation performance comparison
    (Ieee, 2018) Department of Electrical and Electronics Engineering; N/A; N/A; Department of Electrical and Electronics Engineering; Gürbilek, Gökhan; Koca, Mertkan; Turan, Buğra; Ergen, Sinem Çöleri; Researcher; Master Student; PhD Student; Faculty Member; Department of Electrical and Electronics Engineering; College of Sciences; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; N/A; 7211
    Vehicular visible light communication (V2LC) has recently gained popularity as a complementary technology to radio frequency (RF) based vehicular communication schemes due to light emitting diode (LED) s' readily availability on vehicles with its secure and RF-interference free nature. However, vehicular visible light communication (V2LC) system performance mainly depends on LED characteristics. Investigating various LED bulbs for their frequency response and optical OFDM (O-OFDM) based modulation performances, it has been observed that LED and DC-bias voltage selection is key for the V2LC system modulation performance. Experimental results indicate that, on contrary to simulation results in the literature, asymmetrically clipped optical OFDM (ACO-OFDM) is observed to perform better than unipolar OFDM (U-OFDM) as it inherits lower peak-to-average power ratio (PAPR) with lower clipping noise which is crucial for LEDs under consideration with limited linear working region.
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    Dual channel visible light communications for enhanced vehicular connectivity
    (IEEE Computer Society, 2016) N/A; N/A; Department of Electrical and Electronics Engineering; Department of Computer Engineering; Turan, Buğra; Uçar, Seyhan; Ergen, Sinem Çöleri; Özkasap, Öznur; PhD Student; PhD Student; Faculty Member; Faculty Member; Department of Electrical and Electronics Engineering; Department of Computer Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; College of Engineering; N/A; N/A; 7211; 113507
    Visible Light Communication (VLC) has recently been proposed as a low-cost and low-complexity technology for vehicular communications. In this paper, we propose the usage of dual channel VLC with the goal of providing enhanced vehicular connectivity to disseminate safety-critical messages and perform an experimental study to determine the spatial and angular limits of an off-the-shelf automotive Light Emitting Diode (LED) fog light. Single channel VLC refers to the independent transmission of different data packets from each LED fog light, while the dual channel VLC offers the concurrent transmission of the same data packet from both lights. There is a trade-off between increasing the angular limitation and the performance of dual channel VLC, which needs to be experimentally evaluated to identify its efficient usage. We first show the dependency of the received optical power of single channel VLC on the angle and distance, and demonstrate that Lambertian model does not represent the automotive LED fog light radiation pattern accurately. We then demonstrate that dual channel usage increases the angular limitation by up to 10° compared to the single channel VLC. We also show that dual channel improves the packet delivery error rate performance at only short distances due to the photodiode (PD) saturation led by light intensity overlapping at higher distances.