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- BildiriAçık Erişim2024Experimental Demonstration of an Optic-DAC Based Transmitter Structure
Baser, Oguzhan; Küçük, Mehmet Ali; Albayrak, Cenk; Türk, Kadir
In this paper, an optical-DAC (ODAC) based transmitter design is proposed for indoor visible light communication (VLC) applications. The proposed design is practically realized and the communication performance of the experimental VLC system is investigated. In the ODAC transmitter, multilevel communication signal can be generated optically by independently switching light emitting diode (LED) groups with different powers. In this way, multilevel modulation techniques in VLC systems can be realized through a simple transmitter structure that can be digitally driven. In the proposed transmitter design, unlike the existing ODAC-based VLC transmitters in the literature, metal oxide semiconductor field effect transistors (MOSFET) are used as switching elements in order to drive high-power LED for ambient illumination and communication. In the experimental studies, an offline VLC system using the designed ODAC-based transmitter with a power of approximately 10 W is tested at different switching speeds and distances. The results show that by implementing 8 PAM modulation in the proposed transmitter design, a data transmission rate of 6.264 Mbps is successfully achieved.
- BildiriAçık Erişim2024Reconfigurable Optical Filter Based Receiver Structure For Visible Light Communication
Küçük, Mehmet Ali; Albayrak, Cenk; Türk, Kadir
In this paper, a novel receiver structure is proposed to mitigate the inter-channel interference (ICI) effects that limit the data rate in multi-color visible light communication (MC-VLC) systems. Reconfigurable optical filters (ROFs) are used at the receiver side of MC-VLC systems to enable the separation of color channels. ROFs are optical elements that have the ability to electrically change their transmission spectrum. Utilizing this feature of ROFs, a receiver structure is developed that, unlike traditional receiver structures, can adaptively adjust the transmit spectrum based on channel state information. This adaptive adjustment is aimed at maximizing communication performance by effectively separating color channels in MC-VLC systems. The obtained results demonstrate that the proposed receiver structure achieves higher communication performance compared to traditional receivers.
- BildiriYalnız künye2018Experimental Channel Measurement for Indoor Office Visible Light Communication
Yazgan, Ayhan; Simsek, Cemaleddin; Albayrak, Cenk; Tugcu, Emin; Turk, Kadir; Herencsar, N.
Channel measurement for visible light communication (VLC) is theoretically and experimentally performed in a real office platform. Six armatures composed of phosphor based white LED arrays are fed by designed analog LED drivers. Measurements are taken in a 6m x 7.8m office room which is formed as 10×13 matrix with 60 cm grid distance for both simulation and experiment studies. The link distance between LED arrays and optical receiver is kept minimum 2.5 meters for each measurement. Experimental results are generally in good agreement with simulation results, which are obtained using Barry's theoretical channel model.
- BildiriYalnız künye2018Performance of Visible Light Communication with Colour Shift Keying Modulation and Polar Code
Simsek, Cemaleddin; Tugcu, Emin; Albayrak, Cenk; Yazgan, Ayhan; Turk, Kadir; Herencsar, N.
Visible light communication (VLC) is an emerging technology to fulfill both illumination and communication purposes considered as either an alternative or a support system for some of scenarios carried by RF communication systems. Colour shift keying (CSK) is the modulation given in IEEE 802.15.7 VLC standard which proposes Reed-Solomon as error correction code. Polar code is the first theoretically proven capacity achieving error correction code with low encoding and decoding complexities. Performance of Polar code with belief propagation decoder has not been studied under VLC CSK scheme. In this study we investigate performance of Polar code with belief propagation decoder under VLC CSK scheme and compare it with performance of Reed-Solomon code. Result show that Polar code with belief propagation decoder outperforms Reed-Solomon code by at least 1.5dB.