Print Email Facebook Twitter Pulse-Based Modulation for VLC Systems Title Pulse-Based Modulation for VLC Systems: Using Programmable Systems-on-Chip Author Johannsson, Bjarki (TU Delft Electrical Engineering, Mathematics and Computer Science; TU Delft Software Technology) Contributor Langendoen, K.G. (mentor) Degree granting institution Delft University of Technology Programme Electrical Engineering | Embedded Systems Date 2017-10-18 Abstract The use of Light Emitting Diodes (LED) as a main source of illuminationcan help in significantly reducing global energy conspumtions. The LED iswell suited for modulating visible light, enabling a wireless communicationchannel. A popular topic in Visible Light Communication (VLC) researchis to push data throughput past the LED bandwidth limitation of around4-5 MHz. Less attention has been given to systems using cheaper and slowercomponents.This thesis focuses on effectively utilizing the available bandwidth in lowcost dimmable VLC systems, to allow for increased data throughput, wherethe system bandwidth is limited by the receiver. Non-ickering constantperceived light intensity must furthermore be maintained under variabledimming conditions, to ensure positive user experience.A novel modulation scheme for VLC systems with dimming support is pro-posed. Adaptive Rectified Pulse-Width Modulation (ARPWM) modulatesthe light source with fine-grained pulses within a defined symbol period. Thesymbols are demodulated as light intensity levels. This allows for sendingmultiple bits per symbol in a manner similar to Pulse Amplitude Modula-tion (PAM). Upper and lower boundaries are applied to the duty cycle ofthe pulses according to the desired dimming level, reducing the number oflight compensation symbols needed to maintain a constant perceived lightintensity for the user.ARPWM is compared to existing modulation schemes, and a throughputincrease by a factor of 4.3 was observed compared to state-of-the-art Vari-able On-Off Keying (VOOK). With the testbed used for the experimentswe have demonstrated the use of ARPWM in an indoor office environment,with a maximum communication distance of 4.2 meters in a low-noise en-vironment.ARPWM is shown to offer valuable increase in data troughput at a lowcomplexity level. The relatively high SNR requirements of ARPWM makeit best suitable for short-range indoor VLC. Subject Visible light communicationmodulationprogrammable system on chip To reference this document use: http://resolver.tudelft.nl/uuid:707eade1-b9c6-46ad-a39e-d9c6b223ea17 Part of collection Student theses Document type master thesis Rights © 2017 Bjarki Johannsson Files PDF MSc_Thesis_Johannsson_ES_ ... I_2017.pdf 1.55 MB Close viewer /islandora/object/uuid:707eade1-b9c6-46ad-a39e-d9c6b223ea17/datastream/OBJ/view