Performance of dimming control scheme in visible light communication system

Abstract Visible light communication (VLC) has recently drawn more attention due to the existing light sources having a bandwidth that can deliver data transmission at higher bit rates. To maintain desired brightness levels along with reliable data transmission, VLC requires to control dimming levels. In this paper, a dimming control scheme based on pulse position modulation (PPM) is proposed, which constructs a dimming encoded frame per symbol of input data. The scheme utilizes multiple headers, which is selected depending on the dimming levels and the number of bits in a symbol of input data. The proposed scheme for the VLC system supports various dimming levels. The multi header PPM frame generation for input data K = 4 $K=4$ and dimming values α = 0.25, 0.375, and 0.5 is simulated using NI Labview. The proposed dimming scheme has an excellent short-run length property which is well under the maximum flickering time period and is thus capable of flicker mitigation. The slot error performance of the proposed dimming control scheme in a VLC system for varying dimming levels is simulated in Matlab. Simulation results show that the proposed scheme has excellent error performance for a low dimming value of α = 0.25. The experimental results are also carried out in the optisystem considering the practical measured parameters of the indoor environment for free space channel and simulating the VLC system for the proposed scheme. The simulation is carried for different data rates over varying link ranges and the experimental results show that the proposed scheme performs best when dimming value α = 0.25 and data rate 2 Gbps.

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PWM-based PPM format for dimming control in visible light communication system

2012 8th International Symposium on Communication Systems, Networks & Digital Signal Processing (CSNDSP) ◽

10.1109/csndsp.2012.6292778 ◽

2012 ◽

Cited By ~ 3

Author(s):

Hyung-Joon Jang ◽

Joon-Ho Choi ◽

Z. Ghassemlooy ◽

Chung Ghiu Lee

Keyword(s):

Visible Light ◽

Communication System ◽

Visible Light Communication ◽

Dimming Control

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Dimming Techniques for Visible Light Communication System

Indonesian Journal of Electrical Engineering and Computer Science ◽

10.11591/ijeecs.v10.i1.pp258-265 ◽

2018 ◽

Vol 10 (1) ◽

pp. 258

Author(s):

Suriza A.Z. ◽

Sharmin Akter ◽

M. Shahnan

Keyword(s):

Visible Light ◽

Communication System ◽

Light Emitting Diode ◽

New Technology ◽

Visible Light Communication ◽

Modulation Method ◽

Transmission Distance ◽

Modulation Techniques ◽

Dimming Control ◽

Future Work

<p class="thesis-abstract">Visible light communication (VLC) is an emerging and promising new technology in optical wireless communication (OWC). However, dimming has an adverse effect on the performance of visible light communication system. In visible light communication (VLC) system, illumination and communication both are provided simultaneously using a light emitting diode (LED). The specification for lighting is application specific for which dimming control is required. There are different modulation techniques for dimming control in visible light communication. In this thesis, NRZ-OOK modulation method and 4-QAM-OFDM modulation techniques are investigated for different dimming range, transmission distance, beam divergence angle and bit rate. The result shows that for 13m link range, 5Gb/s data speed is achievable for the 4-QAM-OFDM scheme. The analysis of this research is executed only based on system parameters. The scope of this research excluded the following parameters which are shadowing, mobility, multipath interference and inter-symbol interference for multicarrier modulation. These are the related research topic which can be investigated for future work.</p>

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