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Study of Dimming and LED Nonlinearity for ACO-OFDM Based VLC Systems

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Original languageUndefined/Unknown
Title of host publicationProc. of the Wireless Communications and Networking Conference (WCNC)
Place of PublicationParis, France
PublisherInstitute of Electrical and Electronics Engineers (IEEE)
Publication statusPublished - 1 Apr 2012


In this paper, the performance of an asymmetrically clipped optical orthogonal frequency division multiplexing (ACO-OFDM) indoor wireless system is investigated. In particular, the illuminance distribution inside a room (5 m×5 m×3 m) under different brightness conditions, i.e. dimming levels, and the electrical signal-to-noise ratio (SNR) at the receiver are considered. The system performance is also assessed in terms of bit-error-ratio (BER) as a function of average transmitted optical power. Brightness control is achieved using the continuous current reduction (CCR) technique to assure higher luminous efficacy compared to the pulse-width modulation (PWM) dimming technique. In addition, the impact of the induced distortions due to the nonlinear behavior of the light-emitting diode (LED) as a light source is included in the simulation model. For a circular area of about 1 m radius located directly below one of the four LED illumination modules utilized in the room, having illuminance values above 300 lx (10% brightness), a 9 dB average electrical SNR is achieved at the receiver located on a desktop.

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