Design and analysis of visible light communication system using multi carrier modulation techniques

Abstract

In present thesis work, design and analysis of VLC system using multi carrier modulation techniques is presented. The various benefits and applications of VLC system along with the possibility for the next generation communication systems has been discussed. Different modulation techniques are discussed and comparison is also provided with MATLAB simulations. It also provides comprehensive review of various challenges faced by VLC system. The modulation techniques used for the simulation of VLC system model was based on orthogonal frequency division multiplexing (OFDM). DC bias optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACOOFDM) are two main multicarrier modulation (MCM) techniques used for VLC. OFDM suffers from high out of band (OOB) distortion and low spectral efficiency due to the use of cyclic prefix (CP). To overcome the drawbacks of OFDM technique, Filter bank multicarrier (FBMC) modulation scheme has been introduced for VLC system. The advantages of FBMC over OFDM are high spectral efficiency, narrow out-of-band radiations and asynchronous transmission. In recent years FBMC has come out as a capable contender for next generation wireless systems. Both single carrier and multi carrier modulation techniques are used for the analysis of FBMC based VLC system. These modulation schemes consist of intensity modulation/direct detection (IM/DD) channel. Single carrier modulation techniques such as pulse amplitude modulation (PAM) and quadrature amplitude modulation (QAM) based DC bias optical FBMC (DCO-FBMC) and asymmetrically clipped optical FBMC (ACO-FBMC) as multi carrier modulation techniques are used to implement FBMC modulation scheme. Both DC bias and non-DC bias methods are used for analysis. The analytical performance is provided using parameters Bit error rate (BER) and spectral efficiency. newline