High speed Li-Fi system design using LED arrays

Light Fidelity (Li-Fi) is an advanced visible light communication (VLC) technology in which light emitting diodes (LEDs) are used as data transfer tools. Significant increase in the data transmission rate is a need for full potential of VLC technology and to increase its application areas. In this thesis, LED arrays with high optical power are used for high speed Li-Fi system design. Fundamental analyzes of the designed system are made by considering Inter-symbol Interference (ISI) in terms of illuminating room and data transmission. OOK-NRZ is widely used in VLC modeling studies in the literature. In this study, firstly, the system performance is analyzed when OOK-NRZ is used and the studies are taken one step further by appling OOK-RZ and 4-PPM. By this way ISI effect of the system are reduced. When OOK-NRZ is applied to the system, the highest data rate achieved for 60° FOV angle as 100Mbps. When OOK-RZ and 4-PPM are applied, the effect of ISI is reduced and the speed is increased to 500Mbps for same FOV angle. The data rate analyzes are performed based on BER, SNR and RMS delay spread values. The purpose of this study is to contribute widespread usage of Li-Fi by increasing the usability of Li-Fi systems. It is seen from literatür research that OOK-RZ and 4-PPM modulation are not studied for LED arrays in term of BER and RMS delay spread. This study fills this gap in the literature.