Research On OFDM And Timing Synchronization In Visible Light Communication System

Visible light communication(VLC)has recently received extensive attention.VLC utilizes unauthorized spectrum of visible light indicating that a huge amount of potential bandwidth is available.In addition,VLC is also featured by highly safe link,perfect secrecy and energy-friendly mode,etc.In recent years,researchers constantly refresh the record of the capacity of VLC systems.Recently,100 Gbps VLC system has become possible.VLC has become a one of the state-of-art communication technologies for the future indoor high-speed wireless access connection.The traditional visible light communication uses light-emitting diode(LED)as a light source,which helps to seamlessly integrate into home lighting system.However,LED luminous efficiency and bandwidth is a pair of inherent contradictions,the bandwidth of current off-the-shelf LEDs only reach a few MHz.In order to improve the visible light spectrum efficiency while providing fine illumination,researchers turned to the laser diode(LD).Recent studies showed that LD not only satisfy the requirements of basic indoor lighting,also have much larger modulation bandwidth than that of LED.Therefore,visible light laser communication(VLLC)arises at the historic moment.VLLC has drawn extensive attention since the beginning and has become the potential solution of visible light communication system in the future.This paper is elaborated by the following aspects,the history of visible light communication based on LED and LD,the modulation techniques in VLLC system,the design of OFDM base band,the investigation of mixed light methods in VLLC,simulation and analysis on OFDM-VLLC system and the conclusion.