Adaptive OFDM For Visible Light Communication Systems

As a newly rising wireless optical communication technology, VLC (VisibleLight Communication) can communicate by using LED lighting at the same time. Incomparison with traditional wireless communication technology, it is safer, with noelectromagnetic interference and deploys easily, it is an important supplementarymeans to the existing wireless communication system, which is also a maindeveloping direction for the future communication technology. Visible adaptiveOFDM system can adjust the transmit end of the transmission parameters according tothe optical channel state information obtained by channel estimation so as to improvethe performance of the visible light communication system. Due to its excellentperformance, the study of visible light adaptive of OFDM systems in the field ofoptical wireless communication has become a hot spot.This paper mainly studies adaptive OFDM for VLC system, establishes a visibleadaptive OFDM system model, discusses several factors that affect visible lightadaptive OFDM system performance, studies the methods of pilot-based channelestimation that is used in adaptive OFDM for indoor VLC systems, introduces theLMS methods which is commonly used in the RF communication, compares thevisible light LS channel estimation method and analyses its characteristics, thesimulation experiment results show that the bit error rates of the two methods reducealong with the increase of signal-notice rate, bit error rates of LMS channel estimationmethods performs better than LS estimation method，LMS channel estimationmethod of channel tracking ability is stronger, meanwhile, MSE number of the LMSchannel estimation method is lower than LS method.