Channel Estimation for Indoor ACO-OFDM Optical Wireless Communication System

Abstract

Asymmetrically clipped optical Orthogonal Frequency Division Multiplexing (ACO-OFDM) technique has received a lot of interest in optical wireless communication research lately for offering high data rates capability as well as high power efficiency and effectively dealing with the multipath propagation induced intersymbol interference (ISI). The propagation characteristics of optical channel differ from the conventional radio frequency (RF) channel, and the system performance will degrade due to the ISI. To attenuate the influence of ISI, accurate channel estimation of the optical channel is necessary for the ACO-OFDM signals. The channel estimation for ACO-OFDM systems based on LS, MMSE and LMMSE methods are investigated. The simulation results show that comparing to the worst performance of LS channel estimation algorithm and the best performance of MMSE estimation, the LMMSE algorithm of pilot signals gives the best tradeoff between performance and complexity.