In the future, future heterogeneous communications networks may use visible light communications (VLC) as a supplementary technology to WiFi. The signal to noise ratio (SNR) of the received signal determines a VLC system's channel capacity, just like it does for any other communications system. The channel estimate for VLC communication proposed in this study is based on spectral domain wavelet transform. Due to their excellent spectrum and energy efficiency for VLC MIMO communication systems, SMTs have become more and more common. This work focuses on SMTs, or entirely generalized spatial modulation, in which multiple active optical antennas and a constant number of antennae are used to transmit data symbols for VLC at any time interval. In this study, an adaptive channel estimation approach over a time-varying MIMO channel is proposed using the Spectral Domain Wavelet Transform. Furthermore, the broadcast data and optical antenna indices are identified using a maximum likelihood (ML) decoder based on the received signal and the predicted VLC-MIMO channel. Matlab software is used in the implementation of this project.