I. Introduction
In the past two decades, the unprecedented growth of wireless communication systems and the growing demand for wireless data services have limited the availability of limited and expensive RF spectrum, which has driven the demand for complementary wireless transmission technologies. Visible light communication (VLC) technology, as a new wireless communication scheme since the 21st century, is regarded as a very promising technical scheme in future wireless communication because of its advantages of large modulation bandwidth, high data rate, frequency reuse, high SNR [1].