1. School of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China
2. Henan Key Laboratory of Visible Light Communications, Information Engineering University, Zhengzhou 450002, China
3. School of Electrical and Information Engineering, Zhengzhou University, Zhengzhou 450001, China
4. School of Electronic and Information Engineering, Suzhou University of Science and Technology, Suzhou 215000, China