1. Guangxi Key Laboratory of Embedded Technology and Intelligent System, Guilin University of Technology, Guilin, China
2. Key Laboratory of Cognitive Radio and Information Processing (Guilin University of Electronic Technology), Ministry of Education, Guilin, China
3. Key Laboratory of Intelligent Sensing System and Security (Hubei University), Wuhan, China
4. School of Information and Electronics, Beijing Institute of Technology, Beijing, China