1. School of Communication and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China
2. School of Automation, Guangdong University of Technology, Guangzhou, China
3. State Key Lab of Internet of Things for Smart City and the Department of Computer and Information Science, University of Macau, Macau, China
4. College of Information Engineering, Zhejiang University of Technology, Hangzhou, China
5. Department of Communication Engineering, Dalian Maritime University, Dalian, China
6. School of Cyber Science and Engineering, Xi'an Jiaotong University, Xi'an, China