1. School of Computer Science and Technology, Beijing Jiaotong University, Beijing, China
2. Engineering Research Center of Network Management Technology for High Speed Railway of Ministry of Education, the School of Computer Science and Technology, the Innovation Center of Railway Traffic Safety, and the National Engineering Research Center of Advanced Network Technologies, Beijing Jiaotong University, Beijing, China
3. College of Computing and Data Science, Nanyang Technological University, Jurong West, Singapore
4. School of Automation, Guangdong University of Technology, Guangzhou, China
5. Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, ON, Canada
6. Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, USA