1. State Key Laboratory of Rail Traffic Control and Safety and the Frontiers Science Center for Smart High-speed Railway System, Beijing Jiaotong University, Beijing, China
2. State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing, China
3. Department of Electrical and Computer Engineering, University of Houston, Houston, TX, USA
4. School of Information Engineering, Zhengzhou University, Zhengzhou, China
5. Department of Computer Science, Norwegian University of Science and Technology, Gjøvik, Norway