1. College of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing, China
2. School of Electronic and Information Engineering, Beihang University, Beijing, China
3. College of Information and Communication Engineering, Harbin Engineering University, Harbin, China
4. Institute for Communication Technologies and Embedded Systems, RWTH Aachen University, Aachen, Germany
5. International Research Institute of Disaster Science, Tohoku University, Sendai, Japan