1. State Key Laboratory of Industry Control Technology, College of Control Science & Engineering, Zhejiang University, Hangzhou, P.R. China
2. China Academy of Space Technology, Beijing, P.R. China
3. Shanghai Radio Equipment Research Institution, Shanghai, P.R. China
4. Department of Mathematics, Zhejiang University, Hangzhou, P.R. China
5. College of Information Technology and Electrical Engineering, University of Oulu, Finland