中文摘要：

YANG Long, is currently a Ph.D. candidate in tele- communications and information systems at Xidian University, China. His recent research interests include OFDM synchronization technique and cognitive radio. KUO Yonghong, received her B.S. and M.S. degrees from Xi＇an Jiaotong University, China in i989 and 1992 respectively, and her Ph.D. degree from Peking Union Medicat University, China in 1998. She is a Professor in the School of Telecommunications En- gineering in Xidian University, China. Her research interests include OFDM systems, cognitive radio and medical signal processing. ＊The corresponding au- thor. Email： yhkuo@mail.xidian.edu.cn CHEN Jian, received his B.E. degree from Xi＇an Jiaotong University, China in 1989, his MS. degree from Xi＇an Institute of Optics and Precision Mechan- ics of Chinese Academy of Sciences, China in 1992, and his Ph.D. degree from Xidian University, China in 2005. From 2007 to 2008, He was a visiting scholar in the University of Manchester, UK. He is currently a Professor and Ph,D. adviser in the School of Tele- communications Engineering in Xidian University. His research interests include cognitive radio, wireless sensor networks and signal processing. ZHANG Hailin, received his Ph.D. degree from Xi- dian University, China in 3.991. From then, he has been with Xidian University as a member of teaching and researching. He is now a Senior Professor and a Ph.D. adviser with the School of Telecommunications Engineering at Xidian University. He is currently the Dean of this school and one of the state government specially compensated scientists and engineers. His research interests include key transmission technolo- gies and standards on next generation broadband wireless communications and green communication networks.