中文摘要：

LU Luxi： Ph.D candidate at State Key Laboratory of Advanced Optical Communication Systems ＆ Networks, School of EECS, Peking University, Beijing. His main research interests are cognitive radio, dynamic resource allocation. JIANG Wei： got the Ph.D degree in Communication and Information Systems in 2003 from Peking University. He is now an associate professor working at State Key Labo- ratory of Advanced Optical Communication Systems ＆ Networks, School of EECS, Peking University, Beijing. His main research interests are satellite and wireless communications. XIANG Haige： Professor at State Key Laboratory of Advanced Optical Communication Systems ＆ Networks, School of EECS, Peking University, Beijing. His main research interests are satellite and wireless communications. LUO Wu： Ph.D, Professor at State Key Laboratory of Advanced Optical Communication Systems ＆ Networks, School of EECS, Peking University, Beijing. His main research interests are satellite and wireless communications.