作者机构:[1]School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876, China
相关基金:Acknowledgements This work was supported by National Basic Research Program of China (2010CB328300), the National Natural Science Foundation of China (60677004, 60977046, 60702049), the Hi-Tech Research and Development Program of China (2009AA01Z220), the Teaching and Scientific Research Foundation for the Returned Overseas Chinese Scholars (State Education Ministry), and the Program for New Century Excellent Talents in University of China (NECT-07-0111).