Li Xijin, born in 1975. He received his M.S. degree in Computer Science Department of Beijing University of Posts and Telecommunication in 2005. He also received his B.S. degree from Beijing JiaoTong University in 1998. His research interests include the design of algorithms for wireless communication, cognitive radio technology in integrated wireless networks.To whom correspondence should be addressed. E-mail:lixijin@gmall.com