To whom correspondence should be addressed. E-mail: mgao@mail.xidian.edu.cn Gao Ming, bom in 1979. He is working for his Ph. D degrees in Communication Engineering Department of Xidian University now. He received his B.S. and M.S. degrees from Xidian University in 2002 and 2005 respectively. His research interests include information hiding, space-time code and cooperative diversity technology.