To whom correspondence should be addressed. E-mail: z weizhi3000@ 126. com Zhong Weizhi, born in 1981. She is a Ph.D. candidate in Communication Research Center, Harbin Institute of Technology. She received her B.S. and M.S. degrees from Jilin University in 2003 and 2006 respectively. Her research interests include multicarrier modulation technique and spread spectnma communications.