Corresponding Author: Xiangbin Yu, received his Ph.D. in Communication and Information Systems in 2004 from National Mobile Communications Research Laboratory at Southeast University, China. He is a full Professor of Information and Communication Engineering at Nanjing University of Aeronautics and Astronautics. His research interests include Distributed antenna systems, adaptive resource allocation, precoding, MIMO and green communications. *The corresponding author. Email: yxb_xwy@hotmail.com.