Corresponding Author: Zhen Wang, is currently towards the master degree of Information and Communication Engineering at Nanjing University of Posts and Telecommunications. His research interest focuses on resource allocation in heterogeneous networks.;Xiaorong Zhu, is a professor at the wireless communication key lab of Jiangsu Province, Nanjing University of Posts and Telecommunications. She received her PhD degree in wireless communications in 2008 from Southeast University, Nanjing, China. She was a postdoctoral in The Chinese University of Hong Kong in 2008 and 2009. Her research interests include heterogeneous wireless networks, wireless access technology, as well as The Internet of Things. *The corresponding Author. Email: xrzhu@njupt.edu.cn.;Xu Bao, received the Ph.D. degree from Southeast University, Nanjing, China, in 2011. Since 2013, he has been a Postdoctoral Researcher, working with Prof. G. Y. Li, at the Georgia Institute of Technology, Atlanta, GA, USA. He is also an Assistant Professor with Jiangsu University, Zhenjiang, China. His research interests include cognitive wireless networks, visible light communication networks, and green communications.;Su Zhao, is an associate professor at the wireless communication key lab of Jiangsu Province, Nanjing University of Posts and Telecommunications. Her research fields include the Internet of Things and wireless communications.