Ding Jie, is currently working toward the Ph.D. degree in infor- mation and communication engineering at the Key Laboratory of Universal Wireless Communication, Ministry of Education, Bei- jing University of Posts and Telecommunications, Beijing, China. His current research interests include wireless sensor networks, Wireless communications and cross-layer design. Liu Danpu, is currently working at the Key Laboratory of Universal Wireless Communication, Ministry of Education, Beijing University of Posts and Telecommunications, Beijing, China. She is a professor since 2005. Her general research interests include wireless communication, wireless sensor networks and ultra wide band communication. Wu Huari is currently working at Beijing Academy of Agriculture and Forestry Sciences, Beijing, China. He is an associate researcher now. His general research interests include artificial intelligence and mobile computing.