FENG Zhengyong1,2, WEN Guangjun1, HU Ying1, XU Feng3
1.School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China 2.School of Physics and Electronic Information, China West Normal University, Nanchong, Sichuan 637002, China 3.Nanjing Research Institute of Electronic Technology, Nanjing 210013, China