1. Department of Electronic Engineering, National Taipei University of Technology, No. 1, Sec. 3, Zhongxiao E. Road, Taipei 10608, Taiwan
2. School of Electronics and Electrical Engineering, Dongguan Polytechnic/Department of Computer and Communication, Jinwen University of Science and Technology, No. 99, An-Chung Road, Hsin-Tien District, New Taipei City 23154, Taiwan
3. Department of Communication Engineering, Feng Chia University, No. 100 Wenhwa Road, Seatwen District, Taichung 40724, Taiwan