1. Department of Electrical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, Republic of Korea
2. School of Electronic Engineering, Kumoh National Institute of Technology, Gumi, Gyungbuk, Republic of Korea
3. Barkhausen Institut, Dresden, Germany
4. Vodafone Chair Mobile Communication Systems, Technische Universität (TU) Dresden, Dresden, Germany
5. Department of Electrical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea