1. State Key Laboratory of Internet of Things for Smart City and the Department of Electrical and Computer Engineering, University of Macau, Macau SAR, China
2. Department of Electronic Engineering, Shanghai Jiao Tong University, Minhang, China
3. Department of Electrical Engineering, City University of Hong Kong, Hong Kong, China
4. School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, Australia
5. Henry Samueli School of Engineering, Center for Pervasive Communications and Computing, University of California, Irvine, CA, USA