1. School of Information Engineering, Guangdong University of Technology University Town, Guangzhou, Guangdong, China
2. Huawei Technologies Co. Ltd, Nanjing, Jiangsu, China
3. Department of Information and Communications Engineering (formerly Department of Signal Processing and Acoustics), Aalto University, Espoo, Finland
4. School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, China