[1] Univ Elect Sci & Technol China, Natl Key Lab Wireless Commun, Chengdu 611731, Peoples R China
[2] Natl Univ Singapore, Dept Elect & Comp Engn, Singapore 117583, Singapore
[3] Chinese Univ Hong Kong, Shenzhen Res Inst Big Data, Sch Sci & Engn, Shenzhen 518172, Guangdong, Peoples R China
[4] Natl Univ Singapore, Dept Elect & Comp Engn, Singapore 117583, Singapore