[Li, Wenjun;Wang, Jianxin] Cent S Univ, Sch Informat Sci & Engn, Changsha, Hunan, Peoples R China.^[Li, Wenjun] Changsha Univ Sci & Technol, Sch Comp & Commun Engn, Hunan Prov Key Lab Intelligent Proc Big Data Tran, Changsha, Hunan, Peoples R China.^[Cao, Yixin] Hong Kong Polytech Univ, Dept Comp, Hong Kong, Hong Kong, Peoples R China.^[Chen, Jianer] Texas A&M Univ, Dept Comp Sci & Engn, College Stn, TX USA.