[1] Southwest Jiaotong Univ, Key Lab Informat Coding & Transmiss, Chengdu 610031, Peoples R China
[2] Univ Florida, Dept Elect & Comp Engn, Gainesville, FL 32611 USA
[3] China Acad Railway Sci, Commun Signal Res Inst, Beijing 100082, Peoples R China
[4] Chongqing Univ Posts & Telecommun, Sch Commun & Informat Engn, Chongqing 400065, Peoples R China