[1] Nanjing Univ Sci & Technol, Sch Elect & Opt Engn, Nanjing 210094, Peoples R China
[2] Southeast Univ, Natl Mobile Commun Res Lab, Nanjing 210096, Peoples R China
[3] Univ Sci & Technol China, Chinese Acad Sci, Sch Informat Sci & Technol, Key Lab Wireless Opt Commun, Hefei 230027, Peoples R China
[4] Univ Kent, Sch Engn & Digital Arts, Canterbury CT2 7NT, Kent, England