[1] Beijing Univ Posts & Telecommun, State Key Lab Informat Photon & Opt Commun, POB 122, Beijing 100876, Peoples R China
[2] Beijing Univ Posts & Telecommun, Sch Sci, POB 122, Beijing 100876, Peoples R China
[3] Wuhan Donghu Univ, Sch Elect & Informat Engn, Wuhan 430212, Peoples R China
[4] Alabama A&M Univ, Dept Phys Chem & Math, Normal, AL 35762 USA
[5] King Abdulaziz Univ, Dept Math, Jeddah 21589, Saudi Arabia
[6] Natl Res Nucl Univ, Dept Appl Math, Moscow 115409, Russia
[7] Tshwane Univ Technol, Dept Math & Stat, ZA-0008 Pretoria, South Africa