[1] Manchester Metropolitan Univ, Dept Comp & Math, Manchester M1 5GH, Lancs, England
[2] Natl Univ Sci & Technol, Islamabad 44000, Pakistan
[3] Univ Elect Sci & Technol China, Chengdu 611731, Peoples R China
[4] Inst Telecomunicaces, P-3810078 Aveiro, Portugal
[5] SCMS Sch Engn & Technol, Dept Comp Sci & Engn, Ernakulam 683576, India
[6] City Univ Hong Kong, Dept Elect Engn, Hong Kong, Peoples R China