[1] Nanjing Univ Aeronaut & Astronaut, Key Lab Dynam Cognit Syst Electromagnet Spectrum S, Minist Ind & Informat Technol, Nanjing 210016, Peoples R China
[2] Xidian Univ, State Key Lab Integrated Serv Networks, Xian 710071, Peoples R China
[3] ABB Corp Res Sweden, Dept Automat Technol, S-72178 Vasteras, Sweden
[4] Royal Inst Technol KTH, Dept Intelligent Syst, S-11428 Stockholm, Sweden
[5] Southeast Univ, Natl Mobile Commun Res Lab, Nanjing 210096, Peoples R China
[6] UCL, Dept Elect & Elect Engn, London WC1E 7JE, England