[Xu, Yuebing;Zhang, Jing;Chen, Yan] Hunan Univ, Coll Elect & Informat Engn, Changsha 410082, Hunan, Peoples R China.^[Xu, Yuebing] Hengyang Normal Univ, Hunan Prov Key Lab Intelligent Informat Proc & Ap, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.^[Long, Zuqiang] Hengyang Normal Univ, Coll Phys & Elect Engn, Hengyang 421002, Peoples R China.