1. Chongqing Key Laboratory of Signal and Information Processing, School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing, China
2. School of Optoelectric Engineering, Chongqing University of Posts and Telecommunications, Chongqing, China
3. College of Computer Science, Chongqing University, Chongqing, China
4. Department of Electronic and Information Engineering, Hong Kong Polytechnic University, Hong Kong, SAR, China