1. School of Electrical and Information Engineering, Tianjin University, No. 92, Weijin Road, Nankai District, Tianjin 300072, China
2. Future Mobile Technology Lab, China Mobile Research Institute, No. 32, Xuanwumenxi Ave, Xicheng District, Beijing 100053, China
3. Central Research Institute, Unisoc(Shanghai) Technologies Co., Ltd, No. 7, Zhichun Road, Haidian District, Beijing 100089, China