1. School of Information and Communication EngineeringBeijing University of Posts and TelecommunicationsBeijingPeople's Republic of China
2. State Key Laboratory of Wireless Mobile CommunicationsChina Academy of Telecommunications TechnologyBeijingPeople's Republic of China
3. School Of Computer and Communication EngineeringUniversity of Science and Technology BeijingBeijingPeople's Republic of China
4. Key Laboratory of Universal Wireless Communications, Ministry of EducationBeijing University of Posts and TelecommunicationsBeijingPeople's Republic of China