National Engineering Laboratory for Mobile Network Technologies Beijing University of Posts and Telecommunications Beijing 100876 China;
National Engineering Laboratory for Mobile Network Technologies Beijing University of Posts and Telecommunications Beijing 100876 China;
National Engineering Laboratory for Mobile Network Technologies Beijing University of Posts and Telecommunications Beijing 100876 China;
Department of Computer Science New York Institute of Technology Old Westbury NY 11568 USA;
National Engineering Laboratory for Mobile Network Technologies Beijing University of Posts and Telecommunications Beijing 100876 China;