Beijing University of Posts and Telecommunications, Beijing 100876, P.R.China;
Beijing University of Posts and Telecommunications, Beijing 100876, P.R.China;
Beijing University of Posts and Telecommunications, Beijing 100876, P.R.China;
France Telecom Research & Development Center, Beijing 100190, P.R.China;
France Telecom Research & Development Center, Beijing 100190, P.R.China;