IBM Watson Research Center, Yorktown Heights, NY 10598, USA
Atif Shamim
Division of Physical Sciences and Engineering, Electrical Engineering Department, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
Tzyh-Ghuang Ma
Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
Zhinong Ying
Network Research Laboratory, Research and Technology, CTO Office, Sony Ericsson Mobile Communication AB, 22188 Lund, Sweden
