1. Dipartimento di Elettronica, Informazione e Bioingegneria (DEIB), Politecnico di Milano, Milan, Italy
2. Wireless Information and Network Sciences Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
3. Department of Management, Economics and Industrial Engineering (DIG), Politecnico di Milano, Milan, Italy
4. Laboratory for Information and Decision Systems (LIDS), Massachusetts Institute of Technology, Cambridge, MA, USA