1. Communications Laboratory, University of Genoa Research Unit, University of Genoa, National Inter-University Consortium for Telecommunications (CNIT), Savona Multimedia, Via Armando Magliotto 2, 17100 Savona, Italy
2. Department of Communications, Computer and Systems Science (DIST), University of Genoa Research Unit, National Inter-University Consortium for Telecommunications (CNIT), Via Opera Pia 13, 16154 Genova, Italy
3. National Laboratory for Multimedia Communications, Complesso Universitario Monte Sant’Angelo, National Inter-University Consortium for Telecommunications (CNIT), Via Cinthia, Edificio Centri Comuni, 80126 Napoli, Italy