1. University of Aveiro,Department of Electronics, Telecommunications and Informatics,Aveiro,Portugal,3810-193
2. Institute for Technological Development and Innovation in Communications, Universidad de Las Palmas de Gran Canaria,Las Palmas,35001
3. Northumbria University,Faculty of Engineering and Environment,Newcastle upon Tyne,U.K.,NE1 8ST
4. Aalto University,Department of Information and Communications Engineering,Espoo,Finland,02150
5. Instituto de Telecomunicações,Aveiro,Portugal,3810-193