1. SnT, University of Luxembourg, Luxembourg City, Luxembourg
2. Department of Electrical and Computer Engineering, University of Western Macedonia, Kozani, Greece
3. Department of Electrical Engineering, Linkóping University, Linkóping, Sweden
4. NaNoNetworking Center in Catalunya, Universitat Politécnica de Catalunya, Barcelona, Spain
5. Department of Computer Science, KTH, Kista, Sweden
6. Wireless Communications Laboratory of the Institute of Informatics and Telecommunications, National Centre for Scientific Research–“Demokritos,”, Athens, Greece