1. Department of Telecommunications, Brno University of Technology, Technicka 12, 616 00 Brno, Czech Republic
2. Institute of Structural Mechanics, Brno University of Technology, Technicka 12, 616 00 Brno, Czech Republic
3. Department of Electronics and Communications Engineering, Tampere University of Technology, Korkeakoulunkatu 10, 33720 Tampere, Finland
4. Telekom Austria Group, Lassallestraße 9, 1020 Vienna, Austria