1. Electrical, Electronic and Communication Engineering Department, Institute of Smart Cities (ISC), Public University of Navarra, Pamplona, Spain
2. Physics Department, CICECO, University of Aveiro, Aveiro, Portugal
3. Department of Telecommunications, VSB-Technical University of Ostrava, Ostrava, Czech Republic
4. Physics Department, I3N, University of Aveiro, Aveiro, Portugal
5. XLIM UMR CNRS 7252, University of Limoges, Limoges, France