1. COPELABS, Universidade Lusófona, Campo Grande 376, Lisboa, Portugal
2. Department of Electronics and Communication Engineering, Cooch Behar Government Engineering College, Cooch Behar, West Bengal, India
3. Instituto de Telecomunicações, FCT-UNL, Campus de Caparica, Caparica, Portugal
4. Centre for Wireless Communications, University of Oulu, Erkki Koiso-Kanttilan katu 3, Oulu, Finland