Francisco Javier Herraiz-Martínez, Universidad Pontificia Comillas, Spain; Mario Pérez-Escribano, Telecommunication Research Institute (TELMA), Universidad de Málaga, Spain; Paris Sofokleous, Universidad Pontificia Comillas, Spain; Pablo Padilla, Research Centre for Information and Communication Technologies (CITIC-UGR), University of Granada, Spain; Enrique Márquez-Segura, Telecommunication Research Institute (TELMA), Universidad de Málaga, Spain