1. University of Mascara, 257229 Mascara, Algeria, (e-mail: salem@univ-mascara.dz)
2. Department of Signal Theory, Telematics and Communications, ETSIIT-CITIC, UGR, 16741 Granada, Andaluca, Spain, (e-mail: amorag@ugr.es)
3. Department of Computer Architecture and Computer Technology, UGR, 16741 Granada, Andaluca, Spain, (e-mail: jmerelo@geneura.ugr.es)