1. Intel Corporation, Folsom, CA 95630, USA
2. Department of Electronics, Systems, and Informatics, ITESO (Instituto Tecnológico y de Estudios Superiores de Occidente), The Jesuit University of Guadalajara, Tlaquepaque 45604, Jalisco, Mexico
3. Centre Tecnològic de Telecomunicacions de Catalunya (CTTC/CERCA), Castelldefels, 08860 Barcelona, Spain