1. Institute of Informatics, Federal University of Goiás, Goiânia, Brazil
2. Department of Computer and Telecommunication Engineering, Federal University of Pará, Belém, Brazil
3. Wireless Networking and Communications Group, The University of Texas at Austin, Austin, TX, USA
4. Ericsson Research, Stockholm, Sweden
5. Department of Electronics and Computer Engineering, North Carolina State University, Raleigh, NC, USA