[1] Catholic Univ Louvain, Fac Sci Appl, Lab Telecommun & Teledetect, B-1348 Louvain, Belgium
[2] New Jersey Inst Technol, Ctr Wireless Commun, Newark, NJ 07102 USA
[3] Ecole Natl Super Telecommun Bretagne, Dept Signal & Commun, F-29238 Brest, France