[1] Univ Bordeaux, CNRS, Lab IMS, UMR 5218, F-33607 Pessac, France
[2] ST Microelect, 850 Rue Jean Monnet, F-38920 Crolles, France
[3] Eindhoven Univ Technol, NL-5612 AJ Eindhoven, Netherlands
[4] Univ Brescia, Dept Informat Engn, Via Branze 38, I-25123 Brescia, Italy