1. Orange Labs, Châtillon, France, Institut Polytechnique de Paris; Telecom Sud Paris; UMR CNRS, SAMOVAR, Palaiseau, France
2. Institut Polytechnique de Paris; Telecom SudParis; UMR CNRS, SAMOVAR, Palaiseau, France
3. INRIA, Sophia-Antipolis, France
4. Orange Labs, Châtillon, France