1. TKK Helsinki University of Technology, TKK, Finland
2. LAAS-CNRS, Toulouse Cedex, France
3. Bell Laboratories, Alcatel-Lucent, Murray Hill, NJ and CWI, Amsterdam, The Netherlands and Eindhoven University of Technology, Eindhoven, The Netherlands
4. Columbia University, New York, NY
5. CWI, Amsterdam, The Netherlands and TNO Information and Communication Technology, Delft, The Netherlands