1. Department of Electrical Engineering, Stanford University, Stanford, CA 94305, USA
2. Research Laboratory of Electronics, Massachusetts Institute of Technology (MIT),
Cambridge, MA 02139, USA
3. Department of Computer Engineering, Thai-Nichi Institute of Technology,
Bangkok 10250, Thailand
4. Department of Signals and Systems, Chalmers University of Technology, Gothenburg 412 96, Sweden
5. Laboratory for Information and Decision Systems, Massachusetts Institute of Technology (MIT),
Cambridge, MA 02139, USA