[1] Georgia Inst Technol, Broadband Wireless Networking Lab, Sch Elect & Comp Engn, Atlanta, GA 30332 USA
[2] Univ Nebraska, Dept Comp Sci & Engn, Mol & Biochem Telecommun Lab, Lincoln, NE 68588 USA
[3] Waterford Inst Technol, Telecommun Software & Syst Grp, Carriganore X91 P2OH, Waterford, Ireland
[4] Tampere Univ, Fac Informat Technol & Commun Sci, Tampere 33100, Finland