US. Patent Jun. 28, 2011 Sheet 1 013 US 7,970,914 B2 1000 1220 1240 1260 1200 1120 1140 1160 1320 1340 1360 III 1100 III 1300 1550 1500 Network 1600 1720 — 1820 1700 — - - 1740 1840 Fig. 1 1800