doc.: IEEE yy/0847r0 Submission Slide 6Leonardo Lanante, Ochi Lab, KIT July 2009 A) Mixed 11a/n Mode Frame Format Proposed Mixed 11a/n mode: Backward compatible with IEEE802.11a/n Duration=56μs * L-STF L-LTF L-SIG HT-SIG VHT-SIG VHT STF VHT LTF1 VHT LTF4 VHT LTF4 Data 8μs8μs8μs8μs4μs4μs8μs8μs8μs8μs4μs4μs4μs per LTF4/3.6μs per Data * 4 spatial streams L-STF L-LTF L-SIG HT-SIG HT STF HT LTF1 HT LTF4 HT LTF4 Data 8μs8μs8μs8μs4μs4μs8μs8μs4μs4μs4μs per LTF4/3.6μs per Data Duration=48μs * n Mixed Mode Preamble A New SIG field is defined to accommodate changes in VHT while maintaining compatibility