Hi folks, This is a second attempt at a RADIOTAP header for S1G captures. Aaron Lee did the work in creating these definitions. I simply transcribed them. The attached patch defines changes to the Channel field, 0-length-MPDU field and a new S1G field. There is also and associated definition for S1G NPD frames, which are 40-bit non-MAC frames transmitted by S1G STAs. I have included the definition of those in this email, and they are essentially from 802.11ah-2016 with a little bit of helpful framing. 1. Channel field: 3 new values for Mask: 0x0002 for 700 MHz, 0x0004 for 800 MHz and 0x0008 for 900 MHz spectrum channels respectively. 2. 0-length MPDU field: 1 new value: 0x02 in the type value: 2 indicates that an S1G NDP 40-bit frame follows. Note, this seems weird. Maybe the name of the field needs changing to non-MAC frame or something. 3. The new S1G frame. It consists of three 16-bit fields: U16 known, U16 data1, U16 data2 Known: 0x0001 S1G PPDU format known 0x0002 Response indication known 0x0004 Guard Interval known 0x0008 NSS known 0x0010 Bandwidth known 0x0020 MCS Known 0x0040 Color known 0xFF80 Reserved Data1: 0x0003: S1G PPDU Format: 0=S1G_1M, 1=S1G_SHORT, 2=S1G_LONG 0x000C: Response indication: 0=NO_RESPONSE, 1=NDP_RESPONSE, 2=NORMAL_RESPONSE, 3=LONG_RESPPNSE 0x0010: Reserved 0x0020: Guard interval: 0=Long GI, 1=Short GI 0x00C0: Number spatial streams: 0=1 Spatial stream, 1=2, .. 3=4 Spatial streams 0x0F00: Bandwidth: 0=1MHz, 1=2MHz, 2=4MHz, 3=8MHz, 4=16MHz, 5-15 reserved 0xF000: MCS (MCS rate index, 0-10, 11-15 reserved) Data2: 0x000F: Color: 0-7 0xFFF0: Reserved The S1G NPD format is essentially from section 9.9 of 802.11ah-2016 with some additional syntactic sugar: It is a 40-bit field. The first 8 bits distinguishes between Management and Control frames using the values 0x0F (management) and 0x20 (control). The last two bits indicates the bandwidth, between 1MHz and 2MHz, In between, a 1MHz NDP CMAC frame contains 26 used bits and 13 unused bits. The used bits are defined in section 9.9 of 802.11ah-2016. A 1MHz NDP CMAC frame contains 37 used bits and one unused bit. Again, the used bits are defined in 802.11ah-2016. -- Regards, Richard Sharpe (何以解憂?唯有杜康。--曹操)(传说杜康是酒的发明者)