Hi, Thanks for replying Adrian, OK, just for clarity, you are saying for 1-stream STBC NICs (AR9380/9280), when I enable STBC from hostapd, the driver only transmits in STBC (transmits multiple copies of data to each antenna) if it sending at MCSs 0-7 (1 stream rates), due to low signal quality or via fixing the MCS to those values. For all other MCSs STBC is disabled. Does the rate adaptation (minstrel/ath9k) tell the driver to use STBC, or is this done at automatically at a lower level? Any other information about STBC would be appreciated. Cheers On Thu, Jun 30, 2011 at 1:57 AM, Adrian Chadd <adrian@xxxxxxxxxxx> wrote: > I think things are a bit confusing, but here goes. > > The earlier NICs only support either RX STBC (pre ar9280?) or TX > 1-stream STBC (ar9280 or above). Multi-stream STBC isn't in any of the > AR9xxx NICs. It may be in the AR9287; it may be in the AR9300/AR9400. > I've not looked. > > I bet what you're finding is: > > * with STBC enabled, for single stream rates, it's tx'ing using STBC. > It just sets a bit in the TX descriptor. > * with STBC enabled, for multi-stream rates, it's not setting the STBC > TX bit and it's instead sending it as a 2 stream packet w/out STBC. > > The AR9280 is not a one stream NIC - it's a two stream TX/RX NIC. > (Unless you're using the AR9281 - which is an AR9280 1T2R stream > device.) The AR9285 is a 1x1 stream device. The AR9287 is a 2x2 stream > device. > > HTH, > > > Adrian > >> I am using STBC (Space Time Block Coding) 1 stream NICs like the AR9280.I would be very grateful someone can kindly advise on how exactly STBC(transmits multiple copies of a data across each of the antennas) works in ath9k. >> I ask this because when I enable STBC 1-stream, the driver seems to uses Space division multiplexing (can this be disabled/enabled?), since the rate is over 150Mbps. >> When is STBC activated ?, ...Does Minstrel/ath9k rate adaptation mechanism find first check if Spatial multiplexing is better, if not uses STBC ? >> Thank you for your time >> _______________________________________________ >> ath9k-devel mailing list >> ath9k-devel@xxxxxxxxxxxxxxx >> https://lists.ath9k.org/mailman/listinfo/ath9k-devel >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-wireless" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
