Dan, > > I'm not sure. Reading 7.3.2.56.4 seems to imply that, but I'm not sure > > about the "Rx Highest Supported Data Rate" field. Seems like maybe you > > could set the "RX MCS bitmask" to more than is supported, limit it by > > the highest supported data rate, and then use the bitmask for TX? > > First, did you mean 7.3.2.57.4? (I'm using IEEE P802.11n/D7.0, but I > assume the section numbers haven't changed). For me that section > represents the "Supported MCS Set field". I guess they did change then :) > (An aside: I don't actually *have* 7.3.2.56. I'm using IEEE > 802.11-2007 [has up to 7.3.2.35] and IEEE P802.11n/D7.0 [has 7.3.2.57 > and beyond] --- In which document are the missing sections?) I am looking at 802.11n final. > Can you point me at which text in the section you think implies this > requirement? It has a lot of tables .. not easily copied. > In any case, maybe this discussion is silly: I don't know of any > devices with this strange configuration. Typically clients assume > downlink-heavy and might support a 1x2 connection but 2x1, i.e. > designed for uplink, seems unlikely. And APs would typically be symmetric, countering Gabor's argument :) But I don't really understand the standard text here, we'll have to find somebody more familiar with 11n details. > >> A second question: my understanding is that if I am a 2x2 node and I > >> associate to a 3x3 AP, the same code will mask out the fact that the > >> AP can receive 3 streams since I can't transmit 3 streams. Is there a > >> way to access this info from the driver if I want it? > > > > Unfortunately not, at this point. We could keep track of it, what would > > you need it for? > > Okay, that's what I figured; I can hack around it locally. I'm working > on an alternative rate selection algorithm that at one point tries to > take into account how much receive diversity the other endpoint has. > The intuition is that how well (e.g.) 2-stream rates work is going to > depend not just on the channel, but also on how many excess antennas > the receiver has. I would benefit from knowing whether they have 2 or > 3 antennas even if I can only send them at most 2 streams. Ah. That makes some sense. So far nothing has needed it, but it _could_ also be useful for debugging, so I wouldn't necessarily mind tracking it in mac80211. johannes -- 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
