On Mon, Apr 19, 2010 at 2:24 AM, Bruno Randolf <br1@xxxxxxxxxxx> wrote: > On Friday 16 April 2010 22:59:07 Stanislaw Gruszka wrote: >> On Mon, 12 Apr 2010 16:38:47 +0900 >> >> Bruno Randolf <br1@xxxxxxxxxxx> wrote: >> > There was a confusion in the usage of the bits AR5K_STA_ID1_ACKCTS_6MB >> > and AR5K_STA_ID1_BASE_RATE_11B. If they are set (1), we will get lower >> > bitrates for ACK and CTS. Therefore ath5k_hw_set_ack_bitrate_high(ah, >> > false) actually resulted in high bitrates, which i think is what we want >> > anyways. Cleared the confusion and added some documentation. >> >> I thought ACK and other control frames have to be modulated at slow/robust >> bitrates, but can't remember where I read that ... > > this has been discussed on ath5k-devel before. i'm copying it here. please let > me know if i missed something... > > (https://lists.ath5k.org/pipermail/ath5k-devel/2010-March/003391.html) > > control frames have to be sent at one of the lower bitrates - one of the > "basic rates". in G mode these are 1, 2, 5.5, 11, 6, 12, 24Mbps. Aren't basic rates defined so as to exclude any OFDM rates? I.e. are 6M, 12M and 24M really basic rates? > > this is from the 802.11g spec: > "a STA responding to a received frame shall transmit its Control Response > (either CTS or ACK) frames at the highest rate in the BSSBasicRateSet that is > less than or equal to the rate of the immediately previous frame in the frame > exchange sequence (as defined in 9.7)" > > basically we have to make a tradeoff here: using lower rates for ACK/CTS will > improve reliability, but lower performance. for example i could get only > 10Mbps truput with ACK/CTS at the lowest bitrates and RTS/CTS enabled > (iwconfig wlan0 rts 250) and i can get more than 20Mbps with higher bitrates. > so i think it's worth to use high bitrates. actually also this should be > tuneable for the user, too... > > bruno > -- > 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 > -- Vista: [V]iruses, [I]ntruders, [S]pyware, [T]rojans and [A]dware. :-) -- 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
