On Fri, Nov 5, 2010 at 4:56 AM, jd jd <jdiq...@googlemail.com> wrote: > Dear all, > > > > I am trying to measure the optimal performance of 802.11n in a typical > indoor scenario, using the most capable products available that are > compatible with open sourced Linux drivers, and then discover the best > settings to achieve the highest successful rates. > > > > I currently have 2 boards both with an AR9160 Atheros chipset wireless card > and openwrt trunk build (r23637) as well as ath9k driver installed and > functional. > > > > My current setup is: > > [PC1]------------- [Avila- AP MODE] })})})})})})})}) [Avila -STA > MODE]-------------[PC2] > > > > KEY: > > ---------- = Ethernet (currently 100Mbit) > > )})})})} = Wireless > > > > Iperf udp tests between PC1 and PC2 get at best 79 Mbits/s, on 5GHz HT20 > 11na (channel 40) and 77 Mbits/s stable on 2.4GHZ(channel 5) HT40+ 11ng. > Note: both channels have other wireless traffic). > > > > I have a number of questions in terms of ath9k:
I will try to answer upto my understanding(I am a newbie) Any other better answers are most welcome > > > > 1) Is there any way of setting link layer parameters such as frame size > and aggregation(MSDU /MPDU). I think we need to hack the code > > 2) Why do I get a kernel driver error when I set HT40+ or HT40- on 5GHz > 11na channels and why can I not set any HT capabilities such as GP and short > guard on 5GHz. Is there any solution to this? This should work fine we had used 11NAHT40PLUS etc ... > > 3) How can I enable other channels of 5GHz which show as disabled in > “iw list” such as channel 100. Dont know , but as you know it seems to be radar detected why we should enable it > > 4) How can I limit the bitrate of the driver, as I tried with iwconfig > and iw, but it had no effect on my speed tests? Also is there any way I can > disable minstrel rate adaptation, as I wish to test other rate adaptation > mechanisms. You can enable ath9k rate contorl in the .config CONFIG_ATH9K_RATE_CONTROL=y and to enable/disbale change the folowing default things CONFIG_MAC80211_HAS_RC=y CONFIG_MAC80211_RC_MINSTREL=y CONFIG_MAC80211_RC_MINSTREL_HT=y CONFIG_MAC80211_RC_DEFAULT_MINSTREL=y CONFIG_MAC80211_RC_DEFAULT="minstrel_ht" > > 5) How can I change the Modulation scheme (MCS), aka specify 0-15. I think we cannot do it using iwconfig/iw > > 6) What 802.11n MIMO capabilities actually function if I were to add > them in hostapd settings (/etc/config/wireless). This was asked by some one(Andreas) before and answered by Lardy It seems enabling wmm helps Default WMM parameters (IEEE 802.11 draft; 11-03-0504-03-000e): # for 802.11a or 802.11g networks # These parameters are sent to WMM clients when they associate. # The parameters will be used by WMM clients for frames transmitted to the # access point. # # note - txop_limit is in units of 32microseconds # note - acm is admission control mandatory flag. 0 = admission control not # required, 1 = mandatory # note - here cwMin and cmMax are in exponent form. the actual cw value used # will be (2^n)-1 where n is the value given here # wmm_enabled=1 # # WMM-PS Unscheduled Automatic Power Save Delivery [U-APSD] # Enable this flag if U-APSD supported outside hostapd (eg., Firmware/driver) #uapsd_advertisement_enabled=1 # # Low priority / AC_BK = background wmm_ac_bk_cwmin=4 wmm_ac_bk_cwmax=10 wmm_ac_bk_aifs=7 wmm_ac_bk_txop_limit=0 wmm_ac_bk_acm=0 # Note: for IEEE 802.11b mode: cWmin=5 cWmax=10 # # Normal priority / AC_BE = best effort wmm_ac_be_aifs=3 wmm_ac_be_cwmin=4 wmm_ac_be_cwmax=10 wmm_ac_be_txop_limit=0 wmm_ac_be_acm=0 # Note: for IEEE 802.11b mode: cWmin=5 cWmax=7 # # High priority / AC_VI = video wmm_ac_vi_aifs=2 wmm_ac_vi_cwmin=3 wmm_ac_vi_cwmax=4 wmm_ac_vi_txop_limit=94 wmm_ac_vi_acm=0 # Note: for IEEE 802.11b mode: cWmin=4 cWmax=5 txop_limit=188 # # Highest priority / AC_VO = voice wmm_ac_vo_aifs=2 wmm_ac_vo_cwmin=2 wmm_ac_vo_cwmax=3 wmm_ac_vo_txop_limit=47 wmm_ac_vo_acm=0 # Note: for IEEE 802.11b mode: cWmin=3 cWmax=4 burst=102 Can you please search the mailing list with ath9k HT40 performance issues. > > 7) What other settings can I change that may affect throughput and > reduce packet loss. On the higher level this basically depends on the rate control algorithm, and probably some hw/mac configurations(ex :tx under runs) current ath9k rate control is based on PER . > > > > > > Finally will using say an actual desktop computer coupled with a PCI 802.11n > Atheros card perform significantly better and/or enable more features, than > my current avila board and mini-PCI wireless card. Also is there a chipset > better than AR9160 that can achieve higher rates with an open sourced Linux > driver such as ath9k, if yes I would be grateful if you could point me to > where I can purchase this. > > > > Any advice is highly appreciated. > > Thank you all very much for your time. > _______________________________________________ > ath9k-devel mailing list > ath9k-devel@lists.ath9k.org > https://lists.ath9k.org/mailman/listinfo/ath9k-devel > > _______________________________________________ ath9k-devel mailing list ath9k-devel@lists.ath9k.org https://lists.ath9k.org/mailman/listinfo/ath9k-devel
