why single chain?

mkx · Tue Dec 15, 2020 10:08 am

Can anybody spot a problem in configuration of wireless interface which prevents clients and AP from connecting at 2x2 MIMO?

My AP is RB951G, clients are typical 1-3 years old smart phones and tabs. Here's running config:

 1  R name="wifi-42" mtu=1500 l2mtu=1600 mac-address=E4:8D:8C:49:EE:4F arp=enabled disable-running-check=no interface-type=Atheros AR9300
      radio-name="E48D8C49EE4F" mode=ap-bridge ssid="<redacted>" area="" frequency-mode=regulatory-domain country=brazil installation=indoor
      antenna-gain=4 frequency=2472 band=2ghz-g/n channel-width=20mhz secondary-channel="" scan-list=default wireless-protocol=802.11
      rate-set=configured supported-rates-b=1Mbps,2Mbps,5.5Mbps,11Mbps supported-rates-a/g=12Mbps,18Mbps,24Mbps,36Mbps,48Mbps,54Mbps
      basic-rates-b=1Mbps basic-rates-a/g=12Mbps,18Mbps max-station-count=50 distance=indoors tx-power-mode=default
      noise-floor-threshold=default nv2-noise-floor-offset=default vlan-mode=use-tag vlan-id=42 wds-mode=disabled wds-default-bridge=none
      wds-default-cost=100 wds-cost-range=50-150 wds-ignore-ssid=no update-stats-interval=disabled bridge-mode=enabled
      default-authentication=yes default-forwarding=yes default-ap-tx-limit=0 default-client-tx-limit=0 wmm-support=disabled hide-ssid=no
      security-profile=mkxNet wps-mode=disabled station-roaming=enabled disconnect-timeout=3s on-fail-retry-time=100ms preamble-mode=short
      compression=no allow-sharedkey=no station-bridge-clone-mac=00:00:00:00:00:00 ampdu-priorities=0,1 guard-interval=any
      ht-supported-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7,mcs-8,mcs-9,mcs-10,mcs-11,mcs-12,mcs-13,mcs-14,mcs-15,mcs-16,mcs-17,
                 mcs-18,mcs-19,mcs-20,mcs-21,mcs-22,mcs-23
      ht-basic-mcs=mcs-0,mcs-1,mcs-2,mcs-3,mcs-4,mcs-5,mcs-6,mcs-7 tx-chains=0,1 rx-chains=0,1 amsdu-limit=8192 amsdu-threshold=8192
      tdma-period-size=2 nv2-queue-count=2 nv2-qos=default nv2-cell-radius=30 nv2-security=disabled nv2-preshared-key=""
      nv2-mode=dynamic-downlink nv2-downlink-ratio=50 nv2-sync-secret="" hw-retries=7 frame-lifetime=0 adaptive-noise-immunity=none
      hw-fragmentation-threshold=disabled hw-protection-mode=rts-cts hw-protection-threshold=0 frequency-offset=0 rate-selection=advanced
      multicast-helper=default multicast-buffering=enabled keepalive-frames=enabled skip-dfs-channels=disabled

And statistics for the client while running speedtest (DL part):

 1 interface=wifi-42 mac-address=E0:AA:96:F0:C1:22 ap=no wds=no bridge=no rx-rate="72.2Mbps-20MHz/1S/SGI" tx-rate="72.2Mbps-20MHz/1S/SGI"
   packets=40177,26373 bytes=46275354,10338242 frames=40177,26375 frame-bytes=46355734,10180240 hw-frames=42957,26986
   hw-frame-bytes=50014144,11253016 tx-frames-timed-out=0 uptime=6m24s last-activity=0ms signal-strength=-51dBm@12Mbps signal-to-noise=56dB
   signal-strength-ch0=-56dBm signal-strength-ch1=-53dBm
   strength-at-rates=-47dBm@1Mbps 4m54s550ms,-51dBm@12Mbps 70ms,-55dBm@HT20-4 6m22s470ms,-55dBm@HT20-5 6m22s170ms,-54dBm@HT20-6 6m21s890ms,-
                  53dBm@HT20-7 0ms
   tx-ccq=97% p-throughput=64108 last-ip=192.168.42.144 802.1x-port-enabled=yes authentication-type=wpa2-psk encryption=aes-ccm
   group-encryption=aes-ccm management-protection=no wmm-enabled=yes tx-rate-set="OFDM:12-54 BW:1x SGI:1x HT:0-7"

As to other traffic in the area: AP is not exactly isolated from the rest of wireless networks, but it's not too bad:

CHANNEL                             USE        BW NET-COUNT NOISE-FLOOR STA-COUNT
2442/20/gn/P(26dBm)                0.1%      0bps         0        -106         0
2412/20/gn/P(26dBm)                1.2%  11.5kbps         1        -105         1
2417/20/gn/P(26dBm)                  0%      0bps         0        -105         0
2422/20/gn/P(26dBm)                  0%      0bps         0        -106         0
2427/20/gn/P(26dBm)                  0%      0bps         0        -107         0
2432/20/gn/P(26dBm)                0.4%  41.8kbps         2        -106         2
2437/20/gn/P(26dBm)                  0%      0bps         3        -106         5
2447/20/gn/P(26dBm)                0.7%      0bps         0        -106         1
2452/20/gn/P(26dBm)               57.6%  31.0Mbps         1        -106         6
2457/20/gn/P(26dBm)                 15%      0bps         0        -106         0
2462/20/gn/P(26dBm)                3.8%      0bps         2        -107         2
2467/20/gn/P(26dBm)                  0%      0bps         0        -107         0
2472/20/gn/P(26dBm)                  0%      0bps         0        -108         0

WeWiNet · Tue Dec 15, 2020 11:22 am

Hi MKX,

can you also post the "export" of the wireless section if possible?

WeWiNet · Tue Dec 15, 2020 11:43 am

What 2x2 clients do you use to connect to the AP by the way?

mkx · Tue Dec 15, 2020 11:10 pm

As it turns out, it seems like none of my usual wireless clients are mimo-capable (or they don't use that capability). The devices are indeed not high-end, but not exactly basic models either. Anyway, I've a few laptops in the household, but they mainly use wired connections. I just connected one of them (a venerable HP EliteBook 8540w with Intel N6200AGN wireless card) which actually does connect using dual-chains:

 6 interface=wifi-42 mac-address=00:27:10:66:D3:D4 ap=no wds=no bridge=no rx-rate="130Mbps-20MHz/2S" tx-rate="144.4Mbps-20MHz/2S/SGI" packets=8209,6684
   bytes=9425250,704243 frames=8209,6686 frame-bytes=9441664,664377 hw-frames=9206,6862 hw-frame-bytes=11042067,942411 tx-frames-timed-out=0 uptime=4m5s
   last-activity=0ms signal-strength=-44dBm@12Mbps signal-to-noise=63dB signal-strength-ch0=-48dBm signal-strength-ch1=-47dBm
   strength-at-rates=-68dBm@1Mbps 2m11s450ms,-48dBm@6Mbps 1s30ms,-44dBm@12Mbps 0ms,-49dBm@54Mbps 4m4s140ms,-44dBm@HT20-4 1m13s950ms,-45dBm@HT20-5 7s50ms,-
                  44dBm@HT20-6 920ms,-45dBm@HT20-7 0ms
   tx-ccq=100% p-throughput=135128 last-ip=192.168.43.6 802.1x-port-enabled=yes authentication-type=wpa2-psk encryption=aes-ccm group-encryption=aes-ccm
   management-protection=no wmm-enabled=yes tx-rate-set="OFDM:12-54 BW:1x SGI:1x HT:0-15"

I really didn't expect all of my Android gear only to support single chain :-(

r00t · Tue Dec 15, 2020 11:16 pm

Yes, this is very annoying. Many notebooks have 802.11ac card that have only one chain. I actually replaced some NB cards to rather have two chains in 802.11n as that results in better signal and speeds in real world use than just single 802.11ac chain. Only recent notebook models with wave2 (or even ax) often have two or more chains, but anything older than 2-3 years is stuck with single ac chain... stupid, but that's how it it.

anuser · Wed Dec 16, 2020 7:33 am

Intel 6200AGN Supports 2x2 MIMO and your HP 8540W has two antennas for WiFi.
Go to support.intel.com and download the latest drivers die your Wireless Card and Update your MikroTik to the latest long term RouterOS release

mkx · Wed Dec 16, 2020 10:06 am

@anuser: if you actually read my post #4 you'd notice that this laptop actually connected to AP using 2x2 MIMO ... and that was an eye-opener for me. Hence your suggestion is out of place entirely.

why single chain? [SOLVED]

why single chain?

Re: why single chain?

Re: why single chain? [SOLVED]

Re: why single chain?

Re: why single chain?

Re: why single chain?

Re: why single chain?

Who is online