[Solved] 802.11ax worse than 802.11ac with mt76 driver?

Installing and Using OpenWrt Network and Wireless Configuration
97

Regarding your neighbor's setup, I can't really help. But let's at least collect some information other than RSSI. What's the achieved throughput and latency? What are the expectations? Can your neighbor play https://littlebigsnake.com/ for 10 minutes without the game server complaining about a bad connection, and without obvious lags?

My own experience is that on an empty channel (with Arch Linux and a MEDIATEK Corp. MT7612E 802.11acbgn PCI Express Wireless Network Adapter [14c3:7612] as a client) this -75 .. -77 dBm signal is 100% acceptable and stable (desktop-specific trick, not applicable to OpenWRT: force the BSSID in connection properties so that NetworkManager disables background scanning), and suitable even for video calls and this snake game. But the bandwidth is not that great - the maximum that I can get at this point is 90 Mbps goodput, which is still a win over the over-crowded 2.4 GHz at -50 dBm.

98

Thanks. I will test and get back if I get an opportunity. Man that's an addictive game. I had to stop otherwise I'd play all afternoon.

99

It almost seems like Apple devices are getting stuck in power saving mode when RSSI falls below a certain point. I have 1 wall and 1 monitor between my iPhone and RT3200. When the phone is in front of the monitor, LuCI reports the phone’s tx rate is 6mbps. Lifting the phone above the monitor jumps the tx rate to several hundred mbps.

This reflects almost perfectly in speed tests using iperf3

2 Likes
100

Thanks. That's exactly the behavior I am observing.

However with a windows laptop (Intel AX210), while it is not as bad as the iPhone, it still performs better with 802.11ac rather tan 802.11ax.

I still have to test with a Macbook laptop.

1 Like
101

I just tested with a Macbook Air M1 in the same spot iPhone has issues. The results are as follows (iperf3 @80Mhz channel, AX6S 22.03.0 stable):

802.11ax upload: 454 Mbits/sec
802.11ax download: 764 Mbits/sec

802.11ac upload: 576 Mbits/sec
802.11ac download: 676 Mbits/sec

So while results are much better with the Macbook, the 802.11ax upload performace is still worse than 802.11ac.

2 Likes
102

I've been testing with a MBP M1 and a RT3200. Setting he_su_beamformee = 1 and he_bss_color = 8 seems to slightly improve performance, but I still see a sharp decrease by moving as little as one step away from the router.

From:

signal:  	-63 [-68, -70, -70, -67] dBm
signal avg:	-63 [-67, -69, -71, -67] dBm
tx bitrate:	907.4 MBit/s 80MHz HE-MCS 9 HE-NSS 2 HE-GI 1 HE-DCM 0
rx bitrate:	816.7 MBit/s 80MHz HE-MCS 8 HE-NSS 2 HE-GI 1 HE-DCM 0

to:

signal:  	-65 [-67, -70, -71, -72] dBm
signal avg:	-64 [-67, -70, -70, -71] dBm
tx bitrate:	907.4 MBit/s 80MHz HE-MCS 9 HE-NSS 2 HE-GI 1 HE-DCM 0
rx bitrate:	34.0 MBit/s 80MHz HE-MCS 0 HE-NSS 1 HE-GI 1 HE-DCM 0

Notice how the bitrate drops from 816 to 34 and HE-MCS drops from 8 to 0, with a RSSI drop of just 2dB.

3 Likes
103

I've been working on porting OpenWrt to the Xiaomi Redmi AX6000 (MT7986a) and the 802.11ax results are significantly better on this device. With a -86 RSSI on my iPhone and -84 on my MacBook, I see full speeds from my ISP and iPerf3 is 300-400mbit in both directions.

There is 1 wall and 1 floor in between, whereas on my RT3200 there is just 1 wall and the speeds plummet. I'm not sure if this helps narrow things down a bit, but just sharing my 2 cents. Oh and 802.11ax on 2.4GHz is a nice improvement as well :slight_smile:

2 Likes
104

Testing on my Redmi AX6000 (yes I know, not officially supported yet) but enabling 160MHz, even though Apple devices can't use more than 80MHz, seems to fix this issue.

105

I'm very interested in getting more detailed behaviors of the ax chips by leveraging the flent rrul, rrul_be, and tcp_nup tests. Any chance y'all could try those?

2 Likes
106

Master got a new mt76 bump today, FWIW.

6 Likes
107

Is any of you compiling from master, I would like you to try a few patches.

108

what patches?

109

The ones I prepared to achieve this:

110

I'm actually not 100% convinced this is an MT76 issue. I just tested on my QNAP Q-Hora 301W (ath11k, yes I know not perfectly supported yet) and am seeing the same issues on Apple devices.

iPerf3 server on the router.

TX:

Connecting to host 10.0.0.1, port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  15.3 MBytes   128 Mbits/sec                  
[  5]   1.00-2.00   sec   197 KBytes  1.61 Mbits/sec                  
[  5]   2.00-3.00   sec  3.09 MBytes  25.9 Mbits/sec                  
[  5]   3.00-4.00   sec  3.99 MBytes  33.5 Mbits/sec                  
[  5]   4.00-5.00   sec  1.95 MBytes  16.4 Mbits/sec                  
[  5]   5.00-6.00   sec  5.64 MBytes  47.3 Mbits/sec                  
[  5]   6.00-7.00   sec  2.67 MBytes  22.4 Mbits/sec                  
[  5]   7.00-8.00   sec  13.5 MBytes   113 Mbits/sec                  
[  5]   8.00-9.00   sec  1.57 MBytes  13.2 Mbits/sec                  
[  5]   9.00-10.00  sec  14.2 MBytes   119 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.00  sec  62.1 MBytes  52.1 Mbits/sec                  sender
[  5]   0.00-10.39  sec  60.9 MBytes  49.1 Mbits/sec                  receiver

RX:

[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  72.2 MBytes   606 Mbits/sec                  
[  5]   1.00-2.00   sec  75.2 MBytes   631 Mbits/sec                  
[  5]   2.00-3.00   sec  79.3 MBytes   665 Mbits/sec                  
[  5]   3.00-4.00   sec  78.9 MBytes   662 Mbits/sec                  
[  5]   4.00-5.00   sec  76.9 MBytes   646 Mbits/sec                  
[  5]   5.00-6.00   sec  80.1 MBytes   672 Mbits/sec                  
[  5]   6.00-7.00   sec  76.8 MBytes   644 Mbits/sec                  
[  5]   7.00-8.00   sec  76.9 MBytes   645 Mbits/sec                  
[  5]   8.00-9.00   sec  78.1 MBytes   655 Mbits/sec                  
[  5]   9.00-10.00  sec  74.8 MBytes   627 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.02  sec   772 MBytes   646 Mbits/sec    0             sender
[  5]   0.00-10.00  sec   769 MBytes   645 Mbits/sec                  receiver

However LuCI doesn't report insanely low TX rates during the benchmark like it does on MT76 devices:

626.9 Mbit/s, 80 MHz, HE-MCS 6, HE-NSS 2
600.4 Mbit/s, 80 MHz, HE-MCS 11, HE-NSS 1
6 Likes
111

OK so low throughput. For me, I get pretty decent results from a few different iPhone 13 models. No issues from an older macbook pro either. Share your wireless settings?

This is from my Belkin RT3200.

result
result1170×1667 64.6 KB

/etc/config/wireless

config wifi-device 'radio0'
option type 'mac80211'
option path 'platform/18000000.wmac'
option channel '1'
option band '2g'
option htmode 'HT20'
option cell_density '0'
option disabled '1'

config wifi-device 'radio1'
option type 'mac80211'
option path '1a143000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0'
option band '5g'
option beacon_int '101'
option cell_density '0'
option he_bss_color '8'
option he_su_beamformee '1'
option country 'US'
option channel '36'
option htmode 'HE80'

config wifi-iface 'wifinet2'
option device 'radio1'
option network 'lan'
option mode 'ap'
option ssid 'mysid'
option encryption 'sae'
option key 'xxx'
option dtim_period '3'
option ieee80211w '2'
option wpa_disable_eapol_key_retries '1'

112

I have my AP on 160MHz which seems to be a strange mitigation. Could you try putting a wall or 2 in between you and the AP and then testing the uplink speed from the phone to the AP?

1 Like
113

Try upload instead. I get around 300 down and 15 up just a few meters from the router with a floor and a wall in the way. On an iPhone 13 Mini.

114

Wow, I see the effect now with more barriers between the phone and the AP.

For the record, the download screenshot I posted was with a single wall (two sheets of standard dry wall and standard 2x4 wood/no insulation/interior wall). I was about 12 feet from the AP behind that wall.

This test is standing in the same spot at the same distance but measuring 3 streams upload not download:

up
up1170×1087 56.4 KB

But the story changes as I add barriers between me the AP.

  • 2 walls between/about 25 feet away: 449 Mbit/sec avg, 385 min, 503 max
  • 2 walls between and behind a thick couch/about 25 feet away: 55 Mbit/sec avg, 26 min, 105 max

All that on channel 36 with 80 MHz width in AX mode.

Switching from AX to AC (channel 36 with 80 MHz) improved the 2 walls/behind the couch numbers by 8x: 444 Mbits/s avg, 416 min, 509 max.

Testing AX mode @ 160 MHz width did not change the 2 walls/behind the couch numbers, if anything it made it worse: 15 Mbits/s avg, 7 min, 29 max.

@nbd - are you aware of these results?

I am on a snapshot I build 5 days ago. Hardware for me is Belkin RT3200/iPhone 13 Pro

/etc/config/wireless

config wifi-device 'radio0'
option type 'mac80211'
option path 'platform/18000000.wmac'
option channel '1'
option band '2g'
option htmode 'HT20'
option cell_density '0'
option disabled '1'

config wifi-device 'radio1'
option type 'mac80211'
option path '1a143000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0'
option band '5g'
option beacon_int '101'
option cell_density '0'
option he_bss_color '8'
option he_su_beamformee '1'
option country 'US'
option channel '36'
option htmode 'HE80'

config wifi-iface 'wifinet2'
option device 'radio1'
option network 'lan'
option mode 'ap'
option ssid 'mysid'
option encryption 'sae'
option key 'xxx'
option dtim_period '3'
option ieee80211w '2'
option wpa_disable_eapol_key_retries '1'

4 Likes
115

As OP of this topic, thank you for duplicating my setup and confirming the results.

116

Originally posted by @dan3 in Review of the WiFi performance on Belkin RT3200 - #2 by dan3

2 Likes