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Gigabit WiFi with SPR & The 4x4 MT7915

· 3 min read

Intro​

In this post we'll cover how to configure hostapd with the mt7915 to run 160 MHz channels over 5ghz. This allows stations to break gigabit speeds for WiFi with only 2 spatial streams.

Requirements​

Preparation​

  • Set up your AP device according to the SPR Setup Guide
  • For mt7915, run a mainline kernel or a kernel with fixes from https://github.com/openwrt/mt76 and the latest firmware. I'll publish some updates to building SPR with these in the near future. Fixes are needed for DFS support.

Hostapd configuration​

  1. Modify config/wifi/hostpad.conf
  2. Make sure vht_capab includes [VHT160] and [SHORT-GI-160]
  3. Make sure to set vht_oper_chwidth/he_oper_chwidth set to 2.
  4. For the channel configuration, the following are valid 160mhz centers on 5ghz: [50, 114, 163]. Set the vht/he_oper_centr_freq_seg0_idx to these values and the channel to the center value - 14.
  5. Set ieee80211ax to 1
ctrl_interface=/state/wifi/control
country_code=US
interface=wlan0
ssid=TestLab
hw_mode=a
ieee80211d=1
ieee80211h=1
ieee80211n=1
ieee80211ac=1
ieee80211ax=1
he_su_beamformer=1
he_su_beamformee=1
he_mu_beamformer=1
wmm_enabled=1
preamble=1
ht_capab=[LDPC][HT40+][HT40-][GF][SHORT-GI-20][SHORT-GI-40]
vht_capab=[MAX-MPDU-7991][SU-BEAMFORMEE][SU-BEAMFORMER][VHT160][RXLDPC][SHORT-GI-160][SHORT-GI-80][MAX-A-MPDU-LEN-EXP3][RX-ANTENNA-PATTERN][TX-ANTENNA-PATTERN][TX-STBC-2BY1][RX-STBC-1][MU-BEAMFORMER[[MU-BEAMFORMEE]
vht_oper_chwidth=2
he_oper_chwidth=2
channel=36
vht_oper_centr_freq_seg0_idx=50
he_oper_centr_freq_seg0_idx=50
auth_algs=1
wpa=2
wpa_key_mgmt=WPA-PSK WPA-PSK-SHA256 SAE
rsn_pairwise=CCMP

# Security parameters

# Isolate stations and per-station group keys
ap_isolate=1
multicast_to_unicast=1

# Mitigate krack attack
wpa_disable_eapol_key_retries=1

# VLAN
per_sta_vif=1

# Passwords

sae_psk_file=/configs/wifi/sae_passwords
wpa_psk_file=/configs/wifi/wpa2pskfile
  1. Restart hostapd
root@pirouter:~/super# docker compose restart wifid

If anything has gone wrong, check the docker compose logs for the wifid service.

Perf Test​

Running iperf3 on the SPR device, and iperf3 on a client with AX210 chip, we see the following:

On SPR:​

iw wls6 info

Interface wls6
        ifindex 5
        wdev 0x1
        addr 00:0a:52:07:32:c9
        ssid testlab
        type AP
        wiphy 0
        channel 100 (5500 MHz), width: 160 MHz, center1: 5570 MHz
        txpower 23.00 dBm
        multicast TXQ:
                qsz-byt qsz-pkt flows   drops   marks   overlmt hashcol tx-bytes        tx-packets
                0       0       246     0       0       0       0       27114           272

iperf3 -s

On the station:​

iperf3 -c 192.168.2.1

Performance results​

Accepted connection from 192.168.2.26, port 56156
[  5] local 192.168.2.1 port 5201 connected to 192.168.2.26 port 56158
[ ID] Interval           Transfer     Bitrate                                                         
[  5]   0.00-1.00   sec   139 MBytes  1.17 Gbits/sec                   
[  5]   1.00-2.00   sec   126 MBytes  1.06 Gbits/sec                  
[  5]   2.00-3.00   sec   141 MBytes  1.18 Gbits/sec                  
[  5]   3.00-4.00   sec   137 MBytes  1.15 Gbits/sec                  
[  5]   4.00-5.00   sec   152 MBytes  1.27 Gbits/sec                  
[  5]   5.00-6.00   sec   153 MBytes  1.28 Gbits/sec                  
[  5]   6.00-7.00   sec   155 MBytes  1.30 Gbits/sec                  
[  5]   7.00-8.00   sec   148 MBytes  1.24 Gbits/sec                  
[  5]   8.00-9.00   sec   145 MBytes  1.21 Gbits/sec                  
[  5]   9.00-10.00  sec   119 MBytes   995 Mbits/sec                                                  
[  5]  10.00-10.00  sec   482 KBytes  1.22 Gbits/sec