Archer C7 v2 and VHT160 possible?

Hardware Questions and Recommendations
1

Hello,

I am using the actual 19.07.4 Image (OpenWrt 19.07.4 r11208-ce6496d796) without problems.
I use ath10k-firmware-qca988x-ct and kmod-ath10k-ct.
"iw list" gives me the following ouput for 5 GHz:

Wiphy phy0
        max # scan SSIDs: 16
        max scan IEs length: 199 bytes
        max # sched scan SSIDs: 0
        max # match sets: 0
        max # scan plans: 1
        max scan plan interval: -1
        max scan plan iterations: 0
        Retry short limit: 7
        Retry long limit: 4
        Coverage class: 0 (up to 0m)
        Device supports AP-side u-APSD.
        Available Antennas: TX 0x7 RX 0x7
        Configured Antennas: TX 0x7 RX 0x7
        Supported interface modes:
                 * IBSS
                 * managed
                 * AP
                 * monitor
                 * mesh point
                 * P2P-client
                 * P2P-GO
                 * P2P-device
        Band 2:
                Capabilities: 0x19ef
                        RX LDPC
                        HT20/HT40
                        SM Power Save disabled
                        RX HT20 SGI
                        RX HT40 SGI
                        TX STBC
                        RX STBC 1-stream
                        Max AMSDU length: 7935 bytes
                        DSSS/CCK HT40
                Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
                Minimum RX AMPDU time spacing: 8 usec (0x06)
                HT TX/RX MCS rate indexes supported: 0-23
                VHT Capabilities (0x338001b2):
                        Max MPDU length: 11454
                        Supported Channel Width: neither 160 nor 80+80
                        RX LDPC
                        short GI (80 MHz)
                        TX STBC
                        RX antenna pattern consistency
                        TX antenna pattern consistency
                VHT RX MCS set:
                        1 streams: MCS 0-9
                        2 streams: MCS 0-9
                        3 streams: MCS 0-9
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT RX highest supported: 0 Mbps
                VHT TX MCS set:
                        1 streams: MCS 0-9
                        2 streams: MCS 0-9
                        3 streams: MCS 0-9
                        4 streams: not supported
                        5 streams: not supported
                        6 streams: not supported
                        7 streams: not supported
                        8 streams: not supported
                VHT TX highest supported: 0 Mbps
                Frequencies:
                        * 5180 MHz [36] (23.0 dBm)
                        * 5200 MHz [40] (23.0 dBm)
                        * 5220 MHz [44] (23.0 dBm)
                        * 5240 MHz [48] (23.0 dBm)
                        * 5260 MHz [52] (20.0 dBm) (radar detection)
                        * 5280 MHz [56] (20.0 dBm) (radar detection)
                        * 5300 MHz [60] (20.0 dBm) (radar detection)
                        * 5320 MHz [64] (20.0 dBm) (radar detection)
                        * 5500 MHz [100] (26.0 dBm) (radar detection)
                        * 5520 MHz [104] (26.0 dBm) (radar detection)
                        * 5540 MHz [108] (26.0 dBm) (radar detection)
                        * 5560 MHz [112] (26.0 dBm) (radar detection)
                        * 5580 MHz [116] (26.0 dBm) (radar detection)
                        * 5600 MHz [120] (26.0 dBm) (radar detection)
                        * 5620 MHz [124] (26.0 dBm) (radar detection)
                        * 5640 MHz [128] (26.0 dBm) (radar detection)
                        * 5660 MHz [132] (26.0 dBm) (radar detection)
                        * 5680 MHz [136] (26.0 dBm) (radar detection)
                        * 5700 MHz [140] (26.0 dBm) (radar detection)
                        * 5720 MHz [144] (disabled)
                        * 5745 MHz [149] (13.0 dBm)
                        * 5765 MHz [153] (13.0 dBm)
                        * 5785 MHz [157] (13.0 dBm)
                        * 5805 MHz [161] (13.0 dBm)
                        * 5825 MHz [165] (13.0 dBm)
                        * 5845 MHz [169] (13.0 dBm)
                        * 5865 MHz [173] (13.0 dBm)
        valid interface combinations:
                 * #{ managed, P2P-client } <= 16, #{ P2P-GO } <= 3, #{ AP } <= 16, #{ IBSS } <= 1,
                   total <= 16, #channels <= 1, STA/AP BI must match, radar detect widths: { 20 MHz (no HT), 20 MHz, 40 MHz, 80 MHz, 80+80 MHz, 160 MHz }

        HT Capability overrides:
                 * MCS: ff ff ff ff ff ff ff ff ff ff
                 * maximum A-MSDU length
                 * supported channel width
                 * short GI for 40 MHz
                 * max A-MPDU length exponent
                 * min MPDU start spacing
        Supported extended features:
                * [ VHT_IBSS ]: VHT-IBSS
                * [ RRM ]: RRM
                * [ SET_SCAN_DWELL ]: scan dwell setting
                * [ CQM_RSSI_LIST ]: multiple CQM_RSSI_THOLD records
                * [ CONTROL_PORT_OVER_NL80211 ]: control port over nl80211
                * [ TXQS ]: FQ-CoDel-enabled intermediate TXQs

This says: "Supported Channel Width: neither 160 nor 80+80"
Isn't it possible to use VHT160 in 5GHz band?

Uwe

2

Depending on your region, the 5 GHz would allow 160 MHz channels - your hardware however does not.

1 Like
3

Hi slh,

thanks for link. Then I can stop searching for solutions :wink:
I can reach 300MBits/sec true data rate with VHT80 and I hoped to reach a higher rate with VHT160...

Uwe

4

Even on hardware that supports it (e.g. QCA9984), 160 MHz channels are fragile. Given the bandwidth you inevitably touch DFS frequencies and are affected by your neighbours' APs, as a result performance often suffers, if you can establish a 160 MHz connection in the first place. Sadly the real world doesn't correspond that closely to the engineers' lab - and even less to the buzzword bingo of the marketing departments.

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5

See this thread: Archer C7 5GHz performance, sirq 99%
Stock CPU sirq is already maxed out @ 80MHz channel width. By overclocking it and using different ath10k drivers, you can nurse around 400Mbit/sec true data rate from 5GHz WiFi.

That being said, VHT160 is somewhat of curiosity that few devices support. Also, DFS is going to knock it off every now and then.

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6

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