The purpose of this issue is to discuss how we can implement the set_bitrate_mask callback in vwifi and simulate the corresponding behavior for each setting.
In set_bitrate_mask, the most critical input is the cfg80211_bitrate_mask structure. We should store the entire structure within our virtual interface, vwifi_vif.
struct cfg80211_bitrate_mask {
struct {
u32 legacy;
u8 ht_mcs[IEEE80211_HT_MCS_MASK_LEN];
u16 vht_mcs[NL80211_VHT_NSS_MAX];
u16 he_mcs[NL80211_HE_NSS_MAX];
enum nl80211_txrate_gi gi;
enum nl80211_he_gi he_gi;
enum nl80211_he_ltf he_ltf;
} control[NUM_NL80211_BANDS];
};Based on the structure of cfg80211_bitrate_mask, its components can be categorized into legacy, HT_MCS, VHT_MCS, HE_MCS, GI, HE_GI, and HE_LTF.
Users can manually set these components using the following commands.
# Set legacy bitrates (802.11a/b/g)
iw dev <iface> set bitrates legacy-2.4 <rate1> <rate2> ...
iw dev <iface> set bitrates legacy-5 <rate1> <rate2> ...
# Set HT (802.11n) MCS indexes
iw dev <iface> set bitrates ht-mcs-2.4 <idx1> <idx2> ...
iw dev <iface> set bitrates ht-mcs-5 <idx1> <idx2> ...
# Set VHT (802.11ac) MCS indexes
iw dev <iface> set bitrates vht-mcs-2.4 <NSS>:<bitmap> ...
iw dev <iface> set bitrates vht-mcs-5 <NSS>:<bitmap> ...
# Set HE (802.11ax) MCS indexes
iw dev <iface> set bitrates he-mcs-2.4 <NSS>:<bitmap> ...
iw dev <iface> set bitrates he-mcs-5 <NSS>:<bitmap> ...
iw dev <iface> set bitrates he-mcs-6 <NSS>:<bitmap> ...
# Set Guard Interval (GI)
iw dev <iface> set bitrates gi <sgi-2.4 | lgi-2.4 | sgi-5 | lgi-5>
# Set HE-specific GI
iw dev <iface> set bitrates he-gi-2.4 <0.8|1.6|3.2>
iw dev <iface> set bitrates he-gi-5 <0.8|1.6|3.2>
iw dev <iface> set bitrates he-gi-6 <0.8|1.6|3.2>
# Set HE LTF
iw dev <iface> set bitrates he-ltf-2.4 <1|2|4>
iw dev <iface> set bitrates he-ltf-5 <1|2|4>
iw dev <iface> set bitrates he-ltf-6 <1|2|4>
Alternatively, you can check the supported commands available in your iw tool.
$ iw help | grep 'set bitrates'
dev <devname> set bitrates [legacy-<2.4|5> <legacy rate in Mbps>*] [ht-mcs-<2.4|5> <MCS index>*] [vht-mcs-<2.4|5> [he-mcs-<2.4|5|6> <NSS:MCSx,MCSy... | NSS:MCSx-MCSy>*] [sgi-2.4|lgi-2.4] [sgi-5|lgi-5] [he-gi-<2.4|5|6> <0.8|1.6|3.2>] [he-ltf-<2.4|5|6> <1|2|4>]
Since multiple MCS values can be specified at once, it is essential to design a selection algorithm that adapts to dynamic environments.
Our first goal is to enable vwifi to fully support HT mode (802.11n), covering MCS indexes 0 to 31 on the 2.4 GHz band, along with GI (Guard Interval) selection of 0.8 µs or 0.4 µs in 20 MHz bandwidth.
Additionally, the MCS index setting of HT stored in vwifi_vif should be reset every time when the iw dev <iface> set bitrates ht-mcs-2.4 <idx1> <idx2>...... is called, enabling us to test different configurations per command.
The dynamic selection algorithm should be applied not only in station_dump, but also in the transmission time simulation.
By default, the MCS setting should be initialized to HT mode on 2.4 GHz with MCS index 31 and a 0.8 µs GI in vwifi_vif.
To support data rate lookup, we may consider maintaining the MCS table (the yellow-highlighted portion in 20 MHz bandwidth) in a global structure for efficient querying.
@horseface1110
@dingsen-Greenhorn
The purpose of this issue is to discuss how we can implement the
set_bitrate_maskcallback invwifiand simulate the corresponding behavior for each setting.In
set_bitrate_mask, the most critical input is thecfg80211_bitrate_maskstructure. We should store the entire structure within our virtual interface,vwifi_vif.Based on the structure of
cfg80211_bitrate_mask, its components can be categorized intolegacy,HT_MCS,VHT_MCS,HE_MCS,GI,HE_GI, andHE_LTF.Users can manually set these components using the following commands.
Alternatively, you can check the supported commands available in your
iwtool.Since multiple MCS values can be specified at once, it is essential to design a selection algorithm that adapts to dynamic environments.
Our first goal is to enable
vwifito fully support HT mode (802.11n), covering MCS indexes 0 to 31 on the 2.4 GHz band, along with GI (Guard Interval) selection of 0.8 µs or 0.4 µs in 20 MHz bandwidth.Additionally, the MCS index setting of HT stored in
vwifi_vifshould be reset every time when theiw dev <iface> set bitrates ht-mcs-2.4 <idx1> <idx2>......is called, enabling us to test different configurations per command.The dynamic selection algorithm should be applied not only in
station_dump, but also in thetransmission time simulation.By default, the MCS setting should be initialized to HT mode on 2.4 GHz with MCS index 31 and a 0.8 µs GI in
vwifi_vif.To support data rate lookup, we may consider maintaining the MCS table (the yellow-highlighted portion in 20 MHz bandwidth) in a global structure for efficient querying.
@horseface1110
@dingsen-Greenhorn