Implement dynamic MCS selection based on signal strength in vWIFI driver #80
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It seems that you are adjusting the MCS based on the current signal strength. However, what if a user wants to set the MCS manually using a command like iw dev wlan0 set bitrates ht-mcs-2.4 <mcs_index>?
To support this, you could consider implementing the set_bitrate_mask() callback in your cfg80211_ops and storing the specified MCS in the corresponding vwifi interface structure.
Thanks for you suggestion ,I can try to included the MCS for maunally adjust ! |
This commit enhances the vWIFI driver by implementing dynamic Modulation and Coding Scheme (MCS) selection in the `vwifi_get_station` function, adjusting the MCS index based on signal strength After implement dynamic MCS can avoid TX power waste for a bad channel quality
Implement the set_bitrate_mask callback in cfg80211_ops to support manual MCS settings using `iw dev <interface> set bitrates ht-mcs-2.4 <mcs_index>`, addressing reviewer feedback. Store the selected MCS in vwifi_vif->manual_mcs and track its state with vwifi_vif->manual_mcs_set. Support MCS indices 7, 15, 23, and 31, with validation and logging. Enable High Throughput (HT) in nf_band_2ghz with MCS 0–31, using IEEE80211_HT_CAP_SUP_WIDTH_20_40 for 20 MHz compatibility. Fix compilation errors by initializing rx_mask statically and removing const qualifiers from channel/rate arrays. Improve vwifi_connect to ensure stable association. Tested with `iw dev vw1 set bitrates ht-mcs-2.4 15`, achieving MCS 15 at 130.0 MBit/s (bitrate calculation pending refinement to ~52 MBit/s). Test commands format $sudo ip netns exec ns1 iw dev vw1 link $sudo ip netns exec ns1 iw dev vw1 set bitrates ht-mcs-2.4 15 /*(changable 7,15,23,31)*/ $sudo ip netns exec ns1 iw dev vw1 link
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vwifi.c
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| @@ -88,6 +88,8 @@ struct vwifi_vif { | |||
| struct wireless_dev wdev; | |||
| struct net_device *ndev; | |||
| struct net_device_stats stats; | |||
| int manual_mcs; /* ADDED: Store user-specified MCS */ | |||
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Remove "ADDED:" prefix from the comment
vwifi.c
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| @@ -88,6 +88,8 @@ struct vwifi_vif { | |||
| struct wireless_dev wdev; | |||
| struct net_device *ndev; | |||
| struct net_device_stats stats; | |||
| int manual_mcs; /* ADDED: Store user-specified MCS */ | |||
| bool manual_mcs_set; /* ADDED: Flag to indicate manual MCS override */ | |||
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vwifi.c
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| @@ -1728,13 +1743,8 @@ static int vwifi_start_ap(struct wiphy *wiphy, | |||
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| /* Initialize hrtimer of beacon */ | |||
| pr_info("vwifi: init beacon_timer.\n"); | |||
| #if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 15, 0) | |||
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Don't modify unrelated code segment!
You should align with the latest version of vwifi.
First,the code handles MCS selection and modulation assignment, either manually (based on vif->manual_mcs_set and vif->manual_mcs) or automatically (based on signal strength). Second,The vWIFI driver constrains MCS indices to 7, 15, 23, and 31 to simplify rate calculation, testing, and implementation. This avoids the need for a comprehensive calculation of data-rates to handle all 32 MCS indices, varying streams, and channel widths. The chosen indices represent a range of modulations (BPSK to 64-QAM) for 4 streams, supporting both manual (iw commands) and automatic (signal-based) modes. The code’s design prioritizes simplicity for a virtual driver, ensuring functionality (as shown in your test output) while limiting complexity. And thanks for you thoughtful question,it might be the next PR to optimize it ! |
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Nit: It might be better to squash all the “Fix coding style” commits. |
This commit enhances the vWIFI driver by implementing dynamic Modulation and Coding Scheme (MCS) selection in the
vwifi_get_stationfunction, adjusting the MCS index based on signal strengthAfter implement dynamic MCS can avoid TX power waste for a bad channel quality