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Adjust max bitrate SNR floors

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These values were defined in commit a1b790eb9d ("Select AP based on
estimated maximum throughput") with no justification. Other sources
[0,1,2] give a different (consistent) set of SNR floors per MCS index.
Adjust the values accordingly.

[0] http://www.revolutionwifi.net/revolutionwifi/2014/09/wi-fi-snr-to-mcs-data-rate-mapping.html
[1] https://higher-frequency.blogspot.com/2016/10/80211n-80211ac-data-rates-and-snr.html
[2] https://www.wlanpros.com/resources/mcs-index-802-11ac-vht-chart/

Signed-off-by: Matthew Wang <matthewmwang@chromium.org>
This commit is contained in:
Matthew Wang 2020-03-16 14:11:05 -07:00 committed by Jouni Malinen
parent a60a0a43c7
commit 3a25897ef7
1 changed files with 44 additions and 34 deletions
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74
wpa_supplicant/scan.c
View file

@ -2185,67 +2185,77 @@ void scan_snr(struct wpa_scan_res *res)
}
static unsigned int max_ht20_rate(int snr)
static unsigned int max_ht20_rate(int snr, int vht)
{
if (snr < 6)
if (snr < 2)
return 0;
if (snr < 5)
return 6500; /* HT20 MCS0 */
if (snr < 8)
if (snr < 9)
return 13000; /* HT20 MCS1 */
if (snr < 13)
if (snr < 11)
return 19500; /* HT20 MCS2 */
if (snr < 17)
if (snr < 15)
return 26000; /* HT20 MCS3 */
if (snr < 20)
if (snr < 18)
return 39000; /* HT20 MCS4 */
if (snr < 23)
if (snr < 20)
return 52000; /* HT20 MCS5 */
if (snr < 24)
if (snr < 25)
return 58500; /* HT20 MCS6 */
if (snr < 29 || !vht)
return 65000; /* HT20 MCS7 */
return 78000; /* VHT20 MCS8 */
}
static unsigned int max_ht40_rate(int snr)
static unsigned int max_ht40_rate(int snr, int vht)
{
if (snr < 3)
if (snr < 5)
return 0;
if (snr < 8)
return 13500; /* HT40 MCS0 */
if (snr < 6)
if (snr < 12)
return 27000; /* HT40 MCS1 */
if (snr < 10)
if (snr < 14)
return 40500; /* HT40 MCS2 */
if (snr < 15)
if (snr < 18)
return 54000; /* HT40 MCS3 */
if (snr < 17)
if (snr < 21)
return 81000; /* HT40 MCS4 */
if (snr < 22)
if (snr < 23)
return 108000; /* HT40 MCS5 */
if (snr < 24)
if (snr < 28)
return 121500; /* HT40 MCS6 */
if (snr < 32 || !vht)
return 135000; /* HT40 MCS7 */
if (snr < 34)
return 162000; /* VHT40 MCS8 */
return 180000; /* VHT40 MCS9 */
}
static unsigned int max_vht80_rate(int snr)
{
if (snr < 1)
if (snr < 8)
return 0;
if (snr < 2)
return 29300; /* VHT80 MCS0 */
if (snr < 5)
return 58500; /* VHT80 MCS1 */
if (snr < 9)
return 87800; /* VHT80 MCS2 */
if (snr < 11)
return 117000; /* VHT80 MCS3 */
return 29300; /* VHT80 MCS0 */
if (snr < 15)
return 58500; /* VHT80 MCS1 */
if (snr < 17)
return 87800; /* VHT80 MCS2 */
if (snr < 21)
return 117000; /* VHT80 MCS3 */
if (snr < 24)
return 175500; /* VHT80 MCS4 */
if (snr < 16)
if (snr < 26)
return 234000; /* VHT80 MCS5 */
if (snr < 18)
if (snr < 31)
return 263300; /* VHT80 MCS6 */
if (snr < 20)
if (snr < 35)
return 292500; /* VHT80 MCS7 */
if (snr < 22)
if (snr < 37)
return 351000; /* VHT80 MCS8 */
return 390000; /* VHT80 MCS9 */
}
@ -2285,7 +2295,7 @@ unsigned int wpas_get_est_tpt(const struct wpa_supplicant *wpa_s,
if (capab == CAPAB_HT || capab == CAPAB_HT40 || capab == CAPAB_VHT) {
ie = get_ie(ies, ies_len, WLAN_EID_HT_CAP);
if (ie) {
tmp = max_ht20_rate(snr);
tmp = max_ht20_rate(snr, 0);
if (tmp > est)
est = tmp;
}
@ -2295,7 +2305,7 @@ unsigned int wpas_get_est_tpt(const struct wpa_supplicant *wpa_s,
ie = get_ie(ies, ies_len, WLAN_EID_HT_OPERATION);
if (ie && ie[1] >= 2 &&
(ie[3] & HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK)) {
tmp = max_ht40_rate(snr);
tmp = max_ht40_rate(snr, 0);
if (tmp > est)
est = tmp;
}
@ -2305,7 +2315,7 @@ unsigned int wpas_get_est_tpt(const struct wpa_supplicant *wpa_s,
/* Use +1 to assume VHT is always faster than HT */
ie = get_ie(ies, ies_len, WLAN_EID_VHT_CAP);
if (ie) {
tmp = max_ht20_rate(snr) + 1;
tmp = max_ht20_rate(snr, 1) + 1;
if (tmp > est)
est = tmp;
@ -2313,7 +2323,7 @@ unsigned int wpas_get_est_tpt(const struct wpa_supplicant *wpa_s,
if (ie && ie[1] >= 2 &&
(ie[3] &
HT_INFO_HT_PARAM_SECONDARY_CHNL_OFF_MASK)) {
tmp = max_ht40_rate(snr) + 1;
tmp = max_ht40_rate(snr, 1) + 1;
if (tmp > est)
est = tmp;
}