For doing that, you can check the value of the power save mode:

cat /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf 

And change the value to 2 by doing:

sudo sed -i 's/wifi.powersave = 3/wifi.powersave = 2/' /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf

Possible values for the wifi.powersave field are:

NM_SETTING_WIRELESS_POWERSAVE_DEFAULT (0): use the default value
NM_SETTING_WIRELESS_POWERSAVE_IGNORE  (1): don't touch existing setting
NM_SETTING_WIRELESS_POWERSAVE_DISABLE (2): disable powersave
NM_SETTING_WIRELESS_POWERSAVE_ENABLE  (3): enable powersave