The simplest way to verify if you have the airtime fairness stuff is
to look for a sysfs file named "airtime". The best way to test it is
to drive more than one wifi device over it simultaneously from a wired
link, and not through the ISP link.
flent -H device1 -H device2 -H device1 -H device2 rtt_fair_up # example
What is your wifi client presently?