Couple of suggestions:
- Turn of a, only use n/ac
- Don't use anything other then WPA2-AES
- Distance Indoors (if used indoors)
- Turn on WMM
- Rates: 12/24 (basic) and 12 - 54 (supported)
- Choose channel manually
- Lower (max) transmission power by 3dB
@erlinden，could you please let me know where in CAPsMAN to set the WMM ? I did the rest you suggested but cannot find WMM set up. thank you !
CAPSMAN sets WMM, it can not be turned off (says Uldis: viewtopic.php?f=2&t=125152
Worse, WMM is probably only overhead if there are no mangle rules to set the priority.
MCS5 and MCS7 are not the top speed for the "ac" interface rate. Check "registration" for CCQ and retransmits. (it wastes time, lowers the MCS rate).
The % bandwidth you get from an interface depends on aggregation. If there are many retransmits the A-PMDU with smaller A-MSDU should be preferred above A-MSDU at max size.
Tuning is then lowering hw_retry=3, set max VHT MCS, A-MSDU=2048, even going to 2X2 .... all steps that each lower the capacity considerably, but one of them might still give better results.
All of them together would be a very drastic reduction. Don't use them if no gain in throughput.