I am using the Linaro 18_01 release. I am seeing the Throught put drop issue with specific AP (tested with Tp-Link). We are not seen the t-put issue with other STA device.
I verified the sniffer captures where is data rate is dropping like below
- Data re transmitted from AP with 65 Mbps
- RTS sent from the AP with 24 Mbps
- RTS rate is dropped to 12 Mbps
- RTS rate dropped to 1Mbps
- After this point Data rate is dropped to 11Mbps, which never pick up.
If we ran the wifi_scan in between Iperf3 test, also see the T-put low <3Mbps and never pick up again.
STA went to scan without informing AP that it’s going to sleep (the bit in control field of any of data packets should be set to 1 - power save). It could be sniffer issue but both AP and sniffer doesn’t see this packet so most probably station issue.
Since AP didn’t get information that STA went to sleep, it thinks that STA can receive the packets and continue to send it to station. Finally since the station doesn’t respond, it sends BA request to verify last successfully received packets from station and didn’t get response since the station is still in scan and most probably closes aggregation - after that all packets are being sent on lower legacy rates and without aggregation and therefore throughput dropped significantly after station returns from scan.
STA doesn’t inform AP that it’s going to sleep before the scan start by setting Power save bit of any data packets (if STA doesn’t have anything to send data to AP it must send QOS null or Null data packets with Power save bit set - sleep).
[FYI - Also tested with DB410 and release 20_02 as well, same behavior observed]
Do you have any suggestion?