Wi-Fi/WLAN Throughput issues

The main reasons for low throughput are shown below :👉

  • Retries 
  • Device or DUT or Station going to Power save mode while running throughput session , this will  impact the overall throughput
  • Frame Aggregation either AMPDU or AMSDU or AMSDU inside AMPDU , for example : Maximum number of MSDUs can fit inside AMSDU is around 1 or 2 or 3 or 4 this will vary according the vendor implementation , Using maximum number will help achieving the very good throughput numbers
  • Under AMPDU , max we can send upto 64 MPDUs , if we are maintaining this number for entire throughput session , this will also help to achieve max peak throughput values . It may vary according to the Wi-Fi standard 4 or 5 or 6 based on Max AMPDU size and also its number may vary from 64 to 32 or 16 or 8 or some random number of MPDUs under AMPDUs not exceeding 64 
  •   If we are not responding to RTS frames before data transfer from the peer device (either AP or other DUT or Station) then there is chance to lower the data rates of data frames 
  • Blockack holes like ff00ff1001ff00ab or 0100ff1001ff0000 or 0100000000000000 or f000000000000000 and more examples like this will impact the overall throughput 
  • Irregular beaconing from AP also cause for low throughput 
  • Beacon RSSI fluctuation will also impact throughput
  • Sometimes very strong RSSI value also impacts
  • RSSI fluctuation while transferring data frames impacts 
  • Complete retransmissions of AMPDU instead of MDPUs leads to very low throughput
  • With Beamforming enabled , if the feedback matrix is not updated properly by DUT or Station in response to NDPA frames , which will lead to wrong direction of beam projection while transferring data 
  • If DUT or Station sending QoS NULL frames in response to Trigger frames like in OFDMA MU data session , will impact 
  • FCS errors 
  • Check for RF Chamber leakages
  • Check whether any APs operating in the same channel or secondary channels while running throughput session
  • Make sure that any active scanning is not happening while running throughput session
  • Check for the backend LAN Speeds like 10 Gbps or 1 Gbps based on Wi-Fi standards and make sure that backend network generate sufficient speed
  • Try with different iperf version as well
  • Check the CPU Utilization while running throughput
  • Check for TCP Window size 
Work arounds : 👍
  • If throughput is bad for Bandwidths like 160 MHz or 80 MHz then try for 40 MHz or 20MHz  throughputs and compare 
  • Check for AMSDU size like subframes inside AMSDU
  • If station supports for different roles like p2p go or mobile hotspot (softap) then check for individual role performances
  • Adjust the RSSI values or Orientations for achieving the peak performance


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