Part Number: WL1837MOD
Other Parts Discussed in Thread: WL1837
Good Morning,
I am trying to bring up a WiFi/BT solution that supports data transfer via TCP sockets on the WLAN while there is an active BT audio (A2DP) sink running. I can operate both WLAN and BT by themselves and see performance on par with what the TI application documents suggest is reasonable. The issue is that when I attempt to do both simultaneously, I observe a major degradation in the performance of the WLAN link.
I am currently testing with Linux on a BeagleBone Black using the Element14 Connectivity cape (WL1837MOD). I've included some collected performance data below. Most of the numbers look reasonable, however, there is a >90% reduction in performance of the 2.4Ghz WLAN when I enable the A2DP stream. When WiFi is operating at 5Ghz there is no degradation, which makes me suspect that something isn't quite right with the coexistence algorithm rather than a bottleneck in the CPU.
Referencing SWRU424A and comparing the collected numbers in section 9.1 with the numbers in 9.4.1 indicates that the drop in performance should be more along the lines of 50%, rather than >90%. This makes me wonder if I've configured something incorrectly or missed a step that is needed to get the coexistence algorithm to work as designed.
Any thoughts or insight on these results would be appreciated. Ultimately I'd like to get some confidence that these numbers reflect real-world expected performance so that we can adjust our design accordingly. If we should be getting better data rates I'd like to understand what we're missing. Please feel free to let me know if any additional information would be helpful.
Thanks!
Test Details:
- WL1837/BeagleBone running in AP mode (I have also tried client mode using a local router with similar results)
- BeagleBone is running a custom Yocto image based on Linux 4.19. The bluetooth is managed by our own BT stack (ie. not using bluez or Bluetopia)
- iperf3 server running on BeagleBone (iperf3 -s)
- iperf3 running on client device (iperf3 XXX.XXX.X.X -V -t30) (tried from Android phone, iPad, and laptop, all show similar results)
- Results in the table below are shown from the perspective of the client device
- BT is paired/connected for all tests. Have tried variations of streaming from same device as the iperf3 client as well as other devices with no perceptible improvement
- A2DP stream is activated by simply playing music or voice audio via some Android/iPad media player
| AP Config | A2DP Streaming | Channel (width) | iperf3 Result TX (Mbps) | iperf3 Result RX (Mbps) |
|---|---|---|---|---|
| 2.4GHz WPA PSK | Yes | 6 (20 MHz) | 2.44 | 0.229 |
| 2.09 | 0.0779 | |||
| 2.44 | 0.262 | |||
| 2.44 | 0.328 | |||
| 2.44 | 0.264 | |||
| 2.4GHz WPA PSK | No | 6 (20 MHz) | 26.5 | 24.7 |
| 26.2 | 24.2 | |||
| 29.3 | 27.6 | |||
| 30.1 | 28.1 | |||
| 24.1 | 22.1 | |||
| 6 (20 MHz) MIMO | 78 | 58 | ||
| 75 | 65 | |||
| 78 | 50 | |||
| 75 | 46 | |||
| 77 | 62 | |||
| 5GHz WPA PSK | Yes | 44 (20MHz) | 48.0 | 47.1 |
| 47.4 | 46.7 | |||
| 45.9 | 45.6 | |||
| 48.8 | 48.4 | |||
| 48.1 |
47.6 |
|||
| 157/159(40MHz) | 95.4 | 95.3 | ||
| 94.5 | 95.2 | |||
| 95.7 | 95.3 | |||
| 5GHz WPA PSK | No | 44 (20MHz) | 48.4 | 47.9 |
| 50.0 | 50.0 | |||
| 49.9 | 49.5 | |||
| 50.1 | 49.8 | |||
| 49.9 | 49.5 | |||
| 157/159(40MHz) | 92.7 | 92.5 | ||
| 96.2 | 96.1 |
