Frequent ANT + BLE disconnects when running concurrently

[Noxstella]

Hi ,

We have a device running nRF5 SDK 16.0.0 with SoftDevice S332 (BLE + ANT). We use BLE Central/Peripheral links plus multiple ANT sensors. Under load we see frequent disconnects on both BLE and ANT (often within seconds to minutes). Supervision timeouts and ANT channel closures are the common symptoms.

Setup details:

• SDK/SoftDevice: nRF5 SDK 16.0.0, SoftDevice S332 (default config, BLE + ANT enabled).
• Roles: BLE Central to multiple peripherals; sometimes also BLE Peripheral; ANT Master/Slave channels for sensors (BPWR/FE/DI2, etc.).
• Connection params: BLE conn interval ~50–100 ms, latency varies (0–9), supervision 4–6 s. ANT period default (4 Hz / 8 Hz) with channel event length default.
• Data length/PHY: Data length extension enabled, 1M PHY.
• Timers/RTOS: app_timer + FreeRTOS (nrf_sdh_freertos).
• We suspect radio scheduling conflicts between BLE and ANT events but need guidance.

Questions:

       Currently, it is suspected that the issue is related to the configuration of scanning and connection parameters. Are there any optimal configuration strategies for these two parameters?

Thanks for any pointers or known good configurations for stable BLE + ANT coexistence on S332.

[Kenneth]

Hello,

When you try to scan and connect with a BLE enabled peer device, try to define the scan parameters interval = window = 5ms.

When you try to search for an ANT enabled peer device, then disable high priority search, and use low priority search only.

Best regards,
Kenneth

[Lewis Hall]

Hello Kenneth,

In mixed BLE Central + multiple ANT channel setups, is low-priority search generally recommended all the time, or only once the system is under load? Steal Brainrot Game

[Kenneth]

For least impact on existing channels I recommend to use low-priority search. 

Kenneth

[Noxstella]

Hello Kenneth,

Thanks for your answer

When ANT and Bluetooth are performing scanning simultaneously, is the 5 ms scan interval and scan window of Bluetooth too small, which consequently degrades the performance of ANT?

[Kenneth]

If you set 5ms scan window=interval, then it should fit those between other activities. I don't expect that interfere with other activities.

Kenneth