SDK 13.1 NRF52832 Ant+ channel collision

[Linxi]

Dear Nordic ：

Our mass-produced smart trainer(16M external oscillator, 20PPM) supports ANT+ FEC and ANT+ Bicycle Power , so there are two channels alive wtih 4Hz frequency in our firmware.

We have been troubled for a long time about the signal interference. Although, there are many reasons for it, like distance, environment.

Except those uncontrollable reasons, we wanna do out best to optimize our software to improve user experience.

We found some information about channel collision. But I didn't  find any solutions. 

We did  some experiments to track the feature when signal accident happened. We use SimulANT+ to connect with our trainer and printf ANT+ EVENT in the SDK.

We found that when "Rx failed" appearing frequently in SimulANT+,it's also the time to printf  "EVENT_CHANNEL_COLLISION".

If i keep only one channel alive, the signal interference situation becomes acceptable. 

Please give me your comments? Or if you have any idea about enhancing ANT+ signal , share to us.

[Kenneth]

Hi,

The channel period of ANT+ bicycle power is 8182 (/32768 seconds) and the channel period of ANT+ fitness equipment is 8192 (/32768 seconds). This means that intermittently over time they will collide in time, before the drift apart again. There is a difference in channel period of (8192-8182)/32768 seconds = 0.305ms, but since both transmit on average about every ~250ms, they will collide sometimes. There is nothing that can be done about this.

Best regards,
Kenneth