ANT Forum

Hi,

We are testing the reliability of the status during an Acknowledged data transmission and we are noticing about a 3% failure rate.

For example, if A sends to B, A will sometimes receive a response saying EVENT_TRANSFER_TX_FAILED but B would still be able to correctly assemble a complete packet with a correct CRC.

Are the Acknowledged data responses always guaranteed to be correct? Or is it assumed since this is a wireless connection, that these type of response uncertainties will always occur occasionally?

We are not sure if we should adjust our protocol to compensate for occasional uncertainties or if we have a bug in the code.

Thanks,
J      

Hi J,

A response to an acknowledged message is a message packet like any other packet, hence it is subject to the same interference and reliability issues as any wireless communication in your system. As such, it is very possible that a packet will be successfully transmitted, only to have the acknowledge response fail.

This may cause an ambiguity in your system, if your system relies on acknowledged message packets to advance a state machine. For this reason please do not rely on the success or failure of an acknowledged message to advance state machines in your system.

For an example of the proper way to handle state machines in a wireless system such as ANT, please have a look at the ANT-FS Technical Specification, available in the ANT+ Member Zone.

Regards,
Sebastian