RE: Increase OT broadcast message reliability

SimonEMB — Mon, 14 Feb 2022 16:19:25 GMT

Hi Edvin

Thanks for your answer, I will look into it very soon and check what I can do.
In the same time I will check in the openThread lib src what is said about frequency hopping.

Best regards

RE: Increase OT broadcast message reliability

Edvin — Wed, 09 Feb 2022 13:55:59 GMT

Hello,

Openthread is a prebuilt library in the nRF5 SDK, which uses many definitions from the application. So even if it doesn't seem like definitions like the OPENTHREAD_CONFIG_MAC_TX_NUM_BCAST is being used anywhere, it will most likely be used by the openthread libraries.

However in this case, I looked it up this definition (OPENTHREAD_CONFIG_MAC_TX_NUM_BCAST), and it is used in a file called mac.hpp (which in the nRF5 SDK is part of the openthread library). It is used to set a variable called kTxNumBcast, which is only used if another definition OPENTHREAD_CONFIG_MULTI_RADIO is set to1. By default this is set to 1 if:

#if (OPENTHREAD_CONFIG_RADIO_LINK_IEEE_802_15_4_ENABLE && OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE)
#define OPENTHREAD_CONFIG_MULTI_RADIO 1
#else
#define OPENTHREAD_CONFIG_MULTI_RADIO 0
#endif

where OPENTHREAD_CONFIG_RADIO_LINK_IEEE_802_15_4_ENABLE is 1 by default, but OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE is 0 by default.

This means that if you would like OPENTHREAD_CONFIG_MAC_TX_NUM_BCAST to be used, then you need to set OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE to 1. But in order to change OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE in the nRF5 SDK you need to rebuild the openthread libraries. Instructions on how to do this is described in this guide. Please note that in order for the library to be compatible with the SDK, you should check out the same commit that is used to build the openthread library that is used in the SDK, which is mentioned in SDK\external\openthread\project\readme.txt.

To summarize: You either need to move over to NCS, or you need to rebuild the openthread library with OPENTHREAD_CONFIG_RADIO_LINK_TREL_ENABLE set to 1 in order to utilize OPENTHREAD_CONFIG_MAC_TX_NUM_BCAST.

Best regards,

Edvin