10 months ago.


Great presentation, guys. Thanks for it.

I am wondering about a comment Austin made about ABP vs OTAA. Paraphrasing, he said something to the effect of, "ABP would be better for stationary devices whereas OTAA would be better for mobile devices." My understanding is that the justification for the comment is that the join request/accept process associated with OTAA is time/power consuming whereas ABP does not have this issue.

To clarify, would this only be an issue the first time a device joins and/or when a device rejoins the network? IOW, presuming an OTAA device stays connected for an extended period of time, the only delta with an ABP device is from the joins. Correct?

Question relating to:

A dynamic session context (OTAA) can become handy while roaming as the device will be free to change session keys if required to. ABP devices cannot do session context switching. Having said that, I do not see why ABP cannot be used with mobile devices if not roaming. However, I do wish to point out that using OTAA have its added benifits. For example: correct channel plan acquisition through CFList, correct datarate setup, RX1 timing offset and ADR setup. All of this happen right from the onset, i.e, when the device recieves a JoinAccept message. These features help reduce the aggregate band timeoff, which is to say, your DC backoff will be shorter. Ofcourse you can acheive all this with ABP as well if you know all the nitty-gritty details of your NS provider’s setup in your area. I hope this clarifies your question.

posted by Hasnain Virk 14 Aug 2018

Thanks, Hasnain. Our LoRa implementation is intended for stationary devices. For various reasons including those you provided, we use OTAA. We do not foresee utilizing ABP any time soon if at all. So, my question was intended to clarify why OTAA might not be as good as ABP for stationary devices. In other words, why ABP might be acceptable for mobile applications is not important to us.

posted by John Greene 15 Aug 2018
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