Supposing I want the application firmware in my LoRaWAN end device to behave differently when it's in a given geolocation and that geolocation can be defined by the local Helium base station or cell ("gateway" in the LoRaWAN parlance?) that the end device is sitting in.

Suppose also that I'm happy to send one uplink and receive one downlink message in order to determine the gateway ID.

Section 3.2 of the LoRaWAN spec has only this to say about the downlink PHY frame:

Downlink PHY: Preamble PHDR PHDR_CRC PHYPayload

Is there also a gateway ID in there somewhere? Or is there in one of the other layers?

If not, could the application server know this from the uplink message and send it back as part of the downlink message payload?

  • Too lazy to check the specs but IIRC the end-device won’t get the info from the frame. In the other direction it depends on the LNS and application protocol, but the info is often available. Note that the same frame may be received by multiple gateways (depending on the LNS/protocol/settings you may receive multiple copies or only one), and also that the next downlink may be a lot later (it will be after the next uplink).
    – jcaron
    May 31, 2022 at 7:22

1 Answer 1


Yes - there is a gatewayID which you receive on every uplionk message but I see two issues:

  1. Your node might be in the range of more than one gateway and you will receive an array of gateway objects
  2. I can not imagine that it would be feasable to do a downlink after every uplink

BR Cademis

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