Line 354 of the Lora-net packet forwarder protocol suggests that a gateway can receive the command from the server to transmit a downlink at a specific timestamp.
“tmst | number | Send packet on a certain timestamp value (will ignore time)”
Is there a way in Loraserver to configure this value so that I can manually select at what timestamp a downlink is sent? I’m not seeing it as a field in either the HTTP request or the MQTT JSON object, but if it is and simply not listed, that would be tremendously helpful.
How would you make sure that the node would be listening on the correct frequency at exactly that time?
Typically scheduling downlinks is something that the server does, not an application. And for class A nodes, it is done strictly in response to uplinks, with the downlink timing and frequency determined by an agreed mapping from the timing and frequency of the uplink.
We would be forcing a lora-equipped microcontroller to listen on the RX2 frequency every N seconds. It would let us have a device with similar protocol to Class B but more tightly controlled.
You can post your own transmit commands to the gateway MQTT topics, but you’d have to encode them yourself, and you won’t know the downlink counters and keys unless you query them from the API or snoop; also you’d then break loraserver’s downlink counter. If you can give your node a distinct state for the custom downlink vs the lorawan one you could avoid that.
Also you would have no de-confliction, as the server might ask the gateway to transmit at the same time, causing at least one of the requests to be unfulfilled