Lagging downlink data (RAK10701)

LPWAN Nodes
1

Hello there!

I’m using a RAK10701 LoRaWAN field tester with AWS. After the tester sends an uplink, an AWS lambda function is triggered. Inside this function, the payload is processed and a downlink is sent back to the tester.

The data is getting to the device. However, it’s delayed one cycle. After an uplink n is sent, the device shows the downlink data corresponding to uplink n-1.

What could be going on?

Best,
Alex

2

Hi @kaminetzky ,

I suspect that the delay can be on the flow inside AWS.

The gateway is not capable on queuing or buffering downlinks and the end-device that will receive the downlink will just give callback if it gets anything.

Maybe you can have a look on the lambda functions or/and its connection with the AWS LoRaWAN downlink

3

Hello! Thank you for your reply.

I’m using lambda functions to send the downlink. The logs show that the downlink command is sent instantly.

I don’t understand what you mean by:

The gateway is not capable on queuing or buffering downlinks and the end-device that will receive the downlink will just give callback if it gets anything.

4

The idea is that gateways is unlikely the cause because it just transmit any downlink command coming from the LNS which AWS IoT Core for LoRaWAN in this scenario. Same with the end-device, it will just give a call back once a downlink is received.

I could missed something. Maybe you can share serial output from the module?

Take note, that when you send a downlink command, it will not be sent immediately to the device (unless you are in class C). You need to send an uplink so that the downlink message can be received via the RX windows that opens every each uplink in Class A operation.

5

Thank you for looking into my issue.

At the moment, the lagging data is not a critical issue. It’s good enough for now.

I’ll keep investigating and will let you know if I discover something.

6

@kaminetzky i came across this post that you have accomplished using the tester with aws lpwan. Would you be open to sharing the code? I’m at a loss as to how to process the testers uplink data.