LoPy Nanogateway - is NTP sync necessary?

  • I have two LoPys -

    1. LoPy1.0 as nanogateway and connected to a RPi3 running a chirpstack.io (or loraserver.io) LoRaWAN server.
    2. LoPy4.0 end node sending packets every 5 secods over OTAA.

    Since there is no internet on RPi3, I removed the NTP sync lines from the nanogateway.py file.

    The gateway connects and the node also joins the network.

    I can see the data on the RPi3 BUT I do not see them at the required rate i.e. 5 seconds. The packets are received in an interval ranging from 20 seconds to more than 1 minutes. i.e., I can guess there are some losses. At the application side, the time on RX packet is in 1970s. Does this matter?

    The clock at RPi3 is also not set to current local time.

    My question is does NTP sync causing this behaviour OR am I missing something?

    I have gone through all the issues in the pycom forum but nothing solves my problem.

  • @jcaron Yes, I know, just used it for few minutes for testing.

  • @tsemwal one frame every 5 seconds? Which region are you in? What data rate/spreading factor are your using? Which channel(s)/frequency(ies)? What’s the size of your frames?

    In many combinations this could be way above regulations.

  • Thanks @robert-hh . As you said ntp-sync is not the issue, I was able to focus on other areas and finally able to solve my problem. I was using my own code at the end node side which does not remove channels. I switched to the code provided by PyCom.

  • @tsemwal The LoRaWAN messages do not include the time. Given that, the ntp-sync is not required for the LoraWAN communication.
    It just happened here that after a power outage my Lora Gateways started with a wrong time. That does not stop them from working.

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