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LTE Link connecting is blocking?

Hi

In the mqtt_simple example there is a line "modem_configure();" which establishes the LTE Link connection. If connecting the LTE link is not possible (for example no signal), this function never returns.

1. Is this the intention of this function or is there a possibility to configure a timeout?

2. Is it normal, that this function needs several minutes to establish the LTE link, if a provider is present?

regards

ExAg

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  • I got the following reply:

    "Without log from different delays not possible to say what is the reason in that case but sounds like failures are not always because of ESM cause #26.

    If same SIM is always used then there is no difference in "NAS Signalling Low Priority", that is one factor defining UE behavior. If UE is configured for "NAS Signalling Low Priority" next attempt for ESM cause #26 will be done after 10 seconds.
    Network can include backoff timer value in reject and in that case delay given by network is used.
    With different EMM and ESM reject causes UE might be allowed to retry after 10 seconds."

  • Hi Simon

    Thank you for your reply. What exactly does this mean for us? I do not really understand, i am not an expert on LTE network connections. Are we doing something wrong?

    The only thing I can say is that we are always using the same SIM for all our tests.

    regards Michael

  • Nothing is pointing to anything wrong on your side (nRF91), the network seems to have some capacity issues or other issues causing temporary registration failures.

    However, without seeing additional logs from various delays we are not able to say anything for sure, there are always possibilities for errors in modem SW or maybe we can suggest workarounds for certain problems.

    If you can provide more logs we can check those.

    One thing I would suggest is to check with the operator that the SIM they are using is intended for IoT devices and is expected to work in the M1 network.

    Best regards,

    Simon

  • Hi Simon

    Thank you for your answers. So its most likely an issue of our national telecom provider. I will discuss this with them. Because these long connection times have a big influence of the total power consumption of an battery powered IoT device out in the field.

    The SIM card is specially for IoT purpose (for the M1 Network; NB is not yet supported at the moment).

    Best regards
    Michael

  • ExAg said:
    Thank you for your answers. So its most likely an issue of our national telecom provider

     Yes, based on the trace you sent. If you sent more traces from other delays, we can confirm this with more certainty.

    Best regards,

    Simon

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