• State Not Answered
  • Replies 3 replies
  • Subscribers 65 subscribers
  • Views 165 views
  • Users 0 members are here
Attachments (0)
Nordic Case Info
  • Case ID: 328002
Options

Issues connecting to certain cell towers using nRF9160 with NB-IoT on Vodafone UK

c.booth

We are experiencing intermittent connection issues with the nRF9160 using NB-IoT on the Vodafone UK network.

Our devices fail to connect or register with certain cell towers. The issue occurs intermittently, with a few weeks of stable connection followed by weeks of repeated failures. Initially, we identified one specific cell tower with this issue, but we now suspect it may be occurring with other cell towers as well.

When attempting to connect, we observe the log message (from the LTE_LC_EVT_CELL_UPDATE event): "LTE cell changed: Cell ID: 128419339, Tracking area: 42030". However, no further log messages are recorded after this point (such as LTE_LC_EVT_NW_REG_STATUS or LTE_LC_EVT_RRC_UPDATE events). Occasionally, the device eventually connects after an extended period, but most often, it requires a reboot/powered off for extended period to establish a connection.

We have consulted with Vodafone UK, who confirmed there are no issues with the initially identified cell tower.

The issue is reproducible on two different firmware setups:
- nRF Connect SDK v1.8.0 running v1.3.2 Modem Firmware
- nRF Connect SDK v2.5.0 running v1.3.5 Modem Firmware

Are there specific AT commands or notifications we should monitor to debug why we are not able to connect/register with the cell tower? Or would you require a modem trace log to diagnose the problem?

Thank you for your assistance.

Parents Reply Children
  • 0 in reply to dejans

    Hi Dejan,

    Thank you for your response.

    Since raising this ticket, we have not experienced the issue. Previously, it was a persistent problem for several months.

    Could you please close this ticket for now? If the issue reoccurs, I will create a new ticket with the application logs and any additional information required.

    In the meantime, would monitoring notifications from the "AT+CNEC=24" command help us determine the cause of the rejection from the cell tower? The problem affected all devices within a specific location, and all devices are always stationary.

    Thank you for your assistance.

    Best regards,
    Chris

  • 0 in reply to c.booth

    Hi Chris,

    c.booth said:
    In the meantime, would monitoring notifications from the "AT+CNEC=24" command help us determine the cause of the rejection from the cell tower? The problem affected all devices within a specific location, and all devices are always stationary.

    Yes. You can monitor rejection causes using AT+CNEC=24.

    I am closing this ticket. If you need further assistance, please open a new ticket.

    Best regards,
    Dejan

Related