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Nordic Case Info
  • Case ID: 292306
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Enable eDRX seems not work

Tim Chao

Hi,

I am trying to test eDRX function on 9160DK with modem_shell.

The command returns ok.

But when I check the PPK output, it seems that the modem stay in DRX state and never enter sleep.

And here is the trace log.

trace-2022-07-14T06-06-46.613Z.bin

Please help to check what I did wrong.

Thanks.

  • 0

    Hello, 

    the DevZone team and Nordic Semiconductor are currently in a summer vacation period, some delays in answers must be expected due to lower staffing during this period. We apologize for the inconvenience. 

    Are you able to verify that your SIM supports power down mode? From the SIM Card Interface of the nRF9160 PS

    The LTE modem supports powering down the UICC during PSM and eDRX idle mode if the UICC supports this feature as specified in 3GPP TS 24.301. To reach the lowest total power consumption of the complete cellular IoT product, only UICCs supporting power down mode during PSM and eDRX idle mode sleep intervals should be considered.

    Please verify with your local SIM provider.

    Kind regards,
    Øyvind

  • 0 in reply to Øyvind

    I will ask the vendor first.

    But I have one more question. Does there is any command can be used to check if the connected carrier support PSM/eDRX or not? Or even a notification abount it cannot enter sleep.

    We are planing a LTE product that cannot restrict our end user to use specified SIM. We should not tell end user to ask their SIM vendor after they found the device battery is dead.

    And, can you tell me how to verify SIM's power down mode from SIM card interface?

    Thanks.

  • 0 in reply to Tim Chao
    Tim Chao said:
    But I have one more question. Does there is any command can be used to check if the connected carrier support PSM/eDRX or not? Or even a notification abount it cannot enter sleep.

    I believe the AT+CEDRXRDP command should provide more answers. From the output you provided it does look you have received the eDRX values. 


    Tim Chao said:
    We are planing a LTE product that cannot restrict our end user to use specified SIM. We should not tell end user to ask their SIM vendor after they found the device battery is dead.

    I understand that you might feel this way, however, this is what you need to do. At least you need to check with the local network providers if they support misc. settings. Different settings apply from network to network, and is very difficult to control from one side. E.g. iBasis SIM is a roaming SIM but not all networks allow roaming SIMs. GSMA has an information page on network roaming that could provide more information. The GSMA also provides a Mobile IoT Deployment Map which illustrates what different countries support LTE-M and/or NG-IoT. This page also includes LTE-M and NB-IoT deployment guides.

    Have a look at our white paper on Best practices for cellular IoT development (nWP044). 

    Tim Chao said:
    And, can you tell me how to verify SIM's power down mode from SIM card interface?

    From nWP044 

    Our advanced modem automatically optimizes the power consumption of the SIM card, but you can further improve this if the SIM card has the UICC suspend-resume feature enabled (specified in 3GPP TS 31.102 chapter 5.1.11). You can request this when ordering SIM cards to ensure that the SIM card does not use unnecessary current when not in use.

    Kind regards,
    Øyvind

  • 0

    Peaks of 50mA every 2.56s may also be caused by sticking in RRC Connected.

    The UICC requires in my experience about 20-30µA in idle, so far away from that 50mA.

    Though the question is 9 month old, I'm not sure, if you want to invest more time for investigations.

    If you're interested:

    How long a devices stay in RRC Connected is defined by the network operator and may be shorted by using RAI. Without RAI you need to wait for the "RRC Active Timer" until the device switches to RRC Idle and you eDRX settings get active.

    For details, see GSMA Energy Efficiency for Mobile IoT or Nordic - LTE-M vs NB-IoT Field Test: How Distance Affects Power Consumption.

    Currently some network operators are rolling out Rel 14 LTE-M and with that you have a chance of using AS RAI with LTE-M.

  • 0 in reply to Achim Kraus

    I'm sure the latest LTE_LC_EVT_RRC_UPDATE event I saw is RRC Idle, but not sure the reported state is right or not...

    As I know, the RAI is not suitable for TCP connection (please correct me if wrong). Because I am using MQTT protocol for data transmit (some customers even want HTTP...), I guess RAI is not the solution for me.

    BTW, dose current "RRC Active Timer" is readable?

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