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Nordic Case Info
  • Case ID: 323486
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SIM shutdown does not happen during the e-DRX cycle greater than 60 seconds on NRF9151 DK

mnjLC

We recently got the NRF9151-DK and were trting to measure the e-DRX current on the system working on CAT-M1 network. The NRF9151 DK is loaded with Serial LTE Modem application ( Default application that it was shipped with )and Modem firmware v2.0.0 ( Default FW that it was shipped with ). According to this post we have set the follwing at commands 

at+cfun=0

AT%XDATAPRFL=0 // sets the low power mode

AT+SSRDA=0,1,0 // sim shut shutdown

at+cfun=1

at+cedrx=2,4,”0101”

We are still seeing 35uA of floor current during e-DRX cycle. We feel this is a bug in the pre lodaed FW. Can someone from nordic try it on their NRF9151-DK and share the results?. I all attaching the PPK2 trace with this post.

Thanks!

nrf9151_eDRX_80_PTW_1_1NCE_NoShutoff.ppk

Parents Reply
  • 0 in reply to papatel
    papatel said:
    I'd first like to point out that the form factor does indeed make implications on the endurance capability of the NVRAM.  *Usually* MFF2 sims have a significantly higher endurance rating than their plastic counter parts. 

    While MFF2 SIMs often have higher endurance ratings, my point is that there isn't, as far as I know, nothing inherent in the MFF2 form factor that makes it true. You can have plastic SIMs with high endurance rating, and MFF2s with low ratings.

    Any writing to flash will contribute to the flash wear, though as you say, there are many factors that contribute to how big of an issue this is.

    papatel said:
    The best solution would be a software SIM but I'm not getting any answers from my contacts at Nordic or our MVNO as to when that feature will be available.

    SoftSIM is been supported on the nRF9160 and nRF91x1 devices.

    I don't have a full overview of which operators are working on providing it, but at the moment, it is available from at least Onomondo and IIJ:

    https://onomondo.com/product/softsim-for-nordic-semiconductor/

    https://www.iij.ad.jp/en/news/pressrelease/2024/0226.html

Children
  • 0 in reply to Didrik Rokhaug

    Hello Didrik,

    Thank you again for your response.  Given that SoftSim makes this feature obsolete and has several other advantages, I'd really appreciate candid updates on that front.  The community wants it yet there is so little information coming from Nordic on the subject.  If the strategy is to herd people toward using Onomondo, that is something we need to understand now.

  • 0 in reply to papatel
    papatel said:

    We do have a question regarding suspend vs sim shutoff.  If your comment about wearing flash out applies even to proper implementations of the suspend command, that is an alarming concern.  There are a ton of factors here to consider for a physical SIM:

    • Endurance cycle, industrial MFF2 sims claim 500MM write cycles
    • Flash wear level implementation
    • Flash size (larger flash means less wear per cell if you have good wear leveling implemented)

    Questions about flash wear leveling, etc. you have to take with the SIM card provider. That is SIM card internal functionality that our modem has no control over.

    I also checked with our SIM expert about why SIM cards does not allow deactivation. This was his response:

    "I’m not very well aware why deactivation is not allowed by many SIM cards. Haven’t heard card provider’s statements related to that.

    I suppose one reason could be concerns about toolkit application functionality. They get shut down and restarted every time when SIM card is deactivated/activated. Suspend is an improvement to that since it allows the SIM card to store it’s internal state before deactivation and continue from same situation after activation. It requires also implementation on SIM card side, and it looks like very few SIM cards have that done."

    papatel said:
    Given that SoftSim makes this feature obsolete and has several other advantages, I'd really appreciate candid updates on that front.  The community wants it yet there is so little information coming from Nordic on the subject.  If the strategy is to herd people toward using Onomondo, that is something we need to understand now.

    Can you be more specific about what information you think is missing?

    Questions about our roadmap should be taken to your local sales representative. I am not at liberty to discuss those details.

    Our interface SoftSIM interface should support SoftSIMs from any provider. However, it is up to each provider if they want to provide SoftSIMs, and what platforms to support. Onomondo is the first to be generally available (at least as far as I know), and information about their solution is also easily available, which is why they are usually used as the example.

  • 0 in reply to Didrik Rokhaug

    Hello Didrik,

    You make some valid points about SIM concerns being outside the scope of Nordic semiconductor. 

    Regarding the response from your SIM expert, I'm trying to read between the lines that proper implementations of suspend don't actually wear out the flash while SIM shutfoff certainly can.  Can you please check that this assumption is correct?  I believe clarifying this question will help guide integrators tremendously.  More importantly high volume customers can influence the industry in a positive manner by selecting SIM manufacturers that support this valuable feature.  But if you are saying SIM suspend is no better than SIM shutoff then we can stop wasting time on the subject.  This is how Mihir and I interpreted your comment and why we are worried:


    "Not all SIM cards allows you to turn them off (using either suspend or deactivate) during eDRX, as that would wear out their flash too quickly, leaving you with an unusable SIM card (and product)."

    I really appreciate your comments regarding Nordic SoftSIM.  I will ask my Nordic and MVNO representatives more clearly on this point.

    After further research I believe that Noridic is offering access to its SoftSIM platform to everyone who wants it.  It's just that this is not likely a standard that will be widely accepted outside of Nordic (not GSMA adopted) so it's hard for MVNO's and carriers to justify the implementation work until there is a critical mass of adopters.  Onomondo may just be the first instance and more will follow with time.  Either way, this is super concerning and I'm not sure we will use Nordic's SoftSIM offering.  My company is looking 5 years down the line and having several million devices deployed on a dead SoftSIM platform doesn't seem particularly appealing. Or when we have connectivity problems we don't get support from network providers.  Maybe I just need an education that will explain my concerns away?

    I'm hope my rambling here at least conveys that there isn't enough clear information about Nordic's Soft SIM and how it sits in the industry.

    So full circle, I need answers on SIM suspend concerns.  Our MVNO has confirmed this feature is supported (we don't need to force SIM shutoff).  I will reach out to the SIM manufacturer itself if we can't get Nordic to answer this question more broadly for the community at least for the most common SIM hardware used by its customers.

    Nordic an excellent Onomondo reference for SoftSIM implementation, I'm asking for the same toward a proper implementation of SIM Suspend that won't lead to premature connectivity failure.

  • 0 in reply to papatel
    papatel said:
    After further research I believe that Noridic is offering access to its SoftSIM platform to everyone who wants it.  It's just that this is not likely a standard that will be widely accepted outside of Nordic (not GSMA adopted) so it's hard for MVNO's and carriers to justify the implementation work until there is a critical mass of adopters.

    As far as I know (I will try to get this confirmed though) there is no standard interface for SoftSIMs. Though even if it were, there would probably be some porting needed anyway, to adapt a particular SoftSIM solution to the relevant HW and SW platform.

    papatel said:
    Onomondo may just be the first instance and more will follow with time.  Either way, this is super concerning and I'm not sure we will use Nordic's SoftSIM offering.  My company is looking 5 years down the line and having several million devices deployed on a dead SoftSIM platform doesn't seem particularly appealing.

    If you haven't already, I recommend you take this up with your local sales representative. They should have a better overview of any other potentila SoftSIM providers. If you don't know how to contact your local sales representative, you can send me a private message with your location, and I will provide the contact details.

    papatel said:
    Or when we have connectivity problems we don't get support from network providers.

    In my experience, Onomondo is quite helpful when it comes to looking into connectivity problems, and on their web platform you can get network logs. Though as an MVNO, they of course only cover the core network. If you are thinking of RAN problems, you will have the same problem with any MVNO regardless of the type of SIM, and similarly if you use an MNO, but are roaming on a different network.

    papatel said:
    Regarding the response from your SIM expert, I'm trying to read between the lines that proper implementations of suspend don't actually wear out the flash while SIM shutfoff certainly can.  Can you please check that this assumption is correct? 

    I will check and come back to you.

  • 0 in reply to Didrik Rokhaug
    Didrik Rokhaug said:
    As far as I know (I will try to get this confirmed though) there is no standard interface for SoftSIMs.

    Our SIM expert also doesn't know of any standard interface for SoftSIMs.

    Didrik Rokhaug said:
    papatel said:
    Regarding the response from your SIM expert, I'm trying to read between the lines that proper implementations of suspend don't actually wear out the flash while SIM shutfoff certainly can.  Can you please check that this assumption is correct? 

    I will check and come back to you.

    "Suspend uses flash to store the internal state of SIM card, so I think that a proper implementation could be expected to tolerate large number of write cycles. Such SIM card should not wear out too soon due to use of suspend functionality for power saving."

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