PSM active time not Correct

[Hkhan7861]

Good Day

I have enabled power saving on my nrf9160dk and am using NBIOT.  In doing so I found that there was a 60 sec offset to what I selected and what I wanted the active time to be.  IN doing some research I came across this question :  https://devzone.nordicsemi.com/f/nordic-q-a/87330/nrf9160-not-setting-requested-active-time 

The device is probably stuck in RRC idle for 60s before entering power saving mode.  This answer was never really solved and wanted to know if anybody found a way around this or if I will have to contact my provider?  If so, what would i need them to changed?

Kind regards,

Hassan

[Håkon Alseth]

Hi,

 

If the issue is that you're seeing a delay of 60 seconds before the power consumption goes to PSM level (ie. < 10 uA), the issue is highly likely the "RRC inactivity timer" which is set by the network itself.

This is explain here by Jonathan:

 RE: nRF9160-DK - sometimes busy for 1 minute before entering PSM 

 

Kind regards,

Håkon

[Achim Kraus]

> highly likely the "RRC inactivity timer"

That would be true, if the device stucks in RRC connected. But 

> The device is probably stuck in RRC idle for 60s before entering power saving mode.

indicates, that the device enters RRC idle.

[Hkhan7861]

Good day

I have tried to enable tracing but I ran into some errors when doing so.  I think it may be something in my configurations and i'll have a look now.  I have ran the trace collector and will upload the file now.  I hope that it can be of help.  Thank you again!trace-2022-11-23T09-31-05.277Z.bin

[Achim Kraus]

Yep, I also can't read that trace.

I'm looking forward to a readable one.

As you see in the other comments, the main question, which decides, in which parts and function you need to look further, is if the delay occurs in RRC connected or RRC idle.

[Achim Kraus]

> I think it may be something in my configurations and i'll have a look now.

I use

CONFIG_NRF_MODEM_LIB_TRACE_ENABLED=y

in the prj.conf. I disable the logging, but I'm not sure, if that helps. I select then "trace DB" in the "Trace Collector V2 preview v0.3.6" for my mfw. Using the nRF9160-DK it works quite well. 

[Hkhan7861]

Good day 

I must apologize for not getting back to you sooner.  I will reply as soon as I can.  Thank you !

Kind regards,

Hassan 

[Hkhan7861]

Good day 

I was not able to do the trace due to the project goals changing.  I would just like to ask, if the issue is in fact the RRC inactivity timer, what is the shortest time that anybody as seen.  I would like to know to help me decide if it is worthwhile to change our approach.

Kind regards,

Hassan

[Håkon Alseth]

Hi,

 

The RRC inactivity timer usually ranges in the seconds to a couple of minutes, and is set by the network you're connecting to. 60 seconds is quite commonly used.

 

Kind regards,

Håkon

[Achim Kraus]

GSMA NB-IoT Roaming Features April-2022 Landscape

Contains a list for several countries. I consider, the "RRC inactivity timer" is the "RRC activity timer" in that document.

[Achim Kraus]

Just to mention:

Using a UDP based protocol makes using RAI possible and that shortens the "RRC (in)actvitiy time" a lot. If you have a LinkeIn account, see

LinkedIn - Enlit Europe - nRF9160 Demo

(that's really a brilliant value!)

[Hkhan7861]

Thank you !

I am trying to contact my provider as we speak and we cannot shorten that time I will be moving toward a UDP based protocol.  Again, thank you for the assistance.

Kind regards,

Hassan.

[Achim Kraus]

Just to mention:

UDP for it self lucks "reliability". So you usually need a protocol on top of that, which implements something as "retransmission". CoAP/RFC 7252 is one common solution. You may combine it with DTLS (for now 1.2) and hopefully the merged DTLS 1.2 extension "Connection ID" gets available for zephyr as well. It was merged these day in mbedtls and will take some time until it's available in zephyr.

Just in the case, you want to have a "preview", you may also have a look at my demo-client (using the Eclipse stack Californium for the server side, and tinydtls on the nRF9160 device).

zephyr coaps client

As addition option, you may check, if

Access stratum Release Assistance Indication instead of Control plane Release Assistance Indication works for you. It requires your network operator to support Release 14 features. using SO_RAI_NO_DATA e.g.3s after you finished your communication, may have a chance. I had no success using SO_RAI_NO_DATA , but according that comments, there should be no general issue.