Increased current consumption. The nRF9151 negotiates a TAU value of 10,800 seconds for PSM, but PSM is not working.

[freeelex]

Hi,

I’m using the function lte_lc_psm_param_set(rptau, rat). After connecting to LTE, I call lte_lc_psm_get(&psm_cfg.tau, &psm_cfg.active_time) and receive the following response:

PSM is ACTIVE: TAU=10800 s, Active Time=-1 s

It looks like the TAU value is being set correctly. However, Active_Time is returned as -1. Does this response mean that the device is ready to enter PSM?

I'm using the Power Profiler, and it seems that the nRF9151 is waking up approximately every second regardless. I've also added eDRX configuration after establishing the LTE connection, but this doesn't make any difference either. Whether I enable PSM or eDRX, the current consumption profile remains the same. I’ve attached power trace screenshots below.

What can I do to ensure the device actually enters PSM mode? Despite the response I’m receiving, could it be that the device never enters PSM? Also, why isn’t eDRX working either?

Additionally, I disable logging before the device goes to sleep and re-enable it after waking up. I can see a difference in current consumption when doing this - but unfortunately, only in that part.

[freeelex]

Orange Poland. 

At this point, I would focus more on why I’m not receiving any events related to the connection status or IP address assignment.

In addition to the previous masks, I also have the following defined:

#define CONN_LAYER_EVENT_MASK (NET_EVENT_IF_UP | NET_EVENT_IF_DOWN | NET_EVENT_CONN_IF_FATAL_ERROR)

I'm starting to suspect that NCS version 3.0.2 might not be fully stable. Even when compiling the official samples, I get the following warnings:

warning: Experimental symbol COAP_CLIENT is enabled.

warning: Experimental symbol NET_CONNECTION_MANAGER is enabled.

Is it possible that these modules are not fully functional or reliable in this release?

[Achim Kraus]

freeelex said:

Orange Poland. 

The good point, AFAIK Nordic has also engineers in Poland. And though you use the SIM cards bundled, it should be a not too hard for Nordic to test and reproduce this issue.

My own experience in Poland (about 3 years ago, NB-IoT, Telekom) was disappointing, my device didn't get PSM and so the battery was drained quite a lot on that test drive. Anyway, the data arrived.

freeelex said:

official samples

If you go through the forum, you will also get aware, that the samples are samples and not "product ready". I guess you will need to wait until someone of Nordic assists you.

If you don't want to wait and want some faster results and you use a nRF9151-DK, a Thingy:91X, a Feather nRF9151, a Conexio Stratus Pro nRF9151, or a Makerdiary nRF9151 Connect Kit you may also check my coaps client (I'm currently still using NCS 2.9.2).