PSM TAU and AT

[Mohammad Amin]

Hi, 

1. I have been trying to measure the current consumption of the development board of nRF9160 in PSM mode, however, until now I could have not understood the role of TAU and AT on the current consumption. According to "3GPP TS 24.008 Table 10.5.163a/3GPP TS 24.008" that is mentioned in the AT commands document, if bits 8-6 of Tracking area update(TAU) are set to "010", the timer unit will be 10 hours, however, the spikes time difference that I see does not change that much compared to the time when it is set to "001" which is one hour. I also am not sure about the role of AT too. Can anyone please explain this to me?

2. Is this possible to see if the nRF9160 is connected to the network through LTE or LTE-M?

3. I am using iBASIS and HOLOGRAM  IoT SIM cards that connect exactly to the same operator( Rogers), however, iBASIS shows a lot more power consumption than the HOLOGRAM. Why is this happening?

This is one of the current measurements I got:

[Carl Richard]

Hi Mohammad!

We just ran into a somewhat similar issue, it's not resolved yet, but I can maybe provide some helpful info! We also use the iBasis card and have discovered that it forces the <Requested active time> value to 0, effectively disabling PSM. 

You can check if there is a difference in the PSM modes of your different providers by using the AT command AT+CPSMS? after activating PSM. (as stated in the AT Command documentation). It will return the parameters used.

Hope you can utilize this!

For reference: we are situated in Norway, so it could be a different situation.

- Carl

[Mohammad Amin]

Thanks. I used other sim cards and it seems they enter PSM mode.