Hello,
I am using SDK v1.3.0 with modem firmware v1.2.0 with the nRF9160 DK v0.9.0. I am using an AT&T SIM card to connect to their LTE Cat-M1 network.
I would like to use the Asset Tracker application in PSM between transmissions to nRF Cloud. I am not interested in GPS and I only want the device to stay in LTE mode (not go into GPS mode by pressing button 1). I am following the power optimization section of the documentation for the example here (https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.3.0/nrf/applications/asset_tracker/README.html#power-optimization) and I have set the CONFIG_POWER_OPTIMIZATION_ENABLE=y option in my prj.conf file. This should allow me to request eDRX or PSM depending on the position of SW2. By default, the prj.conf file also has the CONFIG_GPS_CONTROL_PSM_ENABLE_ON_START=y option. I left the PSM TAU (10 minutes) and Active Time (1 minute) to the default values in the prj.conf file.
CONFIG_LTE_PSM_REQ_RPTAU="10101010"
CONFIG_LTE_PSM_REQ_RAT="00100001"
When I boot the device, I get connected to nRF Cloud and the device appears to be tranmitting every 30 seconds. Then I move SW2 to GND to enable PSM and I see the following in the LTE Link Monitor. The TAU is -1 sec which indicates to me that it is not going into PSM.
+CEREG: 1,"8B3B","0A125011",7,,,"00011110","11100000"
[00:01:34.362,060] [0m<dbg> lte_lc.at_handler: +CEREG notification: +CEREG: 1,"8B3B","0A125011",7,,,"00011110","11100000"
[00:01:34.373,809] [0m<dbg> lte_lc.parse_psm_cfg: TAU: -1 sec, active time: 60 sec
However the response to AT%XMONITOR is
%XMONITOR: 1,"AT&T","AT&T","310410","8B3B",7,17,"0A125011",44,5780,37,30,"","00011110","11100000","00101010"
which is inline with Active Time = 60 seconds and Periodic TAU = 10 minutes but the extended periodic TAU is reporting deactivated. Does that indicate an issue?
AT+CESQ is showing that I am still connected to the tower and AT+CEREG? is showing that the TAU is deactivated.
AT+CESQ
CESQ: 99,99,255,255,12,37
AT+CEREG=5
OK
AT+CEREG?
+CEREG: 5,1,"8B3B","0A125011",7,,,"00011110","11100000"
Here is the full LTE Link Monitor log for the TAU = 10 minutes: /cfs-file/__key/support-attachments/beef5d1b77644c448dabff31668f3a47-1af7bcd8421c4639abbaf41be953aa50/2020_2D00_06_2D00_29T20_5F00_22_5F00_05.947Z_2D00_log.txt
I also then tried to change the TAU setting in prj.conf to a higher value in case the network was having issue with 10 minutes. I set it to 5 hours and left the Active Time setting as is and kept the Power Optimization setting.
CONFIG_POWER_OPTIMIZATION_ENABLE=y
CONFIG_LTE_PSM_REQ_RPTAU="00100101"
CONFIG_LTE_PSM_REQ_RAT="00100001"
After I boot up and connect to nRF Cloud, I flip SW2 to GND. Then I see the following:
+CEREG: 1,"8B3B","0A125011",7,,,"00011110","00011110"
[00:01:40.825,561] [0m<dbg> lte_lc.at_handler: +CEREG notification: +CEREG: 1,"8B3B","0A125011",7,,,"00011110","00011110"
[00:01:40.837,310] [0m<dbg> lte_lc.parse_psm_cfg: TAU: 18000 sec, active time: 60 sec
It looks like it has the correct timer set this time and the network has granted me PSM but I am continuing to transmit every 30 seconds still and the device does not appear to go into PSM.
Here is the full LTE Link Monitor log for the TAU = 5 hours: /cfs-file/__key/support-attachments/beef5d1b77644c448dabff31668f3a47-1af7bcd8421c4639abbaf41be953aa50/2020_2D00_06_2D00_29T20_5F00_36_5F00_34.361Z_2D00_log.txt
What is the proper way of putting the device in PSM using the Asset Tracker application in between transmissions to nRF Cloud without pressing Button 1 to go into GPS mode?
Regards,
Akash