Enable eDRX seems not work

[Tim Chao]

Hi,

I am trying to test eDRX function on 9160DK with modem_shell.

The command returns ok.

Modem FW version:      mfw_nrf9160_1.3.1
Device ID:             nrf-351358811475208
Operator full name:   ""
Operator short name:  ""
Operator PLMN:        "46692"
Current cell id:       28846103 (0x01B82817)
Current phy cell id:   214
Current band:          3
Current TAC:           12700 (0x319C)
Current rsrp:          27: -114dBm
Current snr:           23: -1dB
Mobile network time and date: 22/07/14,06:06:48+32
PDP context info 1:
  CID:                0
  PDN ID:             0
  PDP context active: yes
  PDP type:           IPV4V6
  APN:                internet.iot
  IPv4 MTU:           1500
  IPv6 MTU:           1500
  IPv4 address:       10.173.94.11
  IPv6 address:       2001:b400:e232:2d7c:7625:b63d:bce6:8597
  IPv4 DNS address:   168.95.1.1, 168.95.192.1
  IPv6 DNS address:   2001:b000:168::1, 2001:b000:168::2
RRC mode: Idle
LTE cell changed: ID: 28662797 (0x01B55C0D), PCI 71, Tracking area: 12700 (0x319C), Band: 3, RSRP: 21 (-120dBm), SNR: 15 (-9dB)
mosh:~$ link edrx -x 0010 -e -m
eDRX parameter update: eDRX: 163.839996, PTW: 2.560000
eDRX enabled
RRC mode: Connected
eDRX parameter update: eDRX: 20.480000, PTW: 2.560000
RRC mode: Idle
LTE cell changed: ID: 28846103 (0x01B82817), PCI 214, Tracking area: 12700 (0x319C), Band: 3, RSRP: 26 (-115dBm), SNR: 23 (-1dB)

But when I check the PPK output, it seems that the modem stay in DRX state and never enter sleep.

And here is the trace log.

trace-2022-07-14T06-06-46.613Z.bin

Please help to check what I did wrong.

Thanks.

[Øyvind]

Hello, 

the DevZone team and Nordic Semiconductor are currently in a summer vacation period, some delays in answers must be expected due to lower staffing during this period. We apologize for the inconvenience. 

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Are you able to verify that your SIM supports power down mode? From the SIM Card Interface of the nRF9160 PS

The LTE modem supports powering down the UICC during PSM and eDRX idle mode if the UICC supports this feature as specified in 3GPP TS 24.301. To reach the lowest total power consumption of the complete cellular IoT product, only UICCs supporting power down mode during PSM and eDRX idle mode sleep intervals should be considered.

Please verify with your local SIM provider.

Kind regards,
Øyvind

[Tim Chao]

I will ask the vendor first.

But I have one more question. Does there is any command can be used to check if the connected carrier support PSM/eDRX or not? Or even a notification abount it cannot enter sleep.

We are planing a LTE product that cannot restrict our end user to use specified SIM. We should not tell end user to ask their SIM vendor after they found the device battery is dead.

And, can you tell me how to verify SIM's power down mode from SIM card interface?

Thanks.

[Øyvind]

Tim Chao said:

But I have one more question. Does there is any command can be used to check if the connected carrier support PSM/eDRX or not? Or even a notification abount it cannot enter sleep.

I believe the AT+CEDRXRDP command should provide more answers. From the output you provided it does look you have received the eDRX values. 

Tim Chao said:

We are planing a LTE product that cannot restrict our end user to use specified SIM. We should not tell end user to ask their SIM vendor after they found the device battery is dead.

I understand that you might feel this way, however, this is what you need to do. At least you need to check with the local network providers if they support misc. settings. Different settings apply from network to network, and is very difficult to control from one side. E.g. iBasis SIM is a roaming SIM but not all networks allow roaming SIMs. GSMA has an information page on network roaming that could provide more information. The GSMA also provides a Mobile IoT Deployment Map which illustrates what different countries support LTE-M and/or NG-IoT. This page also includes LTE-M and NB-IoT deployment guides.

Have a look at our white paper on Best practices for cellular IoT development (nWP044). 

Tim Chao said:

And, can you tell me how to verify SIM's power down mode from SIM card interface?

From nWP044 

Our advanced modem automatically optimizes the power consumption of the SIM card, but you can further improve this if the SIM card has the UICC suspend-resume feature enabled (specified in 3GPP TS 31.102 chapter 5.1.11). You can request this when ordering SIM cards to ensure that the SIM card does not use unnecessary current when not in use.

Kind regards,
Øyvind