PLMN 000000? What does it mean?

IoT Modules 5G Module
1

When querying NAS get cell location info, I get

root@xxx-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm1 --nas-get-cell-location-info
error: couldn’t get cell location info: QMI protocol error (13): ‘NoNetworkFound’
root@xxx-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm1 --nas-get-cell-location-info
error: couldn’t get cell location info: QMI protocol error (13): ‘NoNetworkFound’
root@xxx-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm1 --nas-get-cell-location-info
[/dev/cdc-wdm1] Successfully got cell location info
5GNR ARFCN: ‘641760’
5GNR cell information
PLMN: ‘000000’
Tracking Area Code: ‘32412’
Global Cell ID: ‘21259374081’
Physical Cell ID: ‘793’
RSRQ: ‘-15.0 dB’
RSRP: ‘-117.0 dBm’
SNR: ‘-0.5 dB’
root@xxx-phyboard-pollux-imx8mp-3:~#

It could be that reception quality is not the best, but what does PLMN “000000” mean?

The used RM520N-GL has firmware version: RM520NGLAAR03A03M4G

Is there perhaps already a newer firmware available, which has this problem fixed?

We tried on a second module with same firmware version, but different location, and get same error.

German Telekom SIM card, 100% reproduceable

I tried the same with a RM551N-GL, sitting 50cm beside RM520N-GL, and there it works:

root@xxx-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --dms-get-revision
[/dev/cdc-wdm0] Device revision retrieved:
Revision: ‘RM551EGL00AAR01A04M8G’
root@xxx-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --nas-get-cell-location-info

error: operation failed: Transaction timed out
error: couldn’t release client: Transaction timed out
root@xxx-phyboard-pollux-imx8mp-3:~#
root@xxx-phyboard-pollux-imx8mp-3:~# qmicli -d /dev/cdc-wdm0 --nas-get-cell-location-info
[/dev/cdc-wdm0] Successfully got cell location info
5GNR ARFCN: ‘154570’
5GNR cell information
PLMN: ‘26201’
Tracking Area Code: ‘32412’
Global Cell ID: ‘21248286724’
Physical Cell ID: ‘568’
RSRQ: ‘-15.0 dB’
RSRP: ‘-99.0 dBm’
SNR: ‘-0.5 dB’
root@xxx-phyboard-pollux-imx8mp-3:~#

2

Dear @capiman
I have sent latest firmware to your email, please try again.

3

Dear @silvia ,

many thanks for sending RM520N-GL firmware RM520NGLAAR03A03M4G_A0.304.A0.304.

I have updated my RM520N-GL to this firmware and retested.

The error (?) is also reproduceable with this firmware.

I have found out additional info, which can help narrow the problem:

I can reproduce the error only with configuring the 5G module to 5G SA.

I am doing this with the following commands (extract of a bigger script):

log “Starting 5G SA configuration…”

send_at “AT+QNWPREFCFG=“mode_pref”,NR5G”
send_at “AT+QNWPREFCFG=“nr5g_disable_mode”,2”
send_at “AT+QNWPREFCFG=“ue_usage_setting”,1”
send_at “AT+QCFG=“sms_control”,0,0”
send_at “AT+QCFG=“call_control”,1,1”
send_at “AT+QMBNCFG=“AutoSel”,0”
send_at “AT+QCFG=“ims”,2,0”

Run normal shell commands directly

log “Deleting profiles…”
qmicli -p -d /dev/cdc-wdm0 --wds-delete-profile=3gpp,5
qmicli -p -d /dev/cdc-wdm0 --wds-delete-profile=3gpp,4
qmicli -p -d /dev/cdc-wdm0 --wds-delete-profile=3gpp,3
qmicli -p -d /dev/cdc-wdm0 --wds-delete-profile=3gpp,2
qmicli -p -d /dev/cdc-wdm0 --wds-delete-profile=3gpp,1

log “5G SA configuration completed.”

The AT for configuring “ims” is wrong, gives an error, but does not matter for this case.

Then I am in 5G SA, no more 4G/LTE. And then the error occurs.

I tried with German SIM cards of different providers and with all of them I can reproduce the reported problem.

O2:

# qmicli -p -d /dev/cdc-wdm0 --nas-get-cell-location-info
[/dev/cdc-wdm0] Successfully got cell location info
5GNR ARFCN: ‘152690’
5GNR cell information
        PLMN: ‘000000’
        Tracking Area Code: ‘51583’
        Global Cell ID: ‘8244969584’
        Physical Cell ID: ‘696’
        RSRQ: ‘-11.0 dB’
        RSRP: ‘-77.0 dBm’
        SNR: ‘18.0 dB’



Vodafone:

qmicli -p -d /dev/cdc-wdm0 --nas-get-cell-location-info

[/dev/cdc-wdm0] Successfully got cell location info
5GNR ARFCN: ‘641760’
5GNR cell information
        PLMN: ‘000000’
        Tracking Area Code: ‘32412’
        Global Cell ID: ‘21259374081’
        Physical Cell ID: ‘793’
        RSRQ: ‘-14.0 dB’
        RSRP: ‘-117.0 dBm’
        SNR: ‘0.5 dB’



Telekom SIM card:

# qmicli -p -d /dev/cdc-wdm0 --nas-get-cell-location-info
[/dev/cdc-wdm0] Successfully got cell location info
5GNR ARFCN: '372750'
5GNR cell information
        PLMN: '000000'
        Tracking Area Code: '48075'
        Global Cell ID: '138297566'
        Physical Cell ID: '306'
        RSRQ: '-14.0 dB'
        RSRP: '-105.0 dBm'
        SNR: '-1.0 dB'
# 

For comparison, the output of mode 5G NSA, directly after flashing firmware, where problem is not occuring (at least I have not deteced it yet):

# qmicli -p -d /dev/cdc-wdm0 --nas-get-cell-location-info
[/dev/cdc-wdm0] Successfully got cell location info
Intrafrequency LTE Info
        UE In Idle: 'no'
        PLMN: '26203'
        Tracking Area Code: '51583'
        Global Cell ID: '26427690'
        EUTRA Absolute RF Channel Number: '1600' (E-UTRA band 3: 1800+)
        Serving Cell ID: '208'
        Cell [0]:
                Physical Cell ID: '208'
                RSRQ: '-15.4' dB
                RSRP: '-92.9' dBm
                RSSI: '-54.7' dBm
Interfrequency LTE Info
        UE In Idle: 'no'
        Frequency [0]:
                EUTRA Absolute RF Channel Number: '3350' (E-UTRA band 7: 2600)
                Selection RX Level Low Threshold: '0'
                Cell Selection RX Level High Threshold: '0'
                Cell [0]:
                        Physical Cell ID: '452'
                        RSRQ: '-14.8' dB
                        RSRP: '-94.3' dBm
                        RSSI: '-70.5' dBm
                        Cell Selection RX Level: '0'
                Cell [1]:
                        Physical Cell ID: '451'
                        RSRQ: '-17.7' dB
                        RSRP: '-97.2' dBm
                        RSSI: '-69.3' dBm
                        Cell Selection RX Level: '0'
LTE Info Neighboring GSM
        UE In Idle: 'no'
LTE Info Neighboring WCDMA
        UE In Idle: 'no'
LTE Timing Advance: '0' us
5GNR ARFCN: '152690'
#

Best regards,

Martin