EM9191 Linux Ubuntu NR5G Not Working Only LTE

IoT Modules MC/EM Series
1

I recently setup an Ubuntu system with EM9191 and MBPL USB drivers installed, after running “sudo mbim-network /dev/cdc-wdm0 start” followed by “sudo bash mbim-set-ip /dev/cdc-wdm0 wwan0” I get a very slow LTE connection. When I attempt to run “at!band=0C” my T-Mobile SIM locks to N71 or N41 but is not registered on the network. This behavior does not happen on my Windows machine which typically registers onto N41 but de-registers when I attempt to use band locking to 0C or any custom band lock. Using latest generic FW from Sierra Wireless EM9191 downloads.

FW:

ati
Manufacturer: Sierra Wireless, Incorporated
Model: EM9191
Revision: SWIX55C_03.10.07.00 e32f05 jenkins 2022/12/14 16:18:06
IMEI: 355890340183339
IMEI SV: 24
FSN: 8W1121041903A1
+GCAP: +CGSM

OK

BEFORE BAND LOCK (working connection but slow and on wrong band):

at!gstatus?
!GSTATUS:
Current Time: 83 Temperature: 35
Thermal Mitigation Level: 0
Reset Counter: 1 Mode: ONLINE
System mode: LTE PS state: Attached
LTE band: B2 LTE bw: 15 MHz
LTE Rx chan: 925 LTE Tx chan: 18925
EMM state: Registered Normal Service
RRC state: RRC Idle
IMS reg state: NOT REGISTERED IMS mode: Normal
IMS Srv State: UNKNOWN SMS,UNKNOWN VoIP

PCC RxM RSSI: -68 PCC RxM RSRP: -102
PCC RxD RSSI: -67 PCC RxD RSRP: -99
PCC Tx Power: — TAC: a6f7 (42743)
RSRQ (dB): -12.7 Cell ID: 0054d60b (5559819)
SINR (dB): 0.4

NR5G band: — NR5G bw: —
NR5G Tx Power: — NR5G Tx chan: —
NR5G Rx chan: — NR5G RSRP (dBm): —
NR5G RSRQ (dB): — NR5G SINR (dB): —

OK

AFTER (not working but on right band):
at!gstatus?
!GSTATUS:
Current Time: 902 Temperature: 33
Thermal Mitigation Level: 0
Reset Counter: 1 Mode: ONLINE
System mode: NR5G PS state: Attached
IMS reg state: NOT REGISTERED IMS mode: Normal
IMS Srv State: UNKNOWN SMS,UNKNOWN VoIP

NR5G TAC: a6f700 NR5G Cell ID: 525
NR5G band: n71 NR5G Carrier ID: 0
NR5G dl bw: 10 MHz NR5G ul bw: Unknown
NR5G Tx Power: — NR5G Tx chan: 0
NR5G Rx chan: 125450
NR5G dl MIMO: 0 NR5G ul MIMO: 0
NR5G(mmw) Rx0 RSSI (dBm): — NR5G(mmw) Rx1 RSSI (dBm): —

NR5G RSRP (dBm): -90 NR5G RSRQ (dB): -12
NR5G SINR (dB): 5.5

OK

2

have you tried with the TMO PRI instead of the GENERIC PRI on FW 03.10.07.00?

3

Yes, same issues with band locking on Windows. Haven’t test on Ubuntu but imagine similar results. Still not getting why it’s defaulting to LTE on Linux when Windows can at least grab 5G.

4

what if you set to AT!BAND=0 ?
can it register to 5G ENDC network?

BTW, what did you set for AT!SELRAT?

5

AT!BAND=0 restores to defaults and subsequently back to LTE. Never did anything with AT!SELRAT?, when I issue the command it says “00, Automatic”

6

to register in 5G ENDC network in AT!GSTATUS?, you need to generate some data traffic, for example, ping to google server 8.8.8.8.
After that it should change to 5G ENDC in AT!GSTATUS?

7

Yes, while sitting on AT!BAND=0 I ran speedtest-cli and ping -I wwan0 8.8.8.8 and it still stuck on LTE.

Also in the set-ip script it has old commands for systemd-resolve which no longer is in Ubuntu 22.04 could that be cause issues? Not sure why LTE would work if so.

8

Network registration should not depend on OS environment

How about install virtual machine with linux image in the windows OS?

9

Same results though now Windows shows a LTE band too:

Ubuntu VM from Windows Machine GSTATUS
at!gstatus?
!GSTATUS:
Current Time: 1744 Temperature: 40
Thermal Mitigation Level: 0
Reset Counter: 1 Mode: ONLINE
System mode: LTE PS state: Attached
LTE band: B2 LTE bw: 15 MHz
LTE Rx chan: 925 LTE Tx chan: 18925
EMM state: Registered Normal Service
RRC state: RRC Idle
IMS reg state: NOT REGISTERED IMS mode: Normal
IMS Srv State: UNKNOWN SMS,UNKNOWN VoIP

PCC RxM RSSI: -65 PCC RxM RSRP: -105
PCC RxD RSSI: -67 PCC RxD RSRP: -104
PCC Tx Power: — TAC: a6f7 (42743)
RSRQ (dB): -18.8 Cell ID: 0054d60b (5559819)
SINR (dB): -5.0

NR5G band: — NR5G bw: —
NR5G Tx Power: — NR5G Tx chan: —
NR5G Rx chan: — NR5G RSRP (dBm): —
NR5G RSRQ (dB): — NR5G SINR (dB): —

OK

Windows GSTATUS:
Recieve: !GSTATUS:
Recieve: Current Time: 107 Temperature: 51
Recieve: Thermal Mitigation Level: 0
Recieve: Reset Counter: 1 Mode: ONLINE
Recieve: System mode: ENDC PS state: Attached
Recieve: LTE band: B2 LTE bw: 15 MHz
Recieve: LTE Rx chan: 925 LTE Tx chan: 18925
Recieve: EMM state: Registered Normal Service
Recieve: RRC state: RRC Connected
Recieve: IMS reg state: NOT REGISTERED IMS mode: Normal
Recieve: IMS Srv State: UNKNOWN SMS,UNKNOWN VoIP
Recieve: PCC RxM RSSI: -66 PCC RxM RSRP: -105
Recieve: PCC RxD RSSI: -71 PCC RxD RSRP: -109
Recieve: PCC Tx Power: 23 TAC: a6f7 (42743)
Recieve: RSRQ (dB): -19.2 Cell ID: 0054d60b (5559819)
Recieve: SINR (dB): -7.6
Recieve: SCC1 NR5G band: n41 SCC1 NR5G bw: 100 MHz
Recieve: SCC1 NR5G Tx Power: 22 SCC1 NR5G Tx chan: 528000
Recieve: SCC1 NR5G Rx chan: 528000
Recieve: NR5G RSRP (dBm): -105 NR5G RSRQ (dB): -20
Recieve: NR5G SINR (dB): 0.6
Recieve: OK

11

Did you confirm wwan0 is the MBIM network interface of EM91 module in linux?

have you tried another TMO SIM card?

Did you see same issue with other network operator like Verizon or AT&T?

this is really strange that 5G only works in Windows

12

Very strange for sure. It is the only card on my machine so definitely is the correct wwan0. I could try another SIM. I don’t have access to AT&T/VZW. Could it be anything with my MBIM network command/get-ip script?

I will also reflash the tmo firmware to see if it helps.

13

I used “sudo dhclient wwan0” to get ip address, not with your script

Did you set correct APN in the linux environment?

14

My APN settings from /etc/mbim-network.conf
APN=internet
APN_USER=
APN_PASS=
APN_AUTH=
PROXY=yes

“sudo dhclient wwan0” seems to hang forever with me. I got it work with T-Mobile FW image on Linux however the speeds are horrible compared to the generic FW image I was using. Also I get deprecation warnings about my APN settings, what is the correct APN setting to use?

15

From Linux with TMO FW:

!GSTATUS:
Current Time: 388 Temperature: 45
Thermal Mitigation Level: 0
Reset Counter: 2 Mode: ONLINE
System mode: ENDC PS state: Attached
LTE band: B2 LTE bw: 15 MHz
LTE Rx chan: 925 LTE Tx chan: 18925
EMM state: Registered Normal Service
RRC state: RRC Connected
IMS reg state: UNKNOWN IMS mode: Not Support
IMS Srv State: UNKNOWN SMS,UNKNOWN VoIP

PCC RxM RSSI: -65 PCC RxM RSRP: -102
PCC RxD RSSI: -69 PCC RxD RSRP: -107
PCC Tx Power: 19 TAC: a6f7 (42743)
RSRQ (dB): -17.2 Cell ID: 0054d60b (5559819)
SINR (dB): -2.6

SCC1 NR5G band: n41 SCC1 NR5G bw: 100 MHz
SCC1 NR5G Tx Power: 21 SCC1 NR5G Tx chan: 528000
SCC1 NR5G Rx chan: 528000
NR5G RSRP (dBm): -103 NR5G RSRQ (dB): -18
NR5G SINR (dB): 0.3

speedtest-cli results:
Download: 41.75 Mbit/s
Testing upload speed…
Upload: 12.63 Mbit/s

Generic FW gets about ~120Mbps down right now (band n41 is terrible but I still don’t understand how to switch)

16

I got dhclient to work. Now just need to know best APN settings? Still confused when Generic FW didn’t work as well for Linux.

17

Of course you need to use the tmo firmware as it has the proper carrier setting

I remember tmo is not using internet as APN

18

But generic FW did work on Windows with better speed, that’s what I don’t get. Also seems back on regular machine issue still occurring with TMO firmware only fixed in VM.

19

Are you using internet as APN in windows?

20

Windows says the LTE APN is: fast.t-mobile.com

So I changed that on my mbim-network.conf and it helped with speeds a bit. Still not working on actual device but more concerned with that band locking still doesn’t work. Setting at!band=0C loses network registration.

21

when you set at!band=0C, there is no LTE band, so the 5GNSA (ENDC) is not working.
It must register with 5GSA.
Not sure if your area supports 5GSA, you might double check with TMO.

BTW, what is the return of AT!RATCA? in your module?