Multiple Quectel Modems active in parallel?

Hello everyone,

For a research project, I would like to setup a standalone 5G network and perform benchmarks.
The setup consists of two machines"

  • Ubuntu System with GNB (USRPB210)
  • Ubuntu System connected to 4x Quectel RM520N-GL modems

The Quectel modems successfully register at the GNB. And they are all shown in Ubuntu under the Mobile Settings.
However, so far, it seems I can only have one modem/SIM active at the same time.
I would like to have all 4 Quectel modems active and send data (via iperf3 speedtest) to the GNB in parallel.

I am using NetworkManager to ensure the Quectel modem connect automatically.
I do this like so:

  • I create a new connection:
sudo nmcli c add con-name "srs" type gsm ifname "*" apn "srsapn"
  • I enable auto connect on boot:
sudo nmcli c mod "srs" connection.autoconnect yes
  • I start the connection:
sudo nmcli c up "srs"

The following image illustrates the setup I would like to achieve, and also highlights the problem how in the Mobile Network settings I only have a dropdown where I can only select one modem:

I would like some guidance how I can have both modems not only registered but connected at the same time so I can do performance tests in parallel.

Obviously the ModemManager/NetworkManager would only allow us to use one and cannot use the at the same time.
If for test and you would like to set up data connecttion at the same time , you could try the quectel-CM.