TDD operation unreliable

[smunaut]

Hi all,

I've tried srsRAN_Project theses last few days and I get great and stable results in FDD operation. Running with a B210 on n3 10 MHz wide cell, it's very solid.

However trying the exact same setup running on n41 / n78, I can't get it working. I can sometimes get it to show up on the phone, but rarely and even when it shows up, no way to register.

The config I used for my n78 attempts are basically the one from the examples just enabled external clock source and adapted amf params.

Is there something special I should be paying attention to in TDD mode vs FDD mode ?

Cheers,

Sylvain

PS: Great work btw, my FDD mode experience is much more reliable than when I was using srsRAN gnb.

[andrepuschmann]

Thanks @smunaut for your feedback. We've discovered some IOT issues here ourselves with TDD. Working on it.

[asheeshtripathi]

Yeah, I was able to connect but only when using 20 MHz cell width. For some reason 10 MHz wouldn't be recognized by my phones ...

The network is being detected by Telit modem and OnePlus8T both. I verified the RF transmission with spectrum analyzer it is transmitting perfectly in 10 MHz config. But No attach.

[asheeshtripathi]

Hi @smunaut, I was able to proceed with the UE attach: registration and ip allocation to UE is successful. But UE connection is lost after GTP session is created. I am suspecting issue with the tunnel. I have srsRAN gNB and open5gs core co-located in the same machine. can you share the open5GS config and gnB config (for AMF and GTPU addresses)

[pgawlowicz]

You can try with the Open5gs docker image that we now provide in the srsRAN_Project. You can start as show here:
https://docs.srsran.com/projects/project/en/latest/tutorials/source/srsUE/source/index.html#open5gs-core

Note that the tutorial is on connecting srsUE with the gNB, but Open5GS core and routing configurations can be reused. Please remember to populate the subscriber database using Open5gs Web GUI.

[asheeshtripathi]

Hi @pgawlowicz , Thanks for the reply. The issue was resolved long back, it was related to the UE. One of the UEs that I used initially would first attach, and once PDU session created, it detached; after some time (60-120 seconds), another PDU session was created, and UE worked fine. With other UEs, I did not face any issues. I have tested srsRAN with both the dockerized version and non-dockerized Open5GS core.

[pgawlowicz]

Great! Thank you for the feedback.