I am trying to get carrier aggregation up and running using srsRAN 4G and two USRP N310s. However, when I run the eNB and UE, the UE fails to find the eNB cell. I checked out the signal coming from the eNB with a spectrum analyzer, and it looks like the eNB is transmitting both cell's PSS and SSS on the frequency of the second cell, while the UE is searching on the frequency of the first cell. This results in the UE never finding the eNB cell. Interestingly, the eNB log shows the eNB setting up the cells on the correct frequencies.
One more observation I think is relevant: srsRAN4G seems to use the USRP N310's channels 0 and 1 for the two cells. However, I believe that those two channels do not have independent oscillators, which is my going theory for why both cells end up transmitting on the same frequency. I believe the first cell gets set up correctly, but then as soon as the second cell gets set up, the common oscillator for channels 0 and 1 gets switched to the new frequency. I would think that I need srsRAN4G to use channels 0 and 2, which have independent oscillators.
Thus, my question is how can I configure srsRAN4G to utilize channels 0 and 2 on the USRP? Thanks in advance!
Setup Details
I have my USRP N310s connected as shown below:
My configuration files and log files are attached here:
matth3wh
commented
1 week ago
Issue Description
I am trying to get carrier aggregation up and running using srsRAN 4G and two USRP N310s. However, when I run the eNB and UE, the UE fails to find the eNB cell. I checked out the signal coming from the eNB with a spectrum analyzer, and it looks like the eNB is transmitting both cell's PSS and SSS on the frequency of the second cell, while the UE is searching on the frequency of the first cell. This results in the UE never finding the eNB cell. Interestingly, the eNB log shows the eNB setting up the cells on the correct frequencies.
One more observation I think is relevant: srsRAN4G seems to use the USRP N310's channels 0 and 1 for the two cells. However, I believe that those two channels do not have independent oscillators, which is my going theory for why both cells end up transmitting on the same frequency. I believe the first cell gets set up correctly, but then as soon as the second cell gets set up, the common oscillator for channels 0 and 1 gets switched to the new frequency. I would think that I need srsRAN4G to use channels 0 and 2, which have independent oscillators.
Thus, my question is how can I configure srsRAN4G to utilize channels 0 and 2 on the USRP? Thanks in advance!
Setup Details
I have my USRP N310s connected as shown below:
My configuration files and log files are attached here:
logs_2024-11-15_15-28-43.zip
Expected Behavior
I expect the eNB to transmit the cells on their correct frequencies, and for the UE to detect and connect to them.
Actual Behaviour
The UE cannot find the eNB cell. Logs are in the .zip folder above, and here are some screenshots.
Steps to reproduce the problem
Config files are in the .zip folder above.