UE Not Able to Register to Benetel O-RU RAN 650

[Keilwerth11270]

srsRAN with Benetel O-RU RAN 650 UE Attach Issue

Our Setup

We have a Benetel O-RU RAN 650 which we are integrating with srsRAN CU+DU. We are able to get PTP sync locked on the O-RU. After running srsRAN gNB, multiple COTS UEs (Phones and Modems) are able to see the network but not able to register.

Testbench and Connectivity

Server machine:

• Intel(R) Xeon(R) Silver 4416+, 40 cores
• Ubuntu 22.04.5 LTS with kernel 5.15.0-1032-realtime
• Core: Open5GS
• CU+DU: srsRAN
  • 4X2 configuration
  • 100/40/20MHz bandwidth
  • DPDK is not enabled
• O-RU: RAN 650, RAN650-1v1.2.2-2fa04bc, Band n78

The Core and CU-DU are co-located in the server. The DU and O-RU are connected via Intel NIC E810XXVDA4TGG1, which provides a hardware timestamp for PTP sync. It is connected via a multimode fiber with full-duplex 10G SFP.

Current Status

• The O-RU is powered on and is in sync state
• The RF ports of O-RU are connected with 10-Watt 30 dB attenuators, and the attenuator output is connected to sub-6 multiband antennas
• We are using COTS UEs (OnePlus 8T, Samsung A23, and Quectel Modem - all previously connected to USRP X310, B210, and N310)

Issues and Troubleshooting

• We tried with different PLMN (90170 and 00101) and found that UE is able to scan with both PLMN when UE SIM card has PLMN 00101
• We found that if MTU size is not set to 9600, UE is unable to scan the network
• Restarting the srsRAN gNodeB is somehow setting MTU to 9000 by default, and we need to manually reconfigure to 9600 each time we start it
• We also tried with varying bandwidth: 20MHz, 40MHz, and 100MHz
• We also made an attempt with removing the attenuators and transmitting at a lower power of 24dBm

We raised this as an issue and are bringing this here to get a wider audience for more support. We will be happy to provide if further information/logs/configurations are required.

[omertylmzz]

Hi, hope you’re doing well. I’ve read another issue you opened and saw that you mentioned the problem was resolved. We are currently experiencing the same issue. Would it be possible for you to share your configuration file? Also, do you think the root cause is entirely related to DPDK and version compatibility issues?