srsran4g UE Not Receiving Paging Messages from gNB (Paging Messages Visible on Other Devices)

[yanggao017]

Issue Description

I have set up Open5GS as the core network and SRSRAN Project as the gNB. The UE (using SRSRAN 4G) has successfully completed random access and RRC connection establishment, and it is able to receive MIB and SIB1 messages. However, the UE does not receive Paging Messages even though the gNB is confirmed to be sending them, as it is able to successfully page using a white card and a Motorola mobile phone. No Paging-related logs or capture files indicate that the Paging message is received by srsran4g.

Setup Details

Core Network: Open5GS
gNB: srsran project (modified to send Paging messages)
UE: srsran4g 
Operating System: Ubuntu 22.04
Hardware: B210
RF Front-end: B210

Expected Behavior

The UE should receive the Paging message sent by the gNB, which should be visible in the logs or captured in pcap files. The Paging message should trigger the RRC_IDLE transition in the UE.

Actual Behaviour

The UE completes random access and RRC connection setup but does not receive any Paging message.
There are no Paging-related entries in the logs or pcap captures at the UE side.
No error messages appear indicating any issues with Paging reception.

Steps to reproduce the problem

Set up Open5GS as the core network.
Set up srsran as the gNB, ensuring it sends Paging messages to the UE.
Run srsran4g as the UE with the standard configuration for MIB, SIB1 reception, and random access.
Verify that MIB and SIB1 messages are received, and that RRC connection establishment is successful.
Monitor the UE's logs and pcap captures for any Paging messages being received (none appear).
Test with a white card and mobile to confirm that the gNB sends Paging messages correctly.

Additional Information

The gNB can successfully send Paging messages as verified with other devices (white card, Motorola phone).