5G System Learning - Uplink RAN ​​Configuration Transfer

1. RAN Configuration Transfer in 5G is a NGAP procedure used to transfer RAN configuration information, such as Self-Organizing Network (SON) information, between NG-RAN nodes (e.g., gNBs) and access and AMFs (mobility management functions). This non-UE-associated signaling allows the AMF to relay configuration information to other RAN nodes or manage configuration data by accepting and forwarding information without interpretation, thereby supporting functions such as transferring SON configuration data between different RAN nodes.

2. Configuration Transfer Purpose: There are two types of configuration transfers delivered via NGAP: RAN Configuration Data Transfer: This transfers RAN configuration information from an NG-RAN node to the AMF. SON Information Relay: The AMF can transparently transfer Self-Organizing Network (SON) configuration information to other target RAN nodes, thereby facilitating network automation.

3. Uplink RAN ​​Configuration Transfer Initiation: The purpose of this procedure is to transfer RAN configuration information from the NG-RAN node to the AMF. The AMF does not interpret the transferred RAN configuration information. The transfer procedure is shown in Figure 8.8.1.2-1 below. The transfer procedure uses non-UE-associated signaling. The relevant information is as follows:

• The NG-RAN node initiates the Uplink RAN ​​Configuration Transfer procedure by sending an UPLINK RAN CONFIGURATION TRANSFER message to the AMF.

• If the AMF receives a SON Configuration Transfer IE, it shall transparently transfer the SON Configuration Transfer IE to the NG-RAN node indicated in the Target RAN Node ID IE contained in the SON Configuration Transfer IE. If the NR CGI IE is contained in the Target RAN Node ID IE, the AMF shall (if supported) ignore the Global RAN Node ID IE in the Target RAN Node ID IE and use it to identify the target gNB, as described in TS 38.300.
• If the AMF receives an EN-DC SON Configuration Transfer IE, it shall transparently transfer the EN-DC SON Configuration Transfer IE to the MME serving the eNB indicated in the Target eNB-ID IE contained in the EN-DC SON Configuration Transfer IE.
• If the AMF receives an Inter-System SON Configuration Transfer IE, it shall transparently transfer the Inter-System SON Configuration Transfer IE to the MME serving the eNB indicated in the Target eNB-ID IE contained in the Inter-System SON Configuration Transfer IE.