IMS Parameter Alignment for Roaming Emergency Calls

The system performs preliminary actions by storing multiple sets of IP multimedia subsystem call parameters in the user equipment before roaming occurs. Each parameter set corresponds to a different network (home network and visited networks). When roaming to a visited network, the appropriate parameter set is selected and applied in advance, preventing parameter mismatches during emergency calls without requiring complex real-time adjustments.

The system introduces an intermediary mechanism - a parameter selection module that automatically selects the appropriate IP multimedia subsystem call parameter set based on the current network environment. This intermediary layer between the user equipment and the network ensures that the correct parameters (either from home network or visited network) are applied without requiring manual user intervention, thus maintaining ease of operation while ensuring call success.

The system implements self-service by enabling the user equipment to automatically manage multiple parameter sets without user intervention. The device autonomously identifies the current network type (home or visited), selects the corresponding parameter set, and applies it appropriately. This self-service capability ensures high call reliability across different networks while minimizing the perceived complexity for users.

The system performs parameter adjustment in advance by pre-storing multiple parameter sets corresponding to different network environments. When roaming occurs, the appropriate parameter set is already available and can be quickly selected and applied, eliminating the need for time-consuming dynamic adjustments during call setup. This preliminary preparation ensures both call success and minimal time loss.