MSC Server rSRVCC Prerequisite Verification
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Solution Overview
Problem
The existing technologies lack a reliable method to determine whether a voice call established over a UTRAN/GERAN network can be successfully transferred to an E-UTRAN/HSPA network through the reverse SRVCC procedure, due to unresolved prerequisites such as call anchoring, UE capability, and IMS registration status, which impact network decision-making and user experience.
Innovation Solution
An enhanced MSC server is configured with a reception block for receiving rSRVCC capability indications, a decision block to determine if rSRVCC is allowed based on UE capabilities, authorization, and anchoring, and a transmitting block to send an rSRVCC possible indication to the RNS/BSS, enabling the network to discriminate suitable calls for handover to E-UTRAN/HSPA.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the network triggers rSRVCC procedure without verifying prerequisites, then handover speed is improved, but call continuity reliability deteriorates
Solution Approach 1:
The MSC server performs preliminary verification of rSRVCC prerequisites (UE capability, IMS registration status, call anchoring) before triggering the handover procedure. This advance checking ensures that all necessary conditions are met prior to initiating the handover, preventing failures and ensuring reliable call continuity while maintaining efficient handover execution.
2Reliability
If the network implements comprehensive prerequisite checking, then call continuity reliability is improved, but decision-making complexity worsens
Solution Approach 1:
The MSC server autonomously verifies all rSRVCC prerequisites using information already available in the network (UE capability indications, IMS registration status from HSS, call anchoring status). By self-service verification without requiring additional external checks or complex coordination with other network elements, the system ensures reliable handover decisions while keeping the decision-making process manageable and efficient.
3Reliability
If the network verifies IMS registration status and UE capability, then handover success rate is improved, but signaling overhead worsens
Solution Approach 1:
The MSC server obtains UE capability information and IMS registration status in advance, during normal network operations and registration procedures, before the handover is triggered. By having this information pre-available through earlier network interactions, the system can verify prerequisites without generating additional signaling overhead at the critical handover moment, thus maintaining high handover success rates while minimizing extra signaling.
Data Source
AI summary
MSC server enhanced for rSRVCC from UTRAN/GERAN to E-UTRAN/HSPA, comprising:a reception block (10) configured to receive an rSRVCC capability indication from a user equipment;a decision block (11) configured to determine whether rSRVCC is allowed for a given call based on the rSRVCC capability indication received; anda transmitting block (12) configured to send to a Radio Access Network (RNS/BSS), when rSRVCC has been determined as allowed, an rSRVCC possible indication indicating that a rSRVCC is possible.