MSC Selection for SRVCC Location Services
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Solution Overview
Problem
User Equipment (UE) is unable to complete a location service in the Circuit Switched (CS) domain when the selected Mobile Switching Center (MSC) lacks Single Radio Voice Call Continuity (SRVCC) capability during a Voice over Internet Protocol (VOIP) service, as the MSC selected by the Mobility Management Entity (MME) in combined attach procedures is often SRVCC-incapable.
Innovation Solution
Selecting a Mobile Switching Center (MSC) capable of both Circuit Switched Fallback (CSFB) and Single Radio Voice Call Continuity (SRVCC) for the UE, ensuring that the UE can access and implement the location service in the CS domain by choosing an MSC that supports both CSFB and SRVCC during an SRVCC procedure triggered by a location service in the CS domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the MME selects an MSC in combined attach procedures, then the UE can access the CS domain, but the selected MSC may lack SRVCC capability causing location service failure
Solution Approach 1:
The MME performs preliminary selection of an MSC that possesses both CSFB and SRVCC capabilities during the combined attach procedure, before the UE actually needs to perform location services. This advance selection ensures that when the UE later needs to execute SRVCC for location services, the selected MSC already has the necessary capabilities, eliminating the service failure issue.
Solution Approach 2:
The patent changes the selection criteria parameter for MSC from a generic selection to a specific capability-based selection. The MME now selects MSCs based on their dual capability (CSFB + SRVCC) rather than just basic CS domain access capability, ensuring compatibility with future SRVCC operations.
2Ease of operation
If the UE performs SRVCC procedure during ongoing VOIP service, then the UE can be handed over to CS domain, but the location service cannot be completed if the MSC lacks SRVCC capability
Solution Approach 1:
The system performs preliminary verification and selection of MSC capabilities during the combined attach phase, ensuring that an MSC with SRVCC capability is selected before the UE engages in VOIP services. This prevents the scenario where handover can be executed but location service fails due to insufficient MSC capabilities.
3Reliability
If an MSC capable of both CSFB and SRVCC is selected, then the UE can complete location services, but the selection process becomes more complex
Solution Approach 1:
The MME utilizes feedback information about MSC capabilities (CSFB and SRVCC support) to make informed selection decisions. The system gathers capability information from MSCs and uses this feedback to select the most appropriate MSC that can handle both CSFB and SRVCC operations, ensuring reliable location service completion.
Solution Approach 2:
The patent seeks to select an MSC that provides universal capability - supporting both CSFB and SRVCC functions. This multi-functional MSC can handle various scenarios including voice calls, data services, and location services, simplifying the overall system architecture by having a single MSC handle multiple functions rather than requiring separate specialized MSCs.
Data Source
AI summary
A method, an apparatus and a system for a handover to a circuit switched domain are disclosed. In an embodiment, a system includes a mobility management entity (MME) and at least two a mobile switching center (MSCs), wherein the at least two MSCs comprise a first MSC capable of supporting a circuit switched fallback (CSFB) and a single radio voice call continuity (SRVCC) and a second MSC not capable of supporting the SRVCC, and wherein the MME is configured to select the first MSC for a user equipment (UE) from the at least two MSCs in a combined tracking area update procedure of the UE when a location service of a circuit switched (CS) domain triggers an SRVCC procedure for the UE and when the UE has a Voice over Internet Protocol (VOIP) service in progress.