Controlled VoWiFi Handover via Incoming Access Indication
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Solution Overview
Problem
Current VoWiFi handover mechanisms do not adequately consider whether the Visited Public Mobile Network (VPMN) supports Voice over IMS (VoIMS) or has a roaming agreement, leading to potential call drops and incorrect charging, with no standard support for graceful handover rejection.
Innovation Solution
Implementing a system where the wireless device sends a message to the core network with an incoming access indication, allowing the VPMN to decide whether to accept or reject the handover based on this information, enabling graceful rejection and proper charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE initiates handover to 3GPP network based on HPMN configuration, then the UE can maintain VoWiFi session continuity, but the VPMN cannot control whether to accept or reject the handover based on its own roaming agreements or VoIMS support status
Solution Approach 1:
The patent introduces a feedback mechanism where the VPMN receives handover indication information from the UE and sends back handover rejection information to the UE. This allows the VPMN to control handover based on its roaming agreements and VoIMS support status while maintaining session continuity when conditions are favorable.
Solution Approach 2:
The patent enables preliminary action by allowing the VPMN to make handover decisions before the actual handover execution. The core network node can reject handover requests in advance based on roaming agreement status or VoIMS support, preventing unwanted handovers before they occur.
2Reliability
If the VPMN rejects handover at initial attachment, then the call can be dropped to avoid unsupported VoIMS, but there is no standard support for graceful handover rejection and KPIs are impacted
Solution Approach 1:
The patent converts the harmful effect of handover rejection (which was previously considered a mobility failure impacting KPIs) into a beneficial controlled rejection mechanism. By introducing graceful handover rejection with specific rejection causes, the system can distinguish between voluntary rejections (for policy reasons) and involuntary failures, thereby protecting KPIs while maintaining control.
3Productivity
If the UE does not check VPMN support status before initiating handover, then the attach procedure can proceed quickly, but the VPMN cannot ensure VoIMS support or roaming agreement validity
Solution Approach 1:
The patent enables preliminary verification of VPMN support status during the attach procedure. The core network node can check roaming agreement status and VoIMS support before allowing the handover to proceed, ensuring reliability while maintaining efficient attach procedures through parallel processing and early decision-making.
Data Source
AI summary
Systems and methods are disclosed herein for performing a controlled handover of a wireless device from an incoming access network to a cellular access network of a visited cellular network. In some embodiments, a method for handover of a wireless device from an incoming access network to a cellular access network of a visited cellular network while in roaming comprises, at the wireless device, sending a message to a core network of the visited cellular network. The message is related to a handover of the wireless device from the incoming access network to the cellular access network of the visited cellular network and comprises an incoming access indication. The incoming access indication is an indication of the incoming access network. The method further comprises, at the core network node, receiving the message and making a decision for the handover based on the incoming access indication.