SCC-AS Capability Update for IMS Handover
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Solution Overview
Problem
Existing mechanisms for handover between different radio access technologies in cellular networks, such as from packet switched to circuit switched access, can result in delayed or incomplete signaling, leading to potential disruptions in voice calls and miscommunication of session capabilities to user equipment.
Innovation Solution
A mechanism is introduced within the IP Multimedia Subsystem network to detect changes in session capabilities during handovers and send updated SIP messages to user equipment, ensuring that user interfaces reflect accurate capabilities post-handover, thereby preventing user errors and maintaining seamless communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover between different radio access technologies is implemented, then service continuity is maintained, but session capability signaling may be delayed or lost
Solution Approach 1:
The system implements a feedback mechanism where the network detects capability changes post-handover and actively notifies the user equipment by sending updated SDP messages. This feedback loop ensures that any discrepancies in capability information are corrected promptly, maintaining signaling accuracy while preserving service continuity during handover transitions.
Solution Approach 2:
The system performs preliminary capability verification before and during handover procedures. By checking session capabilities in advance and preparing updated capability information beforehand, the system prevents signaling delays and information loss during the actual handover execution, ensuring seamless transitions.
2Measurement precision
If capability updates are sent frequently to ensure accuracy, then user equipment has accurate capability information, but network signaling overhead increases
Solution Approach 1:
The system changes the parameter of capability update frequency dynamically based on handover events and detected capability changes. Instead of frequent periodic updates, the system triggers capability update signaling only when necessary (upon detecting handover or capability change), thereby maintaining accurate capability information while minimizing unnecessary signaling overhead and energy consumption.
3Adaptability or versatility
If handover between packet switched and circuit switched access is implemented, then access flexibility is improved, but session capability negotiation becomes complex
Solution Approach 1:
The system introduces an intermediary capability verification mechanism that mediates between packet switched and circuit switched access domains. This intermediary layer standardizes capability negotiation by translating and harmonizing capability parameters across different access technologies, simplifying the overall negotiation process while maintaining access flexibility and supporting seamless handovers.
Data Source
AI summary
An apparatus configured to operate as a Service Centralization and Continuity Application Server (SCC-AS) within an IP Multimedia Subsystem network, the apparatus comprises a receiver for receiving a SIP INVITE originating from or sent via an access domain and for determining that the INVITE relates to a handover of a User Equipment (UE) currently served by the SCC-AS, to that access domain and for which a session with a peer UE is ongoing and the apparatus further comprises a message handler for determining if capabilities for the ongoing session, identified within said INVITE, have changed with respect to capabilities previously associated with the ongoing session and, if it is determined that capabilities have changed, for causing a SIP message to be sent to said peer UE, the message containing the changed capabilities.