ISC Session Transfer Signaling Delay Reduction via Media Anchoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The IMS service continuity (ISC) session transfer procedure experiences significant signaling delays, particularly during remote leg updates, which can lead to call interruptions and degraded service experiences, especially during rapid handovers between IP-CAN and circuit domain networks.
Innovation Solution
Introducing a media anchor point to divide the session between local and remote UEs into two independent sub-sessions, allowing only one sub-session to be updated during handovers, thereby reducing signaling delays by terminating SIP signaling at the SCC AS or equivalent entities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing ISC session transfer procedure is used, then service continuity can be maintained, but significant signaling delay occurs during remote leg update
Solution Approach 1:
The patent segments the session into two independent sub-sessions: a local sub-session and a remote sub-session. This segmentation allows the local sub-session to be updated independently during handover without triggering a remote leg update, thereby eliminating the signaling delay while maintaining service continuity through the segmented architecture.
2Reliability
If remote leg update is performed during handover, then service continuity is maintained, but call interruption occurs due to long signaling delay
Solution Approach 1:
By segmenting the session into local and remote sub-sessions, the patent enables independent updates of the local sub-session during handover. This prevents the need for remote leg update during handover, eliminating call interruption while maintaining service continuity through the segmented session architecture.
3Adaptability or versatility
If multiple nodes are involved in SIP signaling path, then comprehensive session control is achieved, but signaling delay increases
Solution Approach 1:
The patent segments the SIP signaling path into two independent paths: one for the local sub-session and one for the remote sub-session. This segmentation allows the local sub-session to be updated locally without involving multiple nodes in the SIP signaling path, thereby reducing signaling delay while maintaining comprehensive session control through the segmented architecture.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention provides a method for shortening signaling delay of ISC session transfer procedure, a network element for controlling ISC session transfer, a network element for anchoring a media path in ISC session transfer and a communication system including at least two terminals and the above two network elements. In the present invention, the SCC AS decides if a media path needs to be anchored in a media anchor point MRF, and if yes, then instructs a MRF to assign respective media endpoints for a local UE and a remote UE and connect the two media endpoints together, so as to divide the session between the local UE and the remote UE into two independent sub-sessions: a session between the local UE and the MRF, and a session between the remote UE and the MRF. For these two sub-sessions, the SIP signaling is terminated and sent out in the SCC AS. Thus, when a local UE or a remote UE triggers handover, only one sub-session needs to be updated/influenced.