Intermediary Node Call Teardown Handling for Seamless RAN Transition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
When a user equipment (UE) served by a first RAN loses connection during a call and transitions to a second RAN, existing systems may prematurely tear down the call due to the loss of connection, leading to call interruptions.
Innovation Solution
An intermediary node intercepts the call-teardown message and determines if the UE has transitioned to a second RAN, establishing a new connection via that RAN to bridge with the existing call, thereby preventing the call from being torn down and allowing it to continue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the call server tears down the call connection upon detecting loss of connection with the UE, then the call server maintains connection integrity and prevents abnormal calls, but the call is prematurely terminated even when the UE has successfully transitioned to a second RAN
Solution Approach 1:
The patent introduces an intermediary node (such as an MSC server or mobile switching center) that acts as a mediator between the call server and the UE. This intermediary monitors the UE's connection status across multiple RANs and determines whether the UE has successfully transitioned to a second RAN before allowing the call to continue. The intermediary intercepts teardown requests from the call server and prevents them from being executed when the UE is still accessible via the second RAN, thus maintaining call continuity while preserving connection integrity through proper verification.
2Duration of action of moving object
If the system monitors connection status frequently to detect UE transitions, then call continuity is improved, but signaling overhead and system complexity increase
Solution Approach 1:
The patent implements preliminary action by having the UE proactively notify the network of its transition to a second RAN before the call server detects connection loss. The UE sends a registration or notification message to the intermediary node when it successfully attaches to the second RAN. This preliminary notification allows the intermediary to maintain an updated view of the UE's location and prevent premature call teardown without requiring continuous monitoring by the call server, thus reducing system complexity while maintaining call continuity.
Data Source
AI summary
A method and system for responding to a call-teardown request generated, for instance, as a result of a user equipment device (UE) losing coverage of a first serving radio access network (RAN) while the UE is engaged in a call with another party. A signaling intermediary receives the call-teardown message en route from a first call server to a second call server and responsively determines whether the UE is now served by a second RAN. Responsive to determining that the UE is served by the second RAN, the intermediary arranges for establishment of a new call connection with the UE via the second RAN and for linking of the new call connection with an existing leg of the call with the other party, and the intermediary discards the call-teardown message rather than forwarding it along to the second call server.