IMS Emergency Call Transfer via Egress Conference Node
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current IMS-based emergency services networks lack the capability to effectively support conferencing and call transfer within IMS-based emergency services networks, as defined in 3GPP specifications, which results in the E-CSCF not being maintained on the call path after initial call transfer, impacting call handling and record generation.
Innovation Solution
The solution involves maintaining the E-CSCF on the call path even after call transfer by invoking conferences at the egress point instead of the ingress point, allowing the Secondary PSAP to conference and transfer calls, and using a Transit and Roaming Function (TRF) to facilitate call routing and conferencing, ensuring the E-CSCF remains on the path to perform its functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conferences are invoked at the ingress point in IMS-based emergency services networks, then call routing is simplified, but the E-CSCF cannot be maintained on the call path after initial call transfer
Solution Approach 1:
The patent introduces a conference node as an intermediary element between the ingress and egress points. This conference node maintains the E-CSCF's presence on the call path by serving as a mediation point where the E-CSCF can continue to monitor and control the call state even after transfer operations, thus resolving the contradiction between routing simplicity and E-CSCF presence.
2Loss of energy
If the E-CSCF is removed from the call path after initial call transfer, then network resource utilization is improved, but call state control and record generation capabilities are lost
Solution Approach 1:
The patent segments the call handling functions by separating the E-CSCF's core call state control responsibilities from the physical call path traversal. The E-CSCF maintains logical control through the conference node without needing to remain physically present on the entire call path, allowing network resources to be optimized while preserving essential call control and record generation capabilities.
3Adaptability or versatility
If Secondary PSAP is enabled to conference and transfer calls, then network flexibility and functionality are enhanced, but the complexity of call handling procedures increases
Solution Approach 1:
The patent implements a universal conference node architecture that can serve multiple PSAPs (both Primary and Secondary) with identical conferencing and transfer capabilities. This multi-functional design allows any PSAP to perform conference and transfer operations without requiring separate specialized systems, enhancing network flexibility while managing complexity through standardized procedures.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Various communication systems may benefit from the appropriate mechanisms for call handling. For example, certain internet protocol (IP) multimedia subsystem (IMS) based emergency services networks may benefit from appropriate initiation of conference calls and of handling of transfers of such calls. A method can include establishing, at an egress node of a network, a media path between an ingress node of the network and the egress node. The method can also include determining that a conference call corresponding to the media path is being invoked. The method can further include contacting, by the egress node, a conference node to establish the conference call.