CSI-AS Call Context for CS to IMS Handoff
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Solution Overview
Problem
Current technologies hinder seamless integration and transition between circuit-switched (CS) voice calls and IP Multimedia Subsystem (IMS) sessions, particularly when public service numbers are involved, as users cannot easily switch between services or hand off calls due to lack of identity information.
Innovation Solution
A system and method that utilize a Circuit Switched Identity Application Server (CSI-AS) to create call contexts and notifications, allowing devices to initiate IMS sessions without knowing the exact terminal identity by using a Universally Unique Identifier (UUID) and SIP event packages for cross-domain service coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Calling Line Identification Restriction (CLIR) is invoked during CS voice call establishment, then the calling party's identity is hidden from the called party, but the called party cannot initiate an IMS session with the calling party
Solution Approach 1:
The patent introduces a CS domain network element (such as an application server or gateway) as an intermediary that maintains the calling party's identity information even when CLIR is active. This intermediary enables the IMS domain to obtain the necessary identity data to establish sessions, thereby resolving the contradiction between privacy protection and service coupling capability.
2Ease of operation
If a user calls a road assistance service with a normal CS call to a service number, then the call is terminated to an available terminal selected dynamically, but the user cannot establish an IMS session with the road assistance representative due to unknown terminal identity
Solution Approach 1:
The patent implements preliminary action by having the CS domain network element store and forward the calling party's identity information to the IMS domain before the IMS session is initiated. This pre-prepared identity information enables the user to seamlessly transition from a simple CS call to a combined IMS session without requiring knowledge of the representative's terminal identity.
3Duration of action of stationary object
If a user wants to handoff a CS call to an IMS network, then call continuity is improved, but the handoff is not possible if the user does not know the other party's identity
Solution Approach 1:
The patent employs the CS domain network element as an intermediary that preserves and transmits identity information throughout the call handoff process. This intermediary ensures that even when the user lacks identity information initially, the system maintains the necessary data to enable seamless handoff from CS to IMS network, thereby ensuring call continuity.
4Adaptability or versatility
If services in the first domain (CS) are coupled to services in the second domain (IMS), then multi-service usability is enhanced, but the coupling is hindered by lack of identity information with public service numbers
Solution Approach 1:
The patent introduces a CS domain network element as an intermediary that captures and forwards identity information from the CS domain to the IMS domain. This intermediary mechanism enables services in both domains to be coupled effectively, even when public service numbers are involved and direct identity information is not available to the user.
Data Source
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AI summary
A system and method in which a notification is received of a call from a first device to a second device in a first domain. A context is created for the first type of call. A notification is received of initiation of a call from the second device to the first device in a second domain. The call context is utilized to notify the first device of the initiation of the call from the second device to the first device.