Cross-Network Session Transfer Between CS and IMS Domains
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Solution Overview
Problem
Current technologies fail to implement a seamless transfer of a speech channel across the Circuit Switched (CS) domain and Internet Protocol (IP) Multimedia Subsystem (IMS) domain, causing inconvenience during call transfers, especially when battery depletion or secondary call handling is required.
Innovation Solution
A session transfer method is implemented where an application server receives a request to terminate a session between users in the CS domain and IMS domain, negotiates media information to establish a new session between users, allowing for cross-network transfer without affecting the calling party.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If call transfer is performed in the CS domain, then call transfer capability is provided, but seamless speech channel transfer cannot be implemented
Solution Approach 1:
The patent introduces an application server as an intermediary component that bridges the CS domain and IMS domain. The application server receives session transfer requests, negotiates media information between users across domains, and coordinates the transfer process, enabling seamless speech channel transfer that neither domain could achieve alone.
Solution Approach 2:
The application server provides multi-functional capabilities by handling both CS domain and IMS domain session management, media negotiation, and cross-domain coordination in a single system, allowing unified call transfer operations across different network domains.
2Adaptability or versatility
If battery runs out or secondary call handling is required, then call transfer is needed, but existing methods cause inconvenience to users
Solution Approach 1:
The system enables automatic session transfer where the application server autonomously negotiates media information and establishes new sessions without requiring user intervention. When battery depletion or secondary call handling is detected, the system self-manages the transfer process, maintaining user convenience while providing adaptability to various call scenarios.
3Ease of operation
If cross-network session transfer is implemented, then user convenience is enhanced, but complex negotiation of media information between domains is required
Solution Approach 1:
The application server acts as a mediator that handles the complex media information negotiation between CS and IMS domains. It manages the intricate details of cross-domain media compatibility, codec negotiation, and session parameter coordination, shielding users from this complexity while enabling convenient cross-network session transfer.
Data Source
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AI summary
Embodiments of the present invention relate to the field of communications and provide a session transfer method, an application server, and a communications system, which implement a cross-network session transfer between a CS domain and an IMS domain. The method includes: after receiving a session transfer request sent by user B or user C in the IMS domain, sending a release message to the user B currently in a call to terminate a session between user A in the CS domain and the user B, and negotiating media information of the user A and media information of the user C to establish a session between the user A and the user C. The embodiments of the present invention apply to a cross-network session between the CS domain and the IMS domain.