IMS Session Transfer via Translation Server Mediator
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Solution Overview
Problem
Current techniques for transferring VoLTE sessions between wireless networks are inefficient and ineffective due to the need for numerous access network nodes to have current contact information for IMS ATCFs and EATFs on a per-session and per-UE basis, which is disrupted when the LTE network changes the P-CSCF during registration.
Innovation Solution
A communication system that includes a translation server to associate User Equipment (UE) with a transfer control server, allowing for efficient media session transfers between wireless communication networks by maintaining a data structure that identifies the appropriate transfer control server for the UE, enabling seamless session transfers across different networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the LTE network changes the P-CSCF for a UE during LTE registration, then the ATCF/EATF for the UE also changes since P-CSCFs and ATCF/EATFs are individually paired, but this causes inefficiency and ineffectiveness in session transfer between networks
Solution Approach 1:
The translation server acts as an intermediary between the access network and the transfer control server. It receives transfer requests from the access network, translates them into appropriate signaling messages, and forwards them to the correct transfer control server. This mediator approach eliminates the need for numerous access network nodes to maintain current contact information for IMS ATCFs and EATFs, while preserving session transfer capability across network changes.
Solution Approach 2:
The patent extracts the complex contact information management function from the access network nodes and consolidates it in the translation server. By removing the burden of maintaining per-session and per-UE contact information for ATCFs and EATFs from access network nodes, the system achieves more efficient session transfer without losing the adaptability to handle P-CSCF changes.
2Reliability
If numerous access network nodes maintain current contact information for IMS ATCFs and EATFs on a per-session and per-UE basis, then session transfer can be controlled, but this increases system complexity and reduces transfer efficiency
Solution Approach 1:
The translation server merges the contact information management functions for multiple ATCFs and EATFs into a single centralized entity. Instead of each access network node maintaining separate contact information for numerous IMS servers, the translation server consolidates all this information and manages it centrally, reducing system complexity while maintaining reliable session transfer control.
Solution Approach 2:
The translation server provides universal service to multiple access network nodes, handling translation requests for various ATCFs and EATFs through a single multi-functional entity. This universal approach allows any access network node to rely on the translation server for contact information, eliminating the need for each node to independently manage complex per-session and per-UE contact data.
3Ease of operation
If the translation server maintains a data structure identifying the appropriate transfer control server for the UE, then seamless session transfers are enabled, but this requires additional information storage and processing
Solution Approach 1:
The translation server performs preliminary actions by maintaining a data structure that pre-identifies the appropriate transfer control server for each UE. This advance preparation ensures that when a session transfer is needed, the translation server can quickly retrieve the correct server information without real-time computation, enabling seamless transfers while the data storage requirement is offset by the efficiency gain.
Solution Approach 2:
The data structure in the translation server is dynamic, automatically updating the association between UEs and transfer control servers as P-CSCFs change during registration. This dynamic maintenance of contact information ensures that the system adapts to network changes without requiring manual intervention, achieving ease of operation with automated information management.
Data Source
AI summary
In a communication system, a session control server receives a session request for User Equipment (UE) over a first network and exchanges signaling with the UE and a transfer control server to establish a media session. The transfer control server sends an association of the UE and the transfer control server to a translation server. The translation server associates the UE with the transfer control server. The translation server receives a transfer request for the UE from a second network and identifies the transfer control server associated with the UE. The translation server transfers the transfer request for delivery to the transfer control server. The transfer control server exchanges signaling with the second network responsive to the transfer request to transfer the media session for the UE from the first network to the second network.