Session State Manager for CS IMS Synchronization
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Solution Overview
Problem
Current telecommunications systems in combinational networks, which combine Circuit Switched (CS) and Packet Switched (PS) networks, lack a mechanism to effectively manage and correlate CS-calls and IMS-sessions, particularly during events like Call Hold, leading to inconsistent Quality of Service (QoS) and lack of integration between CS and IMS services.
Innovation Solution
A method is introduced that utilizes a session state manager node to detect events such as Call Hold in the CS-network and sends corresponding messages to both CS and IMS-networks to control the respective sessions, ensuring coordinated action between CS and IMS sessions, and maintaining session state information for service layer applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If CS and IMS sessions are managed independently in combinational networks, then network architecture simplicity is maintained, but session coordination and QoS consistency deteriorate
Solution Approach 1:
The patent introduces a Session State Manager node as an intermediary component that mediates between CS and IMS sessions. This manager detects events in one network type and triggers corresponding actions in the other network type, ensuring coordinated session control without requiring complete architectural integration. The Session State Manager maintains session state information and enables supplementary services like Call Hold to function across both CS and IMS domains.
2Reliability
If CS bearers are used for voice traffic in current networks, then QoS requirements are met, but PS network capabilities for multimedia services are underutilized
Solution Approach 1:
The patent enables dynamic session management where the system can adaptively control CS and IMS sessions based on service requirements and network conditions. The Session State Manager dynamically triggers actions such as suspending IMS sessions when CS calls are held, or resuming them when calls are retrieved, allowing the network to flexibly allocate resources between traditional voice services and multimedia services depending on current operational context.
3Ease of operation
If User Equipment is used to initiate session control events, then operational flexibility is improved, but trust and security concerns arise
Solution Approach 1:
The Session State Manager acts as a trusted intermediary that receives session control event information from User Equipment and validates/coordinates the corresponding actions in both CS and IMS networks. This intermediary approach maintains the operational flexibility of UE-initiated events while introducing a trusted network entity that ensures proper session coordination and prevents unauthorized or inconsistent session control operations.
Data Source
AI summary
Combinational networks may provide simultaneous connectivity over networks of different type between terminals. Communication sessions on different network types such as Circuit switched and Packet switched, belonging to the same user equipment can be correlated. In case a communication session on a circuit switched network is halted by a supplementary service e.g. at an event such as acceptance of Call Hold, a communication session on a correlated packet switched network should be halted as well. A user equipment that detects the event sends a halt message to the circuit switched network and a message to the packet switched network or a session state manager node. The session state manager node either forwards the halt-message to the packet switched network, or sends a halt-message to the packet switched network when the packet switched network does not notify that a halt has occurred.