Signalling in Wireless Network for Circuit Switched Fallback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The operation of Circuit Switched Fallback feature is impeded when Idle mode Signalling Reduction is enabled, as it prevents the establishment of necessary associations between packet switched and circuit switched network control nodes, affecting features like SMS and voice communications.
Innovation Solution
A method that involves sending a context-related message with association requirement data from the second packet switched network control node to the first packet switched network control node before a user equipment update, allowing the association to be formed independently of further updates and enabling features like Circuit Switched Fallback and SMS over SGs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If Idle mode Signalling Reduction is enabled to reduce signaling load, then signaling load is reduced, but the establishment of association between packet switched and circuit switched network control nodes is prevented
Solution Approach 1:
The patent applies preliminary action by sending the context request message from the second packet switched network control node to the first packet switched network control node before the user equipment performs the further update. This ensures that the association requirement context data is transmitted and processed in advance, allowing the association to be established before Idle mode Signalling Reduction suppresses subsequent signaling. The context request message includes an indicator that the association requirement context data is to be stored, ensuring the data is preserved for future use even when ISR is active.
2Productivity
If user equipment updates to LTE in idle mode when Idle mode Signalling Reduction is enabled, then signaling is reduced, but the association establishment between MME and MSC does not occur
Solution Approach 1:
The patent resolves this contradiction by performing the context data transmission in advance. The second packet switched network control node sends the context request message containing association requirement context data before the user equipment performs further updates to the first radio access network. This preliminary action ensures that the data is available for establishing associations that enable features like Circuit Switched Fallback and SMS, while still allowing Idle mode Signalling Reduction to suppress subsequent unnecessary signaling.
Solution Approach 2:
The patent uses the context request message as an intermediary carrier to transmit the association requirement context data from the second packet switched network control node to the first packet switched network control node. This intermediary mechanism allows the association information to be conveyed through the existing signaling framework without requiring additional dedicated signaling procedures, thus maintaining signaling efficiency while enabling feature functionality.
3Loss of energy
If Idle mode Signalling Reduction suppresses mobility signaling, then signaling load is reduced, but features like Circuit Switched Fallback and SMS are impeded
Solution Approach 1:
The patent applies preliminary action by ensuring that the association requirement context data is sent and stored before Idle mode Signalling Reduction suppresses subsequent mobility signaling. The context request message is transmitted in advance, and the first packet switched network control node stores the association requirement context data with an indicator that it should be retained. This allows features like Circuit Switched Fallback and SMS to operate correctly when the user equipment later returns to the first radio access network, even though subsequent signaling is suppressed by ISR.
Data Source
AI summary
In accordance with a first aspect of the present invention, there is provided a method of signalling in a communications network comprising a user equipment, a first radio access network, a second radio access network and a core network, the core network comprising a first packet switched network control node communicatively coupled to the first radio access network, a circuit switched network control node communicatively coupled to the first radio access network, and a second packet switched network control node communicatively coupled to the second radio access network, wherein the second packet switched network control node is capable of forming an association with the circuit switched network control node, in dependence on the user equipment performing an update to the second radio access network, to enable one or more features which employ said circuit switched network control node, the method comprising: receiving a first update of the user equipment from the first radio access network towards the first packet switched network control node; subsequent to the receipt of said first update, receiving an update of the user equipment from the second radio access network towards the second packet switched network control node; sending a context-related message from the second packet switched network control node to the first packet switched network control node, the context-related message comprising association requirement context data indicating an association requirement between the second packet switched network control node and the circuit switched network control node; and receiving a further update of the user equipment from the first radio access network towards the first packet switched network control node, wherein said context-related message is sent before said further update of the user equipment from the first radio access network is received. This has an advantage that the sending of the context-related association requirement context data is independent of the further update of the user equipment towards the first packet switched network control node. The sending of the association requirement context data may thus be reliably achieved even if the receipt of the further update causes suppression of the sending of context-related messages.