MME CSFB Call Restriction Handling for Mobile Stations
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Solution Overview
Problem
Mobile stations compliant with LTE Release supporting the barring scheme for CSFB are subjected to double call restriction when both first and second countermeasures are applied, leading to improper CSFB call processing.
Innovation Solution
A mobile communication method and system that allow mobile stations to send capability information indicating support for the barring scheme, enabling the switch to perform appropriate CSFB call processing and rejection based on this information, preventing double restriction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both first countermeasure (barring scheme) and second countermeasure (Service Reject with timer) are applied simultaneously, then call restriction coverage is improved to include all mobile stations, but mobile stations supporting the barring scheme are subjected to double call restriction causing service disconnection
Solution Approach 1:
The patent changes the parameter of call restriction application by introducing capability information to differentiate between mobile stations that support the barring scheme and those that do not. This allows the network to adjust the restriction mechanism applied based on the mobile station's capabilities, preventing double restriction on compatible devices while maintaining restriction effectiveness for incompatible devices.
Solution Approach 2:
The patent applies different call restriction treatments to different mobile stations based on their local capability characteristics. Mobile stations supporting the barring scheme receive restriction through the barring mechanism only, while those not supporting it receive restriction through the Service Reject mechanism. This localized differentiation eliminates the harmful double restriction effect.
2Reliability
If the switch applies call restriction using the second countermeasure (Service Reject) to all mobile stations, then call restriction is achieved for mobile stations not supporting the barring scheme, but mobile stations supporting the barring scheme cannot properly judge whether to perform CSFB call processing
Solution Approach 1:
The patent introduces feedback through capability information that mobile stations transmit to the network. This feedback allows the switch to identify whether a mobile station supports the barring scheme and accordingly select the appropriate call restriction method, enabling compatible mobile stations to properly judge whether to perform CSFB call processing without confusion from conflicting restriction mechanisms.
Solution Approach 2:
The patent makes the call restriction mechanism dynamic by allowing the switch to adapt its behavior based on the mobile station's capability information. The restriction method changes dynamically - using barring scheme for compatible devices and Service Reject for incompatible devices - rather than applying a static uniform approach to all mobile stations.
Data Source
AI summary
A mobile communication method according to the present invention includes the steps of: causing an switch MME to perform CSFB-related processing for a mobile station UE when receiving “Extended Service Request” during call restriction and judging that the mobile station UE supports the barring scheme for CSFB on the basis of CSFB restriction capability information; and causing the switch MME to send the mobile station UE “Service Reject” when receiving “Extended Service Request” during the call restriction and judging that the mobile station UE does not support the barring scheme for CSFB on the basis of the CSFB restriction capability information.