Inter-RAT Signaling Reduction via UE Context Parameter
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Solution Overview
Problem
Current 3GPP specifications require unnecessary registration updates during inter-RAT changes, especially after UE context modifications, leading to inefficient signaling reduction during handovers between registered areas, as the ISR deactivation triggers unnecessary updates even when the target area is already registered.
Innovation Solution
The method involves storing a parameter to determine if deactivation events are due to UE context modifications in the source RAT, and upon inter-RAT changes, checking this parameter to cancel or validate the need for registration updates, thereby optimizing signaling reduction by avoiding unnecessary updates during handovers to registered areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the signalling reduction function is deactivated due to UE context modification in source RAT, then the UE context synchronization is ensured at next IRAT change, but unnecessary registration updates are triggered even when moving to already registered target areas
Solution Approach 1:
The invention applies local quality by differentiating the treatment of registration updates based on the target area's registration status. When the UE moves to a target area that is already registered with the target core network, the registration update is cancelled. However, when moving to a new target area requiring registration, the update proceeds normally. This localized differentiation resolves the contradiction by maintaining reliability only where necessary while improving productivity where possible.
Solution Approach 2:
The invention introduces dynamic behavior by making the registration update decision contingent on real-time conditions: whether the target area is already registered with the target core network. The UE dynamically adjusts its behavior based on the inter-RAT change event type and target area status, transitioning between cancelling and validating registration updates as needed, thus resolving the contradiction between reliability and productivity.
2Reliability
If registration update is always performed after ISR deactivation, then UE context is synchronized with target core network, but network load and processing in terminal increase unnecessarily
Solution Approach 1:
The invention extracts the unnecessary registration update procedure from the mandatory process. By checking whether the target area is already registered with the target core network, the UE can take out (remove) the registration update step when it is not needed. This extraction reduces signaling load while maintaining UE context synchronization reliability through the selective application of the update procedure.
3Productivity
If the UE autonomously recovers signaling reduction state without peer-to-peer signaling, then processing in terminal and network load are reduced, but the complexity of UE logic increases
Solution Approach 1:
The invention implements self-service by enabling the UE to autonomously determine whether to perform registration updates based on its own stored information about target area registration status. The UE serves itself by making the decision without requiring peer-to-peer signaling with the network, thus improving signaling reduction efficiency while accepting the necessary increase in UE logic complexity to manage this autonomous decision-making capability.
Data Source
AI summary
Method for optimizing the reduction of mobility signaling after an Inter-RAT change for a UE roaming between a source area covered by a source telecommunication core network and a target area covered by a target core telecommunication network, wherein a signaling reduction function is activated by the source telecommunication core network, and wherein deactivation triggering events of the signaling reduction function generates a need for registration update at next IRAT change occurred. The method comprises the steps: storing in the UE a parameter the value of which indicates whether or not the deactivation triggering events of the signaling reduction function only correspond to the UE context modification, and, after the Inter-RAT change,checking the event generating the Inter-RAT change, and,checking the value of the parameter,cancelling the need for registration update or validating the need for registration update depending on the event generating the Inter-RAT change and on the value of the stored parameter.