Conditional Handover Execution in Non-Terrestrial Networks
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Solution Overview
Problem
Current 5G network technologies lack detailed methods for handling conditional handover execution conditions and mobility robustness optimization in non-terrestrial network environments, such as those using spaceborne or airborne vehicles, which are crucial for ensuring seamless communication and minimizing radio link failures.
Innovation Solution
The proposed solution involves a method and apparatus for user equipment (UE) to receive configuration information and evaluate location-based and measurement-based conditions for conditional handover (CHO) execution, allowing for optimized CHO procedures and mobility management in NTN environments, including the introduction of new CHO execution conditions and a mobility robustness optimization (MRO) mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures are used in NTN environments, then basic mobility support is provided, but radio link failures occur and network robustness is insufficient
Solution Approach 1:
The patent applies preliminary action by configuring execution conditions for conditional handover in advance, including location-based conditions (satellite visibility, distance thresholds) and measurement-based conditions (signal quality thresholds). These conditions are prepared beforehand and stored in the UE, enabling the UE to autonomously evaluate and execute handover without real-time network intervention, thus improving reliability in NTN environments where latency is high.
Solution Approach 2:
The patent implements self-service by enabling the UE to autonomously evaluate execution conditions (location and measurement criteria) and trigger handover procedures without continuous network control. The UE independently determines when to execute CHO based on pre-configured conditions, reducing dependency on real-time network responses and improving network robustness in satellite communication scenarios.
2Measurement precision
If conditional handover with location-based conditions is implemented, then handover accuracy is improved, but evaluation complexity increases
Solution Approach 1:
The patent applies segmentation by dividing execution conditions into distinct categories: location-based conditions (satellite visibility, distance to satellite, geographic area) and measurement-based conditions (signal quality, RSRP thresholds). This segmentation allows the UE to evaluate different condition types independently using specialized algorithms for each, improving handover execution accuracy while managing complexity through modular evaluation processes.
Solution Approach 2:
The patent uses parameter changes by introducing location-specific parameters (satellite orbital position, UE geographic location, distance calculations) alongside traditional measurement parameters. These parameters are dynamically updated and evaluated against pre-configured thresholds, enabling precise handover execution based on the changing NTN environment while maintaining manageable complexity through standardized parameter evaluation frameworks.
3Reliability
If mobility robustness optimization is enhanced, then radio link failure rate decreases, but signaling overhead increases
Solution Approach 1:
The patent reduces signaling overhead by applying preliminary action - all execution conditions (location-based and measurement-based thresholds) are configured in advance during RRC connection setup or handover preparation. The network provides complete CHO configurations including satellite visibility requirements, distance thresholds, and signal quality criteria beforehand, eliminating the need for continuous signaling during the handover evaluation process.
Solution Approach 2:
The patent implements feedback mechanisms where the UE reports execution condition evaluation results and handover status to the network. This feedback loop enables the network to optimize MRO parameters based on actual UE experiences in NTN environments, improving radio link stability while minimizing ongoing signaling overhead through event-triggered reporting rather than continuous communication.
Data Source
AI summary
Embodiments of the present application relate to methods and apparatuses for handling a conditional handover (CHO) execution condition in a non terrestrial network (NTN) environment and a related mobility robustness optimization (MRO) mechanism in the NTN environment. According to an embodiment of the present application, a method which may be performed by a UE can include: receiving, from a network device (e.g., a base station), configuration information for a CHO candidate target cell and an execution condition for the CHO candidate target cell, the execution condition at least includes a location-based condition associated with a location of the UE: evaluating the location-based condition included in the execution condition: and performing a CHO procedure to the CHO candidate target cell, in response to the execution condition being fulfilled.