Cell Selection Using Mobility-Adaptive Beam Quality Scaling
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Solution Overview
Problem
Current cell (re-)selection mechanisms in 5G NR deployment scenarios, particularly in RRC_IDLE or RRC_INACTIVE states, lack robustness due to the absence of network control and incompatibilities with multi-beam operations, leading to inappropriate cell selection or reselection, especially in high-mobility scenarios where seamless transition between multiple beams is necessary for maintaining signal quality.
Innovation Solution
A mobile terminal is configured to measure signal quality from multiple beams of suitable cells and determine cell quality based on a combined beam quality value, which is scaled according to its mobility state, ensuring robust cell selection or reselection by considering the impact of mobility on signal quality measurements from all or a subset of beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cell quality is determined by simply summing all beam signal qualities, then cells with multiple beams are penalized, but this leads to inappropriate cell selection in high-mobility scenarios
Solution Approach 1:
The patent applies dynamics by making the cell quality determination adaptive to mobility state. The weighting factor for combined beam quality is dynamically adjusted based on whether the UE is in high-mobility or normal-mobility state, allowing the system to transition between different evaluation strategies as conditions change
Solution Approach 2:
The patent changes the parameter of cell quality calculation by introducing mobility-state-dependent weighting factors. In high-mobility state, a lower weighting factor is applied to combined beam quality, while in normal-mobility state, a higher weighting factor is used, thereby adapting the measurement precision to operational conditions
2Reliability
If network control is implemented for cell selection, then cell selection robustness is improved, but device complexity increases
Solution Approach 1:
The patent applies self-service by enabling the UE to autonomously determine its own mobility state based on measurement criteria (such as signal quality changes over time) without requiring network control. The UE independently adjusts cell quality determination based on its own operational conditions
Solution Approach 2:
The patent implements feedback mechanisms where the UE continuously monitors signal quality measurements and uses this feedback to determine mobility state. The measured signal qualities are fed back into the cell quality determination process, creating a closed-loop system that adapts to changing conditions
3Measurement precision
If all beam signal qualities are considered equally, then measurement precision is maintained, but reliability decreases in high-mobility scenarios where beam transitions occur
Solution Approach 1:
The patent applies local quality by differentiating the importance of different beam quality measurements based on mobility state. In high-mobility conditions, individual beam measurements are weighted less heavily compared to combined beam quality, while in normal conditions, individual beam measurements carry more weight, creating locally optimized evaluation for different operational contexts
Data Source
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AI summary
The present disclosure relates to a mobile terminal for performing cell (re-)selection in a system with at least two suitable cells,each with a plurality of beams.The terminal is in a normal-or a high-mobility state. The terminal measures a signal quality of the beams of each of the suitable cells, determines the cell quality based on the respective measured signal qualities of the beams; and(re-)selects that cell based on a cell (re-)selection criterion using the determined cell qualities. The cell quality is determined for each one of the suitable cells as a sum of the measured signal quality of the beam, with the best signal quality, and a combined beam quality value for the other beams. The combined beam quality value is scaled with a scaling factor which changes depending on the mobility state such that the combined beam quality value is scaled-up in the high-mobility state and scaled-down in the normal-mobility state.