NTN Cell Selection Using Coverage Time to Cut Beam Handovers
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Solution Overview
Problem
Non-terrestrial networks (NTN) cause excessive power consumption and large overheads due to frequent satellite beam handovers, particularly for latency-sensitive communication services, as UEs frequently reselect cells and update measurement configurations.
Innovation Solution
A cell selection method that considers coverage time information of both cells and network devices, prioritizing cells with longer coverage times and those on the same orbital plane to reduce handover frequency and system information overheads, using weighted metrics for optimal cell selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If UE frequently performs satellite beam handover due to satellite movement, then coverage continuity is maintained, but power consumption increases excessively
Solution Approach 1:
The network device pre-calculates and provides coverage time information for multiple candidate cells before handover is needed. The UE uses this advance information to predict future coverage conditions and select optimal target cells, avoiding frequent measurements and handovers that consume power.
Solution Approach 2:
The UE autonomously selects target cells based on coverage time information and metric values without requiring frequent network coordination or system information updates, reducing the overhead and power consumption associated with network-UE interaction during handovers.
2Reliability
If UE frequently updates measurement handover-related configuration, then handover performance is optimized, but system information overheads increase
Solution Approach 1:
The patent extracts only the essential coverage time information from full system information and provides it separately to the UE. This allows the UE to perform optimized handover decisions without requiring complete system information updates, reducing overhead while maintaining handover performance.
Solution Approach 2:
Coverage time information is provided in advance by the network device, allowing the UE to perform handover optimizations without needing to frequently request or process complete system information updates, thereby reducing information overhead.
3Ease of operation
If UE selects cells based on traditional measurement criteria, then cell selection simplicity is maintained, but handover frequency increases
Solution Approach 1:
The patent introduces coverage time information as an additional parameter in the cell selection metric, transforming the traditional signal-strength-only selection into a multi-parameter optimization that includes temporal coverage stability. This changes the selection criterion to reduce handover frequency while maintaining operational simplicity.
Solution Approach 2:
By providing coverage time information in advance, the UE can perform more informed cell selections that anticipate future coverage conditions, reducing the frequency of handovers while keeping the selection process straightforward through metric calculation.
Data Source
AI summary
This application relates to a cell selection method and apparatus. In an example method, a terminal device performs measurement based on measurement configuration information of N cells and determines M candidate cells based on a measurement result. N is an integer greater than 0, and M is an integer greater than 0 and less than N. The example method further includes the terminal device selecting a target cell from the M candidate cells based on first information. The first information includes coverage information of at least one candidate cell in the M candidate cells.