Satellite Cell Tracking Area Mapping for NTN Paging Load
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Solution Overview
Problem
In non-terrestrial networks (NTNs), the continuous movement of satellites leads to changing cell coverage, causing frequent handoffs and a trade-off between larger tracking areas with high paging loads and smaller areas with frequent handoffs, resulting in inefficient UE registration procedures.
Innovation Solution
A UE determines that a cell serves two or more earth-fixed tracking areas and selectively monitors paging resources based on system information or downlink control information, using a radio temporary network identifier to reduce paging load and prevent unnecessary registration procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a UE monitors paging resources for multiple earth-fixed tracking areas, then paging coverage is improved, but paging load and power consumption increase
Solution Approach 1:
The patent implements dynamic paging resource monitoring by allowing the UE to adaptively select which tracking area's paging resources to monitor based on current cell coverage conditions. When the serving cell covers multiple earth-fixed tracking areas, the UE dynamically determines whether to monitor paging for the current tracking area or a different one, rather than statically monitoring all possible areas. This dynamic approach maintains reliable paging coverage while reducing the overall paging load on the network.
2Stability of the object's composition
If tracking area boundaries are fixed relative to Earth, then geographic consistency is improved, but satellite cell movement causes frequent handoffs
Solution Approach 1:
The patent segments the relationship between satellite cells and tracking areas by introducing a many-to-many mapping where a single earth-fixed tracking area can be served by multiple different satellite cells over time, and a single satellite cell can serve multiple tracking areas. This segmentation allows the tracking area boundaries to remain stable and fixed relative to Earth while the satellite cell coverage moves independently, reducing frequent handoffs as UEs can remain in the same tracking area even as different satellite cells provide coverage.
3Device complexity
If a single TAC is broadcasted by a satellite cell, then cell configuration is simplified, but TAC fluctuation occurs at tracking area borders
Solution Approach 1:
The patent applies multi-functionality by enabling a single satellite cell to broadcast a single TAC that serves multiple earth-fixed tracking areas simultaneously. The cell's paging resources are configured to handle paging for multiple tracking areas, making the cell universally applicable to multiple tracking areas without requiring separate TAC configurations for each. This eliminates TAC fluctuation at tracking area borders while keeping the cell configuration simple.
Data Source
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AI summary
Methods, systems, and devices for wireless communications are described. In some non-terrestrial networks, the movement of satellites may result in the movement of cell coverage. A user equipment (UE) may experience changing cell coverage due to the movement of cell coverage, even if the UE is stationary. A UE may be configured to determine a cell is serving two or more earth-fixed tracking areas, determine whether to monitor paging resources of a first earth-fixed tracking area or a second earth-fixed tracking area, and monitor the selected paging resources. In some aspects, the UE may determine that a cell serves two or more earth-fixed tracking areas based on a received control message including multiple tracking area indicators. In some aspects, the UE may determine which paging resources to monitor based on a geographic position of the UE.