Multi-TAC Paging Selection in Moving NTN Cell Coverage
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Solution Overview
Problem
In non-terrestrial networks (NTNs), UEs experience frequent cell handoffs due to continuous satellite movement, leading to inefficient paging and registration procedures, as they are typically registered for a single tracking area, causing a tradeoff between large paging loads and frequent handoffs.
Innovation Solution
UEs determine that a cell serves multiple earth-fixed tracking areas based on system information, selecting and monitoring appropriate paging resources using tracking area indicators and paging radio network temporary identifiers, thereby reducing paging load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If UEs are registered for a single tracking area in NTNs, then the device complexity is reduced, but the paging load increases and handoff frequency increases
Solution Approach 1:
The patent enables a single cell to serve multiple earth-fixed tracking areas simultaneously. The cell is configured with multiple tracking area codes (TACs), allowing it to function as a universal access point for UEs in different tracking areas. This multi-functionality resolves the contradiction by enabling UEs to be registered for multiple tracking areas without increasing device complexity, while reducing paging load through more efficient area management.
Solution Approach 2:
The patent changes the parameter of tracking area configuration by allowing cells to be associated with multiple TACs instead of a single TAC. This parameter change enables the cell to serve multiple tracking areas, thereby reducing paging load and optimizing handoff behavior without complicating the UE registration process.
2Productivity
If cells in NTNs serve multiple earth-fixed tracking areas, then paging load is reduced, but the device complexity increases
Solution Approach 1:
The network automatically manages the multi-TAC cell configuration without requiring complex manual intervention. The cell self-configures with multiple tracking area codes based on its coverage area and the earth-fixed tracking areas it intersects. This self-service approach reduces the operational complexity despite the enhanced functionality of serving multiple tracking areas.
3Productivity
If satellites move continuously, then network coverage is maintained, but cell handoff frequency increases
Solution Approach 1:
The patent segments the coverage area into multiple earth-fixed tracking areas, each with stable identifiers. As the satellite moves and cell coverage changes, UEs can remain registered for multiple tracking areas, reducing the frequency of registration updates and handoffs. This segmentation allows the network to maintain continuous coverage while reducing the overhead of frequent handoff procedures.
Data Source
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.