NTN Cell Switching Using Shared PCI and Timing Resynchronization
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Solution Overview
Problem
In non-terrestrial networks (NTN), the efficiency of mobility control and radio resource usage is compromised due to the lack of a specific procedure for switching between cells assigned the same physical cell identifier, leading to increased power consumption and signaling overhead.
Innovation Solution
Assigning the same physical cell identifier (PCI) to cells formed by different flying objects and providing control information to enable downlink and uplink resynchronization without a handover procedure, using cell switching notification to manage timing adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cell switching is performed in NTN without a specific procedure, then mobility control can be achieved, but power consumption and signaling overhead increase
Solution Approach 1:
The patent changes the parameter of cell identifier assignment by using the same PCI for multiple cells served by different flying objects. This parameter change enables the terminal to recognize cells as equivalent, allowing seamless switching without triggering handover procedures, thereby reducing power consumption while maintaining mobility control capability
2Ease of operation
If cell switching is performed in NTN without a specific procedure, then mobility control can be achieved, but signaling overhead increases
Solution Approach 1:
The patent changes the parameter of cell identifier assignment by using the same PCI for multiple cells. This enables the terminal to perform autonomous cell switching based on downlink signal quality measurements without requiring network signaling, thereby reducing signaling overhead while maintaining mobility control
Solution Approach 2:
The terminal apparatus is enabled to autonomously perform cell switching decisions based on pre-configured parameters and downlink signal quality measurements. This self-service mechanism eliminates the need for continuous network signaling during cell switching, reducing signaling overhead while maintaining mobility control efficiency
3Reliability
If handover procedure is executed for cell switching, then timing resynchronization can be performed, but device complexity and processing overhead increase
Solution Approach 1:
The patent changes the cell identifier parameter to be identical across cells served by different flying objects. This enables the terminal to perform simplified timing resynchronization using the same PCI for downlink timing acquisition, avoiding complex handover procedures while maintaining synchronization reliability
Solution Approach 2:
The patent extracts the essential function of timing resynchronization from the complete handover procedure. By separating the timing synchronization aspect from the full handover protocol, the terminal can perform resynchronization using only downlink timing acquisition based on the same PCI, reducing device complexity while maintaining reliability
Data Source
AI summary
A terminal apparatus includes: a receiver configured to receive control information from a first satellite which forms a first cell; and processor circuitry configured to: perform, when the control information includes time information related to switching time from the first satellite to a second satellite which forms a second cell and information indicating that the first cell and the second cell have same physical cell IDs, resynchronization processing of downlink of the second cell according to the time information, control, after performing the resynchronization processing, to start a timer for a valid time of uplink of the second cell.