NTN Handover Re-Synchronization for Low-Interruption Cell Changes
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Solution Overview
Problem
In non-terrestrial network (NTN) communication, frequent handovers due to satellite mobility lead to extended interruption times and significant signaling overhead, impacting radio resource efficiency for user data transmission.
Innovation Solution
A method for NTN communication involving a user equipment (UE) that receives a cell change command with re-synchronization information, including re-synchronization time, ephemeris information, and timing advance adjustment, to perform synchronized handovers with target cells using downlink and uplink re-synchronization procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional handover procedures are used in NTN communication, then handover can be performed, but handover interruption time is extended due to high propagation delay
Solution Approach 1:
The network pre-configures synchronization assistance information (including satellite ephemeris data, timing advance values, and reference signal configurations) for target cells before handover is needed. This allows the UE to quickly synchronize with the target cell without performing lengthy synchronization procedures during handover, thereby reducing handover interruption time while ensuring reliable handover completion.
2Reliability
If traditional handover procedures are used in NTN communication, then handover can be performed, but signaling overhead increases due to bursty handover
Solution Approach 1:
The patent combines multiple handover parameters and synchronization information into a single unified handover command message. By merging satellite ephemeris information, timing advance values, reference signal configurations, and other synchronization parameters into one consolidated message, the total signaling overhead is reduced while ensuring all necessary information is transmitted for successful handover.
3Measurement precision
If synchronization assistance information is provided for each handover, then re-synchronization accuracy is improved, but message size increases
Solution Approach 1:
The patent extracts and reuses satellite ephemeris information that is already broadcast in system information blocks (SIBs). Instead of including complete ephemeris data in every handover command, the solution references previously broadcast ephemeris data where applicable, extracting only the essential synchronization parameters needed for handover. This reduces message size while maintaining synchronization accuracy.
Data Source
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AI summary
A method of non-terrestrial network (NTN) communication and a user equipment (UE) using the same method are provided. The method includes: receiving a cell change command comprising re-synchronization information (S1501); and performing a re-synchronization procedure according to the re-synchronization information, wherein the re-synchronization information comprising at least one of the following:a re-synchronization time; ephemeris information associated with a target cell; timing advance adjustment information associated with the target cell; a timing advance command value associated with the target cell; and a re-synchronization indication for indicating the UE to perform the re-synchronization procedure, wherein the re-synchronization procedure comprises a downlink re-synchronization procedure (S1502).