NTN Handover Signaling Using Shared and UE-Specific Configuration
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Solution Overview
Problem
Non-terrestrial network (NTN) systems face significant challenges in managing handover signaling due to the large size of NTN cells and the need for simultaneous handovers of a large number of UEs, leading to increased signaling overhead and potential service continuity issues.
Innovation Solution
Implementing a method where handover configuration is split into common and dedicated parts, with the common configuration being broadcast to multiple UEs in a point-to-multipoint transmission, followed by dedicated configuration for individual UEs, reducing the overall signaling load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If handover configuration is transmitted individually to each UE, then dedicated configuration accuracy is improved, but signaling overhead increases significantly
Solution Approach 1:
The handover configuration is segmented into two distinct parts: common configuration information that applies to all UEs in the cell, and dedicated configuration information specific to each UE. The common configuration is broadcast once to all UEs, while only the dedicated part is transmitted individually, thereby reducing redundant signaling while maintaining complete configuration accuracy for each UE.
Solution Approach 2:
The common configuration information serves multiple UEs simultaneously by being broadcast to all UEs in the cell. This universal configuration covers parameters that are identical for all UEs, eliminating the need to transmit the same information repeatedly to each UE individually, thus reducing overall signaling overhead while maintaining configuration completeness.
2Reliability
If simultaneous handovers for large number of UEs are performed, then service continuity is improved, but signaling capacity is exceeded
Solution Approach 1:
The common configuration information is prepared and broadcast in advance before the actual handover execution. This preliminary action allows UEs to pre-configure themselves with necessary handover parameters, reducing the signaling burden during the critical handover moment and enabling smoother simultaneous handovers for multiple UEs without exceeding signaling capacity.
Data Source
AI summary
Systems and methods discussed herein relate to handover signaling reduction in the cases where one or more user equipments (UEs) are to be handed over from a source serving cell of a source base station to a target serving cell of a target base station based on common configuration information for operating on the target serving cell and dedicated configuration information for each specific UE. In various cases, a point-to-multipoint (PTM) transmission includes the common configuration information for the UEs, a handover command instructs a UE to independently acquire common configuration information from system information blocks (SIBs) of the target serving cell, or a handover command for a UE indicates that the UE is to re-use a common configuration for the source serving cell. Handover commands may be used to provide dedicated configuration information for each UE. Configuration related communications sent on Xn and F1 interfaces are also discussed.