Satellite Assistance Handover Timing for NTN Cell Switching
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Solution Overview
Problem
Handover procedures in wireless communication systems, particularly in non-terrestrial networks (NTN) and 6G networks, face challenges due to the expiration of validity timers and interruption time requirements for satellite assistance information, leading to unsuccessful handovers and increased interruption times when switching between cells with different satellite assistance information.
Innovation Solution
The method involves modifying handover timers and requirements based on the epoch time of satellite assistance information, including extending or postponing timers, relaxing interruption and handover delay requirements, and acquiring updated satellite assistance information to ensure valid information is available for successful handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If handover procedures are performed in NTN networks with satellite assistance information, then mobility between cells is enabled, but validity timer expiration and interruption time requirements cause handover failures
Solution Approach 1:
The patent applies dynamics by making the handover timer and interruption time requirements adaptive rather than fixed. The network configures different timer values and requirement levels based on the specific satellite assistance information characteristics of the target cell, allowing the system to dynamically adjust to varying satellite orbital positions, velocities, and signal conditions during handover procedures.
Solution Approach 2:
The patent implements preliminary action by providing satellite assistance information configuration to the user equipment before the handover is executed. This includes pre-configuring validity timers, epoch times, and interruption time requirements so that the UE is prepared with the necessary parameters in advance, enabling seamless handover without waiting for real-time satellite data during the actual handover execution.
2Manufacturing precision
If satellite assistance information is updated for target cell, then handover accuracy is improved, but processing delay increases
Solution Approach 1:
The patent applies preliminary action by pre-acquiring and configuring satellite assistance information at the network side before handover execution. The source gNB obtains target cell satellite assistance information in advance through inter-node communication, processes epoch times and validity timers beforehand, and prepares configuration messages prior to triggering the handover, thereby minimizing processing delays during actual handover execution.
Solution Approach 2:
The patent segments the handover process into distinct phases: satellite assistance information acquisition, epoch time validation, configuration message preparation, and handover execution. This segmentation allows parallel processing of different tasks and enables the system to work on multiple handovers simultaneously at different stages, reducing overall processing delay while maintaining accuracy.
3Reliability
If handover timer is extended to accommodate satellite information validity, then handover success is improved, but interruption time increases
Solution Approach 1:
The patent applies parameter changes by configuring different timer values and requirement levels based on the specific satellite assistance information characteristics of the target cell. The network can adjust handover timer durations, validity periods, and interruption time requirements as configurable parameters, optimizing the balance between ensuring successful handover completion and minimizing user service interruption based on satellite orbital dynamics and signal conditions.
Data Source
AI summary
There is provided an apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to perform: receiving, from a serving cell, a configuration message for a handover to a target cell associated with a different satellite assistance information than satellite assistance information associated with the serving cell, wherein the configuration message is indicative of at least: the satellite assistance information associated with the target cell; and a validity timer for defining validity of at least part of the satellite assistance information; wherein the satellite assistance information comprises at least: an epoch time and corresponding satellite assistance information, which is to be applied after reaching the epoch time; determining, based on at least the epoch time, whether to modify a handover timer and/or one or more requirements on handover completion.