Satellite Feeder Link Handover Timing Coordination
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Solution Overview
Problem
Current satellite communication systems face significant service interruptions during feeder-link handovers between ground gateways due to the lack of a clear method for negotiating handover times, leading to potential disconnections and delays in user equipment (UE) access to new cells.
Innovation Solution
A method for determining an accurate handover time instant T and target cell activation time T′, where T is the time for disconnecting the previous feeder link and initiating a new one, and T′ is the time required for the new link establishment, allowing the source gateway to initiate handover and instruct UE to synchronize with the target cell, thereby minimizing service interruptions and reducing handover delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a satellite connects to only one ground gateway at a time, then the connection management is simplified, but service interruption occurs during feeder-link handover between gateways
Solution Approach 1:
The patent implements preliminary action by establishing a handover preparation phase where the target gateway is pre-configured with handover parameters and the handover command is prepared in advance. The source gateway sends a handover request to the target gateway before the actual handover occurs, allowing the target gateway to allocate resources and prepare the handover command with appropriate timing parameters, thus reducing service interruption during the actual handover execution.
2Productivity
If handover of tens of thousands of users is performed simultaneously, then all users are transferred to the new gateway, but random-access resource requirements and handover delay increase significantly
Solution Approach 1:
The patent applies segmentation by dividing the handover process into distinct phases: handover preparation, handover execution, and handover completion. The handover command includes a target cell activation time parameter that allows staged activation. This segmentation enables the system to manage large numbers of users more efficiently by controlling the timing and pacing of handover execution, reducing the peak random-access resource requirements and minimizing handover delay.
3Device complexity
If no clear handover negotiation method is implemented between gateways, then system simplicity is maintained, but handover timing coordination fails causing additional service interruptions
Solution Approach 1:
The patent implements feedback mechanisms through the handover request and handover response messaging between source and target gateways. The source gateway sends a handover request containing relevant parameters, and the target gateway responds with a handover response that includes confirmed handover parameters and timing information. This feedback loop ensures proper coordination of handover timing, allowing the source gateway to determine the appropriate handover time instant T and target cell activation time instant T' based on the target gateway's response, thus preventing timing conflicts and service interruptions.
Data Source
AI summary
A feeder link handover method, device and apparatus, and a handover method, device and apparatus for user equipment belonging to a satellite are provided. The method includes: interacting with a target gateway by a source gateway and determining a handover time instant T and/or a target cell activation time instant T′, wherein the handover time instant T is a time instant at which a previous feeder link is disconnected and establishment of a new feeder link is initiated, the target cell activation time instant T′ is T+a time period Δ (delta) required for the establishment of the new feeder link; initiating a feeder-link handover at the handover time instant T, and instructing a user equipment to synchronize with a target cell at the T′.