Satellite Cell Handover Selection Using Random Access Preambles
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Solution Overview
Problem
In satellite communication systems, existing cell handover methods based on ephemeris information and location data fail to accurately select the most suitable target cell due to changing satellite conditions, leading to ping-pong effects and increased signaling overheads.
Innovation Solution
A method where a terminal sends a random access preamble to a satellite, which determines terminal information and cell attribute information to select a second cell most suitable for access, reducing reliance on terminal calculations and minimizing signaling overheads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the terminal calculates service duration based on ephemeris information and location information to select a target cell, then the terminal can autonomously determine a handover target, but the selected cell may not be the most suitable due to changes in cell attributes between trigger generation and handover execution
Solution Approach 1:
The network side performs preliminary actions by pre-calculating and providing service duration information for multiple candidate cells before the terminal makes the handover decision. This allows the terminal to select the most suitable target cell based on accurate, pre-computed service duration data, resolving the contradiction between autonomous determination and selection accuracy.
2Reliability
If multiple candidate cells are provided for conditional handover, then handover reliability is improved, but the complexity of cell selection increases due to multiple trigger conditions and service duration calculations
Solution Approach 1:
The patent extracts the complex service duration calculation function from the terminal and relocates it to the network side. The network side computes service durations for all candidate cells and provides this information to the terminal, thereby reducing terminal complexity while maintaining reliable multi-cell handover capability.
3Productivity
If the terminal determines the target cell based on service duration calculation, then the terminal can select a cell for longest service, but signaling overhead increases due to multiple measurements and evaluations
Solution Approach 1:
The network side acts as an intermediary that centralizes the service duration calculations for all candidate cells. By having the network compute and provide this information rather than having each terminal independently calculate, the system reduces redundant signaling overhead while achieving the same service duration optimization goal.
Data Source
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AI summary
Embodiments of this application relate to a cell handover method and apparatus, to determine a suitable access cell for a terminal in a cell handover process. The cell handover method is: A satellite receives a random access preamble that is of a first cell and that is sent by a terminal, where the random access preamble is used to determine terminal information used for cell handover; the satellite determines, based on the terminal information and cell attribute information that is of the satellite, a second cell most suitable for the terminal to access; and the satellite sends access information of the second cell to the terminal.