LEO Satellite Handover Using Obstruction Prediction
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Solution Overview
Problem
User devices experience radio link failures due to terrestrial obstructions when using low earth orbit communication satellites, leading to degradation of communication services, especially in areas with insufficient terrestrial networks or during emergencies.
Innovation Solution
User devices predict radio link failures using topological terrain maps and track satellite trajectories to proactively perform conditional handovers to unobstructed target satellites, utilizing inter-satellite communication systems and aerial drones as RF relays to maintain connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If user devices use low earth orbit communication satellites for communication services, then communication coverage is improved in areas with insufficient terrestrial networks, but radio link failures occur due to terrestrial obstructions
Solution Approach 1:
The system performs preliminary actions by predicting future radio link failures before they occur. The user device receives configuration for conditional handover, determines satellite trajectories and fields of view, and predicts obstructions using terrain maps in advance. This allows the device to proactively trigger handover to target satellites before the current satellite's signal is blocked, thereby maintaining reliable communication while using LEO satellites for extended coverage.
2Speed
If satellites move at high speed relative to fixed positions on Earth, then communication service speed is improved, but coverage duration is reduced requiring frequent handovers
Solution Approach 1:
The system implements feedback mechanisms by continuously monitoring satellite trajectories, fields of view, and terrain obstruction data. The user device receives configuration parameters, determines current satellite positions and velocities, predicts future obstruction events based on this feedback, and dynamically triggers conditional handover. This feedback loop enables the system to adapt to the high-speed satellite movement by proactively managing handovers, thereby maintaining continuous coverage despite the reduced duration each satellite remains in view.
3Ease of operation
If user devices perform conditional handover based on time passage, then handover simplicity is improved, but handover accuracy is reduced when obstructions occur
Solution Approach 1:
The system changes the handover trigger parameter from simple time-based criteria to obstruction-based criteria. Instead of triggering handover merely based on the passage of time or satellite position, the user device uses terrain maps and satellite trajectory data to predict whether terrestrial obstructions will block the radio link. This parameter change maintains operational simplicity through automated configuration while dramatically improving handover accuracy by triggering handover only when actual obstruction risks are detected, rather than on a fixed time schedule.
Data Source
AI summary
A user device, a method, and a computer program product enable conditional requests by a user device based on predicting a radio link failure due to a terrestrial object. A communication subsystem of the user device receives communication service by a currently serving satellite of a constellation of satellites in low earth orbit (LEO). The serving satellite has a field of view encompassing a target area surrounding the user device. A controller of the communication device determines a location of the user device and tracks trajectories and corresponding fields of view of the constellation of LEO communication satellites. In response to predicting a radio link failure due to a terrestrial obstruction, the controller triggers completion of a conditional handover of radio link to a target satellite that is not predicted to have a radio link failure due to a terrestrial obstruction.