Satellite Handoff Management for Non-Geosynchronous Networks
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Solution Overview
Problem
Non-geosynchronous satellite communication systems face challenges in efficiently handing off user terminals between satellites due to the dynamic movement of satellites relative to ground-based devices, requiring effective techniques to ensure seamless communication coverage.
Innovation Solution
A method and apparatus for identifying and requesting updated handoff entries in a set of handoff entries, which includes determining the need for an updated idle mode handoff table based on time or validity, and sending a request to a ground network to receive updated satellite information for efficient handoff operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a constellation of satellites in non-geosynchronous orbits is used to provide communication coverage, then coverage area is improved, but handoff complexity increases due to satellite movement relative to ground devices
Solution Approach 1:
The system pre-calculates and provides handoff information to user terminals before handoff is needed. The gateway determines handoff parameters including satellite identifiers, timing information, and frequency details in advance, allowing user terminals to prepare for seamless transitions between satellites without complex real-time calculations.
Solution Approach 2:
The gateway acts as an intermediary between the satellite constellation and user terminals. It consolidates satellite movement data, calculates handoff parameters, and delivers processed handoff information to user terminals, simplifying their task and reducing the complexity of handoff operations at the terminal level.
2Measurement precision
If frequent requests for updated handoff entries are sent, then handoff accuracy is improved, but network signaling overhead increases
Solution Approach 1:
The system sends handoff information entries with future validity periods rather than requesting updates continuously. User terminals receive handoff information that covers a range of future times, allowing them to operate without frequent network contact. This partial updating approach reduces signaling overhead while maintaining adequate handoff accuracy.
Solution Approach 2:
Instead of continuous or event-driven requests, the system uses periodic handoff information provision where the gateway sends updated handoff entries at scheduled intervals. This periodic approach balances the need for accurate handoff information with the goal of reducing network signaling overhead by updating only when necessary.
Data Source
AI summary
Various aspects of the disclosure relate to handoff (e.g., idle mode handoff or other types of handoff) for a user terminal. In some aspects, a user terminal (UT) may request idle mode handoff information from a ground network (GN). Idle mode handoff information may include, for example, start times for a set of satellites, whereby each particular start time indicates when the UT may handoff to the corresponding satellite. The UT may send the request for idle mode handoff information to the GN when the UT has a defined number of valid entries (e.g., one unexpired entry) remaining in an idle mode handoff table. In some aspects, the idle UT may send the request for idle mode handoff information to the GN based on a time associated with a particular entry in an idle mode handoff table or based on a time of validity of an idle mode handoff table.