Satellite Beam Handoff via Transition Tables
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Solution Overview
Problem
Non-geosynchronous satellite communication systems face challenges in seamless handoff of user terminals between satellites and beams due to the dynamic nature of satellites in non-geostationary orbits, leading to disruptions and inefficiencies in communication.
Innovation Solution
A system that generates and sends satellite and beam transition information to user terminals, specifying the timing for starting and terminating communication with a particular beam, allowing for smooth handoff between satellites and beams based on ephemeris data, user terminal capabilities, and location information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-geosynchronous satellites are used to provide global coverage, then the number of satellites can be increased and Earth coverage can be improved, but handoff between satellites becomes complex and communication disruptions increase
Solution Approach 1:
The system performs preliminary actions by generating satellite and beam transition information in advance, determining handoff timing and parameters before actual handoff occurs. This allows the user terminal to prepare for handoff proactively, ensuring seamless transition between satellites without communication disruptions.
Solution Approach 2:
A handoff management entity acts as an intermediary between satellites and user terminals, coordinating handoff processes and managing transition information. This intermediary resolves the complexity of multi-satellite coordination by centralizing control, thereby maintaining communication reliability during handoff between multiple satellites.
2Ease of operation
If user terminals independently track satellite ephemeris data for handoff, then handoff autonomy is improved, but device complexity and processing requirements increase
Solution Approach 1:
The system extracts the complex ephemeris data processing and handoff decision-making functions from the user terminal and relocates them to a handoff management entity. The terminal receives simplified transition information, reducing its processing complexity while maintaining effective handoff autonomy through centralized management.
Solution Approach 2:
The handoff management entity provides self-service by autonomously generating and distributing satellite and beam transition information to user terminals. This eliminates the need for terminals to independently perform complex ephemeris calculations, reducing terminal complexity while ensuring coordinated handoff execution.
3Reliability
If geosynchronous satellites are used, then timing shift and Doppler frequency shift are minimized, but the number of satellites is limited and global coverage is restricted
Solution Approach 1:
The system transitions from static geosynchronous satellite positioning to dynamic non-geosynchronous satellite orbits, allowing satellites to move relative to Earth. By implementing dynamic handoff management that tracks and coordinates moving satellites, the system achieves both global coverage versatility and maintains signal stability through proactive transition information provision.
Solution Approach 2:
The system changes the orbital parameters of satellites from fixed geosynchronous orbits to flexible non-geosynchronous orbits. By adjusting satellite orbital parameters and implementing corresponding handoff management, the system expands global coverage capability while compensating for increased timing and Doppler shifts through coordinated transition management.
Data Source
AI summary
Various aspects of the disclosure relate to handoff of a user terminal in communication with a gateway through a satellite in a non-geosynchronous satellite communication system. In some aspects, a gateway and a user terminal use a satellite and beam transition table to determine when to handoff the user terminal from one beam to another and/or from one satellite to another. In some aspects, a user terminal sends capability information, location information, or other information to a gateway whereby, based on this information, the gateway generates a satellite and beam transition table and/or selects a handoff procedure for the user terminal. In some aspects, handoff of a user terminal to a different satellite involves the user terminal conducting satellite signal measurements and sending a measurement message to the gateway. In some aspects, the gateway generates a new satellite and beam transition table as a result of receiving a measurement message.