Satellite Handover Signaling Without Random Access in Earth-Fixed Cells
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Solution Overview
Problem
Non-geostationary non-ground stations in non-terrestrial networks, such as medium earth orbit and low earth orbit satellites, appear to move rapidly, leading to challenges in maintaining stable communication performance, including connection stability, low latency, high reliability, and high throughput, due to frequent handovers and beam direction switching.
Innovation Solution
A communication device acquires information about connection switching from one non-geostationary satellite station to another in advance, allowing seamless transitions without a random access procedure, thereby optimizing communication parameters like timing advance and beam direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a known communication technology is directly applied to the non-terrestrial network, then the device complexity is reduced, but the communication performance (connection stability, latency, reliability, throughput) deteriorates due to high-speed movement of non-geostationary satellite stations
Solution Approach 1:
The patent applies preliminary action by having the non-geostationary satellite station transmit advance notification information before the actual handover occurs. This allows the terminal device to prepare for the upcoming connection switch in advance, adjusting its parameters and establishing necessary protocols before the handover event, thereby maintaining communication reliability without increasing device complexity
Solution Approach 2:
The patent implements feedback through the downlink control information that carries handover notification from the satellite station to the terminal device. This feedback mechanism enables the terminal to receive real-time information about the upcoming handover and adjust its behavior accordingly, maintaining stable connection despite the high-speed movement of the satellite station
2Area of stationary object
If frequent handovers occur due to high-speed movement of non-geostationary satellite stations, then the coverage area is expanded, but the connection stability and communication reliability deteriorate
Solution Approach 1:
The patent uses preliminary action by notifying the terminal device in advance of the upcoming handover before the actual connection switch occurs. This allows the terminal to prepare its parameters and establish necessary protocols ahead of time, ensuring smooth transition and maintaining connection stability while still enabling frequent handovers for expanded coverage
Solution Approach 2:
The patent ensures continuity of useful action by maintaining the communication connection throughout the handover process. The advance notification allows the terminal to continue receiving data without interruption, and the handover is executed in a way that preserves the ongoing communication session, preventing breaks in the useful action despite frequent satellite station movements
3Area of stationary object
If beam direction switching is performed frequently to track non-geostationary satellite stations, then the area coverage is improved, but the signaling overhead and processing load increase
Solution Approach 1:
The patent applies preliminary action by having the satellite station transmit handover notification information in advance before the beam direction needs to be switched. This allows the terminal device to prepare for the upcoming beam change and handover simultaneously, reducing the signaling overhead and processing load during the actual transition while still enabling frequent beam direction switching for improved area coverage
Data Source
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AI summary
A communication device is connected to a first non-geostationary satellite station among a plurality of non-geostationary satellite stations forming a cell positionally fixed on ground. The communication device includes an acquisition section configured to acquire, from the first non-geostationary satellite station in advance before switching processing, information related to switching of connection from the first non-geostationary satellite station to a second non-geostationary satellite station among the plurality of non-geostationary satellite stations, and a switching processing section configured to switch the connection from the first non-geostationary satellite station to the second non-geostationary satellite station without a random access procedure, based on the information related to switching of the connection.