Satellite Terminal GNSS Validity Extension for Uplink Synchronization
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Solution Overview
Problem
Satellite communication terminals face frequent disconnections due to the expiration of GNSS information, leading to continuous random access and exit from connected states, resulting in high signaling overheads and reduced communication duration.
Innovation Solution
Extend the validity duration of GNSS information by determining a longer GNSS second validity duration based on the initial GNSS first validity duration and timing advance command (TAC) to maintain uplink synchronization and reduce disconnections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device continuously initiates random access to enter and exit the connected state due to GNSS information expiration, then the terminal device can maintain uplink synchronization, but signaling overheads increase and power consumption increases
Solution Approach 1:
The network device sends a timing advance command (TAC) to the terminal device before the GNSS information expires. This preliminary action allows the terminal device to extend the validity duration of the GNSS information and maintain uplink synchronization without continuously entering and exiting the connected state, thereby reducing power consumption while maintaining synchronization reliability
Solution Approach 2:
The network device monitors the GNSS information validity status of the terminal device and provides feedback by sending TAC commands when appropriate. This feedback mechanism enables the terminal device to adjust its communication state dynamically, maintaining synchronization while avoiding unnecessary state transitions that would increase power consumption
2Reliability
If the terminal device continuously initiates random access to enter and exit the connected state due to GNSS information expiration, then the terminal device can maintain uplink synchronization, but signaling overheads increase
Solution Approach 1:
The network device sends a timing advance command (TAC) to the terminal device before the GNSS information expires. This preliminary action extends the validity duration of the GNSS information, allowing the terminal device to maintain uplink synchronization without continuously entering and exiting the connected state, thereby reducing signaling overheads while maintaining synchronization
3Reliability
If the terminal device enters idle state after GNSS information expires and then initiates random access again, then the terminal device can re-establish connection, but communication duration is reduced
Solution Approach 1:
The network device sends a timing advance command (TAC) to the terminal device before the GNSS information expires, enabling the terminal device to extend the validity duration and maintain the connected state for a longer period. This preliminary action reduces the frequency of entering idle state and re-establishing connections, thereby increasing overall communication duration while ensuring reliable connection re-establishment when needed
Data Source
AI summary
A satellite communication method, applied to a first communication apparatus, includes determining a global navigation satellite system (GNSS) validity duration. The satellite communication method also determining an extension duration of the GNSS validity duration based on a validity duration of a timing advance command (TAC). The starting point of the extension duration is an ending point of the GNSS validity duration. An ending point of the extension duration is an ending point of the validity duration of the TAC. The validity duration of the TAC is received within the GNSS validity duration. The satellite communication method further includes performing a GNSS measurement or entering an idle state, in response to the GNSS validity duration ending and no information for triggering the GNSS measurement being received.