GNSS-Based Timing Advance Correction for Satellite Uplink Sync
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Solution Overview
Problem
In satellite communication systems, the long distance between terminal devices and satellites results in high signal round trip transmission delays, leading to inaccuracies in timing advance (TA) values due to the manner of sending timing advance commands (TAC) from satellites to terminal devices, which affects communication reliability.
Innovation Solution
The method involves determining a first TA value based on GNSS measurements and adjusting it using a first TA adjustment amount, with conditions set for when to correct errors in GNSS measurements by accumulating previous TACs or using a preset value, thereby improving TA accuracy and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TAC is sent by satellite to terminal device to indicate TA value, then timing synchronization is maintained, but TA value accuracy deteriorates due to long signal round trip transmission delay
Solution Approach 1:
The patent introduces GNSS measurement values as an intermediary to determine TA values. Instead of relying solely on TAC from the satellite (which has large delay), the terminal device uses GNSS timing information as a reference to calculate TA values, thereby improving accuracy while maintaining synchronization reliability
Solution Approach 2:
The terminal device performs GNSS measurements in advance to obtain timing reference information before uplink transmission. This preliminary action allows the device to pre-calculate accurate TA values based on GNSS data, avoiding the large delays inherent in satellite-based TAC feedback
2Measurement precision
If GNSS measurement value is updated after long time, then measurement freshness is improved, but error jump occurs due to accumulation of previous TACs
Solution Approach 1:
The patent extracts the accumulation of previous TACs from the TA value calculation when a new GNSS measurement is obtained. By removing this accumulated component, the system avoids error jumps that would otherwise occur when transitioning between different GNSS measurement cycles, maintaining stability while updating to fresher data
Solution Approach 2:
Instead of continuously accumulating TACs to correct GNSS errors, the patent inverts the approach by using the latest GNSS measurement as the primary reference and only applying TAC adjustments when necessary. This reversal prevents error accumulation and jumps, maintaining stability while improving measurement freshness
Data Source
AI summary
A communication method and a related apparatus are provided. The method includes: receiving a first timing advance TA adjustment amount from a network device; and determining a first TA value, and sending, based on the first TA value, a 1st uplink signal after global navigation satellite system GNSS measurement. When a first condition is met, the first TA value is determined based on a first GNSS measurement value obtained through the GNSS measurement, the first TA adjustment amount, and a first value. When a second condition is met, the first TA value is determined based on the first GNSS measurement value, the first TA adjustment amount, and a second value. The first value is different from the second value.