Satellite Link Timing Advance Control Against Double Correction
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Solution Overview
Problem
In non-terrestrial networks (NTNs), wireless communication devices experience timing inaccuracies due to double correction in timing advance (TA) adjustments caused by location updates and closed loop TA control, leading to unreliable communications.
Innovation Solution
Computing a portion of the timing difference corrected by closed loop TA control and adjusting the total TA to avoid double correction, using an update value for the link-specific TA, thereby ensuring accurate timing between the device and the base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If location updates and closed loop TA control are both applied for timing synchronization, then timing accuracy is improved, but double correction occurs causing timing errors
Solution Approach 1:
The patent implements feedback control by having the base station measure the uplink signal timing and send timing advance commands to the UE. The UE adjusts its transmission timing based on these feedback commands from the base station, creating a closed-loop control system that corrects timing errors without double correction
Solution Approach 2:
The patent applies preliminary timing advance adjustment based on location update information before the closed-loop control takes over. The UE computes a preliminary TA value based on its known location and satellite geometry, then refines this value through closed-loop feedback, avoiding the need to apply both full location-based correction and closed-loop correction simultaneously
2Measurement precision
If timing advance is adjusted frequently to maintain synchronization, then timing accuracy is improved, but timing errors increase due to double correction
Solution Approach 1:
The base station continuously monitors uplink signal timing and provides feedback commands to the UE, enabling frequent timing adjustments without accumulation of errors. The feedback mechanism ensures that each adjustment is based on current timing measurements rather than accumulating previous adjustments
Solution Approach 2:
The patent applies partial timing advance adjustment by only correcting the portion of timing error that has not already been addressed by location-based TA. The UE computes the difference between the location-based TA and previously applied TA, applying only the necessary incremental adjustment to avoid over-correction
Data Source
AI summary
Aspects described herein relate to receiving an update value for a timing advance of a satellite link between the UE and a base station, computing, based on the update value for the timing advance, a portion of a timing difference between the update value and a previous value for the timing advance of the satellite link that is corrected by closed loop timing advance control from the base station, computing, based at least in part on computing the portion, a total value for the timing advance of the satellite link, and applying, at the UE and based at least in part on the total value for the timing advance of the satellite link and the closed loop timing advance control, an applied timing advance for communicating with the base station.