Timing Advance Update in Satellite Uplink
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Solution Overview
Problem
In satellite communication networks, user equipment experiences timing advance synchronization issues due to redundant or contradictory information from closed loop and open loop mechanisms, leading to potential timing advance overcompensation or jumps, which can result in radio link failures and resource wastage.
Innovation Solution
A method where user equipment determines an updated timing advance value by combining data from assistance information, measurements, and timing advance commands, allowing it to selectively choose a transmission time based on a combination of time-related parameters to avoid synchronization losses, by potentially postponing signal transmission to obtain more accurate information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If user equipment uses both closed loop and open loop mechanisms for timing advance update, then timing advance information is more comprehensive, but timing advance overcompensation or jumps occur leading to synchronization loss
Solution Approach 1:
The patent implements dynamic selection between closed loop and open loop timing advance update mechanisms based on current system conditions. The network can dynamically switch between mechanisms or combine them adaptively, allowing the system to optimize timing advance updates according to real-time requirements and avoid overcompensation issues that occur when both mechanisms operate simultaneously without coordination.
Solution Approach 2:
The patent introduces feedback mechanisms where the network monitors timing advance update performance and adjusts the operation of closed loop and open loop mechanisms accordingly. Based on feedback about synchronization status and update accuracy, the network can modify which mechanism is active or how they are combined, preventing timing advance jumps and maintaining reliable uplink synchronization.
2Measurement precision
If user equipment performs frequent timing advance updates, then uplink timing synchronization is maintained more accurately, but radio link failures and resource wastage increase
Solution Approach 1:
The patent applies partial action by selectively updating timing advance only when necessary rather than performing frequent updates continuously. The system determines when timing advance updates are actually needed based on movement detection, signal quality thresholds, or network conditions, avoiding unnecessary updates that could trigger radio link failures while still maintaining sufficient synchronization accuracy.
Solution Approach 2:
The patent changes the parameter of update frequency dynamically based on system conditions. Instead of fixed frequent updates, the system adjusts update timing and frequency according to factors such as user equipment movement speed, signal quality variations, and network load, thereby maintaining timing advance accuracy while reducing excessive updates that lead to radio link instability.
Data Source
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AI summary
A method performed by a user equipment connected to a base station of a satellite communication network for sending a signal using an updated value of timing advance, the user equipment determining values of timing advance based on at least assistance information, measurements, timing advance commands, the method comprising : selecting a transmission time of the signal between at least: -- a target time of transmission of the signal, and -- a postponed time of transmission of the signal, later than the target time, based on a combination of at least two elements among: a time-related parameter, a final timing advance command received at a final command time, final measurements obtained at a final measurement time, final assistance information received at a final assistance time, the final measurement, command and assistance times, transmitting the signal to the base station at the transmission time using the updated value of timing advance.