Uplink Synchronization Validity Timing in High-Mobility NTN

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Solution Overview

Problem

In wireless communication systems, particularly in non-terrestrial networks (NTN) with high mobility satellites, the assistance information for uplink synchronization, such as ephemeris and common timing advance (TA), becomes invalid quickly, leading to potential loss of synchronization due to propagation delay and Doppler effects.

Innovation Solution

The system indicates a valid time period for assistance information, such as ephemeris and common TA, using various methods like broadcasting absolute time instants, time durations, or SIB IDs, and implements transmission restrictions based on the remaining valid time to maintain synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If assistance information is provided for uplink synchronization in high mobility satellite networks, then synchronization accuracy is improved, but the validity period of the assistance information becomes very short due to propagation delay and Doppler effects

Engineering Contradiction:

Improvesynchronization accuracyVSAvoidvalidity period of assistance information

Core Design Contradiction:

Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The network device provides assistance information in advance for uplink synchronization, including timing advance values and validity time indicators. The wireless device uses this pre-provided information to perform synchronization before actual transmission, compensating for the short validity period caused by high mobility satellite conditions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements a feedback mechanism where the network device monitors the validity time of assistance information and provides updated timing advance values and validity indicators to the wireless device. This ensures the wireless device always has current synchronization information within the valid time period

Inventive Principle:

Principle #23Feedback

2Reliability

If the wireless device continuously monitors and updates synchronization information, then synchronization reliability is improved, but access latency increases due to frequent updates and adjustments

Engineering Contradiction:

Improvesynchronization reliabilityVSAvoidaccess latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Instead of continuous monitoring, the system uses periodic action where the network device provides assistance information with explicit validity time indicators. The wireless device performs synchronization at specific intervals based on these validity periods, reducing access latency while maintaining synchronization reliability through structured periodic updates

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS12593289B2Systems and methods for indication of valid time

Publication Date: 2026.03.31 ZTE CORP

AI summary

Methods and systems for techniques for indicating a valid time period for assistance information in mobile communication technology are disclosed. In one example aspect, a wireless communication method includes receiving, by a wireless device, a set of parameters to indicate a validity of assistance information, wherein the assistance information is used to perform a synchronization for transmissions to the network device.