Satellite Cell Synchronization Across Beam Handover Without Reselection

Solution Overview

Problem

Uplink/downlink synchronization issues arise for terminals in satellite networks due to changes in satellite position when the cell identifier remains unchanged, causing out-of-synchronization.

Innovation Solution

A synchronization method and apparatus that involves determining when a cell of a first satellite and a cell of a second satellite have the same cell identifier, and performing a synchronization process with the second satellite, including acquiring timing advance values and using indication information for updating uplink/downlink synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the satellite changes beam coverage for an area but keeps the cell identifier unchanged, then the terminal can maintain continuous service without cell reselection, but the terminal experiences uplink/downlink out-of-synchronization

Engineering Contradiction:

Improvecontinuous serviceVSAvoidsynchronization

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The network side performs preliminary action by notifying the terminal in advance about the satellite change and providing necessary synchronization parameters (timing advance values, frame timing information) before the actual beam switch occurs. This allows the terminal to prepare and apply the correct synchronization parameters proactively, preventing synchronization loss during the transition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where the network side monitors terminal status and satellite position, then provides feedback information including timing advance values and synchronization parameters to the terminal. This feedback loop ensures the terminal can adjust its synchronization state to match the new satellite configuration, maintaining reliable communication.

Inventive Principle:

Principle #23Feedback

2Reliability

If the terminal performs synchronization process with the second satellite, then uplink/downlink synchronization is restored, but additional signaling and processing time are required

Engineering Contradiction:

ImprovesynchronizationVSAvoidsynchronization transition time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The network side performs preliminary action by notifying the terminal in advance about the satellite change and providing necessary synchronization parameters (timing advance values, frame timing information) before the actual beam switch occurs. This allows the terminal to prepare and apply the correct synchronization parameters proactively, preventing synchronization loss during the transition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The network side acts as an intermediary that facilitates the synchronization transition by collecting synchronization information from the second satellite and relaying it to the terminal. This intermediary role eliminates the need for the terminal to independently discover and acquire synchronization parameters, reducing the time and complexity of the re-synchronization process.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the terminal uses timing advance value for accessing the second satellite, then uplink synchronization is achieved, but the terminal must send signals for synchronization acquisition

Engineering Contradiction:

Improveuplink synchronizationVSAvoidsynchronization process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The network side acts as an intermediary that facilitates the synchronization transition by collecting synchronization information from the second satellite and relaying it to the terminal. This intermediary role eliminates the need for the terminal to independently discover and acquire synchronization parameters, reducing the time and complexity of the re-synchronization process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The terminal performs self-service by autonomously determining when a satellite change occurs and automatically initiating the synchronization process with the second satellite using provided parameters. This self-service capability reduces the need for complex network-controlled synchronization procedures, simplifying the overall system operation.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20260012909A1Synchronization method and synchronization apparatus in satellite network

Publication Date: 2026.01.08 DATANG MOBILE COMM EQUIP CO LTD

AI summary

The present application discloses a synchronization method and a synchronization apparatus in a satellite network, which is used to provide a solution of updating uplink/downlink synchronization for a terminal regarding a problem of uplink/downlink out-of-synchronization for the terminal caused by changes in satellite position, when the satellite providing beam coverage for an area to which the terminal belongs changes but a cell identifier is unchanged. The method provided by the present application includes: when a cell of a first satellite and a cell of a second satellite have a same cell identifier, performing a synchronization process between the terminal and the cell of the second satellite, thereby avoiding a problem of uplink/downlink out-of-synchronization for the terminal caused by changes in satellite position.