NTN Cell Switching with Source-Cell Uplink Continuity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

In Non Terrestrial Networks (NTN), the interrupted time of data transmission during cell switching is prolonged due to increased transmission delays, affecting the efficiency of data transmission.

Innovation Solution

The terminal device maintains an uplink in the source cell while performing cell switching, skipping certain messages like Msg1 or MsgA, and synchronizes with the target cell only when necessary, using timers to manage the transition process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the terminal device performs complete cell switching procedure including sending all messages (Msg1, MsgA, etc.), then the cell switching reliability is improved, but the interrupted time of data transmission is prolonged

Engineering Contradiction:

Improvecell switching reliabilityVSAvoidinterrupted time of data transmission

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The terminal device performs preliminary actions by maintaining the uplink connection in the source cell during the cell switching process. This allows data transmission to continue through the source cell while the switching procedure is being completed, thereby reducing the interruption time while ensuring the switching reliability through the complete message exchange sequence

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The uplink data transmission is maintained continuously in the source cell during the cell switching process. By keeping the uplink active and skipping certain messages when conditions permit, the system ensures continuous useful action (data transmission) while still completing the necessary switching procedures to maintain reliability

Inventive Principle:

Principle #20Continuity of useful action

2Loss of time

If the terminal device skips certain messages during cell switching, then the interrupted time of data transmission is reduced, but the cell switching reliability may be compromised

Engineering Contradiction:

Improveinterrupted time of data transmissionVSAvoidcell switching reliability

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The terminal device performs partial cell switching action by skipping certain messages (Msg1, MsgA) when specific conditions are met, such as when the uplink is maintained in the source cell. This partial action is sufficient to reduce interruption time while the maintained uplink connection ensures that reliability is not compromised

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system changes the parameter of message transmission by selectively skipping certain messages based on the current state (whether uplink is maintained in source cell). This parameter change allows the system to adapt the cell switching procedure to minimize interruption while maintaining reliability through conditional message skipping

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12526756B2Cell switching method, terminal device, and storage medium

Publication Date: 2026.01.13 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

A cell switching method, a terminal device and a storage medium are provided. The method comprises: when a terminal device executes cell switching, the terminal device keeping an uplink in a source cell at a moment other than the moment for sending a first message; and the terminal device keeping a downlink in the source cell at a moment other than the moment for downlink synchronization with a target cell.