Uplink Synchronization Resumption via Initial BWP Switching

Solution Overview

Problem

In Non-Terrestrial Networks (NTNs), the expiration of ephemeris validity timers leads to loss of uplink synchronization due to the inability of user equipment (UE) to reacquire essential satellite information, particularly in scenarios where the UE is not capable of reading system information on the activated Bandwidth Part (BWP).

Innovation Solution

A method where a terminal device switches from an active BWP to an initial BWP to read NTN system information, including ephemeris data and common Timing Advance (TA), even if the initial BWP does not have a configured common search space, ensuring continuous uplink synchronization by restarting the validity timer and reacquiring necessary information before expiration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE reads NTN system information on the activated BWP, then uplink synchronization can be maintained, but the UE must have the capability to read system information on the activated BWP which limits applicability to all UE types

Engineering Contradiction:

Improveuplink synchronizationVSAvoidUE capability requirement

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by having the UE read NTN system information in advance on the initial BWP before the validity timer expires. This proactive approach ensures that when the timer expires, the UE already has the necessary ephemeris information and common TA to maintain uplink synchronization without needing to read system information on the activated BWP, thus accommodating UE types that cannot read system information on activated BWPs.

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the validity timer is extended to cover longer periods, then system information reading frequency is reduced, but uplink synchronization accuracy deteriorates due to potential information invalidation

Engineering Contradiction:

Improvesystem information reading frequencyVSAvoiduplink synchronization accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by having the UE read NTN system information in advance on the initial BWP before the validity timer expires. This proactive approach ensures that when the timer expires, the UE already has the necessary ephemeris information and common TA to maintain uplink synchronization without needing to read system information on the activated BWP, thus accommodating UE types that cannot read system information on activated BWPs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces the initial BWP as an intermediary mechanism. Instead of requiring the UE to read system information on the activated BWP (which may not be capable), the initial BWP serves as an intermediary carrier that always contains valid NTN system information. The UE reads this intermediary information before timer expiration to maintain synchronization, resolving the contradiction between extended timer duration and synchronization accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the UE switches to initial BWP to read system information, then uplink synchronization can be maintained for incapable UEs, but BWP switching complexity increases

Engineering Contradiction:

Improveuplink synchronizationVSAvoidBWP switching mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by having the UE read NTN system information in advance on the initial BWP before the validity timer expires. This proactive approach ensures that when the timer expires, the UE already has the necessary ephemeris information and common TA to maintain uplink synchronization without needing to read system information on the activated BWP, thus accommodating UE types that cannot read system information on activated BWPs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies self-service by having the UE automatically switch to the initial BWP and read NTN system information autonomously before the validity timer expires, without requiring network intervention or manual configuration. The UE uses its own capabilities and stored configuration information to perform this self-service operation, maintaining uplink synchronization for UE types that cannot read system information on activated BWPs.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS20240349214A1Method for resuming uplink synchronization, and terminal device and storage medium

Publication Date: 2024.10.17 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD

AI summary

Provides is a method for resuming uplink synchronization. The method includes: reacquiring, by a terminal device, non-terrestrial network (NTN) system information in a case that an NTN ephemeris validity timer expires and the terminal device has a first terminal device capability, wherein the first terminal device capability indicates a capability of the terminal device for reading the NTN system information in a connected state, the NTN system information comprises ephemeris information of a serving satellite and/or a common timing advance (TA), and the terminal device is in the connected state.