Uplink Configuration Activation for Low-Latency Cell Handover

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Solution Overview

Problem

Existing wireless communication systems face challenges in reducing latency and interruption time during cell handovers, particularly in L1/L2-triggered mobility scenarios, due to the need for RRC layer reconfiguration and the clearing of uplink grants upon timeAlignmentTimer expiration.

Innovation Solution

A method that activates RRC layer configuration parameters for uplink transmission during cell handovers without RRC signaling, using pre-configured first and second configuration sets, allowing for L1/L2-triggered mobility to automatically activate uplink grants and reduce latency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If RRC layer reconfiguration is used for cell handover, then handover reliability is ensured, but handover latency and interruption time increase

Engineering Contradiction:

Improvehandover reliabilityVSAvoidhandover latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-configuring uplink grant resources and RRC parameters in advance during L1/L2-triggered mobility before actual handover execution. The terminal receives and stores configuration parameters (PUSCH, PUCCH, SRS, etc.) from the source cell, enabling immediate uplink transmission upon handover without waiting for RRC reconfiguration, thus reducing handover latency while maintaining reliability through pre-validated configurations

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the handover process into independent phases: L1/L2-triggered physical layer handover execution and separate RRC layer configuration activation. The uplink grant configuration is decoupled from the mandatory RRC reconfiguration with synchronization, allowing the terminal to perform uplink transmission in the target cell immediately after physical handover completes, while RRC configuration can be activated later without blocking the handover process

Inventive Principle:

Principle #1Segmentation

2Reliability

If uplink grant is cleared when timeAlignmentTimer expires, then uplink timing synchronization is maintained, but uplink transmission continuity is interrupted

Engineering Contradiction:

Improveuplink timing synchronizationVSAvoiduplink transmission continuity

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent ensures continuity of useful action by maintaining uplink grant configurations across cell handovers through L1/L2-triggered mobility. The terminal preserves uplink grant resources and timing alignment information during the handover process, allowing uninterrupted uplink transmission in the target cell. The configuration parameters are retained and activated seamlessly, eliminating gaps in uplink transmission continuity

Inventive Principle:

Principle #20Continuity of useful action

3Manufacturing precision

If RRC signaling is used for uplink grant activation, then configuration accuracy is ensured, but signaling overhead increases

Engineering Contradiction:

Improveconfiguration accuracyVSAvoidsignaling overhead

Core Design Contradiction:

Manufacturing precisionVSLoss of information

Solution Approach 1:

The patent extracts the uplink grant activation function from the mandatory RRC reconfiguration signaling process. Through L1/L2-triggered mobility, the terminal can activate uplink grants using physical layer signaling (DCI formats) or MAC layer commands separately from RRC reconfiguration. This extraction reduces signaling overhead by eliminating redundant RRC messages while maintaining configuration accuracy through dedicated physical layer activation signals that directly control uplink resource allocation

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentEP4701309A1Method and apparatus used in node for wireless communications

Publication Date: 2026.02.25 APOGEE 5G GLOBAL LLC

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AI summary

Disclosed in the present application are a method and apparatus used in a node for wireless communications. The method comprises: a first node receiving first signaling, wherein the first signal is RRC signaling, and the first signaling comprises a first configuration set and a second configuration set, which are for a first cell; receiving second signaling, wherein the second signaling is physical layer signaling or MAC layer signaling; in response to receiving the second signaling, performing handover to the first cell, wherein the handover to the first cell comprises activating the second configuration set in the first configuration set and the second configuration set, which are comprised in the first signaling, and the first configuration set and the second configuration set are both related to uplink transmission. By means of the present application, an uplink resource can be quickly acquired in a cell handover scenario, which is triggered on a protocol layer below an RRC layer, such that an interruption time is reduced, and signaling overheads are reduced.