Primary-Cell Time Advance Timer Coordination for Uplink Synchronization

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Solution Overview

Problem

In a multi-band carrier aggregation system, maintaining uplink synchronization across different bands is challenging due to varying time advance requirements, leading to potential communication interruptions when time advance timers expire prematurely.

Innovation Solution

The method involves the base station and terminal equipment to prioritize the time advance timer associated with the primary cell, ensuring it expires last by adjusting time advance commands and resource management to maintain synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple time advance timers are maintained for different bands, then uplink synchronization can be adjusted per band, but the time advance timer for the primary cell may expire prematurely causing communication interruptions

Engineering Contradiction:

Improveuplink synchronizationVSAvoidcommunication interruption

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent merges the time advance timer management for the primary cell with the secondary cells by ensuring the primary cell's timer expires last. This is achieved by coordinating timer expiration times across different bands, combining the synchronization management into a unified approach where the primary cell's timer acts as the governing timer for overall system synchronization status.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The base station performs preliminary action by adjusting time advance commands to ensure the primary cell's time advance timer is configured to expire after secondary cell timers. This proactive timing coordination prevents communication interruptions before they occur by pre-establishing the timer expiration sequence.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If the time advance timer for primary cell is extended to expire last, then communication continuity is maintained, but timer management complexity increases

Engineering Contradiction:

Improvecommunication interruptionVSAvoidtimer management

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The base station uses feedback from uplink signal quality measurements to dynamically adjust time advance commands. By monitoring uplink synchronization status and timer expiration sequences, the base station can optimize timer configurations to maintain communication continuity while managing complexity through adaptive control rather than static complex scheduling.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the time parameter of the primary cell's time advance timer dynamically based on the expiration times of secondary cell timers. By adjusting the primary cell timer's duration and expiration time as a variable parameter rather than a fixed value, the system maintains communication continuity while adapting to different network conditions and reducing management complexity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12452804B2Method for maintaining time advance timer, base station and terminal equipment

Publication Date: 2025.10.21 1FINITY INC

AI summary

A base station including: a judging unit configured to judge whether a band to be uplink adjusted includes only a band corresponding to a primary cell; and a transmitter configured to transmit a command for the band corresponding to the primary cell when the judging unit determines that the band to be uplink adjusted includes only the band corresponding to the primary cell, such that a timer relating to an uplink synchronization for the band corresponding to the primary cell is restarted.