Aperiodic TRS Reception for Secondary Cell Time-Frequency Tracking

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Solution Overview

Problem

The inefficiency and resource waste due to the inflexible use of periodic tracking reference signals (TRS) for time-frequency tracking on secondary cells in carrier aggregation, leading to delays and resource wastage in 5G mobile communications systems.

Innovation Solution

Implementing an aperiodic tracking reference signal that can be triggered based on demand, allowing for precise timing of time-frequency tracking on secondary cells, thereby eliminating the need to wait for the next TRS period.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If periodic TRS is used for time-frequency tracking on secondary cell, then time-frequency tracking can be performed, but resource waste occurs and flexibility is poor when TRS is received before MAC CE signaling becomes valid

Engineering Contradiction:
Improveflexibility of time-frequency trackingVSAvoiddelay in performing time-frequency tracking
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent transitions from a static periodic TRS mechanism to a dynamic aperiodic TRS mechanism that adapts to the actual activation state of the secondary cell. The network device dynamically determines whether to send aperiodic TRS based on whether the SCell is activated, and the UE dynamically adjusts its receiving behavior accordingly, eliminating the fixed periodic structure that causes resource waste and delays.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the fundamental parameter of TRS transmission from periodic to aperiodic. This parameter change allows the TRS to be transmitted only when needed (when SCell is activated), rather than following a fixed periodic schedule, thereby resolving the contradiction between maintaining tracking capability and avoiding resource waste.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If periodic TRS is configured for time-frequency tracking, then tracking can be performed, but the UE must wait until the next TRS period causing resource waste

Engineering Contradiction:
Improvetime-frequency tracking accuracyVSAvoidefficiency of secondary cell activation
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The network device performs preliminary action by determining in advance whether the secondary cell is activated before triggering the aperiodic TRS. This preliminary determination ensures that TRS is only transmitted when the SCell is actually activated and can utilize it, preventing both resource waste and ensuring tracking reliability is maintained when needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements self-service through conditional triggering mechanisms where the TRS transmission is automatically enabled or disabled based on the SCell activation state. The network device autonomously decides whether to send aperiodic TRS based on the activation status, and the UE autonomously adjusts its receiving behavior, eliminating the need for wasteful periodic transmissions.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If aperiodic TRS is triggered based on requirement, then flexibility is improved, but precise timing of receiving moment must be defined

Engineering Contradiction:
Improveflexibility of TRS transmissionVSAvoidcomplexity of timing coordination
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements feedback mechanisms through downlink control information (DCI) that carries triggering indications for aperiodic TRS. The network device provides feedback about when aperiodic TRS will be transmitted, and the UE uses this feedback to precisely coordinate its receiving moment, resolving the timing coordination complexity while maintaining flexibility.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3793254B1Method for receiving aperiodic tracking reference signal and terminal
Publication Date: 2025.11.05 VIVO MOBILE COMM CO LTD
  • EP3793254B1 patent drawingFigure 1
  • EP3793254B1 patent drawingFigure 2
  • EP3793254B1 patent drawingFigure 3

AI summary

This disclosure provides a method for receiving an aperiodic tracking reference signal and a terminal. The method includes: receiving downlink control information, where the downlink control information includes information used for triggering an aperiodic tracking reference signal in a secondary cell; receiving the aperiodic tracking reference signal in the secondary cell based on the downlink control information; and if a validation condition of the aperiodic tracking reference signal is met, determining that the aperiodic tracking reference signal is valid, where the validation condition includes at least that a receiving moment of the aperiodic tracking reference signal is after completion of radio frequency retuning between the terminal and the secondary cell.