DRX Timer Counting in TDD-FDD Carrier Aggregation

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Solution Overview

Problem

In carrier aggregation systems, existing methods fail to efficiently count the Discontinuous Reception (DRX) timer, particularly in TDD-FDD joint operation, where PDCCH subframes are not adequately defined for FDD serving cells, leading to inefficiencies in power management and data transmission.

Innovation Solution

A method where the User Equipment (UE) counts DRX timers by configuring time related to DRX operation, specifically counting uplink subframes for all TDD serving cells and not configuring scheduling cell identifiers for FDD serving cells, allowing efficient DRX timer management in TDD-FDD joint operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If existing DRX timer counting methods are used in carrier aggregation systems, then the system can operate with multiple cells, but the DRX timer cannot be efficiently counted in TDD-FDD joint operation

Engineering Contradiction:
ImproveTDD-FDD joint operation capabilityVSAvoidDRX timer counting efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent segments the DRX timer counting mechanism by cell type (TDD vs FDD). For TDD serving cells, the timer is counted in non-uplink subframes, while for FDD serving cells, it is counted in all subframes. This segmentation allows each cell type to be handled according to its specific characteristics, resolving the inefficiency in TDD-FDD joint operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different counting rules to different types of serving cells based on their local characteristics. TDD cells use one counting method (excluding uplink subframes) while FDD cells use another (counting all subframes). This local quality approach ensures that each cell type is managed optimally within the carrier aggregation system.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If PDCCH subframes are counted for all serving cells uniformly, then the counting method is simple, but it leads to power management inefficiencies and data transmission delays

Engineering Contradiction:
ImproveDRX timer counting simplicityVSAvoidbattery consumption
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent introduces dynamic adaptability to the DRX timer counting mechanism by making the counting rule dependent on the cell type and subframe configuration. The system dynamically adjusts which subframes are counted based on whether the cell is TDD or FDD and whether the subframe is an uplink subframe, optimizing power consumption without sacrificing operational simplicity.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If scheduling cell identifiers are configured for all serving cells, then cell identification is complete, but FDD serving cells create inefficiencies in DRX timer management

Engineering Contradiction:
Improvecell identification accuracyVSAvoiddata transmission efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts the scheduling cell identifier configuration requirement specifically for FDD serving cells, treating them differently from TDD cells. By recognizing that FDD cells do not need scheduling cell identifiers for proper DRX timer management, the system removes an unnecessary constraint and improves overall data transmission efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3379894B1Method for counting a DRX (discontinuous reception) timer in a carrier aggregation system and a device therefor
Publication Date: 2020.04.29 LG ELECTRONICS INC
  • EP3379894B1 patent drawingFigure 1
  • EP3379894B1 patent drawingFigure 2A
  • EP3379894B1 patent drawingFigure 2B

AI summary

The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for counting a DRX (Discontinuous Reception) timer in a carrier aggregation system, the method comprising: configuring a plurality of cells including at least one FDD (Frequency Division Duplex) serving cell and at least one TDD (Time Division Duplex) serving cell; and counting a DRX timer in a subframe, wherein the subframe is an uplink subframe for all TDD serving cells.