Half-Duplex FDD Slot Direction Control for Carrier Aggregation

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Solution Overview

Problem

Existing 5G NR technologies are not scalable and cost-effective for lower tier or reduced capability user equipment (UEs), leading to increased hardware costs and reduced battery life due to higher spectrum band usage and high processing demands.

Innovation Solution

Implementing half duplex FDD operation with carrier aggregation in 5G NR systems, allowing for flexible slot directions and reduced UE complexity by eliminating the need for duplexers and optimizing slot patterns through system information or RRC signaling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If 5G NR uses higher spectrum bands with increased processing capability, then throughput is improved, but hardware costs increase and battery life is reduced

Engineering Contradiction:
ImprovethroughputVSAvoidhardware costs
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments 5G NR operation into two distinct modes: full duplex FDD for premium UEs requiring high throughput, and half duplex FDD for lower tier UEs with relaxed requirements. This segmentation allows the system to provide appropriate capabilities based on device tier, reducing hardware complexity and costs for devices that do not require premium performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes key operational parameters including duplexing mode (full vs. half), slot configuration patterns, and carrier aggregation settings to match device capabilities. By adjusting these parameters based on UE tier, the system achieves cost-effective deployment for lower tier devices while maintaining high performance for premium devices.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If 5G NR uses higher spectrum bands with increased processing capability, then throughput is improved, but battery life is reduced

Engineering Contradiction:
ImprovethroughputVSAvoidbattery life
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent segments 5G NR operation into two distinct modes: full duplex FDD for premium UEs requiring high throughput, and half duplex FDD for lower tier UEs with relaxed requirements. This segmentation allows the system to provide appropriate capabilities based on device tier, reducing hardware complexity and costs for devices that do not require premium performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes key operational parameters including duplexing mode (full vs. half), slot configuration patterns, and carrier aggregation settings to match device capabilities. By adjusting these parameters based on UE tier, the system achieves cost-effective deployment for lower tier devices while maintaining high performance for premium devices.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If flexible slot directions are implemented in half duplex FDD, then UE complexity is reduced, but communication efficiency may be affected

Engineering Contradiction:
ImproveUE complexityVSAvoidcommunication efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements dynamic slot direction indication where flexible slots can be dynamically configured as uplink or downlink based on traffic requirements. This dynamic configuration is signaled through slot pattern indications and slot format indicators, allowing the system to optimize communication efficiency while maintaining reduced UE complexity compared to full duplex operation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses periodic slot patterns with regular uplink and downlink slots interspersed with flexible slots. This periodic structure provides predictable communication rhythms while allowing adaptive allocation of flexible slots based on instantaneous traffic demands, balancing complexity and efficiency.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP4094518B1Half duplex FDD user equipment operation
Publication Date: 2026.04.15 QUALCOMM INC
  • EP4094518B1 patent drawingFigure 1
  • EP4094518B1 patent drawingFigure 2A~2D
  • EP4094518B1 patent drawingFigure 3

AI summary

A configuration to enable a UE to determine a slot direction for communication with a base station while operating in half duplex FDD with carrier aggregation. The apparatus receives a first indication of a slot pattern for a plurality of slots associated with at least one component carrier assigned to the UE, wherein the first indication indicates that each of the plurality of slots is one of an uplink slot, a downlink slot, a special slot, or a flexible slot, and the plurality of slots includes a flexible slot. The apparatus receives, from the base station, a second indication indicating whether the flexible slot is the uplink slot or the downlink slot. The apparatus communicates with a base station based on at least one of the first indication or the second indication.