Uplink Subband Transmission Rules for SBFD Interference Control

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Solution Overview

Problem

The emergence of subband full duplex (SBFD) in bandwidth parts (BWPs) leads to strong interference from uplink subbands to neighboring downlink subbands due to existing transmitter requirements designed for carrier bandwidth, as in-band interference is stronger than out-of-band interference.

Innovation Solution

A data transmission method that determines a first transmitter requirement based on the bandwidth of the uplink subband, including in-band emission, out-of-band emission, and maximum output power reduction, to reduce interference to neighboring downlink subbands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing transmitter requirements designed for carrier bandwidth are used, then uplink transmission can be performed, but strong interference is caused to neighboring downlink subbands

Engineering Contradiction:
Improveuplink transmission capabilityVSAvoidinterference to downlink subband
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by differentiating transmitter requirements based on the specific subband context. Instead of using a uniform carrier-bandwidth-based requirement, the patent implements subband-specific transmitter requirements that recognize the dual role of BWPs (uplink and downlink) within the same carrier. This localized approach ensures that uplink transmissions in certain subbands do not cause excessive interference to adjacent downlink subbands, while still maintaining overall uplink transmission capability.

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If stricter transmitter requirements are imposed to reduce interference, then interference to downlink subbands is reduced, but implementation complexity increases

Engineering Contradiction:
Improveinterference to downlink subbandVSAvoidtransmitter requirement implementation
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the transmitter requirements into different levels: carrier-level requirements and subband-level requirements. This segmentation allows the system to apply stricter control only where necessary (in subbands adjacent to downlink BWPs) while maintaining simpler requirements elsewhere. The segmentation reduces overall implementation complexity by avoiding uniformly strict requirements across all transmissions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by implementing stricter transmitter requirements only for specific uplink subbands that are adjacent to downlink BWPs, rather than applying strict requirements to all uplink transmissions. This targeted approach reduces interference where it matters most while minimizing the burden on terminal devices, thereby balancing interference reduction with implementation complexity.

Inventive Principle:
Principle #16Partial or excessive action

3Device complexity

If transmitter requirements are relaxed to reduce implementation complexity, then device complexity is reduced, but interference to neighboring downlink subbands increases

Engineering Contradiction:
Improvetransmitter requirement implementationVSAvoidinterference to downlink subband
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces dynamic transmitter requirements that adapt based on the operational context. Terminal devices dynamically adjust their transmission parameters according to whether they are transmitting in subbands adjacent to downlink BWPs or in other subbands. This dynamic approach allows the system to maintain low complexity for most transmissions while applying stricter control only when necessary to protect downlink subbands, thus resolving the contradiction between complexity and interference.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4686292A1Data transmission method and apparatus
Publication Date: 2026.01.28 HUAWEI TECH CO LTD
  • EP4686292A1 patent drawingFigure 1~2a
  • EP4686292A1 patent drawingFigure 2b~2d
  • EP4686292A1 patent drawingFigure 3~4

AI summary

This application provides a data transmission method and an apparatus. The data transmission method includes: A terminal device receives scheduling information from a network device, where the scheduling information is used to schedule the terminal device to perform data transmission on a first transmission resource, a frequency domain resource of the first transmission resource is located on an uplink subband of an activated bandwidth part BWP of the terminal device, and the BWP further includes a downlink subband neighbor to the uplink subband. The terminal device performs data transmission on the first transmission resource based on a first transmitter requirement, where the first transmitter requirement is determined based on bandwidth of the uplink subband. This application is implemented, to reduce interference caused by data transmission on the uplink subband to a neighboring downlink subband.