SBFD Downlink Reception with Uplink Subband Multiplexing

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Solution Overview

Problem

Existing wireless communication systems face challenges in efficiently multiplexing radio resources based on different numerologies to meet the diverse requirements of enhanced mobile broadband, massive machine-type communication, and ultra-reliable and low-latency communication scenarios in next-generation radio access technology (NR).

Innovation Solution

The implementation of subband full duplex (SBFD) symbols, where uplink subbands are configured within downlink slots or symbols, allowing simultaneous downlink transmission and uplink reception using separate frequency resources, enhances the flexibility and efficiency of downlink transmission/reception in full-duplex communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If downlink transmission and uplink reception are performed in the same time slot using frequency division, then resource utilization efficiency is improved, but self-interference between uplink and downlink signals deteriorates reception quality

Engineering Contradiction:
Improveresource utilization efficiencyVSAvoidself-interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The frequency band is segmented into multiple subbands, with specific subbands allocated for uplink transmission and others for downlink reception within the same time slot. This frequency-domain segmentation enables full-duplex operation by spatially separating uplink and downlink signals in the frequency spectrum, thereby improving resource utilization while managing self-interference through selective subband assignment

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different subbands are assigned different functional qualities - some subbands are optimized for uplink transmission while others are optimized for downlink reception. This local quality differentiation within the frequency spectrum allows simultaneous uplink and downlink operations with reduced interference, as each subband is tailored to its specific communication direction

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If flexible frame structures are designed to meet diverse scenario requirements, then adaptability to different usage scenarios is improved, but system complexity increases

Engineering Contradiction:
Improveadaptability to usage scenariosVSAvoidframe structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The frame structure is designed to be dynamic and configurable, allowing the network to adaptively allocate time slots and frequency subbands based on real-time traffic demands and scenario requirements. This dynamic configuration enables the system to switch between different numerologies and full-duplex modes as needed, achieving high adaptability while managing complexity through standardized configuration mechanisms

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The downlink slot structure is designed to serve multiple functions - it can simultaneously support downlink data transmission, uplink reception in specific subbands, and flexible adaptation to different numerologies. This multi-functional design allows a single frame structure to cater to diverse usage scenarios including eMBB, mMTC, and URLLC, reducing the need for multiple specialized structures

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4651604A1Method and device for performing downlink transmission/reception in full-duplex communication
Publication Date: 2025.11.19 KT CORP
  • EP4651604A1 patent drawingFigure 1
  • EP4651604A1 patent drawingFigure 2
  • EP4651604A1 patent drawingFigure 3

AI summary

Provided is a method of a user equipment (UE) to perform downlink reception in full-duplex communication. The method may include receiving configuration information about a downlink slot or a downlink symbol, receiving downlink resource allocation information including information about allocated frequency resources in the downlink slot or the downlink symbol, and performing downlink reception on the basis of the downlink resource allocation information, wherein the downlink slot or the downlink symbol includes an SBFD symbol in which uplink sub-bands for full-duplex communication are configured, and the frequency resources include frequency resources set as the uplink sub-bands.