Downlink Control Channel QCL Signaling for 5G Beam Management

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Solution Overview

Problem

Existing communication systems face challenges in efficiently managing beamforming and interference in fifth-generation cellular systems, particularly in scenarios like eMBB, URLLC, and mMTC, where complexity and interference between cells and terminal apparatuses are significant.

Innovation Solution

The implementation of Quasi Co-Location (QCL) parameters for reference signals and downlink control channels, enabling efficient communication by indicating and configuring these parameters between terminal and base station apparatuses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If beamforming is used to secure coverage in 5G systems, then coverage and signal strength are improved, but device complexity and interference management become more difficult

Engineering Contradiction:
ImprovecoverageVSAvoidbeam management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The base station performs beam management procedures in advance by transmitting downlink control channels with QCL parameter information before actual data transmission. This preliminary configuration of beam parameters simplifies subsequent communication by pre-establishing the spatial relationship between reference signals and control channels.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

QCL (Quasi Co-Location) parameters serve as an intermediary that bridges the relationship between reference signals and downlink control channels. By indicating spatial QCL parameters, the system provides a reference framework that simplifies beam management and reduces the complexity of direct beam pairing operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple reference signals are used for beam management, then beamforming gain and coverage are improved, but interference between cells and terminal apparatuses increases

Engineering Contradiction:
Improvebeamforming gainVSAvoidinterference between cells
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different QCL parameter configurations to different terminal apparatuses and cells. By locally optimizing the spatial QCL parameters for each terminal's specific beamforming scenario, the system achieves high beamforming gain while managing interference through localized parameter adaptation rather than uniform configuration.

Inventive Principle:
Principle #3Local quality

3Productivity

If QCL parameters are indicated for multiple reference signals, then communication efficiency is improved, but signal processing complexity increases

Engineering Contradiction:
Improvecommunication efficiencyVSAvoidsignal processing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts and transmits only the essential QCL parameter information needed for beam management in the downlink control channel. By selecting and indicating only the critical spatial parameters rather than complete signal characteristics, the system improves communication efficiency while limiting the increase in signal processing complexity to only the necessary elements.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4123914B1Terminal apparatus, base station apparatus and communication methods
Publication Date: 2025.11.05 SHARP KK
  • EP4123914B1 patent drawingFigure 1
  • EP4123914B1 patent drawingFigure 2
  • EP4123914B1 patent drawingFigure 3

AI summary

A terminal apparatus includes a processor and a memory coupled to the processor. The memory stores a computer-executable program that, when executed by the processor, causes the terminal apparatus to: receive, from a base station apparatus, a radio resource control (RRC) message that indicates information of multiple downlink control channel resources; receive, from the base station apparatus, a medium access control (MAC) control element (CE) that indicates one of the multiple downlink control channel resources; and monitor the one of the multiple downlink control channel resources based on the RRC message and the MAC CE. The information includes an index corresponding to at least one of the multiple downlink control channel resources, frequency resource information, and quasi-co-location, QCL, information.