QCL Reference Signal Set Determination for Multi-TRP Beam Management

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Solution Overview

Problem

In New Radio (NR) user equipment (UE) of Release-15, accurately acquiring beams for multi-transmission receiver points (TRPs) is challenging, especially when beams collide or when the terminal cannot receive downlink control information (DCI) in time, affecting spectrum efficiency and robustness of beam communication.

Innovation Solution

The method involves determining a quasi-co-location (QCL) reference signal set using control resources within specific time units, where reference signals satisfy QCL relationships with respect to parameters like Doppler shift and spatial receive parameters, allowing the terminal to select appropriate beams for receiving signals from multiple TRPs simultaneously.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple TRPs transmit signals simultaneously to improve spectrum efficiency and robustness, then the reliability of beam communication is improved, but the difficulty of beam acquisition and management increases

Engineering Contradiction:
Improverobustness of beam communicationVSAvoidbeam acquisition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the beam management process by introducing separate QCL reference signal sets for different TRPs. Each TRP is associated with a specific QCL reference signal set, allowing the UE to independently manage beams for each TRP. This segmentation resolves the contradiction by enabling reliable multi-TRP communication while simplifying beam acquisition through structured reference signal organization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by pre-configuring QCL reference signal sets for multiple TRPs before actual data transmission. The UE acquires and stores these reference signal sets in advance, so when multi-TRP transmission is needed, the beam acquisition is already complete. This eliminates real-time beam search complexity while maintaining communication robustness.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If the UE uses beam-based high-frequency communications to improve spectrum efficiency, then the data transmission rate is improved, but the sensitivity to beam alignment and timing increases

Engineering Contradiction:
Improvespectrum efficiencyVSAvoidbeam alignment precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent enables self-service by allowing the UE to autonomously determine appropriate beams for receiving signals from multiple TRPs using the pre-configured QCL reference signal sets. The UE independently identifies which QCL reference signal set corresponds to which TRP and uses that information to configure receiving beams without requiring complex network coordination. This maintains high spectrum efficiency while reducing the precision burden on network-side beam management.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the terminal cannot acquire beam through DCI in time, then the flexibility of scheduling is improved, but the beam acquisition accuracy deteriorates

Engineering Contradiction:
Improvescheduling flexibilityVSAvoidbeam acquisition accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent resolves this contradiction by performing preliminary beam acquisition through pre-configured QCL reference signal sets. When DCI-based beam indication is not received in time or is unavailable, the UE can immediately use the pre-acquired QCL reference signal sets to determine appropriate receiving beams. This maintains scheduling flexibility while ensuring beam acquisition accuracy through advance preparation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3783825B1Method and device for determining quasi co-located reference signal set
Publication Date: 2024.09.11 ZTE CORP
  • EP3783825B1 patent drawingFigure 1~3B
  • EP3783825B1 patent drawingFigure 3C~6
  • EP3783825B1 patent drawingFigure 7~10

AI summary

Disclosed are a method and device for determining a quasi co-located (QCL) reference signal set. The method comprises: selecting N2 control channel resources from control channel resources contained in N1 time units, wherein N1 and N2 are integers greater than or equal to 1; and determining, according to the N2 control channel resources, at least M QCL reference signal sets of M port sets, wherein M is an integer greater than or equal to 1. In the embodiments of the present disclosure, at least M QCL reference signal sets of M port sets are determined on the basis of selected N2 control channel resources, such that signals or channels transmitted by two or more TRPs are received on the basis of the at least M QCL reference signal sets of the M port sets.