Dynamic TRS Scheduling for 3GPP NR Collision Avoidance

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Solution Overview

Problem

In 3GPP New Radio (NR) systems, time domain collisions occur between Tracking Reference Signals (TRS) and Physical Downlink Shared Channels (PDSCH) due to overlapping transmission scheduling, leading to inefficiencies in beam management and synchronization.

Innovation Solution

A radio access network element and user equipment are configured to detect time domain collisions and adjust transmission scheduling by omitting or puncturing TRS and PDSCH transmissions, based on quasi co-location and Hybrid Automatic Repeat Request (HARQ) status, to avoid collisions and optimize resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If tracking reference signal and shared data channel are transmitted simultaneously in overlapping time resources, then transmission efficiency is improved, but signal collision and interference occur

Engineering Contradiction:
Improvetransmission efficiencyVSAvoidsignal integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic scheduling that adapts TRS transmission based on PDSCH scheduling decisions. When PDSCH is scheduled in a slot, the gNB dynamically adjusts or omits TRS transmission in that same slot, preventing collisions while maintaining synchronization capability when PDSCH is not transmitted.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The gNB performs preliminary detection of potential time domain collisions between TRS and PDSCH before transmission. By detecting overlapping time resources in advance, the system can proactively adjust scheduling decisions to prevent signal interference before it occurs.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If tracking reference signal transmission is maintained continuously, then time and frequency synchronization is improved, but transmission overhead increases

Engineering Contradiction:
Improvesynchronization accuracyVSAvoidtransmission overhead
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

Instead of continuous TRS transmission, the system employs periodic transmission where TRS is sent only in slots where PDSCH is not scheduled. This periodic approach maintains necessary synchronization functionality while significantly reducing transmission overhead by eliminating redundant TRS transmissions in slots dedicated to data transmission.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically changes the transmission parameter of TRS based on scheduling conditions. When PDSCH is scheduled, TRS transmission is adjusted or omitted; when PDSCH is not scheduled, TRS transmission proceeds as normal. This parameter adaptation optimizes the balance between synchronization accuracy and resource efficiency.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If shared data channel is prioritized over tracking reference signal during collision, then data transmission efficiency is improved, but synchronization performance deteriorates

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidsynchronization accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements dynamic priority adjustment based on traffic conditions and scheduling requirements. Rather than fixed priority, the system adaptively determines whether to transmit TRS or PDSCH in conflicting slots, allowing optimization of both data transmission efficiency and synchronization performance based on real-time network conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3718227B1Dynamic scheduling based QCL association for tracking reference signal
Publication Date: 2024.09.11 NOKIA TECHNOLOGIES OY
  • EP3718227B1 patent drawingFigure 1
  • EP3718227B1 patent drawingFigure 2
  • EP3718227B1 patent drawingFigure 3

AI summary

When a time domain collision between Tracking Reference Signal (TRS) symbols and downlink shared data channel symbols is detected, the TRS symbols may be multiplexed with the downlink shared data channel symbols from multiple Transmission Reception Points (TRPs)not sharing quasi co-location (QCL) parameters with each other. If a time domain collision between TRS symbols and dynamically or semi-static (e.g., persistent) downlink shared data channel transmissions is detected, transmission and/or reception of the TRS and/or the downlink shared data channel may be adjusted.